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The lateral cerebral peduncle: Its functional significance for the acquisition of visual and kinesthetic discriminations in the rat

1974; Springer Nature; Volume: 2; Issue: 4 Linguagem: Inglês

10.3758/bf03333067

0090-5046

Marsha A. Howzet,

Neuroscience and Neuropharmacology Research

Previous studies have failed to support the theory of transcortical connections as the mechanism of sensorimotor integration and a subcortical pathway has been implicated. The purpose of this study was to demonstrate the significance of the lateral portion of the cerebral peduncle for the acquisition of visual pattern discrimination habits and to show its specificity for visual tasks. Twenty-two albino rats received bilateral lesions in the cerebral peduncle. Ten rats served as sham-operate controls. Following a 2-week recovery period, all Ss were overtrained on both a horizontal-vertical visual discrimination problem and an inclined-plane kinesthetic discrimination problem. A three-way analysis of variance with repeated measures indicated that the Ss did not differ with respect to the number of errors prior to the attainment of criterion on either problem. The analysis did indicate, however, that the experimental animals were inferior to the control rats in the number of days required to reach criterion, and acquisition of the visual problem required more days than acquisition of the kinesthetic problem. The Ss did not differ in the percentage of correct responses made during overtraining on either problem. It was also found that no significant relationship existed between the performance on the visual or kinesthetic problem and the amount of damage to the cerebral peduncle, substantia nigra, pedunculo-nigral area, or total damage to the brain. These results are interpreted as support of the theory of the existence of a mesencephalic mechanism for the integration of sensory, motor, attentional, and emotional-motivational systems and points to the cerebral peduncle as an important corticoreticular pathway in that system.