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Visually directed behavior is influenced by the posterior ectosylvian gyrus in the cat
Source: Brain Research 1979 Dec;178(2-3):606-608.
Author: Toga AW, Layton BS, Horenstein S.
PubMed ID: 509223
Abstract:
It has been shown by Winer et al. that the cat dorsal posterior ectosylvian gyrus (Epd) differs from other divisions of the dorsal temoral lobe because only the latter receives projections from both auditory and non-auditory (pulvinar and lateral nuclei) portions of the thalamus. Additionally, functional maps of the cochlear projections onto the cortex of the cat fail to show tonotopic representation within Epd. Thus, anatomic and physiologic work do not suggest a unitary function of Epd in behavior. In this report we shall present evidence of a relationship between Epd and visually directed behavior. METHODS: We used the ablation technique and an adaption of the clinical neurological method of double bilateral simultaneous stimulation. Food deprived cats were tested before and after cortical ablation in an equiangular Y-maze in which small incandescent lamps were placed at the end of each alley just above a food apparatus. Subjects were required to move into the alley where thelight was exposed, but when lights on two sides were flashed simultaneously, the cat could find its reward by movinginto either alley. The task was made progressively more difficult and cats were not trained at the next level of difficulty until previous performance equalled or exceeded 80% correct responses to the unilateral cues. For 8 cats, either the entire dorsal ectosylvian cortex or some component therein was ablated unilaterally. In 2 cats suprasylvian cortex was unilaterally ablated. RESULTS: That our main finding is not the result of the creation of a visual field deficit is supported by continued accuracy in postoperative responding to unilateral stimulation. The maintenance of correct response to unilateral stimulation following the second operation provides additional support for the conslusion that our results cannot be explained by the production of visual field deficits. Our results do indicate that a change in visually directed behavior upon DSS occurs only following the loss of specific cortical tissue. This study contributes evidence establishing that the Epd cortex of the cat is involved in the regulation of visual behavior. Since Epd also receives projections from AI, AII and parts of the auditory thalamus, it may play a role in auditory-visual association.
Source: Brain Research 1979 Dec;178(2-3):606-608.
Author: Toga AW, Layton BS, Horenstein S.
PubMed ID: 509223
Abstract:
It has been shown by Winer et al. that the cat dorsal posterior ectosylvian gyrus (Epd) differs from other divisions of the dorsal temoral lobe because only the latter receives projections from both auditory and non-auditory (pulvinar and lateral nuclei) portions of the thalamus. Additionally, functional maps of the cochlear projections onto the cortex of the cat fail to show tonotopic representation within Epd. Thus, anatomic and physiologic work do not suggest a unitary function of Epd in behavior. In this report we shall present evidence of a relationship between Epd and visually directed behavior. METHODS: We used the ablation technique and an adaption of the clinical neurological method of double bilateral simultaneous stimulation. Food deprived cats were tested before and after cortical ablation in an equiangular Y-maze in which small incandescent lamps were placed at the end of each alley just above a food apparatus. Subjects were required to move into the alley where thelight was exposed, but when lights on two sides were flashed simultaneously, the cat could find its reward by movinginto either alley. The task was made progressively more difficult and cats were not trained at the next level of difficulty until previous performance equalled or exceeded 80% correct responses to the unilateral cues. For 8 cats, either the entire dorsal ectosylvian cortex or some component therein was ablated unilaterally. In 2 cats suprasylvian cortex was unilaterally ablated. RESULTS: That our main finding is not the result of the creation of a visual field deficit is supported by continued accuracy in postoperative responding to unilateral stimulation. The maintenance of correct response to unilateral stimulation following the second operation provides additional support for the conslusion that our results cannot be explained by the production of visual field deficits. Our results do indicate that a change in visually directed behavior upon DSS occurs only following the loss of specific cortical tissue. This study contributes evidence establishing that the Epd cortex of the cat is involved in the regulation of visual behavior. Since Epd also receives projections from AI, AII and parts of the auditory thalamus, it may play a role in auditory-visual association.