ABSTRACT
Operant discrimination learning was analyzed in pigeons after massive telencephalic lesions. Twenty-one pigeons were divided into the three groups: non-lesioned (N=6), sham-lesioned (N=5) and telencephalon lesioned (N=10). Lesion surgeries were carried out before any experimental training. Learning procedures were run in the same sequence for all groups and under a food deprivation of 80 percent of the ad libitum weight. Successive discrimination was programmed by the alternation of red and yellow lights in the right key of a standard operant chamber: the red key was correlated with extinction. Sessions were run until steady-state key peck rates were obtained. The following results demonstrate discrimination learning required a larger number of sessions for lesioned pigeons (P<0.05). They showed increased response rates in red (26.43 +/- 2.59) and yellow (11.17 +/- 2.86) components...