a1 Schools of Psychology and Biomedical Sciences, University of Nottingham, University Park, Nottingham, UK
There is good evidence that forebrain serotonergic systems modulate cognitive flexibility. Latent inhibition (LI) is a cross-species phenomenon which manifests as poor conditioning to a stimulus that has previously been experienced without consequence and is widely considered an index of the ability to ignore irrelevant stimuli. While much research has focused on dopaminergic mechanisms underlying LI, there is also considerable evidence of serotonergic modulation. However, the neuroanatomical locus of these effects remains poorly understood. Previous work has identified the nucleus accumbens (NAc) as a key component of the neural circuit underpinning LI and furthermore, this work has shown that the core and shell subregions of the NAc contribute differentially to the expression of LI. To examine the role of the serotonergic input to NAc in LI, we tested animals with 5,7-dihydroxytryptamine (5,7-DHT) lesions to the core and shell subregions on LI assessed under experimental conditions that produce LI in shams and subsequently with weak stimulus pre-exposure designed to prevent the emergence of LI in shams. We found that serotonergic deafferentation of the core disrupted LI whereas 5,7-DHT lesions to the shell produced the opposite effect and potentiated LI.
(Received December 21 2010)
(Reviewed January 29 2011)
(Revised February 28 2011)
(Accepted March 21 2011)
(Online publication April 18 2011)
c1 Address for correspondence: Dr A. J. D. Nelson, School of Psychology, University of Nottingham, University Park, Nottingham NG7 2RD, UK. Tel.: +44 (0)115 8468578 Fax: +44 (0) 115 951 5324 Email: email@example.com