Journal articles: 'Visual pathways'

1

Bilaniuk, Larissa T., Robert A. Zimmerman, and Peter J. Savino. "VISUAL PATHWAYS." Neuroimaging Clinics of North America 3, no. 1 (1993): 71–83. https://doi.org/10.1016/s1052-5149(25)00143-1.

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Eustace, Peter. "Retrochiasmal visual pathways." Current Opinion in Ophthalmology 1, no. 5 (1990): 447–52. http://dx.doi.org/10.1097/00055735-199001050-00004.

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Eustace, Peter. "Retrochiasmal visual pathways." Current Opinion in Ophthalmology 1, no. 5 (1990): 447–52. http://dx.doi.org/10.1097/00055735-199010000-00004.

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Casagrande, V. "Evolution of visual pathways." Journal of Vision 5, no. 12 (2005): 32. http://dx.doi.org/10.1167/5.12.32.

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Sadun, Alfredo A., and Richard M. Rubin. "The Anterior Visual Pathways." Journal of Neuro-Ophthalmology 16, no. 2 (1996): 137–51. http://dx.doi.org/10.1097/00041327-199606000-00011.

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Dräger, Ursula C. "Albinism and Visual Pathways." New England Journal of Medicine 314, no. 25 (1986): 1636–38. http://dx.doi.org/10.1056/nejm198606193142508.

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SIBTAIN, N. "Imaging posterior visual pathways." Acta Ophthalmologica 86 (September 4, 2008): 0. http://dx.doi.org/10.1111/j.1755-3768.2008.3332.x.

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MADRID, M., and M. A. CROGNALE. "Long-term maturation of visual pathways." Visual Neuroscience 17, no. 6 (2000): 831–37. http://dx.doi.org/10.1017/s0952523800176023.

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Previous research in adults has demonstrated the utility of the visual evoked potential (VEP) to measure the integrity of the chromatic and achromatic visual pathways. The VEP has also been shown to be a valuable indicator of maturation of these pathways in infants up to 1 year of age. The present manuscript reports changes in the visual pathways from 2 years to adulthood as measured by the spatio-chromatic VEP. The responses to achromatic reversal stimuli designed to preferentially activate the low spatial-frequency achromatic (luminance) pathways appear adult-like by 1 year of age. The responses to low spatial-frequency isoluminant onset stimuli designed to preferentially activate the chromatic pathway do not appear as they do in the adult until after 12–13 years of age. The shapes of the chromatic VEP waveforms shift from a positive–negative complex to a negative–positive complex. These changes can be modeled by a decrease in the latency of a large negative component between the ages of 1 year and adulthood. The results suggest that for low spatial-frequency stimuli, there are long-term changes in the development of the chromatic pathways that are not observed in the low spatial-frequency achromatic pathways. The changes in the chromatic VEP waveforms with age may be a physiological correlate of reported behavioral changes.

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Kovacs-Balint, Z., E. Feczko, M. Pincus, et al. "Early Developmental Trajectories of Functional Connectivity Along the Visual Pathways in Rhesus Monkeys." Cerebral Cortex 29, no. 8 (2018): 3514–26. http://dx.doi.org/10.1093/cercor/bhy222.

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Abstract Early social interactions shape the development of social behavior, although the critical periods or the underlying neurodevelopmental processes are not completely understood. Here, we studied the developmental changes in neural pathways underlying visual social engagement in the translational rhesus monkey model. Changes in functional connectivity (FC) along the ventral object and motion pathways and the dorsal attention/visuo-spatial pathways were studied longitudinally using resting-state functional MRI in infant rhesus monkeys, from birth through early weaning (3 months), given the socioemotional changes experienced during this period. Our results revealed that (1) maturation along the visual pathways proceeds in a caudo-rostral progression with primary visual areas (V1–V3) showing strong FC as early as 2 weeks of age, whereas higher-order visual and attentional areas (e.g., MT–AST, LIP–FEF) show weak FC; (2) functional changes were pathway-specific (e.g., robust FC increases detected in the most anterior aspect of the object pathway (TE–AMY), but FC remained weak in the other pathways (e.g., AST–AMY)); (3) FC matures similarly in both right and left hemispheres. Our findings suggest that visual pathways in infant macaques undergo selective remodeling during the first 3 months of life, likely regulated by early social interactions and supporting the transition to independence from the mother.

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Edwards, Mark, Stephanie C. Goodhew, and David R. Badcock. "Using perceptual tasks to selectively measure magnocellular and parvocellular performance: Rationale and a user’s guide." Psychonomic Bulletin & Review 28, no. 4 (2021): 1029–50. http://dx.doi.org/10.3758/s13423-020-01874-w.

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AbstractThe visual system uses parallel pathways to process information. However, an ongoing debate centers on the extent to which the pathways from the retina, via the Lateral Geniculate nucleus to the visual cortex, process distinct aspects of the visual scene and, if they do, can stimuli in the laboratory be used to selectively drive them. These questions are important for a number of reasons, including that some pathologies are thought to be associated with impaired functioning of one of these pathways and certain cognitive functions have been preferentially linked to specific pathways. Here we examine the two main pathways that have been the focus of this debate: the magnocellular and parvocellular pathways. Specifically, we review the results of electrophysiological and lesion studies that have investigated their properties and conclude that while there is substantial overlap in the type of information that they process, it is possible to identify aspects of visual information that are predominantly processed by either the magnocellular or parvocellular pathway. We then discuss the types of visual stimuli that can be used to preferentially drive these pathways.

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SHATZ, C. J. "Visual Neurobiology: Development of Visual Pathways in Mammals." Science 228, no. 4695 (1985): 67–68. http://dx.doi.org/10.1126/science.228.4695.67.

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Kaposvári, Péter, Gergő Csete, Anna Bognár, et al. "Audio–visual integration through the parallel visual pathways." Brain Research 1624 (October 2015): 71–77. http://dx.doi.org/10.1016/j.brainres.2015.06.036.

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Sumner, Petroc, Parashkev Nachev, Sarah Castor-Perry, Heather Isenman, and Christopher Kennard. "Which Visual Pathways Cause Fixation-Related Inhibition?" Journal of Neurophysiology 95, no. 3 (2006): 1527–36. http://dx.doi.org/10.1152/jn.00781.2005.

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Visual stimuli can both inhibit and activate motor mechanisms. In one well-known example, the latency of saccadic eye movements is prolonged in the presence of a fixation stimulus, relative to the case in which the fixation stimulus disappears before the target appears. This automatic sensory-motor effect, known as the gap effect or fixation-offset effect, has been associated with inhibitory connections within the superior colliculus (SC). Visual information is provided to the SC and other oculomotor areas, such as the frontal eye fields (FEF), mainly by the magnocellular geniculostriate pathway, and also by the retinotectal pathway. We tested whether signals in these pathways are necessary to create fixation-related inhibition, by using stimuli invisible to them. We found that such stimuli, visible only to short-wave–sensitive cones (S cones), do produce fixation-related inhibition (including when warning effects were equated). We also demonstrate that this fixation-related inhibition cannot be explained by residual activation of luminance pathways and must be caused by a route separate from that of luminance fixation signals. Thus there are at least two routes that cause fixation-related inhibition, and direct sensory input to the SC or FEF by the magnocellular or retinotectal pathways is not required. We discuss the implications that there may be both cortical and collicular mechanisms.

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De Moraes, Carlos Gustavo. "Anatomy of the Visual Pathways." Journal of Glaucoma 22 (2013): S2—S7. http://dx.doi.org/10.1097/ijg.0b013e3182934978.

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Crish, Samuel D., and David J. Calkins. "Central Visual Pathways in Glaucoma." Journal of Neuro-Ophthalmology 35 (September 2015): S29—S37. http://dx.doi.org/10.1097/wno.0000000000000291.

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Vidyasagar, T. R. "Eyeing visual pathways in dyslexia." Science 345, no. 6196 (2014): 524. http://dx.doi.org/10.1126/science.345.6196.524-a.

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Leruez, S., P. Amati-Bonneau, C. Verny, et al. "Mitochondrial dysfunction affecting visual pathways." Revue Neurologique 170, no. 5 (2014): 344–54. http://dx.doi.org/10.1016/j.neurol.2014.03.009.

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18

Schreiber, Falk. "Visual comparison of metabolic pathways." Journal of Visual Languages & Computing 14, no. 4 (2003): 327–40. http://dx.doi.org/10.1016/s1045-926x(03)00030-2.

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Murcia-Belmonte, Verónica, and Lynda Erskine. "Wiring the Binocular Visual Pathways." International Journal of Molecular Sciences 20, no. 13 (2019): 3282. http://dx.doi.org/10.3390/ijms20133282.

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Retinal ganglion cells (RGCs) extend axons out of the retina to transmit visual information to the brain. These connections are established during development through the navigation of RGC axons along a relatively long, stereotypical pathway. RGC axons exit the eye at the optic disc and extend along the optic nerves to the ventral midline of the brain, where the two nerves meet to form the optic chiasm. In animals with binocular vision, the axons face a choice at the optic chiasm—to cross the midline and project to targets on the contralateral side of the brain, or avoid crossing the midline and project to ipsilateral brain targets. Ipsilaterally and contralaterally projecting RGCs originate in disparate regions of the retina that relate to the extent of binocular overlap in the visual field. In humans virtually all RGC axons originating in temporal retina project ipsilaterally, whereas in mice, ipsilaterally projecting RGCs are confined to the peripheral ventrotemporal retina. This review will discuss recent advances in our understanding of the mechanisms regulating specification of ipsilateral versus contralateral RGCs, and the differential guidance of their axons at the optic chiasm. Recent insights into the establishment of congruent topographic maps in both brain hemispheres also will be discussed.

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LI, ZHENG, and KATHERINE V. FITE. "GABAergic visual pathways in the frog Rana pipiens." Visual Neuroscience 18, no. 3 (2001): 457–64. http://dx.doi.org/10.1017/s0952523801183124.

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Gamma-aminobutyric acid (GABA) is the most prevalent inhibitory neurotransmitter in the vertebrate brain. It can exert its influence either as GABAergic projection pathways or as local interneurons, which play an essential role in many visual functions. However, no GABAergic visual pathways have been studied in frogs so far. In the present study, GABAergic pathways in the central visual system of Rana pipiens were investigated with double-labeling techniques, combining immunocytochemistry for GABA with Rhodamine microspheres for retrograde tracing. Three GABAergic visual pathways were identified: (1) a retino-tectal projection, from retina to the contralateral optic tectum (OT); (2) an ipsilateral projection from the nucleus of the basal optic root (nBOR) to the pretectal nucleus lentiformis mesencephali (nLM); and (3) a second-order pathway from the nucleus isthmi (NI), bilaterally, to the optic tectum. These results indicate that GABA is involved in both first-order (retina to optic tectum) as well as second-order (nucleus isthmi to optic tectum) visual projections in Rana pipiens, and may play a major role in mediating visuomotor reflexs such as optokinetic nystagmus or other visually guided behaviors.

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21

Zhuang, Xiaohua, Tam Tran, Doris Jin, Riya Philip, and Chaorong Wu. "Aging effects on contrast sensitivity in visual pathways: A pilot study on flicker adaptation." PLOS ONE 16, no. 12 (2021): e0261927. http://dx.doi.org/10.1371/journal.pone.0261927.

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Contrast sensitivity is reduced in older adults and is often measured at an overall perceptual level. Recent human psychophysical studies have provided paradigms to measure contrast sensitivity independently in the magnocellular (MC) and parvocellular (PC) visual pathways and have reported desensitization in the MC pathway after flicker adaptation. The current study investigates the influence of aging on contrast sensitivity and on the desensitization effect in the two visual pathways. The steady- and pulsed-pedestal paradigms were used to measure contrast sensitivity under two adaptation conditions in 45 observers. In the non-flicker adaptation condition, observers adapted to a pedestal array of four 1°×1° squares presented with a steady luminance; in the flicker adaptation condition, observers adapted to a square-wave modulated luminance flicker of 7.5 Hz and 50% contrast. Results showed significant age-related contrast sensitivity reductions in the MC and PC pathways, with a significantly larger decrease of contrast sensitivity for individuals older than 50 years of age in the MC pathway but not in the PC pathway. These results are consistent with the hypothesis that sensitivity reduction observed at the overall perceptual level likely comes from both the MC and PC visual pathways, with a more dramatic reduction resulting from the MC pathway for adults >50 years of age. In addition, a similar desensitization effect from flicker adaptation was observed in the MC pathway for all ages, which suggests that aging may not affect the process of visual adaptation to rapid luminance flicker.

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Jaekl, Philip, Alexis Pérez-Bellido, and Salvador Soto-Faraco. "On the ‘visual’ in ‘audio-visual integration’: a hypothesis concerning visual pathways." Experimental Brain Research 232, no. 6 (2014): 1631–38. http://dx.doi.org/10.1007/s00221-014-3927-8.

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Clarke, Stephanie. "Vision et langage: quelle importance du traitement en parallèle?" Travaux neuchâtelois de linguistique, no. 33 (December 1, 2000): 67–81. http://dx.doi.org/10.26034/tranel.2000.2681.

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The visual system of man and of non-human primates is organised in a way which favours parallel processing. Different aspects of visual information, such as colour, shape or motion are processed independantly. Focal hemispheric lesions can thus cause very selective deficits. The parvo- and magnocellular pathways, specialised in the processing of psychophysically different visual stimuli, have separate representations at the cortical level. Two main pathways are involved in visual recognition and in visuo-spatial functions respectively. Lesions that occur in the adult and remain restricted to one or the other pathway are accompanied with distinct types of visual agnosia. Early occurring deficit in magnocellular processing was proposed to play a role in developmental dyslexia. Models of reading based on observations in normal subjects and the occurrence of different types of alexia following brain damage suggest that several neural pathways are involved in reading. Although these pathways have not been yet identified anatomically, recent experimental work demonstrated the largely parallel connections between structures known to be involved in reading.

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Nakano, Tamami, and Kazuko Nakatani. "Cortical networks for face perception in two-month-old infants." Proceedings of the Royal Society B: Biological Sciences 281, no. 1793 (2014): 20141468. http://dx.doi.org/10.1098/rspb.2014.1468.

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Newborns have an innate system for preferentially looking at an upright human face. This face preference behaviour disappears at approximately one month of age and reappears a few months later. However, the neural mechanisms underlying this U-shaped behavioural change remain unclear. Here, we isolate the functional development of the cortical visual pathway for face processing using S-cone-isolating stimulation, which blinds the subcortical visual pathway. Using luminance stimuli, which are conveyed by both the subcortical and cortical visual pathways, the preference for upright faces was not observed in two-month-old infants, but it was observed in four- and six-month-old infants, confirming the recovery phase of the U-shaped development. By contrast, using S-cone stimuli, two-month-old infants already showed a preference for upright faces, as did four- and six-month-old infants, demonstrating that the cortical visual pathway for face processing is already functioning at the bottom of the U-shape at two months of age. The present results suggest that the transient functional deterioration stems from a conflict between the subcortical and cortical functional pathways, and that the recovery thereafter involves establishing a level of coordination between the two pathways.

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Frost, Douglas O. "Functional organization of surgically created visual circuits." Restorative Neurology and Neuroscience 15, no. 2-3 (1999): 107–13. https://doi.org/10.3233/rnn-1999-00125.

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Lesions of eerebral targets of the retina in newborn hamsters, when combined with transection of lemniscal pathways to the primary auditory or somatosensory thalamic nuclei or the secondary thalamic visual nucleus, can induce the formation of permanent retinal projections to the deafferented non-visual structures. These projections are retinotopically organized and form functional synapses. Consequently, neurons in the auditory or somatosensory cortices, which normally are not driven by visual stimuli, become visually responsive and have receptive field properties that ressemble, in several important ways, those of neurons in the visual cortex of normal animals. The surgically-induced retinothalamo-cortical pathways can mediate visually guided behaviors whose normal substrate, the pathway from the retina to the primary visual cortex via the thalamic dorsal lateral geniculate nucleus, is missing.

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Allen, Christopher P. G., Petroc Sumner, and Christopher D. Chambers. "The Timing and Neuroanatomy of Conscious Vision as Revealed by TMS-induced Blindsight." Journal of Cognitive Neuroscience 26, no. 7 (2014): 1507–18. http://dx.doi.org/10.1162/jocn_a_00557.

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Following damage to the primary visual cortex, some patients exhibit “blindsight,” where they report a loss of awareness while retaining the ability to discriminate visual stimuli above chance. Transient disruption of occipital regions with TMS can produce a similar dissociation, known as TMS-induced blindsight. The neural basis of this residual vision is controversial, with some studies attributing it to the retinotectal pathway via the superior colliculus whereas others implicate spared projections that originate predominantly from the LGN. Here we contrasted these accounts by combining TMS with visual stimuli that either activate or bypass the retinotectal and magnocellular (R/M) pathways. We found that the residual capacity of TMS-induced blindsight occurs for stimuli that bypass the R/M pathways, indicating that such pathways, which include those to the superior colliculus, are not critical. We also found that the modulation of conscious vision was time and pathway dependent. TMS applied either early (0–40 msec) or late (280–320 msec) after stimulus onset modulated detection of stimuli that did not bypass R/M pathways, whereas during an intermediate period (90–130 msec) the effect was pathway independent. Our findings thus suggest a prominent role for the R/M pathways in supporting both the preparatory and later stages of conscious vision. This may help resolve apparent conflict in previous literature by demonstrating that the roles of the retinotectal and geniculate pathways are likely to be more nuanced than simply corresponding to the unconscious/conscious dichotomy.

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Brandes, Ulrik, Tim Dwyer, and Falk Schreiber. "Visual Understanding of Metabolic Pathways Across Organisms Using Layout in Two and a Half Dimensions." Journal of Integrative Bioinformatics 1, no. 1 (2004): 11–26. http://dx.doi.org/10.1515/jib-2004-2.

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Summary We propose a method for visualizing a set of related metabolic pathways across organisms using 2 1/2 dimensional graph visualization. Interdependent, twodimensional layouts of each pathway are stacked on top of each other so that biologists get a full picture of subtle and significant differences among the pathways. The (dis)similarities between pathways are expressed by the Hamming distances of the underlying graphs which are used to compute a stacking order for the pathways. Layouts are determined by a global layout of the union of all pathway graphs using a variant of the proven Sugiyama approach for layered graph drawing. Our variant layout approach allows edges to cross if they appear in different graphs.

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28

IWATA, MAKOTO. "Visual Association Pathways in Human Brain." Tohoku Journal of Experimental Medicine 161, Supplement (1990): 61–78. http://dx.doi.org/10.1620/tjem.161.supplement_61.

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29

Lindblom, Bertil. "Optic chiasm and retrochiasmal visual pathways." Current Opinion in Ophthalmology 2, no. 5 (1991): 538–43. http://dx.doi.org/10.1097/00055735-199110000-00004.

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30

Wattam-Bell, John, Melissa Chiu, and Louisa Kulke. "Developmental Reorganisation of Visual Motion Pathways." i-Perception 3, no. 4 (2012): 230. http://dx.doi.org/10.1068/id230.

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31

Boets, B. "Eyeing visual pathways in dyslexia--Response." Science 345, no. 6196 (2014): 524. http://dx.doi.org/10.1126/science.345.6196.524-b.

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32

Rushton, D. "Development of Visual Pathways in Mammals." Journal of Neurology, Neurosurgery & Psychiatry 48, no. 2 (1985): 197–98. http://dx.doi.org/10.1136/jnnp.48.2.197-a.

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33

Wandell, Brian A., and Alex R. Wade. "Functional imaging of the visual pathways." Neurologic Clinics 21, no. 2 (2003): 417–43. http://dx.doi.org/10.1016/s0733-8619(03)00003-3.

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34

Jacobson, Daniel M. "Gliomas of the Anterior Visual Pathways." Neurosurgery Clinics of North America 10, no. 4 (1999): 683–98. http://dx.doi.org/10.1016/s1042-3680(18)30166-9.

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35

Beauchamp, Ross. "DEVELOPMENT OF VISUAL PATHWAYS IN MAMMALS." Optometry and Vision Science 62, no. 5 (1985): 357. http://dx.doi.org/10.1097/00006324-198505000-00010.

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36

Fortuyn, J. Droogleever. "Development of visual pathways in mammals." Clinical Neurology and Neurosurgery 87, no. 2 (1985): 154. http://dx.doi.org/10.1016/0303-8467(85)90126-x.

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37

Sadun, Alfredo A., and Richard M. Rubin. "The Anterior Visual Pathways???Part II." Journal of Neuro-Ophthalmology 16, no. 3 (1996): 212???222. http://dx.doi.org/10.1097/00041327-199609000-00012.

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Madill, S. A. "Disorders of the anterior visual pathways." Journal of Neurology, Neurosurgery & Psychiatry 75, suppl_4 (2004): iv12—iv19. http://dx.doi.org/10.1136/jnnp.2004.053421.

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Kudo, Motoi, Yasuhisa Nakamura, and Hironobu Tokuno. "Central visual pathways in the mole ()." Neuroscience Research Supplements 9 (January 1989): 183. http://dx.doi.org/10.1016/0921-8696(89)90968-7.

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de Lima Silveira, Luiz Carlos, Cézar Akiyoshi Saito, Harold Dias de Mello, et al. "Division of labor between M and P visual pathways: Different visual pathways minimize joint entropy differently." Psychology & Neuroscience 1, no. 1 (2008): 3–13. http://dx.doi.org/10.3922/j.psns.2008.1.002.

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atilgan, nilsu, and Sheng He. "Visual crowding effect in the Parvocellular and Magnocellular visual pathways." Journal of Vision 18, no. 10 (2018): 847. http://dx.doi.org/10.1167/18.10.847.

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Clifford-Jones, R. E., K. Cunningham, A. M. Halliday, et al. "Visual evoked potentials in meningiomas compressing the anterior visual pathways." Electroencephalography and Clinical Neurophysiology 61, no. 3 (1985): S52. http://dx.doi.org/10.1016/0013-4694(85)90227-5.

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Atilgan, Nilsu, Seung Min Yu, and Sheng He. "Visual crowding effect in the parvocellular and magnocellular visual pathways." Journal of Vision 20, no. 8 (2020): 6. http://dx.doi.org/10.1167/jov.20.8.6.

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Taylor, J. Eric T., Davood G. Gozli, David Chan, Greg Huffman, and Jay Pratt. "A touchy subject: advancing the modulated visual pathways account of altered vision near the hand." Translational Neuroscience 6, no. 1 (2015): 1–7. http://dx.doi.org/10.1515/tnsci-2015-0001.

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AbstractA growing body of evidence demonstrates that human vision operates differently in the space near and on the hands; for example, early findings in this literature reported that rapid onsets are detected faster near the hands, and that objects are searched more thoroughly. These and many other effects were attributed to enhanced attention via the recruitment of bimodal visual-tactile neurons representing the hand and near-hand space. However, recent research supports an alternative account: stimuli near the hands are preferentially processed by the action-oriented magnocellular visual pathway at the expense of processing in the parvocellular pathway. This Modulated Visual Pathways (MVP) account of altered vision near the hands describes a hand position-dependent trade-off between the two main retinal-cortical visual pathways between the eye and brain. The MVP account explains past findings and makes new predictions regarding near-hand vision supported by new research.

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Pietersen, A. N. J., S. K. Cheong, S. G. Solomon, C. Tailby, and P. R. Martin. "Temporal response properties of koniocellular (blue-on and blue-off) cells in marmoset lateral geniculate nucleus." Journal of Neurophysiology 112, no. 6 (2014): 1421–38. http://dx.doi.org/10.1152/jn.00077.2014.

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Visual perception requires integrating signals arriving at different times from parallel visual streams. For example, signals carried on the phasic-magnocellular (MC) pathway reach the cerebral cortex pathways some tens of milliseconds before signals traveling on the tonic-parvocellular (PC) pathway. Visual latencies of cells in the koniocellular (KC) pathway have not been specifically studied in simian primates. Here we compared MC and PC cells to “blue-on” (BON) and “blue-off” (BOF) KC cells; these cells carry visual signals originating in short-wavelength-sensitive (S) cones. We made extracellular recordings in the lateral geniculate nucleus (LGN) of anesthetized marmosets. We found that BON visual latencies are 10–20 ms longer than those of PC or MC cells. A small number of recorded BOF cells ( n = 7) had latencies 10–20 ms longer than those of BON cells. Within all cell groups, latencies of foveal receptive fields (<10° eccentricity) were longer (by 3–8 ms) than latencies of peripheral receptive fields (>10°). Latencies of yellow-off inputs to BON cells lagged the blue-on inputs by up to 30 ms, but no differences in visual latency were seen on comparing marmosets expressing dichromatic (“red-green color-blind”) or trichromatic color vision phenotype. We conclude that S-cone signals leaving the LGN on KC pathways are delayed with respect to signals traveling on PC and MC pathways. Cortical circuits serving color vision must therefore integrate across delays in (red-green) chromatic signals carried by PC cells and (blue-yellow) signals carried by KC cells.

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Ye, Qiaona, Kezheng Xu, Zidong Chen, et al. "Early impairment of magnocellular visual pathways mediated by isolated-check visual evoked potentials in primary open-angle glaucoma: a cross-sectional study." BMJ Open Ophthalmology 9, no. 1 (2024): e001463. http://dx.doi.org/10.1136/bmjophth-2023-001463.

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ObjectiveTo explore different performances in the magnocellular (MC) and parvocellular (PC) visual pathways in patients with primary open-angle glaucoma (POAG) and to objectively assess impairment in early stage of POAG.Methods and analysisThis is a cross-sectional study. MC and PC visual pathways were assessed using isolated-check visual evoked potential (ic-VEP). Visual acuity, intraocular pressure, fundus examination, optical coherence tomography and visual field were measured. Signal-to-noise ratios (SNRs), mediated by ic-VEP were recorded. The Spearman’s correlation analysis was used to estimate the relationships between visual functions and structures. Receiver-operating-characteristic (ROC) curves were used to estimate the accuracy in detection of early POAG.Results60 participants (30 early POAG eyes and 30 age-matched control subjects) were recruited. MC visual pathway showed a non-linear response function, while PC visual pathway was a linear response function as contrast increased. Early POAG eyes exhibited significantly weaker initial contrast gains and lower maximum responses in the MC visual pathway (p=0.001, p=0.004, respectively). The SNRs at 8% and 32% depths of modulation (DOM) were significantly correlated with temporal-side retinal nerve fibre layer (RNFL) thickness in early POAG in MC-biased stimulation (p=0.017, p=0.020, respectively). The areas under ROC of 16% DOM were 0.780 (sensitivity 80.0%, specificity 63.3%) with the cut-off SNR of 2.07.ConclusionsThe MC visual pathway was damaged in the early stage of POAG. The SNRs at 8% and 32% DOM of MC-biased stimulation were significantly correlated with temporal-side RNFL thickness in early POAG, which helped in understanding the mechanisms of visual impairment in the early stage of POAG.

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Findlay, John M., and Robin Walker. "A model of saccade generation based on parallel processing and competitive inhibition." Behavioral and Brain Sciences 22, no. 4 (1999): 661–74. http://dx.doi.org/10.1017/s0140525x99002150.

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During active vision, the eyes continually scan the visual environment using saccadic scanning movements. This target article presents an information processing model for the control of these movements, with some close parallels to established physiological processes in the oculomotor system. Two separate pathways are concerned with the spatial and the temporal programming of the movement. In the temporal pathway there is spatially distributed coding and the saccade target is selected from a “salience map.” Both pathways descend through a hierarchy of levels, the lower ones operating automatically. Visual onsets have automatic access to the eye control system via the lower levels. Various centres in each pathway are interconnected via reciprocal inhibition. The model accounts for a number of well-established phenomena in target-elicited saccades: the gap effect, express saccades, the remote distractor effect, and the global effect. High-level control of the pathways in tasks such as visual search and reading is discussed; it operates through spatial selection and search selection, which generally combine in an automated way. The model is examined in relation to data from patients with unilateral neglect.

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Khairunnisa, Aulia. "Homonymous Hemianopia dan Stroke: Aspek Visual dari Penyakit Serebrovaskular." Majalah Kesehatan Indonesia 2, no. 2 (2021): 45–48. http://dx.doi.org/10.47679/makein.202129.

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Visual impairment due to stroke impacts quality of life and causes loss of vision pathways and depression. Vascular occlusion in afferent or efferent visual pathways can cause a myriad of effects. Homonymous hemianopia is a visual field list that, if there is a lesion in one area, can cause visual disturbances. Vascular causes are the most common cause of lesion occlusion in the retro chiasmal visual pathway. Clinical manifestations can include blindness of one eye, bitemporal hemianopia, binasal hemianopia, hemianopia homonym dextra / left. In the history, the patient often complains of crashing while walking, tripping easily, reduced visual fields, especially difficulty while driving. Visual field tests in the form of confrontation, campimeter or perimeter tests, sometimes a head CT-scan radiological examination is needed to help see any small infarction/mass. Stroke is the most common cause. Homonymous hemianopia, cerebrovascular involvement can be identified by knowing the anatomy of the optic tract, including monocular visual loss due to prechiasmal ischaemia, bitemporal hemianopia due to chiasmal ischaemia, Eefferent visual dysfunction due to lesions outside the afferent visual pathways. Gangguan penglihatan akibat stroke berdampak pada kualitas kehidupan dan menyebabkan hilangnya jaras penglihatan dan depresi. Oklusi vaskular pada jalur visual aferen atau eferen dapat menyebabkan banyak sekali efek. Homonymus hemianopia merupakan dafek lapang pandang yang apabila terdapat lesi disuatu bagian dapat menyebabkan gangguan penglihatan. Penyebab vaskular menjadi penyebab tersering oklusi lesi pada jalur visual retrochiasmal. Manifestasi klinis dapat berupa kebutaan satu mata, hemianopia bitemporal, hemianopia binasal, hemianopia homonim dextra/sinistra.Pada anamnesis yan sering dikeluhkan pasien sering menabrak saat berjalan, mudah tersandung, lapang pandang berkurang, terutama kesulitan saat berkendara. Uji lapang pandang berupa uji konfrontasi, kampimeter atau perimeter, terkadang dibutuhkan pemeriksaan radiologi CT-Scan kepala untuk membantu melihat adanya infark/massa yang kecil. Stroke merupakan penyebab tersering Homonymus hemianopia, keterlibatan serebrovaskular dapat diketahui lokasinya dengan mengetahui anatomi dari traktus optikus, diantaranya monocular visual loss due to prechiasmal ischaemia, Bitemporal hemianopia due to chiasmal ischaemia, Efferent visual dysfunction due to lesions outside the afferent visual pathways.

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Freud, Erez, Marlene Behrmann, and Jacqueline C. Snow. "What Does Dorsal Cortex Contribute to Perception?" Open Mind 4 (August 2020): 40–56. http://dx.doi.org/10.1162/opmi_a_00033.

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According to the influential “Two Visual Pathways” hypothesis, the cortical visual system is segregated into two pathways, with the ventral, occipitotemporal pathway subserving object perception, and the dorsal, occipitoparietal pathway subserving the visuomotor control of action. However, growing evidence suggests that the dorsal pathway also plays a functional role in object perception. In the current article, we present evidence that the dorsal pathway contributes uniquely to the perception of a range of visuospatial attributes that are not redundant with representations in ventral cortex. We describe how dorsal cortex is recruited automatically during perception, even when no explicit visuomotor response is required. Importantly, we propose that dorsal cortex may selectively process visual attributes that can inform the perception of potential actions on objects and environments, and we consider plausible developmental and cognitive mechanisms that might give rise to these representations. As such, we consider whether naturalistic stimuli, such as real-world solid objects, might engage dorsal cortex more so than simplified or artificial stimuli such as images that do not afford action, and how the use of suboptimal stimuli might limit our understanding of the functional contribution of dorsal cortex to visual perception.

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Newman, Nancy J., and Valérie Biousse. "Approach to Vision Loss." CONTINUUM: Lifelong Learning in Neurology 31, no. 2 (2025): 328–55. https://doi.org/10.1212/con.0000000000001546.

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ABSTRACT OBJECTIVE Diagnosing and differentiating among the many possible localizations and causes of vision loss is an essential skill for neurologists. This article outlines the examination of the eye and visual pathways and the differential diagnosis of pathophysiologic processes that can affect visual function. LATEST DEVELOPMENTS The eyes, optic nerves, and intracranial pathways of vision account for more than one-third of the volume of the human brain, and patients with vision loss are commonly seen by both eye care specialists and neurologists. A basic examination of the eye and visual pathways allows the neurologist to localize the abnormality causing the vision impairment and generate a differential diagnosis of the potential pathophysiologic processes that can cause a vision problem at that particular location. Neurologists should be aware of the many ocular causes of vision loss and recognize when a visual problem is not the result of an optic neuropathy or brain parenchymal lesion. The standard bedside examination of the visual system can be augmented using specialized ancillary testing of visual pathway structure and function, which is most often the purview of eye care specialists, although portable instruments such as small visual field machines and nonmydriatic ocular fundus imaging can be easily used in hospitals and neurology clinics. ESSENTIAL POINTS The approach to vision loss should include a history and examination geared toward localization, followed by a differential diagnosis based on the likely location of the pathophysiologic process. Coordinated care between neurologists and eye care specialists is essential for patients with optic neuropathy or other lesions of the intracranial pathways.

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Journal articles on the topic 'Visual pathways'

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