Multiple memory systems and extinction

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Title: Multiple memory systems and extinction
Author: Gabriele, Amanda
Abstract: Several lines of evidence suggest that initial acquisition of learned behavior involves multiple memory systems . In particular , lesions of the hippocampus impair the acquisition of cognitive or relational memory , but do not impair the acquisition of stimulus -response habits . Extinction behavior also involves new learning , and therefore it is possible that multiple forms of memory may also underlie extinction . We examined this hypothesis by training rats in a task in which extinction behavior could putatively be acquired by either a cognitive or habit memory system . Adult male Long -Evans rats were initially trained to run in a straight alley maze for food reward . Following training they were placed into one of two extinction conditions . In one condition rats were allowed to run to an empty goal box (i .e . response extinction ) . In a second condition rats were placed into an empty goal box without making a running response (i .e . latent or non -response extinction ) . Prior to each daily session of extinction training , rats received intra -hippocampal infusions of either the local anesthetic bupivacaine (0 .75 % solution /0 .5 ul ) , or saline . Rats receiving saline infusions displayed extinction behavior in both the response and non -response conditions . In contrast , rats receiving intra -hippocampal infusions ofbupivacaine extinguished normally in the response condition , but did not display nonresponse extinction . This latent extinction effect was enhanced by decreasing the amount of time between the last extinction trial and the probe trial . Additionally , administering extinction training and probe trials in different contexts did not appear to prevent latent extinction , however large variability may be masking this effect . The new context administered during extinction prevented latent extinction in some animals , but not others . These findings suggest that , similar to initial acquisition , the learning that occurs during extinction also involves multiple memory systems . Specifically , the hippocampus may selectively mediate extinction under conditions in which new stimulus -response learning is prevented .
URI: http : / /hdl .handle .net /1969 .1 /2384
Date: 2005-08-29


Multiple memory systems and extinction. Available electronically from http : / /hdl .handle .net /1969 .1 /2384 .

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