PT  - JOURNAL ARTICLE
AU  - Han, JS
AU  - Gallagher, M
AU  - Holland, P
TI  - Hippocampal lesions disrupt decrements but not increments in conditioned stimulus processing
AID  - 10.1523/JNEUROSCI.15-11-07323.1995
DP  - 1995 Nov 01
TA  - The Journal of Neuroscience
PG  - 7323--7329
VI  - 15
IP  - 11
4099  - http://www.jneurosci.org/content/15/11/7323.short
4100  - http://www.jneurosci.org/content/15/11/7323.full
SO  - J. Neurosci.1995 Nov 01; 15
AB  - Studies recording hippocampal neural activity show widespread registration of events during associative learning. Recent computational models of hippocampal function have stressed its role in attentional processes specified by well-developed modern theories of associative learning. These modeling efforts are largely aimed at accounting for the behavioral outcomes of damage to the hippocampal system in terms of underlying changes in information processing. Two experiments examined the effects of neurotoxic lesions of the hippocampus on changes in attentional processing of a conditioned stimulus (CS) in appetitive Pavlovian conditioning in rats. In Experiment 1, hippocampal lesions eliminated the reduction in associability of a CS usually produced by preexposure to that cue (latent inhibition). In Experiment 2, hippocampal lesions interfered with the loss in associability of a CS normally produced when that CS consistently predicts another event. In contrast, in Experiment 2, hippocampal lesions did not prevent the enhancement of CS associability when a previously consistent predictive relation between two events was made inconsistent. This research supports previous claims that the hippocampus is involved in regulating the processing of CSs in Pavlovian conditioning, and provides new evidence for a hippocampal role in decremental, but not incremental, changes in attention.