Effects of frontal, median cortical and caudate lesions on two-way avoidance learning by rats☆

Abstract

Abstract Spontaneous activity and visual shuttle-box avoidance conditioning were studied in rats with either caudate lesions or cortical lesions (dorsal frontal, anterior median or posterior cingulate). Frontal operates had higher avoidance scores than rats with anterior median lesions or controls which had received the same amount of damage to the skull. Median cortical lesions produced an avoidance deficit only in those animals with anterior damage. Rats with caudate lesions were unaffected. Intertrial activity was above normal in the groups with frontal and anterior median cortical lesions. These data, and those obtained by studying correlations within groups and across groups, indicated that changes in spontaneous and intertrial activity were not a major factor in determining the direction of the effects on avoidance conditioning. The same animals were also given additional training with a reversed cue (light off as CS). The performances during reversal were positively correlated to those during original learning.