Receptive fields of neurons of cat suprasylvian gyrus studied by stimuli of different colors

Kezeli, A.

doi:10.1007/bf01060242

Cited by 2 publications

(5 citation statements)

References 21 publications

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“…The most surprising finding of the present study is that the vast majority of PMLS neurons are orientation sensitive to flashed light or dark bars. This result clearly is at odds with previous reports, including reports from our own laboratory (Spear & Baumann, 1975;Camarda & Rizzolatti, 1976;Palmer et al, 1978;Smith & Spear, 1979;Kezeli, 1983;Tong et al, 1984;McCall et al, 1988). There are several possible reasons for this discrepancy.…”

Section: Discussioncontrasting

confidence: 90%

“…A second possible reason for the difference in results between the present study and previous studies is that many cells in previous studies were tested for orientation sensitivity by comparing responses to moving spots and bars rather than to flashed bars (Spear & Baumann, 1975;Camarda & Rizzolatti, 1976;Palmer et al, 1978;Smith & Spear, 1979;Kezeli, 1983;Tong et al, 1984;McCall et al, 1988). This sort of test is most informative if directional tuning is compared for the two types of stimuli; an orientation-selective cell has a narrower directionaltuning curve to elongated bars (moving in directions orthogonal to bar orientation) than to small spots (cf.…”

Section: 6contrasting

confidence: 70%

“…Even though PMLS cells are sensitive to stimulus orientation, which is a spatial parameter, it seems unlikely that this represents a central aspect of PMLS function. Indeed, the orientation tuning is relatively broad, and PMLS cells respond as well to mov-ing spots as to moving elongated bars (Spear & Baumann, 1975;Camarda & Rizzolatti, 1976;Kezeli, 1983;Blakemore & Zumbroich, 1987;Hamada, 1987;Gizzi et al, 1990). Thus, we do not think that the presence of orientation sensitivity to bar as well as to grating stimuli indicates that spatial processing is an important function of PMLS cortex.…”

Section: 6mentioning

confidence: 87%

“…A third possible reason for the difference is the anesthetics that were used. All previous studies in which a lack of orientation sensitivity to bar stimuli was reported used unanesthetized cats or cats maintained under nitrous oxide (Spear & Baumann, 1975;Camarda & Rizzolatti, 1976;Palmer et al, 1978;Smith & Spear, 1979;Kezeli, 1983;Tong et al, 1984;McCall et al, 1988). In the present study, the cats were anesthetized with halothane in air.…”

Section: 6mentioning

confidence: 97%

“…Henry et al, 1974a,b;Pettigrew, 1974). Other studies that have tested PMLS cells with spot and bar stimuli also have reported that few, if any, cells are orientation selective (Camarda & Rizzolatti, 1976;Palmer et al, 1978;Smith & Spear, 1979;Kezeli, 1983;Tong et al, 1984;McCall et al, 1988).…”

Section: Introductionmentioning

confidence: 99%

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Are neurons in cat posteromedial lateral suprasylvian visual cortex orientation sensitive? Tests with bars and gratings

et al. 1995

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There is controversy in the literature concerning whether or not neurons in the cat's posteromedial lateral suprasylvian (PMLS) visual cortex are orientation selective. Previous studies that have tested cells with simple bar stimuli have found that few, if any, PMLS cells are orientation selective. Conversely, studies that have used repetitive stimuli such as gratings have found that most or all PMLS cells are orientation selective. It is not known whether this difference in results is due to the stimuli used or the laboratories using them. The present experiments were designed to answer this question by testing individual PMLS neurons for orientation sensitivity with both bar and grating stimuli. Using quantitative response measures, we found that most PMLS neurons respond well enough to stationary flashed stimuli to use such stimuli to test for orientation sensitivity. On the basis of these tests, we found that about 85% of the cells with well-defined receptive fields are orientation sensitive to flashed gratings, and a similar percentage are orientation sensitive to flashed bars. About 80% of the cells were orientation sensitive to both types of stimuli. The preferred orientations typically were similar for the two tests, and they were orthogonal to the preferred direction of movement. The strength of the orientation sensitivity (measured as the ratio of discharge to the preferred and nonpreferred orientations) was similar to both types of stimuli. However, the width of the orientation tuning curves was systematically broader to bars than to gratings. Several hypotheses are considered as to why previous studies using bars failed to find evidence for orientation sensitivity. In addition, a mechanism for the difference in orientation tuning to bars and gratings is suggested.

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