The neural substrate of memory impairment demonstrated by the intracarotid amobarbital procedure
K. J. Sass, T. Lencz, M. Westerveld, R. A. Novelly, D. D. Spencer and J. H. Kim
Department of Surgery, Yale University School of Medicine, New Haven, Conn 06510.
The intracarotid amobarbital sodium (Amytal) procedure (IAP) was performed
for 46 patients with temporal lobe epilepsy (21 with left seizure foci; 25
with right seizure foci). After anteromedial temporal lobectomy, neuronal
densities were established for hippocampal subfields CA1, CA2, and CA3; the
hilum; and the dentate granule cell layer. Intracarotid amobarbital
procedure memory results were related to CA3 neuronal loss only. Patients
who did not demonstrate memory after injection contralateral to the seizure
focus had significantly fewer cells in CA3 than patients who did.
Additionally, a significant correlation was observed between the
intracarotid amobarbital procedure memory examination raw score after
injection contralateral to the seizure focus and CA3 cell density. Using
chi 2 analysis, significant differences were documented in the frequency
with which memory was demonstrated after injection contralateral to the
seizure focus for groups of patients classified by degree of CA3 neuronal
loss. This finding supports prior research showing subfield specificity in
some memory processes.
