Journal articles: 'Opercular'

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Bouthillier, Alain, Werner Surbeck, Alexander G. Weil, Tania Tayah, and Dang K. Nguyen. "The Hybrid Operculo-Insular Electrode." Neurosurgery 70, no. 6 (December 19, 2011): 1574–80. http://dx.doi.org/10.1227/neu.0b013e318246a3b7.

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Abstract BACKGROUND: Precise localization of an epileptic focus in the perisylvian/insular area is a major challenge. The difficult access and the high density of blood vessels within the sylvian fissure have lead to poor coverage of intrasylvian (opercular and insular) cortex by available electrodes. OBJECTIVE: To report the creation of a novel electrode designed to record epileptic activity from both the insular cortex and the hidden surfaces of the opercula. METHODS: The hybrid operculo-insular electrode was fabricated by Ad-Tech Medical Instrument Corporation (Racine, Wisconsin). It was used in combination with regular subdural and depth electrodes for long-term intracranial recordings. The hybrid electrode, which contains both a depth and a strip (opercular) component, is inserted after microsurgical opening of the sylvian fissure. The depth component is implanted directly into the insular cortex. The opercular component has 1 or 2 double-sided recording contacts that face the hidden surfaces of the opercula. RESULTS: The hybrid operculo-insular electrode was used in 5 patients. This method of invasive investigation allowed including (2 patients) or excluding (3 patients) the insula as part of the epileptic focus and the surgical resection. It also allowed extending the epileptogenic zone to include the hidden surface of the frontal operculum in 1 patient. There were no complications related to the insertion of this new electrode. CONCLUSION: The new hybrid operculo-insular electrode can be used for intracranial investigation of perisylvian/insular refractory epilepsy. It can contribute to increasing cortical coverage of this complex region and may allow better definition of the epileptic focus.

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MARKOVIĆ, VANJA, VUKICA VUJIĆ, MARIJA ILIĆ, JELENA TOMOVIĆ, VERA NIKOLIĆ, and TAMARA KARAN-ŽNIDARŠIČ. "Operculum shape variation in Theodoxus Montfort, 1810 (Gastropoda: Neritidae)." Zootaxa 4560, no. 3 (February 26, 2019): 563. http://dx.doi.org/10.11646/zootaxa.4560.3.8.

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The operculum morphology of neritid snails of genus Theodoxus Montfort, 1810 yields important species-specific taxonomic characters. This study is the first attempt to describe morphological differences in snails based on operculum shapes using a geometric morphometric approach. We examined the variability of opercular shapes between sexes and among populations and species based on 91 opercula of adult specimens belonging to six populations of three species of Theodoxus from the central Balkan and the southern border of the Pannonian plain. There are no sex-related differences in operculum shape and size in the studied species. The presence of shape variations influenced by size (allometry) was confirmed for T. danubialis (C. Pfeiffer, 1828) indicating that allometry could be a component of the morphological variation of this species. At the intraspecific level, phenotypic plasticity of operculum shape was found in T. danubialis and T. fluviatilis (Linnaeus, 1758). Of particular interest is the lack of morphological variability in the rare and endangered T. transversalis (C. Pfeiffer, 1828). At the species level a clear morphological distinction of T. fluviatilis from T. danubialis and T. transversalis was detected, confirming that the operculum with a rib could be used as a species-specific morphological character. The main morphological differences between species are an outwardly-stretched opercular/apophysal rib and a shortened tip of the opercular plate in T. fluviatilis, compared to the same structures in T. danubialis and T. transversalis.

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Majima, Ryuichi. "Life positions of fossil naticid opercula (Mollusca: Gastropoda)." Journal of Paleontology 61, no. 1 (January 1987): 62–65. http://dx.doi.org/10.1017/s0022336000028201.

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Two life positions of fossil naticid opercula are recognized in Pliocene deposits of Hokkaido, northern Japan. In one position, the operculum seals the aperture. In the other position, the operculum is pressed against the shell base adjacent to the aperture. The death position of the head-foot mass can be reconstructed from the two opercular positions, which coincide, respectively, to naticids that died with the head-foot mass retracted into the shell, and those that died with it entirely extended from the shell.

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Tetlie, O. Erik, and Simon J. Braddy. "The first Silurian chasmataspid, Loganamaraspis dunlopi gen. et sp. nov. (Chelicerata: Chasmataspidida) from Lesmahagow, Scotland, and its implications for eurypterid phylogeny." Transactions of the Royal Society of Edinburgh: Earth Sciences 94, no. 3 (September 2003): 227–34. http://dx.doi.org/10.1017/s0263593300000638.

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ABSTRACTA new chasmataspid (Chelicerata: Chasmataspidida) is described from the Early Silurian (Late Llandovery–Early Wenlock) of Lesmahagow, Scotland, as Loganamaraspis dunlopi gen. et sp. nov. It is distinguished from related forms by the low tapering ratio of the postabdomen, pediform sixth prosomal appendage and a heart-shaped metastoma. Additionally, a genital operculum with a genital appendage is preserved. The recognisable morphology of L. dunlopi gen. et sp. nov. bridges some of the gap between the Ordovician Chasmataspididae and the Devonian Diploaspididae. Traces of the gut are reported for the first time from a chasmataspid. Chasmataspids are regarded as sister group to the eurypterids: an anterior opercular plate anterior to the genital appendage in L. dunlopi gen. et sp. nov. is regarded as homologous to the anterior opercular plate of the three-segmented genital operculae of Dolichopterus and Stylonurina. This is considered a plesiomorphic character within Eurypterida, whilst the two-segmented genital operculum (with deltoid plates) of Eurypterina is considered apomorphic.

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Checa, Antonio G., and Antonio P. Jiménez-Jiménez. "Constructional morphology, origin, and evolution of the gastropod operculum." Paleobiology 24, no. 1 (1998): 109–32. http://dx.doi.org/10.1017/s0094837300020005.

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Gastropod opercula are classified here on a new morphogenetic basis, which distinguishes three main types: (1) flexiclaudent spiral (mostly multispiral) operculum, the shape of which does not coincide with that of the aperture, (2) rigiclaudent spiral (usually paucispiral) operculum, the shape of which fits that of the aperture, and (3) rigiclaudent concentric operculum, also aperture-fitting. The first type fits by flexing into the aperture and is secreted when the soft parts are partly or wholly extended (i.e., when the operculum is not in a closed position). The other two types do not flex upon retraction (except at the very margin) and grow when the operculum closes over the aperture, with or without rotation. A study of opercular types at the family level confirms the systematic and evolutionary significance of opercula. Types 1 and 2 are the only ones present in archaeogastropods, Type 1 being predominant. Opercula (if present) in Neritopsina are always rigiclaudent. Within Caenogastropoda, Type 2 predominates; the only flexiclaudent spiral opercula are found in certain basal cerithioidean families. Concentric opercula are predominant in higher neotaenioglossans and exclusive in neogastropods. Except for one family, opercula in Heterostropha are always rigiclaudent spiral. Morphological, systematic, and histological criteria point to the flexiclaudent spiral operculum as the ancestral form. This leads us to propose the “periostracum shaving” model in prosobranchs to account for the origin of this kind of operculum. According to this model, in the earliest trochospiral gastropods the periostracum ceased to serve a shell-formation function at the band of overlap between whorls (the parietal band). The periostracal band was then extruded from the shell to constitute an incipient operculum, taking on the appearance of a spiral strip coiling opposite to the shell. The parietal segment of the periostracal groove migrated toward the epipodium and became independent from the rest of the mantle. The concomitant development of an opercular disc allowed the successive turns of periostracal strip to seal together. In this way, a spiral operculum emerged, coiling counterclockwise without matching the aperture shape. During the course of prosobranch evolution, rigiclaudent spiral opercula emerged several times from the ancestral flexiclaudent type, although they were always restricted to apertures with a spiral-shaped outer (labral) edge. Such opercula enlarged the range of shell morphologies for which the operculum constituted an efficient protective barrier to include those of neritoidean or naticoidean type. The onset of calcification in opercula took place with the rigiclaudent type. Concentric opercula also evolved independently from rigiclaudent spiral opercula in several gastropod groups, thus further broadening the spectrum of apertures and, hence, of shell morphologies using opercula for protection. From the standpoint of adaptation, the concentric type was probably the only one available to neogastropods having long and wide siphonal canals.

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Bakar, M., H. S. Kirshner, and F. Niaz. "The Opercular-Subopercular Syndrome: Four Cases with Review of the Literature." Behavioural Neurology 11, no. 2 (1998): 97–103. http://dx.doi.org/10.1155/1998/423645.

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We present four cases of the ‘opercular syndrome’ of volitional paresis of the facial, lingual, and laryngeal muscles (bilateral facio-glosso-pharyngo-masticatory paresis). Case histories and CT brain images are presented, along with a review of the literature concerning this long-recognized but little-known syndrome. The neuroanatomic basis of the syndrome classically involves bilateral lesions of the frontal operculum. We propose, on the basis of our cases and others, that the identical syndrome can arise from lesions of the corticobulbar tracts, not involving the cortical operculum. Our cases included one with bilateral subcortical lesions, one with a unilateral left opercular lesion and a possible, non-visualized right hemisphere lesion, one with unilateral cortical and unilateral subcortical pathology, and one with bilateral cortical lesions. These lesion localizations suggest that any combination of cortical or subcortical lesions of the operculum or its connections on both sides of the brain can produce a syndrome indistinguishable from the classical opercular syndrome. We propose the new term ‘opercular-subopercular syndrome’ to encompass cases with predominantly or partially subcortical lesions.

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Milanlioglu, Aysel, Mehmet Nuri Aydın, Alper Gökgül, Mehmet Hamamcı, Mehmet Atilla Erkuzu, and Temel Tombul. "Ischemic Bilateral Opercular Syndrome." Case Reports in Medicine 2013 (2013): 1–3. http://dx.doi.org/10.1155/2013/513572.

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Opercular syndrome, also known as Foix-Chavany-Marie syndrome, is a paralysis of the facial, pharyngeal, masticatory, tongue, laryngeal, and brachial muscles. It is a rare cortical form of pseudobulbar palsies caused by vascular insults to bilateral operculum. Its clinical presentations include anarthria, weakness of voluntary muscles involving face, tongue, pharynx, larynx, and masticatory muscles. However, autonomic reflexes and emotional activities of these structures are preserved. In the present case, an 81-year-old male presented with acute onset of anarthria with difficulties in chewing, speaking, and swallowing that was diagnosed with opercular syndrome.

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S, Sajan. "Record Of Semi-Operculum Deformity In Sahyadria Denisonii (Teleostei: Cyprinidae)." Aquaculture & Fisheries 4, no. 1 (May 6, 2020): 1–3. http://dx.doi.org/10.24966/aaf-5523/100029.

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Semi-operculum deformity was recorded in a wild specimen of Sahyadria denisonii from Western Ghats, India. Morphological study of a normal and deformed fish revealed semi-operculum malformation. The possible etiologies of opercular deformity are discussed.

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Murrills, R. J., T. A. J. Reader, and V. R. Southgate. "Studies on the invasion of Notocotylus attenuates (Notocotylidae: Digenea) into its snail host, Lymnaea peregra. In vitro observations on the hatching mechanism of the egg." Parasitology 91, no. 3 (December 1985): 545–54. http://dx.doi.org/10.1017/s0031182000062788.

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SUMMARYMedia are described which stimulate the eggs of Notocotylus attenuatus to hatch in vitro. Hatching involves opening of the operculum and emergence of the opercular cord to form a tube measuring approximately 75 μm in length along which the sporocyst passes. The sporocyst is then released from the end of the tube. It is suggested that in vivo the opercular cord serves to inject the sporocyst through the snail host's gut wall into the haemocoel.

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Scheide, J. I., and J. A. Zadunaisky. "Effect of atriopeptin II on isolated opercular epithelium of Fundulus heteroclitus." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 254, no. 1 (January 1, 1988): R27—R32. http://dx.doi.org/10.1152/ajpregu.1988.254.1.r27.

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The effect of atriopeptin II (ANF) on the in vitro opercular epithelium was investigated by use of short-circuit current techniques. Serosal addition of ANF stimulates chloride secretion (short-circuit current) 19% above control values with a 7% increase in tissue conductance. Mucosal addition of ANF to the opercular epithelium was without effect. The ANF stimulation of the current was dose dependent with a maximum at 10(-7) M. The addition of ANF had no effect on the current or the conductance of opercular epithelia bathed in Cl--free Ringer. The opercular current could be stimulated above the ANF response by isoproterenol (10(-6) M). Pretreatment of the opercular epithelium with propranolol (10(-5) M) did not inhibit the stimulation of the short-circuit current by ANF but did inhibit the isoproterenol response indicating that the ANF stimulatory activity was independent of the beta-adrenergic receptors. The ANF-stimulated short-circuit current was found in operculi pretreated with tetrodotoxin (10(-6) or 10(-5) M) or diltiazem (10(-4) M) indicating the ANF response was not due to nerve stimulation. Pretreatment of opercular tissue with dibutyryl adenosine 3',5'-cyclic monophosphate, 8-bromoadenosine 3',5'-cyclic monophosphate, or 8-bromoguanosine 3',5'-cyclic monophosphate (10(-4) M) had no effect on the ANF stimulatory response. Opercular epithelia from short-term freshwater-adapted killifish also showed the ANF-induced response. The stimulation of chloride secretion in Fundulus heteroclitus chloride cells by ANF may have a role in teleost ion regulation.

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PILLAI, T. GOTTFRIED. "Knightjonesia, a new genus (Polychaeta: Spirorbidae) with a winged opercular peduncle, and its taxonomy." Zootaxa 2059, no. 1 (April 1, 2009): 46–50. http://dx.doi.org/10.11646/zootaxa.2059.1.4.

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It had hitherto been assumed in publications on serpulimorph systematics that spirorbids are characterized by an operculum borne on a wingless peduncle. However, while examining various spirorbid collections in the Natural History Museum, London, it was found that the type specimens of Helicosiphon platyspira Knight-Jones, 1978 possess a winged opercular peduncle, a character that had hitherto been used to distinguish between other serpulimorph genera. Accordingly, Helicosiphon platyspira is transferred to a new genus, Knightjonesia, in which the opercular peduncle is winged, in contrast with Helicosiphon in which it is wingless.

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Madani, Nadine, Jennifer A. O’Malley, Brenda E. Porter, and Fiona M. Baumer. "Lacosamide-Induced Dyskinesia in Children With Intractable Epilepsy." Journal of Child Neurology 35, no. 10 (June 11, 2020): 662–66. http://dx.doi.org/10.1177/0883073820926634.

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Lacosamide, an antiepileptic drug prescribed for children with refractory focal epilepsy, is generally well tolerated, with dose-dependent adverse effects. We describe 4 children who developed a movement disorder in conjunction with the initiation and/or uptitration of lacosamide. Three patients developed dyskinesias involving the face or upper extremity whereas the fourth had substantial worsening of chronic facial tics. The patients all had histories suggestive of opercular dysfunction: 3 had seizure semiologies including hypersalivation, facial and upper extremity clonus while the fourth underwent resection of polymicrogyria involving the opercula. Onset, severity, and resolution of dyskinesias correlated with lacosamide dosing. These cases suggest that pediatric patients with dysfunction of the opercular cortex are at increased risk for developing drug-induced dyskinesias on high-dose lacosamide therapy. Practitioners should be aware of this potential side effect and consider weaning lacosamide or video electroencephalography (EEG) for differential diagnosis, particularly in pediatric patients with underlying opercular dysfunction.

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Richardson, Jo, Takanori Shono, Masataka Okabe, and Anthony Graham. "The presence of an embryonic opercular flap in amniotes." Proceedings of the Royal Society B: Biological Sciences 279, no. 1727 (June 2011): 224–29. http://dx.doi.org/10.1098/rspb.2011.0740.

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The operculum is a large flap consisting of several flat bones found on the side of the head of bony fish. During development, the opercular bones form within the second pharyngeal arch, which expands posteriorly and comes to cover the gill-bearing arches. With the evolution of the tetrapods and the assumption of a terrestrial lifestyle, it was believed that the operculum was lost. Here, we demonstrate that an embryonic operculum persists in amniotes and that its early development is homologous with that of teleosts. As in zebrafish, the second pharyngeal arch of the chick embryo grows disproportionately and comes to cover the posterior arches. We show that the developing second pharyngeal arch in both chick and zebrafish embryos express orthologous genes and require shh signalling for caudal expansion. In amniotes, however, the caudal edge of the expanded second arch fuses to the surface of the neck. We have detailed how this process occurs and also demonstrated a requirement for thyroid signalling here. Our results thus demonstrate the persistence of an embryonic opercular flap in amniotes, that its fusion mirrors aspects of amphibian metamorphosis and gives insights into the origin of branchial cleft anomalies in humans.

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Bubel, A., C. H. Thorp, Ruth H. Fenn, and D. Livingstone. "Opercular regeneration in Pomatoceros lamarckii Quatrefages (Polychaeta: Serpulidae). Differentiation of the operculum and deposition of the calcareous opercular plate." Journal of Zoology 1, no. 1 (August 20, 2009): 49–94. http://dx.doi.org/10.1111/j.1469-7998.1985.tb00068.x.

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Becker, P. Scott, Ann M. Dixon, and Juan C. Troncoso. "Bilateral opercular polymicrogyria." Annals of Neurology 25, no. 1 (January 1989): 90–92. http://dx.doi.org/10.1002/ana.410250115.

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Taubner, R. W., Anastasia M. Raymer, and Kenneth M. Heilman. "Frontal-Opercular Aphasia." Brain and Language 70, no. 2 (November 1999): 240–61. http://dx.doi.org/10.1006/brln.1999.2157.

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Yoshii, Fumihito, Hiromi Sugiyama, Kazuyuki Kodama, and Takahito Irino. "Foix-Chavany-Marie Syndrome due to Unilateral Anterior Opercular Damage with Contralateral Infarction of Corona Radiata." Case Reports in Neurology 11, no. 3 (November 21, 2019): 319–24. http://dx.doi.org/10.1159/000503856.

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Foix-Chavany-Marie syndrome (FCMS) is a rare type of pseudobulbar palsy characterized by automatic-voluntary dissociation of movements of the face, tongue, pharynx, and masticatory muscles. Most cases are due to bilateral ischemic lesions of the anterior operculum, but the syndrome has also been described after unilateral opercular damage, either isolated or associated with contralateral cortico-nuclear tract involvement. We report a patient with FCMS due to right anterior opercular lesion with contralateral infarction of the corona radiata. The patient presented with paralysis of the face and tongue with automatic and voluntary dissociation. To our knowledge, FCMS with this peculiar lesion topography has rarely been reported. We discuss the underlying mechanism with reference to MRI and diffusion tensor imaging.

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Anderson, DT, and JT Anderson. "Functional morphology of the balanomorph barnacles Tesseropora rosea (Krauss) and Tetraclitella purpurascens (Wood) (Tetraclitidae)." Marine and Freshwater Research 36, no. 1 (1985): 87. http://dx.doi.org/10.1071/mf9850087.

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Tesseropora rosea of eastern Australia inhabits exposed, wave-washed rocks, is an extension feeder in fast currents, and has monometric growth, with orifice enlargement by erosion. It has a deep, mobile operculum. Tergal depressor muscles are large, scutal depressors moderately large. The opercular valves play an active part in respiratory pumping beat. Tergal depressors effect opercular withdrawal. Rostral scutal depressors assist in pumping beat. Lateral scutal depressors assist in opercular opening. Cim IV-VI of T. rosea unfurl rapidly in response to fast water currents and are captorial, either singly or in concert. The antenniform third maxillipeds (cirrus 111) turn back laterally in the extended position but fold over and hold down the captorial cirri in the curled position. Tetraclitella purpurascens of southern Australia inhabits crevices and overhangs on rocky shores, is an extension feeder in moderate currents, and has diametric growth, with orifice enlargement by circumferential growth of radii and parietes. It has a shallow operculum with only slight mobility. Tergal depressors are large, scutal depressors small. Valve action is mainly hinge-like and slow, with little apicobasal movement. The small scutal depressors assist the large tergal depressors in opercular withdrawal and have only a very minor role in pumping beat. Cirri IV-VI of T. purpurascens are held erect for long periods in moderate water currents. Captorial movements are similar to but slower than those of T. rosea. The third maxillipeds have short rami involved in forward food transfer. Setation correlates with function on the cirri of both species. The oral cone of T. rosea is broader and the mouthparts relatively larger than those of T. purpurascens, possibly mediating a more powerful triturating mechanism. A comparison of structure and function shows that T. purpurascens retains many primitive balanomorph features, whereas T. rosea has a more advanced functional configuration. In the evolution of tetraclitids, it seems likely that the tetraclitellines diverged early, before the austrobalanines gave rise to the tetraclitines. The four-plated wall may have evolved independently in tetraclitellines and austrobalanines.

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Simone, Luiz Ricardo L. "Convergence with naticids: phenotypic phylogenetic study on some Antarctic littorinoideans, with description of the zerotulid new genusPseudonatica, and its presence in Brazil (Mollusca, Caenogastropoda)." Journal of the Marine Biological Association of the United Kingdom 98, no. 6 (March 20, 2017): 1365–81. http://dx.doi.org/10.1017/s002531541700025x.

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Some Antarctic littorinoideans have a remarkable convergence with Naticoidea in shell and operculum features. Two naticid-like species of that group are studied in their phenotypic features in order to improve their taxonomy and to discuss the meaning of that convergence, as the former are herbivore-detritivore and the latter active predatory organisms. One of the studied species is the littorinidLaevilacunaria antarctica(Martens, 1885). The other belongs to a new genus –Pseudonatica, with the type species also newly described:P. antarctica, the genus is tentatively placed in Zerotulidae. Another Pseudonatica is also described,P. ampullarica, based only on shells collected by Marion-Dufresne French expedition off Brazilian coast, this finding expands the occurrence of zerotulids northwards. Besides the similarities of shell and operculum, other structures of these Antarctic species also show singular similarities with naticoideans, such as the wide foot, the complexity of opercular attachment in pedal opercular pad, the wide oesophageal gland, and the coiled arrangement of the pallial oviduct. The phenotypic characters were coded and inserted in a previous large phylogenetic analysis on Caenogastropoda (Simone, 2011), furnishing a wide basis for discussion on the characters, taxonomic position, evolution and adaptations of these organisms.

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Naqash, Mohd Mubarik, Feroze Ahmad, Arif Nabi Bhat, and Umar Jalalie. "Bilateral anterior opercular syndrome." International Journal of Research in Medical Sciences 5, no. 9 (August 26, 2017): 4181. http://dx.doi.org/10.18203/2320-6012.ijrms20174008.

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Opercular syndrome, also known as Foix-Chavany-Marie syndrome is a rare disorder due to bilateral lesions of opercular cortex surrounding the insula. It is characterized by paralysis of facial, lingual, pharyngeal, and masticatory voluntary muscles with preservation of autonomic, involuntary, and reflexive functions. In the present case, a 71-years old female presented with acute onset of anarthria with difficulties in chewing, speaking, and swallowing that was diagnosed with opercular syndrome.

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Benninger, D. H., S. G. Mueller, V. Treyer, S. Kollias, A. Buck, and H. G. Wieser. "Transient epileptic opercular syndrome." Seizure 16, no. 3 (April 2007): 276–82. http://dx.doi.org/10.1016/j.seizure.2006.12.005.

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Hashemilar, Maziyar, Mirmohsen Sharifi-Bonab, and Homayoun Sadeghi-Bazargani. "Unilateral posterior opercular syndrome." American Journal of Case Reports, The 12 (2011): 14–18. http://dx.doi.org/10.12659/ajcr.881416.

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Bogousslavsky, J., K. Dizerens, F. Regli, and P. A. Despland. "Opercular Cheiro-oral Syndrome." Archives of Neurology 48, no. 6 (June 1, 1991): 658–61. http://dx.doi.org/10.1001/archneur.1991.00530180116027.

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Saidane, Hafed Amin, Helle Klingenberg Iversen, Hanne Søndergaard, and Faisal Mohammad Amin. "Importance of Rapid Clinical Recognition of the Anterior Opercular Syndrome (Foix-Chavany-Marie Syndrome): A Case Report." Case Reports in Neurology 13, no. 1 (March 10, 2021): 166–70. http://dx.doi.org/10.1159/000513110.

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We have described a 55-year-old woman with the anterior opercular syndrome (Foix-Chavany-Marie syndrome). The clinical presentation included acute onset of bilateral facial palsy and anarthria. Immediate MRI of the brain revealed acute ischemia in the right opercular region and sequelae after a previous infarction involving the left opercular region. The patient was treated with intravenous thrombolysis resulting in full recovery. The anterior opercular syndrome is rare, and the most common reason is sequential stroke. We emphasize the importance of recognizing this syndrome early, and in all cases, consulting a revascularization center immediately.

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Obana, William G., Kenneth D. Laxer, Philip H. Cogen, John A. Walker, Richard L. Davis, and Nicholas M. Barbaro. "Resection of dominant opercular gliosis in refractory partial epilepsy." Journal of Neurosurgery 77, no. 4 (October 1992): 632–39. http://dx.doi.org/10.3171/jns.1992.77.4.0632.

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✓ Frontal opercular gliosis in the dominant hemisphere caused medically refractory partial epilepsy in two patients. Both patients were aphasic during their seizures, but otherwise had normal speech. Magnetic resonance images showed well-demarcated lesions resembling tumors in each patient; on heavily T2-weighted images, the lesions were hyperintense compared with normal brain. Cortical mapping with subdural grids localized speech to the area of the lesions; therefore, the resections were performed under local anesthesia and speech was tested throughout the procedure. Postoperatively, both patients were seizure-free and had no new neurological deficits. Well-demarcated lesions, even in the dominant operculum, can be safely removed in patients with medically refractory partial epilepsy.

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Rolston, John D., Dario J. Englot, Arnau Benet, Jing Li, Soonmee Cha, and Mitchel S. Berger. "Frontal operculum gliomas: language outcome following resection." Journal of Neurosurgery 122, no. 4 (April 2015): 725–34. http://dx.doi.org/10.3171/2014.11.jns132172.

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OBJECT The dominant hemisphere frontal operculum may contain critical speech and language pathways, and due to these properties, patients with tumors of the opercular region may be at higher risk for postoperative speech dysfunction. However, the likelihood of incurring temporary or permanent language dysfunction is unknown. METHODS The authors retrospectively analyzed their cohort of patients with frontal gliomas to identify those tumors that predominantly involved the dominant frontal operculum. Each tumor was classified as involving the pars orbitalis, pars triangularis, pars opercularis, or a combination of some or all of these areas. The authors then identified and compared characteristics between those patients experiencing transient or permanent speech deficits, as opposed to those with no language dysfunction. RESULTS Forty-three patients were identified for inclusion in this analysis. Transient deficits occurred in 12 patients (27.9%), while 4 patients (9.8%) had persistent deficits involving language. Individuals with preoperative language deficits and patients with seizures characterized by speech dysfunction appear to be at the highest risk to develop a deficit (relative risks 3.09 and 1.75, respectively). No patient with a tumor involving the pars orbitalis experienced a persistent deficit. CONCLUSIONS Resection of gliomas is widely recognized as a critical element of improved outcome. Given the low rate of language morbidity reported in this group of patients, resection of gliomas within the dominant frontal operculum is well-tolerated with acceptable morbidity and, in this particular location, should not be a deterrent in the overall management of these tumors.

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Santos Lasaosa, Sonia, Teresa Casadevall Codina, Consuelo Ríos Gómez, Elena López García, Carlos Tejero Juste, Moisés Garcés Redondo, Óscar Fabre Pi, and Enrique Mostacero Miguel. "Síndrome opercular de etiología vascular." Revista de Neurología 34, no. 12 (2002): 1129. http://dx.doi.org/10.33588/rn.3412.2002043.

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28

Hadi, Ameer Shaker, Faiq I. Gorial, Qusay Abed Fahad, and Hayder Adnan Fawzi. "Foix-Chavany-Marie Opercular Syndrome." Turkish Journal Of Neurology 24, no. 4 (December 12, 2018): 342–43. http://dx.doi.org/10.4274/tnd.67355.

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Torres-Ramírez, Luis, Miriam Vélez-Rojas, Martha Flores-Mendoza, Carlos Cosentino-Esquerre, Jimmy Palacios-García, and Vanesa Ipurre-Guerra. "Síndrome opercular: Reporte de caso." Diagnóstico 58, no. 4 (February 9, 2020): 205–9. http://dx.doi.org/10.33734/diagnostico.v58i4.178.

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Presentamos un paciente con un síndrome opercular con síntomas y signos pseudobulbares bilaterales; la mayoría de casos presentan afectación de ambos hemisferios cerebrales, nuestro paciente tuvo afectación unilateral. Caso Clínico: Varón de 65 años, diestro, con antecedente de Hipertensión arterial, con un tiempo de enfermedad de un año y un mes de evolución, caracterizado por presentar en forma súbita monoparesia en miembro superior derecho, asimetría facial, anartria con compromiso pseudobulbar bilateral. En Resonancia Magnética se evidenció lesión isquémica del área opercular izquierda. Discusión: El síndrome opercular o biopercular conocido también como síndrome de Foix-Chavany-Marie, es una entidad poco frecuente caracterizada por la afectación del área opercular cerebral bilateral, que compromete la vía cortico-bulbar/protuberancial, es importante la presencia de la disociación motora automática-voluntaria y cuya etiología más frecuente en adultos es isquémica, como en nuestro caso. Se desconoce el motivo por el que una sola lesión puede producir afectación bilateral pseudobulbar, se postula una predominancia del haz cortico protuberancial/bulbar del hemisferio dominante. En los casos publicados el pronóstico no es favorable desde el punto de vista del lenguaje, pero en nuestro paciente hubo mejoría de la anartria, la deglución, masticación y fuerza muscular; recibió terapia física con buena evolución.

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30

Thomas, Pierre, Michel Borg, Georges Suisse, and Marcel Chatel. "Opercular Myoclonic-Anarthric Status Epilepticus." Epilepsia 36, no. 3 (March 1995): 281–89. http://dx.doi.org/10.1111/j.1528-1157.1995.tb00997.x.

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31

Scott, T. R., S. Yaxley, Z. J. Sienkiewicz, and E. T. Rolls. "Gustatory responses in the frontal opercular cortex of the alert cynomolgus monkey." Journal of Neurophysiology 56, no. 3 (September 1, 1986): 876–90. http://dx.doi.org/10.1152/jn.1986.56.3.876.

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The responses of 165 single taste neurons in the anterior operculum of the alert cynomolgus monkey were analyzed. Chemicals were deionized water, blackcurrant juice, and the four basic taste stimuli: glucose, NaCl, HCl, and quinine HCl. Taste-evoked responses could be recorded from an opercular region that measured approximately 4.0 mm in its anteroposterior extent, 2.0 mm mediolaterally, and 3.0 mm dorsoventrally. Within this area, taste-responsive neurons were sparsely distributed such that multiunit activity was rarely encountered and neuronal isolation was readily achieved. Intensity-response functions were determined for nine cells.In each case, the lowest concentration of the dynamic response range conformed well to human electrophysiological and psychophysical thresholds for the basic taste stimuli. There was some evidence of chemotopic organization. Cells that responded best to glucose tended to be distributed toward the anterior operculum, whereas most acid-sensitive neurons were located more posteriorly. The proportion of cells responding best to NaCl peaked in the middle of the area, whereas quinine sensitivity was rather evenly distributed throughout. Opercular neurons in the monkey showed moderate breadth of sensitivity compared with taste cells of other species and at other synaptic levels. A breadth-of-tuning coefficient was calculated for each neuron. This is a metric that can range from 0.0 for a cell that responds specifically to only one of the four basic stimuli to 1.0 for one that responds equally to all four stimuli. The mean coefficient for 165 cells in the operculum was 0.67 (range = 0.12-0.99). Efforts were made to determine whether neurons could be divided into a discrete number of types, as defined by their responsiveness to the stimulus array used here. It was concluded that most taste cells may be assigned to a small number of groups, each of which is statistically independent of the others, but within which the constituent neurons are not identical. An analysis of taste quality indicated that the sweet and salty stimuli evoked patterns of activity that were significantly intercorrelated. Similarly, patterns representing HCl, quinine HCl, and water were related.

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Wong, A., T. Chavez, S. O'Neil, J. Votava-Smith, D. Miller, S. delCastillo, A. Panigrahy, and L. Paquette. "Synchronous Aberrant Cerebellar and Opercular Development in Fetuses and Neonates with Congenital Heart Disease: Correlation with Early Communicative Neurodevelopmental Outcomes, Initial Experience." American Journal of Perinatology Reports 07, no. 01 (January 2017): e17-e27. http://dx.doi.org/10.1055/s-0036-1597934.

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AbstractPatients with congenital heart disease (CHD) demonstrate multidomain cognitive delays. Cingulo-opercular and cerebellar brain networks are critical to language functions. This is a description of our initial experience aiming to identify an anatomic correlate for CHD patients with expressive language delays. Fetal CHD patients, prospectively enrolled, underwent serial fetal (1.5T), postnatal pre- and postoperative (3T) MRI. Non-CHD patients were enrolled retrospectively from the same epoch. Comparable fetal and neonatal T2 contrast was used for manual linear cross-sectional measurement. Multivariable analysis was used for adjustments and curve fitting. Neurodevelopment was assessed with Battelle Developmental Inventory, 2nd ed. between 9 and 36 months of age. This interim analysis included patients from our longitudinal CHD study who had fetal, postnatal imaging and neurodevelopmental data—yielding a total of 62 mothers (11 CHD fetuses and 51 non-CHD fetuses). Altered brain trajectories were seen in selected cerebellar and opercular measurements in CHD patients compared with the non-CHD group. Smaller inferior cerebellar vermis measurements were associated with multiple communication-related abnormalities. Altered early structural development of the cerebellum and operculum is present in patients with CHD, which correlates with specific neurodevelopmental abnormalities.

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Kumabe, Toshihiro, Shuichi Higano, Shoki Takahashi, and Teiji Tominaga. "Ischemic complications associated with resection of opercular glioma." Journal of Neurosurgery 106, no. 2 (February 2007): 263–69. http://dx.doi.org/10.3171/jns.2007.106.2.263.

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Object Opercular glioma inferolateral to the hand/digit sensorimotor area can be resected safely using a neuronavigation system and functional brain mapping techniques. However, the surgery can still sometimes cause postoperative ischemic complications, the character of which remains unclear. The authors of this study investigated the occurrence of infarction associated with resection of opercular glioma and the arterial supply to this region. Methods The study involved 11 consecutive patients with gliomas located in the opercular region around the orofacial primary motor and somatosensory cortices but not involving either the hand/digit area or the insula, who had been treated in their department after 1997. Both pre- and postoperative diffusion-weighted magnetic resonance (MR) imaging was performed in the nine consecutive patients after 1998 to detect ischemic complications. All patients underwent open surgery for maximum tumor resection. Postoperative MR imaging identified infarction beneath the resection cavity in all patients. Permanent motor deficits associated with infarction involving the descending motor pathway developed in two patients. Cadaveric angiography showed that the distributing arteries to the corona radiata were the long insular arteries and/or medullary arteries from the opercular and cortical segments of the middle cerebral artery. Conclusions Subcortical resection around the upper limiting sulcus of the posterior region of the insula and wide resection in the anteroposterior and cephalocaudal directions of the opercular region were considered to be risk factors of the critical infarction. Surgeons should be aware that resection of opercular glioma can disrupt the blood supply of the corona radiata, and carries the risk of permanent motor deficits.

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Weller, Michael, Michael Poremba, and Johannes Dichgans. "Opercular syndrome without opercular lesions: Foix-Chavany-Marie syndrome in progressive supranuclear motor system degeneration." European Archives of Psychiatry and Neurological Sciences 239, no. 6 (November 1990): 370–72. http://dx.doi.org/10.1007/bf01734544.

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35

Cohen, Noga, Aya Ben-Yakov, Jochen Weber, Micah G. Edelson, Rony Paz, and Yadin Dudai. "Prestimulus Activity in the Cingulo-Opercular Network Predicts Memory for Naturalistic Episodic Experience." Cerebral Cortex 30, no. 3 (November 18, 2019): 1902–13. http://dx.doi.org/10.1093/cercor/bhz212.

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Abstract Human memory is strongly influenced by brain states occurring before an event, yet we know little about the underlying mechanisms. We found that activity in the cingulo-opercular network (including bilateral anterior insula [aI] and anterior prefrontal cortex [aPFC]) seconds before an event begins can predict whether this event will subsequently be remembered. We then tested how activity in the cingulo-opercular network shapes memory performance. Our findings indicate that prestimulus cingulo-opercular activity affects memory performance by opposingly modulating subsequent activity in two sets of regions previously linked to encoding and retrieval of episodic information. Specifically, higher prestimulus cingulo-opercular activity was associated with a subsequent increase in activity in temporal regions previously linked to encoding and with a subsequent reduction in activity within a set of regions thought to play a role in retrieval and self-referential processing. Together, these findings suggest that prestimulus attentional states modulate memory for real-life events by enhancing encoding and possibly by dampening interference from competing memory substrates.

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Sim, Valerie L., Alan Guberman, and Matthew J. Hogan. "Acute Bilateral Opercular Strokes Causing Loss of Emotional Facial Movements." Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 32, no. 1 (February 2005): 119–21. http://dx.doi.org/10.1017/s0317167100017005.

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The classic anterior opercular syndrome of Foix-Chavany-Marie presents with loss of voluntary facial, pharyngeal, lingual, and mastication movements, with preservation of emotional and automatic movements. Most commonly, sequential strokes affecting bilateral opercula cause this syndrome. The inverse clinical presentation, with selective loss of emotional facial movements, has only rarely been reported, and is less well-localized.Case report:We report a case of selective loss of emotional facial movements which resulted from bilateral acute infarcts. No etiology was discovered, and the syndrome was reversible.Discussion:The available literature, and findings in this case, suggest that voluntary and automatic facial movements have distinct pathways, and damage to the insula bilaterally may lead to the selective loss of emotional facial movements. The clinical presentation of this inverse automatic/voluntary dissocation needs to be recognized as a rare syndrome with bilateral localization, so that patients at higher risk of further stroke can quickly be identified.

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37

Geerinckx, Tom, Frank Huysentruyt, and Dominique Adriaens. "A descriptive myology of Corydoras aeneus (Gill, 1858) (Siluriformes: Callichthyidae), with a brief discussion on adductor mandibulae homologies." Animal Biology 57, no. 4 (2007): 433–52. http://dx.doi.org/10.1163/157075607782232170.

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AbstractCranial and postcranial myology of adult Corydoras aeneus is described and results discussed in comparison to other ostariophysan, siluriform and/or loricarioid fishes. Further, a brief discussion on m. adductor mandibulae homologies is given providing arguments for the use of the terminology proposed by Diogo and Chardon (2000) in future studies dealing with the myology of Siluriformes. Doing this, we here identified an A1OST, A2, and A′3 section in C. aeneus and recognised the homology of the m. retractor tentaculi muscle with the A″3. Next to this, the opercular system is discussed, focussing on similarities in this system in both a callichthyid (C. aeneus) and loricariid (Ancistrus cf. triradiatus) representative. In both these families, the m. dilatator operculi is enlarged and the direction of the operculo-hyomandibular articulation has shifted. In addition, in both lineages, the m. hyohyoidei abductor has also shifted its orientation, acting as an adductor. These similarities seem to corroborate the 'decoupling hypothesis' by Schaefer and Lauder (1986) in which a decoupling of elements in primitive members of a lineage leads to a higher morphological diversity within that lineage combined with the possible acquisition of new functions.

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Usman, M., J. A. Umaru, and A. A. Kigbu. "Acute toxicity of Jatropha curcas (barbados nut) latex extracts to Oreochromis niloticus juveniles." Tropical Freshwater Biology 29, no. 2 (April 29, 2021): 47–58. http://dx.doi.org/10.4314/tfb.v29i2.4.

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The effects of the latex extract of Jatropha curcas on mortality rate, opercular ventilation rate and some behavioural responses of Oreochromis niloticus juveniles were investigated under laboratory conditions over a 96 hours exposure period. Juveniles of Oreochromis niloticus (Trewavas) were exposed in plastic aquaria to 0.00mg.l-1 (control), 10mg.l-1, 15mg.l-1, 20mg.l-1, 25mg.l-1 and 30mg.l-1. Their opercular beats per minute, tail fin beats per minute, mortality and probit kill were determined. Symptoms of toxicosis observed include agitated swimming, loss of equilibrium, air gulping, periods of quiescence and death. Within 24 hours the opercular ventilation beats and tail fin beats of the exposed fish were significantly higher than in control fish (p<0.05). At 72 hours and 96 hours the opercular and tailfin beats in the control fish were significantly higher (P<0.05) than the exposed fish. The 96 hours LC50 was determined as 5.23 ml/l. Include significance of this study to conclude abstract. Key words: acute toxicity, Jatropha curcas latex extract, Oreochromis niloticus, haematological parameters.

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39

Gillardin, P., R. Van Eetvelde, T. Kostermans, R. De Potter, D. Dewilde, and M. Lemmerling. "Foix-Chavany-Marie or opercular syndrome." Journal of the Belgian Society of Radiology 98, no. 1 (February 1, 2015): 56. http://dx.doi.org/10.5334/jbr-btr.762.

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40

Coste, Clio P., and Andreas Kleinschmidt. "Cingulo-opercular network activity maintains alertness." NeuroImage 128 (March 2016): 264–72. http://dx.doi.org/10.1016/j.neuroimage.2016.01.026.

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41

Amir, Naomi, Orly El-Peleg, and Varda Gross. "Opercular sign: Significance beyond cerebral dysgenesis." Annals of Neurology 27, no. 2 (February 1990): 213–14. http://dx.doi.org/10.1002/ana.410270222.

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42

Amit, Rani, Yehuda Shapira, and Julia Berginer. "Significance of the open opercular sign." Annals of Neurology 27, no. 2 (February 1990): 214. http://dx.doi.org/10.1002/ana.410270223.

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43

Kakisaka, Yosuke, Masaki Iwasaki, Andreas V. Alexopoulos, Rei Enatsu, Kazutaka Jin, Zhong I. Wang, John C. Mosher, Anne-Sophie Dubarry, Dileep R. Nair, and Richard C. Burgess. "Magnetoencephalography in fronto-parietal opercular epilepsy." Epilepsy Research 102, no. 1-2 (November 2012): 71–77. http://dx.doi.org/10.1016/j.eplepsyres.2012.05.003.

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44

Ma˘rga˘rit, Monica, Valentin Radu, and Dragomir Nicolae Popovici. "From operculum to bead: Production of pearls from opercular bones ofCyprinus carpioin the Romanian Eneolithic." Environmental Archaeology 21, no. 4 (June 10, 2014): 351–60. http://dx.doi.org/10.1179/1749631414y.0000000019.

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45

SUN, YANAN, MANAL AL-KANDARI, PRITI KUBAL, NITIN WALMIKI, and ELENA K. KUPRIYANOVA. "Cutting a Gordian knot of tubeworms with DNA data: the story of the Hydroides operculata-complex (Annelida, Serpulidae)." Zootaxa 4323, no. 1 (September 20, 2017): 39. http://dx.doi.org/10.11646/zootaxa.4323.1.3.

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Hydroides operculata (Treadwell, 1929) was originally very briefly described from a single specimen as Eupomatus operculata, collected in the Gulf of Aden, Somalia. Later the species was reported from the Mediterranean as a potential Lessepsian migrant. The taxa Hydroides inornata Pillai (1960) from Sri Lanka, as well as H. basispinosa and H. gradata described by Straughan (1967) from Australia, were synonymised with H. operculata based only on their similar opercular morphology, making the latter species’ distribution to include South and East Africa, India, Pakistan, Sri Lanka, Hong Kong, tropical Australia, and the eastern Mediterranean. Here we examined the taxonomic status of H. operculata using standard molecular techniques to determine whether this species is a global invader, a complex of regionally distributed morphologically similar species, or a combination of both. The study revealed three well supported clades suggesting a natural phylogeographic pattern. Thus, we argue that the taxa H. inornata (India and Hong Kong) and H. basispinosa (Australia) should be re-instated to full species, but that the Australian H. gradata should be synonymised with H. basispinosa.

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Bichuette, Maria Elina, Mario César Cardoso de Pinna, and Eleonora Trajano. "A new species of Glaphyropoma: the first subterranean copionodontine catfish and the first occurrence of opercular odontodes in the subfamily (Siluriformes: Trichomycteridae)." Neotropical Ichthyology 6, no. 3 (2008): 301–6. http://dx.doi.org/10.1590/s1679-62252008000300002.

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A new species of the rare copionodontine genus Glaphyropoma is described from subterranean waters in the Diamantina Plateau, Bahia State, central northeastern Brazil. This is the first troglomorphic species in the subfamily Copionodontinae. It is distinguished from all other copionodontines by the presence of opercular odontodes, and further distinguished from its only congener, G. rodriguesi, by the reduction of dark integumentary pigmentation. The new species shares the single synapomorphy previously proposed for Glaphyropoma, the marked narrowing of the first hypobranchial and indirect character evidence also supports its inclusion in the genus. The presence of opercular odontodes in the new species, in combination with a reviewed hypothesis of sister group relationship between Copionodontinae and Trichogeninae, indicate that the absence of opercular odontodes in previously-known copionodontines is secondary, rather than primitive.

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Carvalho, V. S., L. M. Ribeiro, P. S. N. Lopes, C. O. Agostinho, L. J. Matias, M. O. Mercadante-Simões, and L. N. F. Correia. "Dormancy is modulated by seed structures in palms of the cerrado biome." Australian Journal of Botany 63, no. 5 (2015): 444. http://dx.doi.org/10.1071/bt14224.

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The aim of the present study was to evaluate the influence of the seed structures on the dormancy of the palms Attalea vitrivir Zona, Butia capitata (Mart.) Becc. and Acrocomia aculeata (Jacq.) Lodd. ex Mart., which are found in the cerrado biome (Brazilian savanna). The effects of seed structures on the imbibition and effects of the operculum on germination were evaluated. The effects of the collection area on the seed biometric characteristics and influence of the embryo mass and length on their germination capacity and vigour were also evaluated. The operculum was anatomically characterised, and the effects of the operculum thickness on seed germination were evaluated. The seed structures partially restricted water absorption by the embryos, but this did not affect germination; however, removing the operculum promoted germination. The mass of A. vitrivir and A. aculeata embryos positively influenced their germination capacity and vigour, and the thicknesses of the opercular seed coat and operculum negatively controlled the germination capacity of B. capitata. The greater thickness and rigidity of the operculum of A. aculeata increased the intensity of seed dormancy and possibly contributed to the wider distribution pattern of this species. The interaction between the embryo and operculum structures modulate the dormancy and possibly influence the distribution patterns of the palms in the cerrado biome.

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Rajput, Shweta, Nidhi Gupta, Vikram Khan, Arun Kumar Saxena, and V. D. Joshi. "Microtopography of the eggshell of Menacanthus eurysternus (Phthiraptera: Amblycera)." Journal of Applied and Natural Science 2, no. 1 (June 1, 2010): 111–13. http://dx.doi.org/10.31018/jans.v2i1.108.

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The egg laying sites, pattern and the egg morphology (SEM) of an amblyceran louse parasitizing Bank Myna (Acridotheres ginginianus) have been recorded. Unlike most of the species of the genus, Menacanthus studied so far, the eggshell of M. eurysternus lacks the apophyses (bristle like outgrowths arising from anterior portion of the eggshell). However, the opercular disc of M. eurysternus bears a polar thread and the micropyles are set along the opercular rim.

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WOSIACKI, WOLMAR BENJAMIN, DANIEL PIRES COUTINHO, and LUCIANO FOGAÇA DE ASSIS MONTAG. "Description of a new species of sand-dwelling catfish of the genus Stenolicmus (Siluriformes; Trichomycteridae)." Zootaxa 2752, no. 1 (January 31, 2011): 62. http://dx.doi.org/10.11646/zootaxa.2752.1.3.

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Stenolicmus ix, new species, is described from Igarapé Curuá, left tributary of the Rio Amazonas, Pará, Brazil. It can be distinguished from S. sarmientoi by the length of the nasal barbels that reach the base of the first opercular odontodes; length of the maxillary barbels that reach the posterior margin of the opercular odontode plate; seven well-developed opercular odontodes; seven well-developed interopercular odontodes; color pattern of the dorsal region of trunk composed of agglomerated chromatophores forming circular patches twice the diameter of the eye; proportionally large eyes, 11.8% HL; caudal peduncle tall, 11.6% SL, without dark bar at base of the caudal fin; length of the head proportionately larger, 17.9% SL; unbranched rays of caudal fin reaching distal margin of fin. Comparisons with other Sarcoglanidinae and Trichomycteridae are presented. Some comments on the systematics and phylogenetic relationships of the group are made.

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Al-Kadhomiy, N. K., and G. M. Hughes. "Histological study of different regions of the skin and gills in the mudskipper, Boleophthalmus boddarti with respect to their respiratory function." Journal of the Marine Biological Association of the United Kingdom 68, no. 3 (August 1988): 413–22. http://dx.doi.org/10.1017/s0025315400043319.

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Gills are the typical respiratory organ of fish in their usual habitat of well-aerated water. The transition from water- to air-breathing required many modifications to the structural and physiological adaptations of the gas-exchange surfaces, i.e. gill, skin, swimbladder and other accessory organs of the alimentary canal. The skin is particularly important among air-breathing fish. This histological study showed varying degrees of adaptation of parts of the skin from different body regions, paying particular attention to the water/blood barrier. The results suggest a general importance in gas exchange in the following order: gill, inner operculum, nasal, body and outer opercular skin, as indicated by increasing thickness of the water/blood barrier.

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Journal articles on the topic 'Opercular'

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