Further analysis of visual discrimination deficits following foveal prestriate and inferotemporal lesions in rhesus monkeys.

Abstract

Visual discrimination performance of normal monkeys and monkeys with inferotemporal or foveal prestriate lesions was compared. In Experiment 1 the inferotemporal group was impaired in learning object and color discriminations but the foveal prestriate group showed a deficit only on the object problems. The inferotemporal group showed impaired retention of color discrimination after interpolation of an object discrimination and impaired retention of object discrimination after interpolation of a color discrimination, but normal retention when the original and interpolated problems were both either object or color discriminations. By contrast, retention by the other groups was not affected by the type of interpolated material. In Experiment 2, only the foveal prestriate group was impaired on pattern discrimination when irrelevant stimuli were added. Results are discussed in terms of perceptual and associative learning disorders.

Cerebral Achromatopsia in Monkeys

“…This finding is consistent with sporadic but neglected reports of impaired colour discrimination following inferotemporal removal where the nature of the visual discriminanda has rarely been adequately specified (Gross et al, 1971;Wilson et al, 1972;Heywood et al, 1988;Aggleton and Mishkin, 1990;Cowey, 1994) The present result shows striking parallels with that observed in the human clinical condition of cerebral achromatopsia (Heywood et al, 1991). Results from the tasks of hue detection and discrimination were concordant in that monkeys performing poorly on the former task were impaired on the latter.…”

Components of recognition memory: Dissociable cognitive processes or just differences in representational complexity?

“…We examined the importance of the combination of stimulus material and task design to investigations of object processing in a recent paper that extended the representational-hierarchical view in a posterior direction (Cowell et al, 2010b). In this study, we used connectionist simulations to revisit and reinterpret the results of an important and influential body of literature from the 1960s and '70s, in which the function of the VVS was examined in monkeys (e.g., Iwai and Mishkin, 1968;Cowey and Gross, 1970;Gross et al, 1971;Wilson et al, 1972;Blake et al, 1977). These studies used visual discrimination learning tasks in combination with lesions of either posterior or anterior areas of the VVS.…”

Dissociable Forms of Inhibitory Control within Prefrontal Cortex with an Analog of the Wisconsin Card Sort Test: Restriction to Novel Situations and Independence from “On-Line” Processing

“…A study by Iversen and Mishkin (1970) did show that lesions restricted to areas 13 and 14 on the orbital surface abolished the improvement in performance that is normally seen across a series of visual discrimination reversals, an impairment that could have reflected the failure of such an attentional mechanism (Mackintosh and Little, 1969). Certainly, these regions are interconnected with the inferotemporal cortex (Ungerleider et al, 1989), which has been implicated specifically in visual selective attention (Butter, 1969;Gross et al, 1971).…”