A ROLE OF SUBICULAR AND HIPPOCAMPAL AFTERDISCHARGES IN INITIATION OF LOCOMOTOR-ACTIVITY IN RATS

The possible role of a hippocampal afterdischarge (AD) episode in elic iting locomotor movements was evaluated in freely moving rats. Electri cal stimulation of either the ventral subiculum (VSB) or the hippocamp al CA1 region evoked an AD of 6-50 s in duration, which was followed b y an increase in locomotor activity. Similar results were also observe d after unilateral injection of N-methyl-D-aspartic acid (NMDA, 0.25 m u g or 1 mu g), a glutamate receptor agonist, into the VSB. Locomotor activity was not observed when either electrical or chemical stimulati on of the VSB, or electrical stimulation of the CA1 region did not eli cit an AD. In addition, the duration of the AD was positively correlat ed with the number of locomotor movements induced by stimulation of VS B or CA1 region. It is suggested that the hippocampal/subicular AD may be a necessary condition to induce locomotor activity by either chemi cal or electrical stimulation of the hippocampus in rats. (C) 1998 Els evier Science B.V. All rights reserved.