Sensory gating in the human hippocampal and rhinal regions.
OBJECTIVE
The objective of this work was to ascertain if sensory gating can be demonstrated within the human medial temporal lobe.


METHODS
Eight patients with intractable epilepsy with depth electrodes implanted in the medial temporal lobe for pre-surgery evaluation underwent evoked response recording to auditory paired-stimuli (S1-S2). Each of the eight subjects had a diagnosis of left medial temporal lobe epilepsy (MTLE).


RESULTS
Data from the non-focal right hippocampi revealed a large negative response on S1 (starting at about 190 ms and lasting for approximately 300 ms from stimulus onset). Rhinal region recordings revealed a positive response (starting at about 240 ms with a rapid incline, followed by a long-lasting decline). A significant attenuation of both responses to S2 stimuli was observed.


CONCLUSIONS
Data are suggestive of an involvement of the human medial temporal lobe in the processing of simple auditory information which occurs in a time frame later than the neocortical auditory evoked components. The exact role of these anatomical structures in the sensory gating process remains to be defined.


CONCLUSIONS
This study provides the first evidence of an activation of the rhinal cortex after simple auditory stimulation and provides new evidence that the activation of the medial temporal lobe structures occurs at a later stage than that of the neocortex.
Boutros
N N
NN
Wayne State University School of Medicine, Department of Psychiatry and Behavioral Neurosciences, School of Medicine, UPC-Jefferson, 2751 E Jefferson, Suite 401, Detroit, MI 48207, USA. nboutros@med.wayne.edu
Trautner
P
P
Rosburg
T
T
Korzyukov
O
O
Grunwald
T
T
Schaller
C
C
Elger
C E
CE
Kurthen
M
M
D000161:Acoustic Stimulation; D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D004833:Epilepsy, Temporal Lobe; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006624:Hippocampus / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013702:Temporal Lobe / Q000502:physiology*