Very early EEG responses to a meaningful auditory stimulus in the frontal lobes: an intracerebral study in humans.
Frontal auditory evoked potentials (FAEPs) obtained as a response to the warning auditory stimulus of a contingent negative variation task from depth electrodes were investigated. The second, imperative stimulus was visual. Thirteen epileptic patients participated in the study. Records from 20 electrodes of 10 patients exhibited signs of local generation. They were localized in the motor cortices (7 cases), in the superior, medial, and inferior frontal gyri (7 cases), in the cingulate gyrus (5 cases), and in the nucleus caudatus (1 case). A typical FAEP from these generators consisted of three components: (i) first negative wave peaking at 99+/-13 ms; (ii) positive wave peaking at 181 +/- 21 ms; (iii) second negative wave peaking at 324 +/- 63 ms. In 11 generators no evoked activity to visual stimulus was observed; in the remaining 9 generators both auditory and visual stimuli evoked a response. FAEPs with very early onsets (onset latency below 20 ms) were found in three sites in the precentral gyrus.
Kukleta
M
M
Department of Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic. mkukleta@med.muni.cz
Turak
B
B
Louvel
J
J
D000161:Acoustic Stimulation; D000328:Adult; D004569:Electroencephalography / Q000379:methods*; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000502:physiology*; D006179:Gyrus Cinguli / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011930:Reaction Time / Q000502:physiology