The entorhinal cortex (Brodmann's area 28) is located at the anterior aspec
t of the parahippocampal gyrus ventral to the amygdala and the hippocampus.
It is reciprocally interconnected with the hippocampus via glutamatergic p
athways. We investigated whether the entorhinal cortex is damaged in human
temporal lobe epilepsy (TLE). The volume of the entorhinal cortex was measu
red using magnetic resonance imaging (MRI) in 36 patients with cryptogenic
TLE and in 21 controls. The mean volumes of the entorhinal cortex on the fo
cal side did not differ from controls. In Ii of 36 patients, however, the e
ntorhinal cortex volume was reduced by 25%. Entorhinal volume correlated wi
th hippocampal volume in TLE (ipsilaterally, r = 0.454, P < 0.01; contralat
erally, r = 0.340, P < 0.05). Further, 64% of patients with 25% entorhinal
cortex damage had ipsilateral hippocampal atrophy. On the other hand, right
focal TLE patients with hippocampal atrophy had a 19% volume reduction of
the ipsilateral entorhinal cortex (P < 0.05). The Volume of the entorhinal
cortex correlated with the duration of TLE (r = -0.335, P < 0.05). The pres
ent study indicates that the entorhinal cortex might be damaged in a subpop
ulation of patients with cryptogenic TLE. In most cases, volume reduction w
as associated with hippocampal damage. These data suggest that entorhinal d
amage contributes to the symptomatology in TLE. (C) 2000 BEA Trading Ltd.