The contribution of the corpus callosum to receptive fields in the lateral suprasylvian visual areas of the cat

Marzi, Carlo Alberto; Antonini, Antonella; Stefano, M. Di; Legg, Charles

doi:10.1016/0166-4328(82)90070-5

Cited by 32 publications

(16 citation statements)

References 67 publications

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“…It should be added that the primary visual areas also receive callosal input from nonprimary visual areas, in particular areas 19, 21, and the suprasylvian complex (Segraves and Rosenquist 1982; Segraves and Innocenti 1985). The present data do not allow inferences on the role of these heterotopic inputs on areas 17 and 18 nor can they be safely generalized to callosal connections in extrastriate visual areas where they seem to contribute to a substantial part of the receptive fields (Gross et al 1977; Marzi et al 1982). …”

Section: Discussioncontrasting

confidence: 65%

Specificity of Neuronal Responses in Primary Visual Cortex Is Modulated by Interhemispheric CorticoCortical Input

2010

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Within the visual cortex, it has been proposed that interhemispheric interactions serve to re-establish the continuity of the visual field across its vertical meridian (VM) by mechanisms similar to those used by intrinsic connections within a hemisphere. However, other specific functions of transcallosal projections have also been proposed, including contributing to disparity tuning and depth perception. Here, we consider whether interhemispheric connections modulate specific response properties, orientation and direction selectivity, of neurons in areas 17 and 18 of the ferret by combining reversible thermal deactivation in one hemisphere with optical imaging of intrinsic signals and single-cell electrophysiology in the other hemisphere. We found interhemispheric influences on both the strength and specificity of the responses to stimulus orientation and direction of motion, predominantly at the VM. However, neurons and domains preferring cardinal contours, in particular vertical contours, seem to receive stronger interhemispheric input than others. This finding is compatible with interhemispheric connections being involved in horizontal disparity tuning. In conclusion, our results support the view that interhemispheric interactions mainly perform integrative functions similar to those of connections intrinsic to one hemisphere.

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Section: Discussioncontrasting

confidence: 65%

Specificity of Neuronal Responses in Primary Visual Cortex Is Modulated by Interhemispheric CorticoCortical Input

2010

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“…Given the lack of effect of visual field and an effect of SOA that is approaching significance, one might question whether the ipsilateral visual field is a valid control for parietal stimulation sites. Abundant interhemispheric connections between the parietal cortices (Ffytche, Howseman, Edwards, Sandeman, & Zeki, 2000; Gross, Bender, & Mishkin, 1997; Marzi, Antonini, Di Stefano, & Legg, 1982) contribute to a less spatially precise topography in visual parietal areas as compared to that of the occipital cortex. Consistent with this neuroanatomy, parietal phosphenes are less precisely organized in retinotopic space than occipital phosphenes (Fried et al, 2011; Mazzi et al, under review ).…”

Section: Resultsmentioning

confidence: 99%

Phosphene-guided transcranial magnetic stimulation of occipital but not parietal cortex suppresses stimulus visibility

et al. 2014

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Transcranial magnetic stimulation (TMS) applied over the occipital lobe approximately 100 ms after the onset of a stimulus decreases its visibility if it appears in the location of the phosphene. Because phosphenes can also be elicited by stimulation of the parietal regions, we asked if the same procedure that is used to reduce visibility of stimuli with occipital TMS will lead to decreased stimulus visibility when TMS is applied to parietal regions. TMS was randomly applied at 0 to 130 ms after the onset of the stimulus (SOA) in steps of 10 ms in occipital and parietal regions. Participants responded to the orientation of the line stimulus and rated its visibility. We replicate previous reports of phosphenes from both occipital and parietal TMS. As previously reported, we also observed visual suppression around the classical 100 ms window both in the objective line orientation and subjective visibility responses with occipital TMS. Parietal stimulation, on the other hand, did not consistently reduce stimulus visibility in any time window.

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“…Although abnormal callosal connections between primary visual cortices seem to cause the deficit in depth perception in strabismus, callosal connections between suprasylvian areas of strabismics (Di Stefano et al ., 1991) and Siamese cats (Marzi et al ., 1980, 1982; Zeki & Fries, 1980) appear to contribute to the preserved cortical binocularity in these areas, where RFs are much larger than in primary visual areas and binocular units display disparate but still overlapping receptive fields (Von Grunau, 1982; Marzi et al ., 1986; Grant & Berman, 1991; Sireteanu & Best, 1992). Differences in connectivity might account for the different susceptibility of both areas to strabismus; while striate cortex receives its main input from the lateral geniculate nucleus, a structure that is markedly affected by strabismus, suprasylvian areas receive major inputs from extrageniculate pathways, particularly from the superior colliculus, which is only weakly affected by eye deviation (Gordon & Gummow, 1975).…”

Section: Discussionmentioning

confidence: 99%

Visual interhemispheric transfer to areas 17 and 18 in cats with convergent strabismus

Milleret

Houzel²

2001

Eur J of Neuroscience

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Commissural connections between primary visual cortical maps of the two hemispheres are essential to unify the split representation of the visual field. In normal adult cats, callosal connections are essentially restricted to the border between areas A17 and A18, where the central vertical meridian is projected. In contrast, early convergent strabismus leads to an expanded callosal-receiving zone, as repeatedly indicated by anatomical experiments. We investigated here the functional correlates of this widespread distribution of callosal terminals by analysing transcallosal visual responses in five anaesthetized and paralysed 4-10-month-old cats whose right eye had been surgically deviated on postnatal day 6. After acute section of the optic chiasm, single-unit activity was recorded from A17 and A18 of the right hemisphere while the left eye was visually stimulated. A total of 108/406 units were transcallosally activated. While they were more frequent at the 17/18 border (46% of the units recorded within this region), numerous transcallosally activated units were located throughout A17 (16%), A18 (27%) or within the white matter (17%). In all regions, transcallosally driven units displayed functional deficits usually associated with strabismus, such as decreased binocularity and ability to respond to fast-moving stimuli, and increased receptive field size. Many units also displayed reduced orientation selectivity and increased position disparity. In addition, transcallosal receptive fields were manifestly located within the hemifield ipsilateral to the explored cortex, with almost no contact with the central vertical meridian. Comparison with data from normal adults revealed that strabismus induced a considerable expansion of the callosal receiving zone, both in terms of the cortical region and of the extent of the visual field involved in interhemispheric transfer, with implications in the integration of visual information across the hemispheres.

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The contribution of the corpus callosum to receptive fields in the lateral suprasylvian visual areas of the cat

Cited by 32 publications

References 67 publications

Specificity of Neuronal Responses in Primary Visual Cortex Is Modulated by Interhemispheric CorticoCortical Input

Specificity of Neuronal Responses in Primary Visual Cortex Is Modulated by Interhemispheric CorticoCortical Input

Phosphene-guided transcranial magnetic stimulation of occipital but not parietal cortex suppresses stimulus visibility

Visual interhemispheric transfer to areas 17 and 18 in cats with convergent strabismus

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