High temporal resolution dynamic mapping of instantaneous EEG amplitude modulation after tone-burst auditory stimulation.
A new method of instantaneous EEG analysis based on amplitude modulation (AM-EEG) was applied to analyze the AM-EEG changes in the alpha frequency band (8.20-12.89 Hz) for successive 5 ms epochs. Repeated auditory tone-burst stimuli (of 220 ms duration) were presented at fixed 2.56 second intervals to 12 attending right-handed young female volunteers, who were EEG-recorded over 19 EEG channels at 200 Hz sampling frequency. The time-course of functional activation was characterized in terms of percent decrease in instantaneous amplitude modulation, as compared to baseline, in analogy with the classical event-related desynchronization paradigm. A dynamic sequence of the successive 122 AM-EEG maps obtained for the 610 ms from beginning of tone-burst was stored and later animated on PC microcomputer. Topological changes among successive maps were extracted into 40 specific AM-EEG maps. Early left temporal and centro-temporal activation was observed, followed first by strong bilateral frontal, and then by left temporal activation. These changes induced by a warning tone-burst are discussed in terms of functional neurophysiology. The present method therefore allows an improved time-resolution for functional brain activation paradigms.
Etévenon
P
P
INSERM U. 320, Université de Caen, France. inserm-u320@cyceron.fr
Lebrun
N
N
Clochon
P
P
Perchey
G
G
Eustache
F
F
Baron
J C
JC
D000161:Acoustic Stimulation / Q000379:methods*; D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D002540:Cerebral Cortex / Q000502:physiology*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D013997:Time Factors