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R J Ferrier

Publications and source records attributed to R J Ferrier.

9 recordsLinked to original sources
PubMed1978

Reversal set formation in the visually decorticate rat.

Rats given large visual cortex lesions demonstrated a simultaneous task reversal deficit previously reported to follow more extensive cortical ablation. However, no deficit appeared in an operant discrimination that deemphasized visuospatial cues, and the simultaneous task deficit vanished when translucent eye occluders were applied to eliminate spatial, but not intensity, cue use. Because the lesion subjects showed an impairment only when visuospatial cues were available and relevant to correct reversal performance, they seemed hindered by their incompetent processing of visuospatial information. The results are interpreted as support for spatial rather than learning approaches to visual cortex function.

Animals↗
PubMed1976

Striate cortex ablation and spatial vision.

Normal and visually decorticate rats were trained to orient to a luminous target. All subjects reached the same criterion of orientation accuracy, but operated subjects required more training and exhibited greater response latency throughout testing. To determine if visually decorticate subjects located the target according to the retinal position of its image, or only by sampling luminous flux density at different points in space, field-displacing wedge prisms were placed before the subjects' eyes to laterally displace the retinal locus of the target image without affecting luminous flux information. Prism imposition shifted orientation toward the virtual target position for all subjects. In a second study, translucent plastic was place over the subjects' eyes to disrupt the retinal topography and location of the target image while again leaving luminoux flux unaffected as a potential cue. All animals showed a dramatic and complete disruption of target localization once the diffusing material was applied. The data were considered as support for the hypothesis that 'spatial' vision survives visual decortication.

Animals↗
PubMed1976

Effects of pretectal lesions on rats wearing light-diffusing occluders.

The study provides behavioral evidence that the pretectal region of the subcortical visual system primarily mediates responses to diffuse rather than to patterned light stimuli: pretectal lesions induced greater transoperative deficits in performance of a light-dark discrimination task for rats wearing light-diffusing occluders than for non-occluded animals. Pretectal lesions also produced less transoperative disruption in animals trained to perform a pattern discrimination task (horizontal vs. vertical stripes). These results are precisely the opposite of those which follow ablation of visual cortex.

Animals↗