Event-related desynchronization during an auditory oddball task.
OBJECTIVE
The present study addressed what kind of mental processes would be presented by the event-related desynchronization (ERD) relevant to the stimuli of an auditory oddball count task.


METHODS
Electroencephalogram (EEG) was recorded from nine healthy subjects while target tones (2000 Hz, P = 0.2) and non-target tones (1000 Hz, P = 0.8) were presented randomly with constant stimulus onset asynchrony (SOA) of 3.3 s. To improve time resolution of ERD analysis, obtained EEG epochs were digitally convoluted by Gabor wavelet and averaged respectively.


RESULTS
For target stimulus, prominent ERD was observed in left parieto-occipital areas (peak latency: 400-600 ms), but there were no significant ERD for non-target stimulus.


CONCLUSIONS
Our result suggests that magnitude of ERD would reflect amount of mental effort which was associated with intentional and voluntary processes rather than automatically sensory process.
Sutoh
T
T
Department of Neuropsychiatry, Hirosaki University School of Medicine, Zaifu-cho 5, Hirosaki, Japan. takeyuki@jomon.ne.jp
Yabe
H
H
Sato
Y
Y
Hiruma
T
T
Kaneko
S
S
D000161:Acoustic Stimulation; D000328:Adult; D001931:Brain Mapping; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009778:Occipital Lobe / Q000502:physiology*; D010296:Parietal Lobe / Q000502:physiology*; D012016:Reference Values; D013997:Time Factors