A discrete interpedunculo-central tegmental region critical for retention of visual discrimination habits in the white rat.

Abstract

In Exp. I 27 male albino Wistar rats were assigned to a normal control or 1 of 4 experimental groups sustaining electrolytic lesions at different levels of the midline tegmentum following learning of a brightness and pattern discrimination problem. The group with lesions destroying the caudal 1/2 of the interpeduncular nucleus and/or the overlying decussations of the brachium conjunctivum showed losses in retention, while the remaining groups having lesions anterior or posterior to these structures exhibited excellent retention. Exp. II with 15 Ss showed that severance of the decussating fibers of the brachium conjunctivum by means of an ophthalmic knife also led to retention deficits. Results indicate that dysfunction of the red nuclei may underlie visual discrimination losses following midline tegmental damage. (21 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved)