Motor cortex lesions do not affect learning or performance of the eyeblink response in rabbits

The possible modulatory role of motor cortex in classical conditioning of the eyeblink response was examined by ablating anterior neocortex in rabbits and training them with an auditory conditioned stimulus (CS) and an airpuff unconditioned stimulus (US) in either a delay (Experiment 1) or a trace (Experiment 2) conditioning paradigm. Topographic measures such as amplitude and onset latency were assessed during conditioning sessions for conditioned responses (CRs) and on separate test days for unconditioned responses (URs) by using a range of US intensities. No lesion effects were observed for learning or performance measures in acquisition or retention of either delay or trace conditioning. During trace conditioning, lesioned rabbits did, however, exhibit a trend toward impairment and demonstrated significantly longer CR latencies. Damage to motor and frontal cortex does not significantly affect eyeblink response performance or learning in either a delay or a trace conditioning paradigm.