Simple and choice reaction-time performance following occlusion of the anterior cerebral arteries in the rat

Abstract

 Focal cerebral ischemia in the rat has traditionally been studied by examining the consequences of middle-cerebral artery occlusion. However, the anterior-cerebral arteries of the rat may now also be bilaterally occluded by stereotaxic injection of the vasoconstrictor endothelin-1, resulting in ischemic damage to medial prefrontal cortex and the anteromedial basal forebrain. The behavioural consequences of anterior-cerebral artery occlusion (ACAo) were studied in two experiments using simple and choice reaction-time tasks designed to dissociate response impairments from dysfunction of motivation and attention, respectively. Following ACAo, reaction-time increased post-surgery in the choice, but not simple reaction-time task. There was also an increase in incorrect choices in the choice reaction-time task. However, the impairments were independent of motivational or attentional function, which remained intact. Although the ACAo-induced ischemic damage did not disrupt motivation or attention, the results suggest that the lesion results in an executive impairment in selecting and initiating responses.