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The effects of hippocampal ablation on acquisition rates and temporal characteristics of classically conditioned nictitating membrane responses were examined in groups of rabbits trained with a 150-, 300-, or 600-ms interstimulus interval. Acquisition rates were accelerated in the 150- and 600-ms groups. No effect was present in the 300-ms group. Response(More)
The effects of fimbrial and cortical lesions on sensory preconditioning in the rabbit were examined. Damage to the cortex or the fimbria had no apparent effect on the acquisition of classically conditioned responses. However, fimbrial lesions virtually abolished the effects of preconditioning, whereas cortical lesions had no significant effect. Because(More)
The effects of dorsal hippocampal lesions on retention of classical trace conditioned responses were examined using the rabbit nictitating membrane preparation. Animals were trained to criteria and then lesioned either in the cortex or in the hippocampus and the cortex. Hippocampal damage had no effect on the retention of responses but produced(More)
The role of the hippocampus in the association of two conditional stimuli was evaluated using the conditioned rabbit NM preparation and a sensory preconditioning paradigm. Multiple-unit activity was recorded from field CA1 during preconditioning. Paired presentations of CS1 and CS2 resulted in increased excitability which was highly correlated with later(More)
These experiments were conducted to examine extinction and retention of a classically conditioned response in acute spinal cats. Conditioning was obtained by pairing a mild electrical stimulus to the superficial peroneal sensory nerve (CS) with a stronger electrical stimulus to the ankle skin (US) of the same leg. Subsequent extinction was produced by(More)
Unilateral lesions of the cerebellar dentate-interpositus (DI) nuclei abolished or impaired the reacquisition of a nictitating membrane (NM) conditioned avoidance response (CAR) in rabbits. Animals that sustained damage to the DI nuclei and surrounding areas displayed little or no reacquisition of the NM-CAR ipsilateral to the lesion, but displayed(More)
The effects of amphetamine injection, hippocampal lesions, and cortical lesions were examined during classical conditioning of the rabbit nictitating membrane response. An optimal interstimulus interval was employed. Whereas neocortical and hippocampal damage had no significant effect on the rate of acquisition, amphetamine treatment produced a marked(More)
Neuronal unit activity was recorded from the abducens (6th nerve) nucleus, the "final common path," during classical conditioning of the nictitating membrane (NM) response in the rabbit, with the use of a tone conditioned stimulus, an air puff unconditioned stimulus (UCS), 250-msec interstimulus interval, and 60-sec intertrial interval. Animals were given 2(More)
Present knowledge of its central nervous system makes the cat a desirable subject for studies of brain-behavior relationships. Response frequencies and latency characteristics in conditioning and control groups indicate that the response of the nictitating membrane can be classically conditioned in a new restraint system in which detailed brain and behavior(More)