To see the other types of publications on this topic, follow the link: Cortical layers.
Journal articles on the topic 'Cortical layers'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Cortical layers.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Crochet, Sylvain, and Carl C. H. Petersen. "Cortical Dynamics by Layers." Neuron 64, no. 3 (November 2009): 298–300. http://dx.doi.org/10.1016/j.neuron.2009.10.024.
Full text
2
Gotz, M., N. Novak, M. Bastmeyer, and J. Bolz. "Membrane-bound molecules in rat cerebral cortex regulate thalamic innervation." Development 116, no. 3 (November 1, 1992): 507–19. http://dx.doi.org/10.1242/dev.116.3.507.
Full textAbstract:
During development of the thalamocortical projection, afferent fibers from the thalamus reach the cortex at a time when their target cells have just been generated but have not yet migrated to their final position. Thalamic axons begin to invade the cortex only shortly before their target layer 4 is formed. The mechanisms responsible for the innervation and termination of thalamic fibers in the cortex are not known. Here we show that the growth of thalamic axons in vitro is influenced by the age of cortical explants. Cortical explants of early embryonic stages were not invaded by thalamic explants, whereas thalamic fibers entered explants from postnatal cortices and terminated properly in their target layer 4 in vitro. Outgrowth assays on cortical cell membranes prepared at different developmental stages revealed that the growth of thalamic axons is selectively influenced by growth- promoting molecules that are up-regulated during development. Moreover, experiments with postnatal cortical membranes isolated from distinct layers revealed that the growth of thalamic axons is selectively reduced on membranes prepared from layer 4. These results provide evidence that membrane-bound molecules in the cortex are involved in both the regulation of thalamic innervation into the cortical layers and their termination in the correct target layer.
3
Castellani, V., and J. Bolz. "Opposing roles for neurotrophin-3 in targeting and collateral formation of distinct sets of developing cortical neurons." Development 126, no. 15 (August 1, 1999): 3335–45. http://dx.doi.org/10.1242/dev.126.15.3335.
Full textAbstract:
Neurotrophin-3 and its receptor TrkC are expressed during the development of the mammalian cerebral cortex. To examine whether neurotrophin-3 might play a role in the elaboration of layer-specific cortical circuits, slices of layer 6 and layers 2/3 neurons were cultured in the presence of exogenously applied neurotrophin-3. Results indicate that neurotrophin-3 promotes axonal branching of layer 6 axons, which target neurotrophin-3-expressing layers in vivo, and that it inhibits branching of layers 2/3 axons, which avoid neurotrophin-3-expressing layers. Such opposing effects of neurotrophin-3 on axonal branching were also observed with embryonic cortical neurons, indicating that the response to neurotrophin-3 is specified at early developmental stages, prior to cell migration. In addition to its effects on fiber branching, axonal guidance assays also indicate that neurotrophin-3 is an attractive signal for layer 6 axons and a repellent guidance cue for layers 2/3 axons. Experiments with specific antibodies to neutralize neurotrophin-3 in cortical membranes revealed that endogenous levels of neurotrophin-3 are sufficient to regulate branching and targeting of cortical axons. These opposing effects of neurotrophin-3 on specific populations of axons demonstrate that it could serve as one of the signals for the elaboration of local cortical circuits.
4
Martinez, A. M. B., and W. De Souza. "A quick-frozen, freeze-fracture and deep-etched study of the cuticle of adult forms of Strongyloides venezuelensis (Nematoda)." Parasitology 111, no. 4 (November 1995): 523–29. http://dx.doi.org/10.1017/s0031182000066038.
Full textAbstract:
SUMMARYThe cuticle of adult forms of Strongyloides venezuelensis was studied by routine transmission electron microscopy, conventional freeze-fracture and also using quick-freeze and deep-etch techniques. In routine thin sections the cuticle of S. venezuelensis comprises 7 layers: epicuticle, outer cortical, inner corticcal, external medial, internal medial, fibrous and basal. Observation of replicas of specimens fractured across the thickness of the body wall, revealed at the epicuticle an ordered array of particles accompanying the cuticular annulations. At the level of the cortical and medial layers we observed few scattered particles embedded in an amorphous matrix without a particular arrangement. The fibrous layer was represented by several parallel lines of ordered particles of similar size. In tangentially fractured specimens, the epicuticle cleaves readily exposing 2 faces, one exhibiting intramembranous particles without any particular arrangement, immersed in a smooth matrix (P face), and the other showing depressions and very few particles (E face). In replicas of fractures submitted to etching, we observed at the level of the cortical, medial fibrous and basal layers an interconnecting fibrous and globous structure which was organized in a different direction at the fibrous layer. The association of freeze-fracture to deep-etch technique revealed the internal structural organization of the cuticle layers showing details that were not seen before using conventional freeze–fracture technique.
5
Johnson, M. J., and K. D. Alloway. "Cross-correlation analysis reveals laminar differences in thalamocortical interactions in the somatosensory system." Journal of Neurophysiology 75, no. 4 (April 1, 1996): 1444–57. http://dx.doi.org/10.1152/jn.1996.75.4.1444.
Full textAbstract:
1. Spontaneous and stimulus-induced activity were recorded from corresponding somatotopic representations in the ventroposterolateral nucleus (VPL) of the thalamus and primary somatosensory (SI) cortex of intact, halothane-anesthetized cats. Thalamic and cortical neurons with overlapping receptive fields on the hairy skin of the forelimb were excited by a series of interleaved air jets aimed at multiple skin sites. 2. The laminar locations of 68% (240 of 355) of the neurons recorded in SI cortex were histologically reconstructed and responses of these 240 SI neurons were analyzed with respect to responses recorded from 118 thalamic neurons. Maximum responsiveness during the initial onset (1st 100 ms) of air jet stimulation was similar for neurons distributed throughout all layers of SI cortex (2-4 spikes per stimulus) and did not differ significantly from VPL responses. During the subsequent plateau phase of the stimulus, VPL neurons discharged at a mean rate of 19.0 spikes/ s and neurons in cortical layers II, IIIa, IIIb, and IV discharged at similar rates. Mean responsiveness during the plateau phase of the stimulus was significantly reduced among neurons in cortical layers V and VI and only averaged 7.1 and 3.9 spikes/s, respectively. 3. Responses recorded simultaneously from pairs of thalamic and cortical neurons were analyzed with cross-correlation analysis to determine differences in the incidence and strength of neuronal interactions as a function of cortical layer. Among 421 thalamocortical neuron pairs displaying stimulus-induced responses, 68 neuron pairs exhibited significant interactions during air jet stimulation. A laminar analysis revealed that 28% (45 of 163) of the neurons in the middle cortical layers displayed significant interactions with thalamic neurons, whereas only 14% (13 of 92) of superficial layer neurons and 6% (10 of 166) of deep layer neurons were synchronized with thalamic activity during air jet stimulation. When thalamocortical efficacy for different layers of cortex was plotted as a cumulative frequency distribution, the strongest interactions in the middle cortical layers were twice as strong as interactions involving the superficial or deep cortical layers. 4. More than 70% of stimulus-induced interactions involved thalamic discharges followed by subsequent cortical discharges and the majority of these interactions involved interspike intervals of < or = 3 ms. Nearly 75% (27 of 37) of interactions in the thalamocortical direction that involved cortical neurons in layers IIIb and IV transpired within a 3-ms interspike interval. For interactions with superficial or deep cortical layers, the proportion of thalamocortical interactions transpiring within 3 ms was only 58% (7 of 12) and 33% (2 of 6), respectively. 5. Cross-correlation analysis of spontaneous activity indicated that 124 pairs of thalamic and cortical neurons displayed synchronous activity in the absence of sensory stimulation. A laminar analysis indicated that similar proportions of cortical neurons in each layer were synchronized with thalamic activity in the absence of cutaneous stimulation. Thus 27% (44 of 163) of middle layer neurons, 30% (28 of 92) of superficial layer neurons, and 31% (51 of 166) of deep layer neurons displayed spontaneous interactions with thalamic neurons. The temporal pattern of spontaneous activity was examined with autocorrelation analysis to determine whether neuronal oscillations were essential for coordinating thalamic and cortical activity in the absence of peripheral stimulation. Only 18.5% (23 of 124) of spontaneous interactions between thalamic and cortical neurons were associated with periodic activity, which suggests that thalamocortical synchronization occurs before the constituent neurons begin to oscillate. 6. The influence of sensory stimulation on spontaneous interactions was examined in 31 pairs of thalamic and cortical neurons that exhibited interactions during prestimulus and stimulus in
6
Tsau, Yang, Li Guan, and Jian-Young Wu. "Epileptiform Activity Can Be Initiated in Various Neocortical Layers: An Optical Imaging Study." Journal of Neurophysiology 82, no. 4 (October 1, 1999): 1965–73. http://dx.doi.org/10.1152/jn.1999.82.4.1965.
Full textAbstract:
The initiation site for triggering epileptiform activity was investigated via optical imaging using voltage-sensitive dyes in the neocortical slice perfused with artificial cerebral spinal fluid containing nominally zero magnesium. The neocortical slices (400-μm thick) were harvested from Sprague-Dawley rats (P21–28). Optical imaging was made by using a high speed photodiode array. Spontaneous epileptiform activity emerged 20–40 min after the preparation was perfused with zero-magnesium solution. There was a good correspondence between electrical and optical signals ( n = 46), although the details of the two recordings were somewhat different. The initiation sites were measured optically in 11 preparations. Among them, four were found to be located in superficial layers, two were found in middle layers, and five were found in deep layers. Repeated recordings revealed that these initiation sites were relatively stable; shifting of the initiation site was not observed. Therefore spontaneous epileptiform activity could be initiated in various cortical layers, from layer I to layer VI. The activation started from a small area <0.04 mm3 and spread smoothly from the initiation site to adjacent cortical areas, suggesting that the initiation site is very confined to one of the cortical layers. The initiation sites were distributed randomly in various cortical areas, and no higher probability was found in a special cortical region. Electrical stimulation delivered via a glass microelectrode filled with 2 M NaCl (2–5 MΩ) could reliably trigger epileptiform activity that had the same characteristics as the spontaneous activity. The cortical neurons activated directly by the stimulation were around the electrode’s tip and estimated to be within a 50-μm area, suggesting that only a few neurons were needed to form an initiation site. Because the timing for stimulation was arbitrary and the evoked events were initiated independent of discharges of neurons in any other layers, it is likely that the initiation site for epileptiform activity in various cortical layers is independent of the control of layer V pyramidal neurons. Together these finding suggest that the epileptiform focus is confined and can be formed in several (probably all) neocortical layers and in many cortical areas. The initiating neurons may be of different types because neuronal types in various cortical layers are different.
7
Gilmore, Edward C., and Karl Herrup. "Cortical development: Layers of complexity." Current Biology 7, no. 4 (April 1997): R231—R234. http://dx.doi.org/10.1016/s0960-9822(06)00108-4.
Full text
8
EU. "Tissue mimics brain's cortical layers." Science 345, no. 6199 (August 21, 2014): 887. http://dx.doi.org/10.1126/science.345.6199.887-a.
Full text
9
Hotta, Harumi, Kazuto Masamoto, Sae Uchida, Yuta Sekiguchi, Hiroyuki Takuwa, Hiroshi Kawaguchi, Kazuhiro Shigemoto, et al. "Layer-Specific Dilation of Penetrating Arteries Induced by Stimulation of the Nucleus Basalis of Meynert in the Mouse Frontal Cortex." Journal of Cerebral Blood Flow & Metabolism 33, no. 9 (June 12, 2013): 1440–47. http://dx.doi.org/10.1038/jcbfm.2013.92.
Full textAbstract:
To clarify mechanisms through which activation of the nucleus basalis of Meynert (NBM) increases cerebral cortical blood flow, we examined whether cortical parenchymal arteries dilate during NBM stimulation in anesthetized mice. We used two-photon microscopy to measure the diameter of single penetrating arteries at different depths (~800 μm, layers I to V) of the frontal cortex, and examined changes in the diameter during focal electrical stimulation of the NBM (0.5 ms at 30 to 50 μA and 50 Hz) and hypercapnia (3% CO2 inhalation). Stimulation of the NBM caused diameter of penetrating arteries to increase by 9% to 13% of the prestimulus diameter throughout the different layers of the cortex, except at the cortical surface and upper part of layer V, where the diameter of penetrating arteries increased only slightly during NBM stimulation. Hypercapnia caused obvious dilation of the penetrating arteries in all cortical layers, including the surface arteries. The diameters began to increase within 1 second after the onset of NBM stimulation in the upper cortical layers, and later in lower layers. Our results indicate that activation of the NBM dilates cortical penetrating arteries in a layer-specific manner in magnitude and latency, presumably related to the density of cholinergic nerve terminals from the NBM.
10
Sellers, Kristin K., Davis V. Bennett, Axel Hutt, James H. Williams, and Flavio Fröhlich. "Awake vs. anesthetized: layer-specific sensory processing in visual cortex and functional connectivity between cortical areas." Journal of Neurophysiology 113, no. 10 (June 2015): 3798–815. http://dx.doi.org/10.1152/jn.00923.2014.
Full textAbstract:
During general anesthesia, global brain activity and behavioral state are profoundly altered. Yet it remains mostly unknown how anesthetics alter sensory processing across cortical layers and modulate functional cortico-cortical connectivity. To address this gap in knowledge of the micro- and mesoscale effects of anesthetics on sensory processing in the cortical microcircuit, we recorded multiunit activity and local field potential in awake and anesthetized ferrets ( Mustela putoris furo) during sensory stimulation. To understand how anesthetics alter sensory processing in a primary sensory area and the representation of sensory input in higher-order association areas, we studied the local sensory responses and long-range functional connectivity of primary visual cortex (V1) and prefrontal cortex (PFC). Isoflurane combined with xylazine provided general anesthesia for all anesthetized recordings. We found that anesthetics altered the duration of sensory-evoked responses, disrupted the response dynamics across cortical layers, suppressed both multimodal interactions in V1 and sensory responses in PFC, and reduced functional cortico-cortical connectivity between V1 and PFC. Together, the present findings demonstrate altered sensory responses and impaired functional network connectivity during anesthesia at the level of multiunit activity and local field potential across cortical layers.
11
Malpeli, J. G., C. Lee, H. D. Schwark, and T. G. Weyand. "Cat area 17. I. Pattern of thalamic control of cortical layers." Journal of Neurophysiology 56, no. 4 (October 1, 1986): 1062–73. http://dx.doi.org/10.1152/jn.1986.56.4.1062.
Full textAbstract:
Reversible inactivation of individual layers of the cat lateral geniculate and medial interlaminar nuclei was used to investigate the necessary and sufficient inputs for maintaining visually driven activity and receptive field properties in area 17. Neither orientation selectivity nor direction selectivity depends on any individual geniculate layer. We identified two groups of cortical layers on the basis of the pattern of thalamic inputs providing visual driving through the contralateral eye. One group, consisting of layers 4 and 6, has geniculate layer A as its only necessary and sufficient input. The other, consisting of supragranular layers, integrates at least two sufficient thalamic inputs, one of which is layer A. Several major receptive field properties are independently generated in these two groups of layers.
12
Wertz, Adrian, Stuart Trenholm, Keisuke Yonehara, Daniel Hillier, Zoltan Raics, Marcus Leinweber, Gergely Szalay, et al. "Single-cell–initiated monosynaptic tracing reveals layer-specific cortical network modules." Science 349, no. 6243 (July 2, 2015): 70–74. http://dx.doi.org/10.1126/science.aab1687.
Full textAbstract:
Individual cortical neurons can selectively respond to specific environmental features, such as visual motion or faces. How this relates to the selectivity of the presynaptic network across cortical layers remains unclear. We used single-cell–initiated, monosynaptically restricted retrograde transsynaptic tracing with rabies viruses expressing GCaMP6s to image, in vivo, the visual motion–evoked activity of individual layer 2/3 pyramidal neurons and their presynaptic networks across layers in mouse primary visual cortex. Neurons within each layer exhibited similar motion direction preferences, forming layer-specific functional modules. In one-third of the networks, the layer modules were locked to the direction preference of the postsynaptic neuron, whereas for other networks the direction preference varied by layer. Thus, there exist feature-locked and feature-variant cortical networks.
13
Ferro, Demetrio, Jochem van Kempen, Michael Boyd, Stefano Panzeri, and Alexander Thiele. "Directed information exchange between cortical layers in macaque V1 and V4 and its modulation by selective attention." Proceedings of the National Academy of Sciences 118, no. 12 (March 15, 2021): e2022097118. http://dx.doi.org/10.1073/pnas.2022097118.
Full textAbstract:
Achieving behavioral goals requires integration of sensory and cognitive information across cortical laminae and cortical regions. How this computation is performed remains unknown. Using local field potential recordings and spectrally resolved conditional Granger causality (cGC) analysis, we mapped visual information flow, and its attentional modulation, between cortical layers within and between macaque brain areas V1 and V4. Stimulus-induced interlaminar information flow within V1 dominated upwardly, channeling information toward supragranular corticocortical output layers. Within V4, information flow dominated from granular to supragranular layers, but interactions between supragranular and infragranular layers dominated downwardly. Low-frequency across-area communication was stronger from V4 to V1, with little layer specificity. Gamma-band communication was stronger in the feedforward V1-to-V4 direction. Attention to the receptive field of V1 decreased communication between all V1 layers, except for granular-to-supragranular layer interactions. Communication within V4, and from V1 to V4, increased with attention across all frequencies. While communication from V4 to V1 was stronger in lower-frequency bands (4 to 25 Hz), attention modulated cGCs from V4 to V1 across all investigated frequencies. Our data show that top-down cognitive processes result in reduced communication within cortical areas, increased feedforward communication across all frequency bands, and increased gamma-band feedback communication.
14
Self, Matthew W., and Pieter R. Roelfsema. "Paying Attention to the Cortical Layers." Neuron 93, no. 1 (January 2017): 9–11. http://dx.doi.org/10.1016/j.neuron.2016.12.032.
Full text
15
Scheeringa, René, and Pascal Fries. "Cortical layers, rhythms and BOLD signals." NeuroImage 197 (August 2019): 689–98. http://dx.doi.org/10.1016/j.neuroimage.2017.11.002.
Full text
16
Qin, Luye, Hannah S. Actor-Engel, Moon-Sook Woo, Faariah Shakil, Yi-Wen Chen, Sunghee Cho, and Chiye Aoki. "An Increase of Excitatory-to-Inhibitory Synaptic Balance in the Contralateral Cortico-Striatal Pathway Underlies Improved Stroke Recovery in BDNF Val66Met SNP Mice." Neurorehabilitation and Neural Repair 33, no. 12 (September 15, 2019): 989–1002. http://dx.doi.org/10.1177/1545968319872997.
Full textAbstract:
Despite negative association in cognition and memory, mice harboring Val66Met BDNF SNP (BDNFM/M) exhibit enhanced motor recovery accompanied by elevated excitatory synaptic markers VGLUT1 and VGLUT2 in striatum contralateral to unilateral ischemic stroke. The cortico-striatal pathway is a critical gateway for plasticity of motor/gait function. We hypothesized that enhanced excitability of the cortico-striatal pathway, especially of the contralateral hemisphere, underlies improved motor recovery. To test this hypothesis, we examined the key molecules involving excitatory synaptogenesis: Thrombospondins (TSP1/2) and their neuronal receptor α2δ-1. In WT brains, stroke induced expressions of TSP1/2-mRNA. The contralateral hemisphere of BDNFM/M mice showed heightened TSP2 and α2δ-1 mRNA and protein specifically at 6 months post-stroke. Immunoreactivities of TSPs and α2δ-1 were increased in cortical layers 1/2 of stroked BDNFM/M animals compared with BDNFM/M sham brains at this time. Areal densities of excitatory synapses in cortical layer 1 and striatum were also increased in stroked BDNFM/M brains, relative to stroked WT brains. Notably, the frequency of GABAergic synapses was greatly reduced along distal dendrites in cortical layer 1 in BDNFM/M brains, whether or not stroked, compared with WT brains. There was no effect of genotype or treatment on the density of GABAergic synapses onto striatal medium spiny neurons. The study identified molecular and synaptic substrates in the contralateral hemisphere of BDNFM/M mice, especially in cortical layers 1/2, which indicates selective region-related synaptic plasticity. The study suggests that an increase in excitatory-to-inhibitory synaptic balance along the contralateral cortico-striatal pathway underlies the enhanced functional recovery of BDNFM/M mice.
17
Contreras, Diego, Niklaus Dürmüller, and Mircea Steriade. "Absence of a Prevalent Laminar Distribution of IPSPs in Association Cortical Neurons of Cat." Journal of Neurophysiology 78, no. 5 (November 1, 1997): 2742–53. http://dx.doi.org/10.1152/jn.1997.78.5.2742.
Full textAbstract:
Contreras, Diego, Niklaus Dürmüller, and Mircea Steriade. Absence of a prevalent laminar distribution of IPSPs in association cortical neurons of cat. J. Neurophysiol. 78: 2742–2753, 1997. The depth distribution of inhibitory postsynaptic potentials (IPSPs) was studied in cat suprasylvian (association) cortex in vivo. Single and dual simultaneous intracellular recordings from cortical neurons were performed in the anterior part of suprasylvian gyrus (area 5). Synaptic responses were obtained by stimulating the suprasylvian cortex, 2–3 mm anterior to the recording site, as well as the thalamic lateral posterior (LP) nucleus. Neurons were recorded from layers 2 to 6 and were classified as regular spiking (RS, n = 132), intrinsically bursting (IB, n = 24), and fast spiking (FS, n = 4). Most IB cells were located in deep layers (below 0.7 mm, n = 19), but we also found some IB cells more superficially (between 0.2 and 0.5 mm, n = 5). Deeply lying corticothalamic neurons were identified by their antidromic invasion on thalamic stimulation. Neurons responded with a combination of excitatory postsynaptic potentials (EPSPs) and IPSPs to both cortical and thalamic stimulation. No consistent relation was found between cell type or cell depth and the amplitude or duration of the IPSPs. In response to thalamic stimulation, RS cells had IPSPs of 7.9 ± 0.9 (SE) mV amplitude and 88.9 ± 6.4 ms duration. In IB cells, IPSPs elicited by thalamic stimulation had 7.4 ± 1.3 mV amplitude and 84.7 ± 14.3 ms duration. The differences between the two (RS and IB) groups were not statistically significant. Compared with thalamically elicited inhibitory responses, cortical stimulation evoked IPSPs with higher amplitude (12.3 ± 1.7 mV) and longer duration (117 ± 17.3 ms) at all depths. Both cortically and thalamically evoked IPSPs were predominantly monophasic. Injections of Cl− fully reversed thalamically as well as cortically evoked IPSPs and revealed additional late synaptic components in response to cortical stimulation. These data show that the amount of feed forward and feedback inhibition to cat's cortical association cells is not orderly distributed to distinct layers. Thus local cortical microcircuitry goes beyond the simplified structure determined by cortical layers.
18
Bohner, A. P., R. M. Akers, and S. K. McConnell. "Induction of deep layer cortical neurons in vitro." Development 124, no. 4 (February 15, 1997): 915–23. http://dx.doi.org/10.1242/dev.124.4.915.
Full textAbstract:
Transplantation studies suggest that the laminar fates of cerebral cortical neurons are determined by environmental signals encountered just before mitosis. In ferret, E29 progenitor cells normally produce neurons of layers 5 and 6. When transplanted during S-phase into an older ventricular zone, E29 progenitors produce neurons that change their fates and migrate to layer 2/3; however, cells transplanted later in the cell cycle migrate to their normal deep-layer positions even in an older environment (McConnell and Kaznowski, 1991). Here we utilize three culture systems to investigate the nature of the environmental signals involved in laminar specification. E29 cells were first cultured at low density to ascertain whether cell contact and/or short-range cues are required for deep layer specification. Neurons transplanted after a short time in low-density culture failed to adopt their normal fates and migrated instead to the upper layers. When crude cell contacts were restored by pelleting E29 cells together, most transplanted neurons cells became specified to their normal deep layer fates. Finally, E29 cells were transplanted after being cultured in explants that maintained the architecture of the cerebral wall. Explants allowed normal deep layer specification to occur, as transplanted cells migrated to layers 5 and 6. These results suggest that short-range cues induce multipotent progenitors to produce deep layer neurons.
19
Shcherbak, N. S., M. M. Galagoudza, D. A. Ovchinnikov, E. O. Shcherbakova, G. U. Yukina, E. R. Barantsevich, V. V. Thomson, and E. V. Shlyakhto. "Influence of cerebral global ischemia-reperfusion on succinate dehydrogenase activity in neurons of different neocortical layers." Scientific Notes of the I. P. Pavlov St. Petersburg State Medical University 21, no. 3 (September 30, 2014): 25–28. http://dx.doi.org/10.24884/1607-4181-2014-21-3-25-28.
Full textAbstract:
The aim of the study was to investigate changes in activity of succinate dehydrogenase (SDH) in cytoplasm of neurons of different cortical layers in early and late reperfusion period after global cerebral ischemia in rats. Reversible global cerebral ischemia was modeled by occlusion of the brachiocephalic trunk, left subclavian artery and left common carotid artery for 10 minutes and following reperfusion during 2 or 7 days. The SDH activity in cytoplasm of neurons of II, III and V cortical layers was determined histoenzymatically. It is shown that the SDH activity in neurons of the studied cortical layers was characterized by the increased reperfusion period to the 2 days with a subsequent increased activity of the reperfusion period to the 7 days. The change in the SDH activity in cytoplasm of cortical neurons depends on the particular cerebral layer and duration of postischemic reperfusion.
20
Ding, Y., and V. A. Casagrande. "The distribution and morphology of LGN K pathway axons within the layers and CO blobs of owl monkey V1." Visual Neuroscience 14, no. 4 (July 1997): 691–704. http://dx.doi.org/10.1017/s0952523800012657.
Full textAbstract:
AbstractThe lateral geniculate nucleus (LGN) of primates contains three classes of relay cells, the magnocellular (M), parvocellular (P), and koniocellular (K) cells. At present, very little is known about either the structure or function of the K relay cells in New or Old World monkeys (simian primates). In monkeys, K cells are located between the main LGN layers and adjacent to the optic tract. For convenience, these intercalated cell layers are numbered K1-K4 starting closest to the optic tract with K1. The objective of this study was to examine the details of K axon morphology in the primary visual cortex (V1) of owl monkeys and to determine if different K layers give rise to distinct axon types. For this purpose, injections of WGA-HRP or PHA-L were made into specific K LGN layers and the distribution and morphology of the resulting labeled axons were analyzed. Injections of fluorescent tracers also were made within the superficial layers of V1 to further document connections via analysis of the patterns of retrogradely labeled cells in the LGN. Our main finding is that K axons in owl monkeys terminate as delicate focused arbors within single cytochrome oxidase (CO) blob columns in cortical layer III and within cortical layer I. Overall, the morphology of the K axons in these monkeys is quite similar to what we described previously for K geniculocortical axons in the distantly related bush baby (prosimian primate), suggesting that the basic features of this pathway are common to all primates. Our results also provide evidence that the axon arbors from different K layers are morphologically distinct; axons from LGN layer K1 project mainly to cortical layer I, while axons from LGN layer K3 chiefly terminate in cortical layer III. Taken together, these results imply that the basic features of axons within the K pathway are conserved across primates, and that the K axons from different K layers are likely to differ in function based upon their different morphologies.
21
Ito, M. "Processing of vibrissa sensory information within the rat neocortex." Journal of Neurophysiology 54, no. 3 (September 1, 1985): 479–90. http://dx.doi.org/10.1152/jn.1985.54.3.479.
Full textAbstract:
Neuronal response properties were compared among different layers of the urethan-anesthetized rat vibrissa cortex. Measurements were made of the receptive-field (RF) size, the degree of directional selectivity, the latency of driving, the velocity threshold, and the tuning-curve slope. The RF size was defined by the number of whiskers that, when deflected individually, activated a neurons. For the center whisker of the RF (usually whisker C3), the response to deflection in the most preferred direction was compared with that in the opposite direction to classify the neuron as either strongly directional, weakly directional, or nondirectional. For the most preferred direction of the center whisker, the minimum velocity of deflection required to drive the unit was defined as the velocity threshold, the latency of driven response to a standard supramaximal velocity was measured, and finally, using exponential ramp-and-hold deflection, the threshold amplitude was determined at different values of time constant to construct a tuning-curve slope. Cortical layer IV neurons, as a whole, have the lowest threshold velocity. Layer Vb neurons stand on the opposite extreme in having the highest mean velocity threshold value. Although this difference is consistent with the generally held view that the "barrels" in layer IV represent the input stage of cortical information processing, the lack of laminar differences in latency and RF size support the idea that neurons of other cortical layers also receive direct thalamocortical inputs. The population of cortical neurons thus appears quite homogeneous across different layers as far as the results of examination with short-pulsed stimulation are concerned. Correlation of pairs of parameters (RF, directionality, velocity threshold, and latency) was tested in the two layers (layer IV and layer Vb). The latency and velocity threshold are highly correlated within both layers. Also, most of correlation coefficients of the corresponding pairs of the two layers are similar. However, the use of exponential ramp-and-hold deflection of whiskers revealed a difference in tuning-curve slope between layer IV and layer Vb (also layers II-III); layer IV neurons show flatter tuning-curve slopes (more oriented for detection of the amplitude component of whisker deflection) than neurons of layer Vb and layers II-III, which are more oriented for velocity detection. During the hold phase of whisker deflection, layer IV neurons tend to show sustained discharges, whereas layer Vb (also layers II-III) neurons mainly exhibit transient responses.(ABSTRACT TRUNCATED AT 400 WORDS)
22
Schwark, H. D., J. G. Malpeli, T. G. Weyand, and C. Lee. "Cat area 17. II. Response properties of infragranular layer neurons in the absence of supragranular layer activity." Journal of Neurophysiology 56, no. 4 (October 1, 1986): 1074–87. http://dx.doi.org/10.1152/jn.1986.56.4.1074.
Full textAbstract:
Response properties of cells in the infragranular layers of cortical area 17 of the cat were examined in the absence of input from supragranular layers. Supragranular activity was silenced either reversibly by cooling the surface of cortex or permanently by making a cryogenic lesion of the supragranular layers. Visually driven responses of cells throughout the cortical column were recorded with a linear array of electrodes. Most infragranular layer cells continued to be visually responsive in the absence of supragranular layer input. These cells were similar to normal infragranular layer cells on measures of visual responsiveness, orientation selectivity, and direction selectivity. Special complex, but not standard complex, cells were absent in layer 5 when supragranular layers were destroyed. We found no evidence for a selective effect of removal of supragranular activity on the response properties of cells in layer 6. We propose that the intracolumnar projection from the supragranular layers drives the special complex cells of layer 5, but is not necessary for the visual driving of most other infragranular layer cells. This projection does not impose selectivity for stimulus orientation or direction on the remaining active cells of the infragranular layers.
23
Sellers, Kristin K., Davis V. Bennett, Axel Hutt, and Flavio Fröhlich. "Anesthesia differentially modulates spontaneous network dynamics by cortical area and layer." Journal of Neurophysiology 110, no. 12 (December 15, 2013): 2739–51. http://dx.doi.org/10.1152/jn.00404.2013.
Full textAbstract:
Anesthesia is widely used in medicine and research to achieve altered states of consciousness and cognition. Whereas changes to macroscopic cortical activity patterns by anesthesia measured at the spatial resolution of electroencephalography have been widely studied, modulation of mesoscopic and microscopic network dynamics by anesthesia remain poorly understood. To address this gap in knowledge, we recorded spontaneous mesoscopic (local field potential) and microscopic (multiunit activity) network dynamics in primary visual cortex (V1) and prefrontal cortex (PFC) of awake and isoflurane anesthetized ferrets ( Mustela putoris furo). This approach allowed for examination of activity as a function of cortical area, cortical layer, and anesthetic depth with much higher spatial and temporal resolution than in previous studies. We hypothesized that a primary sensory area and an association cortical area would exhibit different patterns of network modulation by anesthesia due to their different functional roles. Indeed, we found effects specific to cortical area and cortical layer. V1 exhibited minimal changes in rhythmic structure with anesthesia but differential modulation of input layer IV. In contrast, anesthesia profoundly altered spectral power in PFC, with more uniform modulation across cortical layers. Our results demonstrate that anesthesia modulates spontaneous cortical activity in an area- and layer-specific manner. These finding provide the basis for 1) refining anesthesia monitoring algorithms, 2) reevaluating the large number of systems neuroscience studies performed in anesthetized animals, and 3) increasing our understanding of differential dynamics across cortical layers and areas.
24
Tarabykin, Victor, Anastassia Stoykova, Natalia Usman, and Peter Gruss. "Cortical upper layer neurons derive from the subventricular zone as indicated bySvet1gene expression." Development 128, no. 11 (June 1, 2001): 1983–93. http://dx.doi.org/10.1242/dev.128.11.1983.
Full textAbstract:
The cerebral cortex is composed of a large variety of different neuron types. All cortical neurons, except some interneurons, are born in two proliferative zones, the cortical ventricular (VZ) and subventricular (SVZ) zones. The relative contribution of both proliferative zones to the generation of the diversity of the cortical neurons is not well understood. To further dissect the underlying mechanism, molecular markers specific for the SVZ are required. Towards this end we performed a subtraction of cDNA libraries, generated from E15.5 and E18.5 mouse cerebral cortex. A novel cDNA, Svet1, was cloned which was specifically expressed in the proliferating cells of the SVZ but not the VZ. The VZ is marked by the expression of the Otx1 gene. Later in development, Svet1 and Otx1 were expressed in subsets of cells of upper (II-IV) and deep (V-VI) layers, respectively. In the reeler cortex, where the layers are inverted, Svet1 and Otx1 label precursors of the upper and deeper layers, respectively, in their new location. Interestingly, in the Pax6/small eye mutant, Svet1 activity was abolished in the SVZ and in the upper part of the cortical plate while the Otx1 expression domain remained unchanged. Therefore, using Svet1 and Otx1 as cell-type-specific molecular markers for the upper and deep cortical layers we conclude that the Sey mutation affects predominantly the differentiation of the SVZ cells that fail to migrate into the cortical plate. The abnormality of the SVZ coincides with the absence of upper layer cells in the cortex. Taken together our data suggest that while the specification of deep cortical layers occurs in the ventricular zone, the SVZ is important for the proper specification of upper layers.
25
Saito, Kengo, Keishi Mizuguchi, Toshihide Horiike, Tung Anh Dinh Duong, Yohei Shinmyo, and Hiroshi Kawasaki. "Characterization of the Inner and Outer Fiber Layers in the Developing Cerebral Cortex of Gyrencephalic Ferrets." Cerebral Cortex 29, no. 10 (December 12, 2018): 4303–11. http://dx.doi.org/10.1093/cercor/bhy312.
Full textAbstract:
Abstract Changes in the cerebral cortex of mammals during evolution have been of great interest. Ferrets, monkeys, and humans have more developed cerebral cortices compared with mice. Although the features of progenitors in the developing cortices of these animals have been intensively investigated, those of the fiber layers are still largely elusive. By taking the advantage of our in utero electroporation technique for ferrets, here we systematically investigated the cellular origins and projection patterns of axonal fibers in the developing ferret cortex. We found that ferrets have 2 fiber layers in the developing cerebral cortex, as is the case in monkeys and humans. Axonal fibers in the inner fiber layer projected contralaterally and subcortically, whereas those in the outer fiber layer sent axons to neighboring cortical areas. Furthermore, we performed similar experiments using mice and found unexpected similarities between ferrets and mice. Our results shed light on the cellular origins, the projection patterns, the developmental processes, and the evolution of fiber layers in mammalian brains.
26
Chia, Thomas H., and Michael J. Levene. "Microprisms for In Vivo Multilayer Cortical Imaging." Journal of Neurophysiology 102, no. 2 (August 2009): 1310–14. http://dx.doi.org/10.1152/jn.91208.2008.
Full textAbstract:
Cortical slices allow for simultaneous imaging of multiple cortical layers. However, slices lack native physiological inputs and outputs. Although in vivo, two-photon imaging preserves the native context, it is typically limited to a depth of <500 μm. In addition, simultaneous imaging of multiple cortical layers is difficult due to the stratified organization of the cortex. We demonstrate the use of 1-mm microprisms for in vivo, two-photon neocortical imaging. These prisms enable simultaneous imaging of multiple cortical layers, including layer V, at an angle typical of slice preparations. Images were collected from the mouse motor and somatosensory cortex and show a nearly 900-μm-wide field of view. At high-magnification imaging using an objective with 1-mm of coverglass correction, resolution is sufficient to resolve dendritic spines on layer V neurons. Images collected using the microprism are comparable to images collected from a traditional slice preparation. Functional imaging of blood flow at various neocortical depths is also presented, allowing for quantification of red blood cell flux and velocity. H&E staining shows the surrounding tissue remains in its native, stratified organization. Estimation of neuronal damage using propidium iodide and a fluorescent Nissl stain reveals cell damage is limited to <100 μm from the tissue–glass interface. Microprisms are a straightforward tool offering numerous advantages for INTO NEOCORTICAL STISSUE.
27
Rockland, Kathleen S. "Distinctive Spatial and Laminar Organization of Single Axons from Lateral Pulvinar in the Macaque." Vision 4, no. 1 (December 18, 2019): 1. http://dx.doi.org/10.3390/vision4010001.
Full textAbstract:
Pulvino-cortical (PC) projections are a major source of extrinsic input to early visual areas in the macaque. From bulk injections of anterograde tracers, these are known to terminate in layer 1 of V1 and densely in the middle cortical layers of extrastriate areas. Finer, single axon analysis, as reviewed here for projections from the lateral pulvinar (PL) in two macaque monkeys (n = 25 axons), demonstrates that PL axons have multiple arbors in V2 and V4, and that these are spatially separate and offset in different layers. In contrast, feedforward cortical axons, another major source of extrinsic input to extrastriate areas, are less spatially divergent and more typically terminate in layer 4. Functional implications are briefly discussed, including comparisons with the better investigated rodent brain.
28
Moore, Jean K. "Maturation of Human Auditory Cortex: Implications for Speech Perception." Annals of Otology, Rhinology & Laryngology 111, no. 5_suppl (May 2002): 7–10. http://dx.doi.org/10.1177/00034894021110s502.
Full textAbstract:
This project traced the maturation of the human auditory cortex from midgestation to young adulthood, using immunostaining of axonal neurofilaments to determine the time of onset of rapid conduction. The study identified 3 developmental periods, each characterized by maturation of a different axonal system. During the perinatal period (3rd trimester to 4th postnatal month), neurofilament expression occurs only in axons of the marginal layer. These axons drive the structural and functional development of cells in the deeper cortical layers, but do not relay external stimuli. In early childhood (6 months to 5 years), maturing thalamocortical afferents to the deeper cortical layers are the first source of input to the auditory cortex from lower levels of the auditory system. During later childhood (5 to 12 years), maturation of commissural and association axons in the superficial cortical layers allows communication between different subdivisions of the auditory cortex, thus forming a basis for more complex cortical processing of auditory stimuli.
29
Westerberg, Jacob A., Michele A. Cox, Kacie Dougherty, and Alexander Maier. "V1 microcircuit dynamics: altered signal propagation suggests intracortical origins for adaptation in response to visual repetition." Journal of Neurophysiology 121, no. 5 (May 1, 2019): 1938–52. http://dx.doi.org/10.1152/jn.00113.2019.
Full textAbstract:
Repetitive visual stimulation profoundly changes sensory processing in the primary visual cortex (V1). We show how the associated adaptive changes are linked to an altered flow of synaptic activation across the V1 laminar microcircuit. Using repeated visual stimulation, we recorded layer-specific responses in V1 of two fixating monkeys. We found that repetition-related spiking suppression was most pronounced outside granular V1 layers that receive the main retinogeniculate input. This repetition-related response suppression was robust to alternating stimuli between the eyes, in line with the notion that repetition-related adaptation is predominantly of cortical origin. Most importantly, current source density (CSD) analysis, which provides an estimate of local net depolarization, revealed that synaptic processing during repeated stimulation was most profoundly affected within supragranular layers, which harbor the bulk of cortico-cortical connections. Direct comparison of the temporal evolution of laminar CSD and spiking activity showed that stimulus repetition first affected supragranular synaptic currents, which translated into a reduction of stimulus-evoked spiking across layers. Together, these results suggest that repetition induces an altered state of intracortical processing that underpins visual adaptation. NEW & NOTEWORTHY Our survival depends on our brains rapidly adapting to ever changing environments. A well-studied form of adaptation occurs whenever we encounter the same or similar stimuli repeatedly. We show that this repetition-related adaptation is supported by systematic changes in the flow of sensory activation across the laminar cortical microcircuitry of primary visual cortex. These results demonstrate how adaptation impacts neuronal interactions across cortical circuits.
30
Mann, Fanny, Christiane Peuckert, Frank Dehner, Renping Zhou, and Jürgen Bolz. "Ephrins regulate the formation of terminal axonal arbors during the development of thalamocortical projections." Development 129, no. 16 (August 15, 2002): 3945–55. http://dx.doi.org/10.1242/dev.129.16.3945.
Full textAbstract:
The development of connections between thalamic afferents and their cortical target cells occurs in a highly precise manner. Thalamic axons enter the cortex through deep cortical layers, then stop their growth in layer 4 and elaborate terminal arbors specifically within this layer. The mechanisms that underlie target layer recognition for thalamocortical projections are not known. We compared the growth pattern of thalamic explants cultured on membrane substrates purified from cortical layer 4, the main recipient layer for thalamic axons, and cortical layer 5, a non-target layer. Thalamic axons exhibited a reduced growth rate and an increased branching density on their appropriate target membranes compared with non-target substrate. When confronted with alternating stripes of both membrane substrates, thalamic axons grew preferentially on their target membrane stripes. Enzymatic treatment of cortical membranes revealed that growth, branching and guidance of thalamic axons are independently regulated by attractive and repulsive cues differentially expressed in distinct cortical layers. These results indicate that multiple membrane-associated molecules collectively contribute to the laminar targeting of thalamic afferents. Furthermore, we found that interfering with the function of Eph tyrosine kinase receptors and their ligands, ephrins, abolished the preferential branching of thalamic axons on their target membranes, and that recombinant ephrin-A5 ligand elicited a branch-promoting activity on thalamic axons. We conclude that interactions between Eph receptors and ephrins mediate branch formation of thalamic axons and thereby may play a role in the establishment of layer-specific thalamocortical connections.
31
Kutová, M., J. Mrzílková, J. Riedlová, and P. Zach. "Asymmetric Changes in Limbic Cortex and Planum Temporale in Patients with Alzheimer Disease." Current Alzheimer Research 15, no. 14 (November 2, 2018): 1361–68. http://dx.doi.org/10.2174/1567205015666181004142659.
Full textAbstract:
Background: There are several cortical areas related to the limbic system that form the output from the hippocampal formation whose cellular and morphological features are important for the onset and progression of AD. We hypothesized that there would be a significant difference in the size of cortical pyramidal neurons and that there would also be a hemispheric asymmetry between Alzheimer disease patients and controls. These differences would potentially be accompanied by an increase in the numbers of Fluoro-Jade B-positive degenerating cortical neurons and a corresponding decrease in the numbers of DAPI-stained cortical neuronal nuclei in subjects with AD compared to controls. Such changes could potentially be used as another marker in postmortem neuropathological diagnosis of AD. Methods: We measured absolute numbers of DAPI and Fluoro-Jade B stained cells in five cortical areas of the limbic system and four subareas of planum temporale in the post-mortem brains of subjects with Alzheimer disease. We also measured the size of pyramidal neurons in layer III in the five cortical areas of the limbic system in these subjects. All measurements were performed separately for the left and right hemisphere in order to identify asymmetries between the two hemispheres. Results: We observed a significant decrease in numbers of DAPI stained cells in layers IV-VI of the anterior cingulate gyrus on the right side, in layers I-III of the posterior cingulate gyrus on the left side, in layers IV-VI in the transition region from superior temporal gyrus into planum temporale on the right and in layers IV-VI in the transition from planum temporale to insular cortex on the left. We also observed a significant increase in the numbers of Fluoro-Jade stained cells in layers I-III of the anterior cingulate gyrus and in layers I-III on the left and layers IV-VI of the right gyrus of Heschl. Shortening of the size of layer III pyramidal neurons in subjects with Alzheimer´s disease was found in the anterior cingulate gyrus on the right, in the posterior cingulate gyrus and entorhinal cortex on the left and on the right in the parahippocampal gyrus. Conclusion: Our study demonstrates asymmetries in different cortical regions of the temporal lobe that can be used as another marker in the postmortem diagnosis of AD.
32
Wagstyl, Konrad, Stéphanie Larocque, Guillem Cucurull, Claude Lepage, Joseph Paul Cohen, Sebastian Bludau, Nicola Palomero-Gallagher, et al. "BigBrain 3D atlas of cortical layers: Cortical and laminar thickness gradients diverge in sensory and motor cortices." PLOS Biology 18, no. 4 (April 3, 2020): e3000678. http://dx.doi.org/10.1371/journal.pbio.3000678.
Full text
33
Pluta, Scott R., Greg I. Telian, Alexander Naka, and Hillel Adesnik. "Superficial Layers Suppress the Deep Layers to Fine-tune Cortical Coding." Journal of Neuroscience 39, no. 11 (January 16, 2019): 2052–64. http://dx.doi.org/10.1523/jneurosci.1459-18.2018.
Full text
34
Pelled, Galit, and Gadi Goelman. "Different physiological MRI noise between cortical layers." Magnetic Resonance in Medicine 52, no. 4 (2004): 913–16. http://dx.doi.org/10.1002/mrm.20229.
Full text
35
Jarvis, W. R., and J. A. Traquair. "Sclerotia of Aspergillus aculeatus." Canadian Journal of Botany 63, no. 9 (September 1, 1985): 1567–72. http://dx.doi.org/10.1139/b85-217.
Full textAbstract:
Sclerotial development in Aspergillus aculeatus is described for the first time. The sclerotium originates as a knot of interwoven hyphae. The mature sclerotium has a rind of flattened hyphae, below which are two cortical layers and a medulla. The outer cortical layer has isodiametric cells and the inner layer has somewhat radially elongated polyhedral cells. The thick walls of the cortical cells are perforated by simple septal pores. The medulla comprises a loosely interwoven mass of hyphae. Sclerotia remain pale luteous.
36
Pais-Vieira, Miguel, Carolina Kunicki, Po-He Tseng, Joel Martin, Mikhail Lebedev, and Miguel A. L. Nicolelis. "Cortical and thalamic contributions to response dynamics across layers of the primary somatosensory cortex during tactile discrimination." Journal of Neurophysiology 114, no. 3 (September 2015): 1652–76. http://dx.doi.org/10.1152/jn.00108.2015.
Full textAbstract:
Tactile information processing in the rodent primary somatosensory cortex (S1) is layer specific and involves modulations from both thalamocortical and cortico-cortical loops. However, the extent to which these loops influence the dynamics of the primary somatosensory cortex while animals execute tactile discrimination remains largely unknown. Here, we describe neural dynamics of S1 layers across the multiple epochs defining a tactile discrimination task. We observed that neuronal ensembles within different layers of the S1 cortex exhibited significantly distinct neurophysiological properties, which constantly changed across the behavioral states that defined a tactile discrimination. Neural dynamics present in supragranular and granular layers generally matched the patterns observed in the ventral posterior medial nucleus of the thalamus (VPM), whereas the neural dynamics recorded from infragranular layers generally matched the patterns from the posterior nucleus of the thalamus (POM). Selective inactivation of contralateral S1 specifically switched infragranular neural dynamics from POM-like to those resembling VPM neurons. Meanwhile, ipsilateral M1 inactivation profoundly modulated the firing suppression observed in infragranular layers. This latter effect was counterbalanced by contralateral S1 block. Tactile stimulus encoding was layer specific and selectively affected by M1 or contralateral S1 inactivation. Lastly, causal information transfer occurred between all neurons in all S1 layers but was maximal from infragranular to the granular layer. These results suggest that tactile information processing in the S1 of awake behaving rodents is layer specific and state dependent and that its dynamics depend on the asynchronous convergence of modulations originating from ipsilateral M1 and contralateral S1.
37
Villalba, Rosa M., Joseph A. Behnke, Jean-Francois Pare, and Yoland Smith. "Comparative Ultrastructural Analysis of Thalamocortical Innervation of the Primary Motor Cortex and Supplementary Motor Area in Control and MPTP-Treated Parkinsonian Monkeys." Cerebral Cortex 31, no. 7 (March 2, 2021): 3408–25. http://dx.doi.org/10.1093/cercor/bhab020.
Full textAbstract:
Abstract The synaptic organization of thalamic inputs to motor cortices remains poorly understood in primates. Thus, we compared the regional and synaptic connections of vGluT2-positive thalamocortical glutamatergic terminals in the supplementary motor area (SMA) and the primary motor cortex (M1) between control and MPTP-treated parkinsonian monkeys. In controls, vGluT2-containing fibers and terminal-like profiles invaded layer II–III and Vb of M1 and SMA. A significant reduction of vGluT2 labeling was found in layer Vb, but not in layer II–III, of parkinsonian animals, suggesting a potential thalamic denervation of deep cortical layers in parkinsonism. There was a significant difference in the pattern of synaptic connectivity in layers II–III, but not in layer Vb, between M1 and SMA of control monkeys. However, this difference was abolished in parkinsonian animals. No major difference was found in the proportion of perforated versus macular post-synaptic densities at thalamocortical synapses between control and parkinsonian monkeys in both cortical regions, except for a slight increase in the prevalence of perforated axo-dendritic synapses in the SMA of parkinsonian monkeys. Our findings suggest that disruption of the thalamic innervation of M1 and SMA may underlie pathophysiological changes of the motor thalamocortical loop in the state of parkinsonism.
38
Krienen, Fenna M., B. T. Thomas Yeo, Tian Ge, Randy L. Buckner, and Chet C. Sherwood. "Transcriptional profiles of supragranular-enriched genes associate with corticocortical network architecture in the human brain." Proceedings of the National Academy of Sciences 113, no. 4 (January 6, 2016): E469—E478. http://dx.doi.org/10.1073/pnas.1510903113.
Full textAbstract:
The human brain is patterned with disproportionately large, distributed cerebral networks that connect multiple association zones in the frontal, temporal, and parietal lobes. The expansion of the cortical surface, along with the emergence of long-range connectivity networks, may be reflected in changes to the underlying molecular architecture. Using the Allen Institute’s human brain transcriptional atlas, we demonstrate that genes particularly enriched in supragranular layers of the human cerebral cortex relative to mouse distinguish major cortical classes. The topography of transcriptional expression reflects large-scale brain network organization consistent with estimates from functional connectivity MRI and anatomical tracing in nonhuman primates. Microarray expression data for genes preferentially expressed in human upper layers (II/III), but enriched only in lower layers (V/VI) of mouse, were cross-correlated to identify molecular profiles across the cerebral cortex of postmortem human brains (n = 6). Unimodal sensory and motor zones have similar molecular profiles, despite being distributed across the cortical mantle. Sensory/motor profiles were anticorrelated with paralimbic and certain distributed association network profiles. Tests of alternative gene sets did not consistently distinguish sensory and motor regions from paralimbic and association regions: (i) genes enriched in supragranular layers in both humans and mice, (ii) genes cortically enriched in humans relative to nonhuman primates, (iii) genes related to connectivity in rodents, (iv) genes associated with human and mouse connectivity, and (v) 1,454 gene sets curated from known gene ontologies. Molecular innovations of upper cortical layers may be an important component in the evolution of long-range corticocortical projections.
39
Palomero-Gallagher, Nicola, and Karl Zilles. "Cortical layers: Cyto-, myelo-, receptor- and synaptic architecture in human cortical areas." NeuroImage 197 (August 2019): 716–41. http://dx.doi.org/10.1016/j.neuroimage.2017.08.035.
Full text
40
Ahissar, Ehud, Ronen Sosnik, Knarik Bagdasarian, and Sebastian Haidarliu. "Temporal Frequency of Whisker Movement. II. Laminar Organization of Cortical Representations." Journal of Neurophysiology 86, no. 1 (July 1, 2001): 354–67. http://dx.doi.org/10.1152/jn.2001.86.1.354.
Full textAbstract:
Part of the information obtained by rodent whiskers is carried by the frequency of their movement. In the thalamus of anesthetized rats, the whisker frequency is represented by two different coding schemes: by amplitude and spike count (i.e., response amplitudes and spike counts decrease as a function of frequency) in the lemniscal thalamus and by latency and spike count (latencies increase and spike counts decrease as a function of frequency) in the paralemniscal thalamus (see accompanying paper). Here we investigated neuronal representations of the whisker frequency in the primary somatosensory (“barrel”) cortex of the anesthetized rat, which receives its input from both the lemniscal and paralemniscal thalamic nuclei. Single and multi-units were recorded from layers 2/3, 4 (barrels only), 5a, and 5b during vibrissal stimulation. Typically, the input frequency was represented by amplitude and spike count in the barrels of layer 4 and in layer 5b (the “lemniscal layers”) and by latency and spike count in layer 5a (the “paralemniscal layer”). Neurons of layer 2/3 displayed a mixture of the two coding schemes. When the pulse width of the stimulus was reduced from 50 to 20 ms, the latency coding in layers 5a and 2/3 was dramatically reduced, while the spike-count coding was not affected; in contrast, in layers 4 and 5b, the latencies remained constant, but the spike counts were reduced with 20-ms stimuli. The same effects were found in the paralemniscal and lemniscal thalamic nuclei, respectively (see accompanying paper). These results are consistent with the idea that thalamocortical loops of different pathways, although terminating within the same cortical columns, perform different computations in parallel. Furthermore, the mixture of coding schemes in layer 2/3 might reflect an integration of lemniscal and paralemniscal outputs.
41
Pettine, Warren W., Nicholas A. Steinmetz, and Tirin Moore. "Laminar segregation of sensory coding and behavioral readout in macaque V4." Proceedings of the National Academy of Sciences 116, no. 29 (June 27, 2019): 14749–54. http://dx.doi.org/10.1073/pnas.1819398116.
Full textAbstract:
Neurons in sensory areas of the neocortex are known to represent information both about sensory stimuli and behavioral state, but how these 2 disparate signals are integrated across cortical layers is poorly understood. To study this issue, we measured the coding of visual stimulus orientation and of behavioral state by neurons within superficial and deep layers of area V4 in monkeys while they covertly attended or prepared eye movements to visual stimuli. We show that whereas single neurons and neuronal populations in the superficial layers conveyed more information about the orientation of visual stimuli than neurons in deep layers, the opposite was true of information about the behavioral relevance of those stimuli. In particular, deep layer neurons encoded greater information about the direction of planned eye movements than superficial neurons. These results suggest a division of labor between cortical layers in the coding of visual input and visually guided behavior.
42
Opris, Ioan, Robert E. Hampson, Terrence R. Stanford, Greg A. Gerhardt, and Sam A. Deadwyler. "Neural Activity in Frontal Cortical Cell Layers: Evidence for Columnar Sensorimotor Processing." Journal of Cognitive Neuroscience 23, no. 6 (June 2011): 1507–21. http://dx.doi.org/10.1162/jocn.2010.21534.
Full textAbstract:
The mammalian frontal cortex (FCx) is at the top of the brain's sensorimotor hierarchy and includes cells in the supragranular Layer 2/3, which integrate convergent sensory information for transmission to infragranular Layer 5 cells to formulate motor system outputs that control behavioral responses. Functional interaction between these two layers of FCx was examined using custom-designed ceramic-based microelectrode arrays (MEAs) that allowed simultaneous recording of firing patterns of FCx neurons in Layer 2/3 and Layer 5 in nonhuman primates performing a simple go/no-go discrimination task. This unique recording arrangement showed differential encoding of task-related sensory events by cells in each layer with Layer 2/3 cells exhibiting larger firing peaks during presentation of go target and no-go target task images, whereas Layer 5 cells showed more activity during reward contingent motor responses in the task. Firing specificity to task-related events was further demonstrated by synchronized firing between pairs of cells in different layers that occupied the same vertically oriented “column” on the MEA. Pairs of cells in different layers recorded at adjacent “noncolumnar” orientations on the MEA did not show synchronized firing during the same task-related events. The results provide required evidence in support of previously suggested task-related sensorimotor processing in the FCx via functionally segregated minicolumns.
43
Kurokawa, Rumi, Hisato Maruoka, Shun Tsuruno, and Toshihiko Hosoya. "Single-cell level multi-layered substructures in the deep cortical layers." Neuroscience Research 68 (January 2010): e249. http://dx.doi.org/10.1016/j.neures.2010.07.1103.
Full text
44
Lotan, Eyal, Ido Tavor, Daniel Barazany, Shani Ben-Amitay, Chen Hoffmann, Galia Tsarfaty, Yaniv Assaf, and David Tanne. "Selective atrophy of the connected deepest cortical layers following small subcortical infarct." Neurology 92, no. 6 (January 11, 2019): e567-e575. http://dx.doi.org/10.1212/wnl.0000000000006884.
Full textAbstract:
ObjectiveTo explore whether in patients with chronic small subcortical infarct the cortical layers of the connected cortex are differentially affected and whether these differences correlate with clinical symptomatology.MethodsTwenty patients with a history of chronic small subcortical infarct affecting the corticospinal tracts and 15 healthy controls were included. Connected primary motor cortex was identified with tractography starting from infarct. T1-component probability maps were calculated from T1 relaxation 3T MRI, dividing the cortex into 5 laminar gaussian classes.ResultsFocal cortical thinning was observed in the connected cortex and specifically only in its deepest laminar class compared to the nonaffected mirrored cortex (p < 0.001). There was loss of microstructural integrity of the affected corticospinal tract with increased mean diffusivity and decreased fractional anisotropy compared to the contralateral nonaffected tract (p ≤ 0.002). Clinical scores were correlated with microstructural damage of the corticospinal tracts and with thinning of the cortex and specifically only its deepest laminar class (p < 0.001). No differences were found in the laminar thickness pattern of the bilateral primary motor cortices or in the microstructural integrity of the bilateral corticospinal tracts in the healthy controls.ConclusionOur results support the concept of secondary neurodegeneration of connected primary motor cortex after a small subcortical infarct affecting the corticospinal tract, with observations that the main cortical thinning occurs in the deepest cortex and that the clinical symptomatology is correlated with this cortical atrophy pattern. Our findings may contribute to a better understanding of structural reorganization and functional outcomes after stroke.
45
Cortes, Nelson, Bruno O. F. de Souza, and Christian Casanova. "Pulvinar Modulates Synchrony across Visual Cortical Areas." Vision 4, no. 2 (April 10, 2020): 22. http://dx.doi.org/10.3390/vision4020022.
Full textAbstract:
The cortical visual hierarchy communicates in different oscillatory ranges. While gamma waves influence the feedforward processing, alpha oscillations travel in the feedback direction. Little is known how this oscillatory cortical communication depends on an alternative route that involves the pulvinar nucleus of the thalamus. We investigated whether the oscillatory coupling between the primary visual cortex (area 17) and area 21a depends on the transthalamic pathway involving the pulvinar in cats. To that end, visual evoked responses were recorded in areas 17 and 21a before, during and after inactivation of the pulvinar. Local field potentials were analyzed with Wavelet and Granger causality tools to determine the oscillatory coupling between layers. The results indicate that cortical oscillatory activity was enhanced during pulvinar inactivation, in particular for area 21a. In area 17, alpha band responses were represented in layers II/III. In area 21a, gamma oscillations, except for layer I, were significantly increased, especially in layer IV. Granger causality showed that the pulvinar modulated the oscillatory information between areas 17 and 21a in gamma and alpha bands for the feedforward and feedback processing, respectively. Together, these findings indicate that the pulvinar is involved in the mechanisms underlying oscillatory communication along the visual cortex.
46
Alloway, K. D., M. J. Johnson, and M. B. Wallace. "Thalamocortical interactions in the somatosensory system: interpretations of latency and cross-correlation analyses." Journal of Neurophysiology 70, no. 3 (September 1, 1993): 892–908. http://dx.doi.org/10.1152/jn.1993.70.3.892.
Full textAbstract:
1. Isolated extracellular neuronal responses to cutaneous stimulation were simultaneously recorded from corresponding peripheral representations in the ventrobasal nucleus and primary somatosensory cortex of intact, halothane-anesthetized rats. Thalamic and cortical neurons representing hairy skin on the forelimb were activated by hair movements produced by a series of 50 or 100 discrete air jets. A corresponding set of neurons representing the glabrous pads of the hind paw were activated by a similar number of punctate mechanical displacements. 2. Cortical electrode penetrations were histologically reconstructed, and 118 neurons in the glabrous skin representation exhibited cutaneous responses that were categorized into supragranular, granular, or infragranular groups according to their laminar position. Minimum latencies of cortical neurons responding to glabrous skin displacement were analyzed, and significant differences were found in the distribution of minimum latencies for the different cortical layers. Mean values for minimum latencies in the infragranular and granular layers were 15.8 and 16.3 ms, respectively, whereas supragranular neurons were characterized by minimum latencies having a mean of 20 ms. The differences between these groups suggests that stimulus-induced afferent activity reaches infragranular and granular layers before contacting supragranular neurons. Average latencies were also calculated on responses occurring during the 1st 20 trials, but the cortical distributions of these values overlapped considerably, and differences between the laminar groups were not statistically significant. 3. In several recording sites, two cortical neurons were recorded simultaneously, and the response latencies of these matched pairs were often substantially different despite the similarity in laminar position. This result indicates that laminar location is not the only determinant of response latency and that serially organized circuits are distributed within, as well as between, cortical layers. 4. From a sample of 302 neurons exhibiting cutaneous responses within histologically identified regions of thalamus or cortex, a set of 143 pairs of neurons recorded simultaneously from both regions was available for cross-correlation analysis. Significant thalamocortical interactions were found in 38 neurons pairs. Analysis of these significant interactions revealed that thalamocortical connection strength, as measured by neuronal efficacy, was two to four times larger for neuron pairs having the cortical cell in granular layer IV than for neuron pairs having an extragranular layer cortical neuron. There was no difference in thalamocortical connection strength between neuron pairs containing supra- or infragranular cortical neurons. 5. Summed peristimulus time histograms revealed stimulus-locked inhibition of spontaneous activity in 4% (8/195) or cortical and 18% (20/107) of thalamic neurons.(ABSTRACT TRUNCATED AT 400 WORDS)
47
Desai, A. R., and S. K. McConnell. "Progressive restriction in fate potential by neural progenitors during cerebral cortical development." Development 127, no. 13 (July 1, 2000): 2863–72. http://dx.doi.org/10.1242/dev.127.13.2863.
Full textAbstract:
During early stages of cerebral cortical development, progenitor cells in the ventricular zone are multipotent, producing neurons of many layers over successive cell divisions. The laminar fate of their progeny depends on environmental cues to which the cells respond prior to mitosis. By the end of neurogenesis, however, progenitors are lineally committed to producing upper-layer neurons. Here we assess the laminar fate potential of progenitors at a middle stage of cortical development. The progenitors of layer 4 neurons were first transplanted into older brains in which layer 2/3 was being generated. The transplanted neurons adopted a laminar fate appropriate for the new environment (layer 2/3), revealing that layer 4 progenitors are multipotent. Mid-stage progenitors were then transplanted into a younger environment, in which layer 6 neurons were being generated. The transplanted neurons bypassed layer 6, revealing that layer 4 progenitors have a restricted fate potential and are incompetent to respond to environmental cues that trigger layer 6 production. Instead, the transplanted cells migrated to layer 4, the position typical of their origin, and also to layer 5, a position appropriate for neither the host nor the donor environment. Because layer 5 neurogenesis is complete by the stage that progenitors were removed for transplantation, restrictions in laminar fate potential must lag behind the final production of a cortical layer. These results suggest that a combination of intrinsic and environmental cues controls the competence of cortical progenitor cells to produce neurons of different layers.
48
Colby, C. L. "Corticotectal circuit in the cat: a functional analysis of the lateral geniculate nucleus layers of origin." Journal of Neurophysiology 59, no. 6 (June 1, 1988): 1783–97. http://dx.doi.org/10.1152/jn.1988.59.6.1783.
Full textAbstract:
1. The dorsal lateral geniculate nucleus (LGN) of the cat is a major thalamic relay between the retina and several visual cortical areas. These cortical areas in turn project to the superior colliculus (SC). The aim of the present experiment was to determine which LGN layers provide a necessary input to the corticotectal circuit. 2. Individual layers of the LGN were reversibly inactivated by microinjection of cobalt chloride during recording of visual responses in the retinotopically corresponding part of the superior colliculus. 3. For cells driven through the contralateral eye, inactivation of layer A or the medial interlaminar nucleus (MIN) had little effect on visual responsiveness in the superior colliculus. In contrast, inactivation of layer C abolished visual responses at one-quarter of the SC recording sites, reduced responses at another quarter, and left half of the recording sites unaffected. 4. For cells driven through the ipsilateral eye, inactivation of layer C1 or the MIN had no effect. Inactivation of layer A1 uniformly reduced visual responses in the superior colliculus and usually abolished them entirely. 5. These results are compatible with previous work showing that cortical input to the SC originates from Y-cells. They indicate that two of the five Y-cell containing layers (A1 and C) provide major inputs to the corticotectal circuit. The results suggest that layer A1 is functionally allied to layer C as well as to layer A.
49
Modenesi, P., and C. Vanzo. "The Cortical Surfaces in Parmelia Saxatilis and P.Caperata: A Histochemical Approach." Lichenologist 18, no. 4 (October 1986): 329–38. http://dx.doi.org/10.1017/s002428298600052x.
Full textAbstract:
AbstractHistochemical aspects of the amorphous layers in two species of Parmelia apseudocyphellate and a pored epicorticate, were compared. In P. saxatilis this layer, called the ‘ syncortex ’ (a new term), is composed of strongly acidic (sulphated) polysaccharides containing hyaluronic acid. It is easily distinguishable histochemically from the cortical interhyphal matrix. In P. caperata the mild acidic polysaccharidic composition of the epicortex and the interhyphal matrix is shown. The function of these amorphous layers is discussed on the basis of these results.
50
Chapman, Barbara, and Imke Gödecke. "No on-off Maps in Supragranular Layers of Ferret Visual Cortex." Journal of Neurophysiology 88, no. 4 (October 1, 2002): 2163–66. http://dx.doi.org/10.1152/jn.2002.88.4.2163.
Full textAbstract:
Primary visual cortex contains functional maps of a number of stimulus properties including ocular dominance, orientation, direction, color, and spatial frequency. These maps must be organized with respect to each other and to a single continuous retinotopic map of visual space such that each stimulus parameter is represented at each point in space. In the ferret, geniculo-cortical inputs to cortical layer IV are segregated into on- andoff-center patches, suggesting the possibility that there might be an additional cortical map in this species. We have used optical imaging of intrinsic signals to search for on-offmaps in ferret visual cortical cells and have found none. This suggests that the high degree of on-off segregation seen subcortically in the ferret may play a role in the development of visual cortical receptive fields rather than in adult cortical function.