OBSERVATIONS ON THE RELATIONSHIP BETWEEN VERBAL EXPLICIT AND IMPLICITMEMORY AND DENSITY OF NEURONS IN THE HIPPOCAMPUS

The relationship between neuronal density and verbal memory in left an d right hippocampal subfields was investigated in patients who underwe nt surgery for alleviation of temporal lobe epilepsy. The surgery cons isted of unilateral partial removal of the hippocampus along with the anterior temporal lobe and amygdala. Study 1 looked at post-surgical e xplicit vs implicit verbal memory for lists of words while Study 2 loo ked at pre- and post-surgical explicit memory for word pairs. Left sub field CA1 appeared to be the most consistently involved in explicit an d implicit memory. The results of the two studies confirm presence of hemispheric asymmetry in verbal memory. The notion that hippocampal co ntrol of memory is most apparent in post-surgical performance is discu ssed. (C) 1998 Elsevier Science Ltd. All rights reserved.