The effect of spreading depression on the consolidation of learning

Abstract

The consolidation of an interhemispherically transferred avoidance response was studied using spreading depression to control transfer and consolidation times. Transmission of the learning required 3 min. The length of time following transfer when consolidation could be disturbed varied with the duration of spreading depression, from 3 min to 2 hr. The effect appears not to be due to disruption of neural firing, but to the cortical potential change caused by spreading depression since a pulsating cathodal current (8.5 [mu]A/mm2) passed through medial (but not anterior, lateral, or posterior) cortex can abolish retention. It is suggested that the consolidation process may require electrical potential gradients in the cortex and that it is disturbed by agents which decrease or reverse them.