Visual intensity discrimination in pigeons following unilateral and bilateral tectal lesions.

Abstract

Intensity discrimination was investigated in pigeons following unilateral or bilateral tectal lesions. Both unilateral and bilateral tectal lesions produced deficits in the acquisition of the discrimination as compared with operated control Ss. Following a 10-day retention interval, there were no differences in the number of trials required to relearn the problem to the original criterion. However, the lesioned Ss did require more trials to attain an extinction criterion. The results are discussed with respect to an ascending visual pathway that may mediate intensity discrimination in the bird.