Y.P. and F.M. contributed equally to this study.
Neonatal functional blockade of the entorhinal cortex results in disruption of accumbal dopaminergic responses observed in latent inhibition paradigm in adult rats
Version of Record online: 16 APR 2007
European Journal of Neuroscience
Volume 25, Issue 8, pages 2504–2513, April 2007
How to Cite
Peterschmitt, Y., Meyer, F. and Louilot, A. (2007), Neonatal functional blockade of the entorhinal cortex results in disruption of accumbal dopaminergic responses observed in latent inhibition paradigm in adult rats. European Journal of Neuroscience, 25: 2504–2513. doi: 10.1111/j.1460-9568.2007.05503.x
- Issue online: 16 APR 2007
- Version of Record online: 16 APR 2007
- Received 22 November 2006, revised 25 February 2007, accepted 27 February 2007
- conditioned olfactory aversion;
- in vivo voltammetry;
- nucleus accumbens;
- recognition memory;
Latent inhibition (LI) has been found to be disrupted in non-treated patients with schizophrenia. Dopaminergic (DAergic) dysfunctioning is generally acknowledged to occur in schizophrenia. Various abnormalities in the entorhinal cortex (ENT) have been described in patients with schizophrenia. Numerous data also suggest that schizophrenia has a neurodevelopmental origin. The present study was designed to test the hypothesis that reversible inactivation of the ENT during neonatal development results in disrupted DA responses characteristic of LI in adult rats. Tetrodotoxin (TTX) was microinjected locally in the left ENT at postnatal day 8 (PND8). DA variations were recorded in the dorsomedial shell and core parts of the nucleus accumbens (Nacc) using in vivo voltammetry in freely-moving grown-up rats in a LI paradigm. In the first session the animals were pre-exposed (PE) to the conditional stimulus (banana odour) alone. In the second they were aversively conditioned to banana odour. In the third (test) session the following results were obtained in PE animals subjected to temporary inactivation of the ENT at PND8: (1) aversive behaviour was observed in TTX–PE conditioned animals; (2) DA variations in the dorsomedial shell and core parts of the Nacc were similar in TTX–PE and non-pre-exposed conditioned rats.
These findings strongly suggest that neonatal disconnection of the ENT disrupts LI in adult animals. They may further our understanding of the pathophysiology of schizophrenia.