The Behavioural Syndrome of Septal Damage in Laboratory Rats

Abstract

<p>Experiment 1 included a study of the following behaviours in normal and septal-damages rats: drinking; hyperemotionality (rated with a new scale); escape from electric shock; movement inhibition (MI) shaping and performance; jump avoidance conditioning with no handling and a 15 sec. CS-US interval (JA-15); and weight gain.</p> <p>Experiment 2 included jump avoidance conditioning with a 5 sec. CS-US interval (JA-5) and MI (without shaping) tested in counterbalance order. Seven groups received either sham, unilateral septal, bilateral septal, preoptic, septal-preoptic, caudate-septal, and frontal cortex-septal lesions.</p> <p>Experiment 3 included JA-5 with below-the-grid lighting tested in septal damaged and control rats.</p> <p>Septal lesions disrupted directed movements made during exploration, escape, MI and JA. This disruption correlated with hyperemotionality when tested after prior handling but not when tested before handling and not with weight gain. A new hyperemotionality scale was developed which correlated with Brady and Nauta's (1953) scale but was more reliable, especially for the less emotional rats (in control rats reliability for the new scale was .95 and for the old it was .77).</p> <p>For the septal damaged animals prior experience with JA improved MI performance but prior experience with MI impaired JA performance . These effects were mitigated by adding preoptic damage to the septal damage .</p> <p>Below-the-grid lighting had no detectable effect on the JA-5 impairment caused by septal dmage.</p> <p>Generalizations about behaviour after septal damage were discussed with emphasis on generalized fragmentation of voluntary responses into isolated, component acts .</p>