EFFECTS OF THALAMIC AND OLFACTORY CORTICAL-LESIONS ON CONTINUOUS OLFACTORY DELAYED-NONMATCHING-TO-SAMPLE AND OLFACTORY DISCRIMINATION IN RATS (RATTUS-NORVEGICUS)

We conducted 2 studies to determine the importance of several brain sy stems for remembering odorants in a go/no-go delayed nonmatching-to-sa mple (DNMTS) task. In Experiment 1, impairments were observed for lesi ons of pyriform cortex or (to a lesser extent) the lateral internal me dullary lamina of thalamus. Lesions of the entorhinal cortex or the me diodorsal (MDn) or the paracentral and centrolateral (PC-CL) thalamic nuclei did not affect DNMTS. In Experiment 2, an impairment comparable to the pyriform lesion was observed for a lesion of the intralaminar nuclei (PC-CL plus the central medial nucleus) but not for a larger le sion of MDn. None of the lesions in either study affected the ability to learn a 2-choice odor discrimination using go/no-go procedures comp arable with the DNMTS task.