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Procedures are described for lesioning two components of the hippocampal formation (hippocampus, subiculum) using multiple injections of small amounts of ibotenic acid (IBO). The resulting loss of cells is more selective and limited than can be obtained with conventional techniques. Thus, problems associated with damage to adjacent areas, fibers-of-passage,(More)
Theoretical, behavioral, and electrophysiologic evidence suggests that the hippocampal formation may play a role in path integration, a form of spatial navigation in which an animal can return to a starting point by integrating self-movement cues generated on its outward journey. The present study examined whether the hippocampus (Ammon's horn and the(More)
An overview of lesion experiments concerned with the involvement of the hippocampus in learning and memory in the rat is presented. Multiple injections of small amounts of ibotenic acid were used to selectively remove the hippocampus (dentate gyrus, hilar cells, CA1-CA3 pyramidal cells). Similar selective, axon-sparing ibotenate lesions of hippocampus were(More)
Damage to either the fimbria-fornix or to the hippocampus can produce a deficit in spatial behavior and change in locomotor activity but the extent to which the two kinds of damage are comparable is not known. Here we contrasted the effects of cathodal sections of the fimbria-fornix with ibotenic acid lesions of the cells of the hippocampus (Ammon's horn(More)
Experiment 1 investigated the effects of catecholaminergic deafferentation or cell body lesions of the amygdala on fear conditioning to explicit and contextual cues. Bilateral infusions of quinolinic acid mainly damaged neurons within the basolateral region of the amygdala. 6-Hydroxydopamine infusions at the same coordinates resulted in an 86% depletion of(More)
The behavioral effects of interrupting the axons that pass in the fimbria and dorsal fornix were compared with the effects of selective removal of the cells that comprise the hippocampus with ibotenic acid. Starting 4.5 months after surgery, lesioned and control rats were (i) trained in both the Morris water maze and the eight-arm radial maze using(More)
Auditory information can reach the lateral nucleus of the amygdala (LA) through a monosynaptic thalamic projection or a polysynaptic cortical route. The polymodal input from the perirhinal cortex (PR) is a major informational gateway to the LA and nearby structures. Pretraining PR lesions impair fear conditioning to a context, but there have been no reports(More)
Using adult Long-Evans male rats, this experiment compared spontaneous (assessed 15 days and 4.5 months after surgery) and amphetamine-induced (assessed from 4.5 months after surgery onwards; 1 mg/kg, i.p., ten injections, 48 h apart) locomotor activity following N-methyl-D-aspartate lesions of the entorhinal cortex, electrolytic lesions of the(More)
Rats were given injections of ibotenic acid that made lesions of neurons throughout the hippocampus (CHC), or restricted to area CA3 (CA3), or to the subiculum (SUB), and were trained to lever press on a differential reinforcement of low rates (DRL) schedule. Their performance efficiency was compared with that of sham-operated (SO) rats in three(More)