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Neural Plasticity
Volume 2007, Article ID 29821, 9 pages
Research Article

Effects of Methamphetamine on Single Unit Activity in Rat Medial Prefrontal Cortex In Vivo

1Neuroscience Laboratory, Institute for Medical Sciences, Ajou University School of Medicine, Suwon 443-721, South Korea
2Digital Biotech Corporation, Singil-dong, Danwon-gu, Ansan 425-838, South Korea
3Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA
4Department of Psychiatry, Ajou University School of Medicine, Suwon 443-721, South Korea

Received 13 April 2007; Revised 14 June 2007; Accepted 14 June 2007

Academic Editor: Donald A. Wilson

Copyright © 2007 Jinhwa Jang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


To investigate how neuronal activity in the prefrontal cortex changes in an animal model of schizophrenia, we recorded single unit activity in the medial prefrontal cortex of urethane-anesthetized and awake rats following methamphetamine (MA) administration. Systemic MA injection (4 mg/kg, IP) induced inconsistent changes, that is, both enhancement and reduction, in unit discharge rate, with a subset of neurons transiently (<30 min) elevating their activities. The direction of firing rate change was poorly predicted by the mean firing rate or the degree of burst firing during the baseline period. Also, simultaneously recorded units showed opposite directions of firing rate change, indicating that recording location is a poor predictor of the direction of firing rate change. These results raise the possibility that systemic MA injection induces random bidirectional changes in prefrontal cortical unit activity, which may underlie some of MA-induced psychotic symptoms.