Perceptual Capacity of the Isolated Visual Cortex in the Cat

Abstract

The split-brain approach was utilized in 6 cats to test the degree of functional autonomy in the visual system. The central visual cortex of one hemisphere was isolated by the removal of most of the extravisual neocortex of the same hemisphere. Visual inflow was restricted to the isolated side in four cases by sectioning the crossed optic fibres at the chiasma and masking one eye and in two cases by section of the contralateral optic tract. The isolation produced severe deficits in visual performance, although all cases retained some ability to learn and to recall simple pattern discriminations. The results of two- and three-stage removals of the non-visual cortex, and of terminal section of the callosum, as well as histology of the lateral geniculate nucleus indicated that geniculo-striate damage was not the limiting factor. Removal of fronto-parietal cortex produced as much or more decrement in visual discrimination than did removal of temporal cortex.

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References

Chow

K. L.

Orbach

(1957). Performance of visual discriminations presented tachistoscopically in monkeys with temporal neocortical ablations. J. comp. physiol. 50, 636–40.

Downer

J. L.

(1958). Role of corpus callosum in transfer of training in Macaca mulatta. Fed. Proc. 17, 37.

Downer

J. L.

(1959). Relation of optic pathways and corpus callosum to visual tracking behaviour in monkey. Fed. Proc. 18, 38.

Franklin

Desmedt

J. E.

(1957). Sensibilisation progressive d'une aire corticale parteillement denervée à ses afferences residuelles. Compt. rend. 151, 2204–8.

Fulton

J. F.

(1955). Cerebral cortex and motor functions. Textbook of Physiology Philadelphia.

Lashley

K. S.

(1942). The mechanism of vision: XVII. Autonomy of the visual cortex. J. genet. Psychol. 60, 197–221.

Lashley

K. S.

(1950). In search of the engram. Symp. Soc. exp. Biol. 4, 454–82.

Myers

Ronald E.

(1955). Interocular transfer of pattern discrimination in cats following section of crossed optic fibers. J. comp. physiol. Psychol. 48, 470–3.

Myers

Ronald E.

(1956). Function of corpus callosum in interocular transfer. Brain 79, 358–63.

10.

Schrier

A. M.

Sperry

R. W.

(1959). Visual-motor integration in split-brain cats. Sci. 129, 1275–6.

11.

Smith

K. U.

Kappauf

W. E.

Bojar

(1940). The functions of the visual cortex in optic nystagmus at different velocities of movement in the visual field. J. gen. Physiol. 22, 341–57.

12.

Sperry

R. W.

(1959). Preservation of high-order function in isolated somatic cortex in callosum-sectioned cat. J. Neurophysiol. 22, 78–87.

13.

Sperry

R. W.

(1958). Corpus callosum and interhemispheric transfer in the monkey (Macaca mulatto). Anat. Rec. 131, 297.

14.

Sperry

R. W.

Miner

Nancy

Myers

R. E.

(1955). Visual pattern perception following subpial slicing and tantalum wire implantations in the visual cortex. J. comp. physiol. Psychol. 48, 50–8.

15.

Sperry

R. W.

Stamm

J. S.

Miner

Nancy

(1956). Relearning tests for interocular transfer following division of optic chiasma and corpus callosum in cats. J. comp. physiol. Psychol. 49, 529–33.