Cortical oscillatory power changes during auditory oddball task revealed by spatially filtered magnetoencephalography.
OBJECTIVE
To investigate the neural sources and associated changes in oscillatory activity involved in auditory attention and memory updating processing using spatially filtered magnetoencephalography.


METHODS
We recorded magnetic responses during an auditory oddball task in 12 normal subjects. Synthetic aperture magnetometry (SAM)-permutation analysis was used to visualize the multiple brain regions associated with event-related magnetic fields (ERFs), and event-related oscillations during target detection processing.


RESULTS
SAM-permutation results showed the topographical distribution of N1m over the bilateral primary auditory cortex. Post-stimulus delta (1.5-4 Hz) activity sources, likely related to the P300 slow-waveform, were distributed over the right frontocentral and parietal regions. Source locations of theta (4-8 Hz) and alpha (8-13 Hz) event-related synchronization (ERS) were identified over the dorsolateral and medial prefrontal cortex. We visualized bilateral central-Rolandic suppresions for mu (8-15 Hz), beta (15-30 Hz), and low-gamma (30-60 Hz) activities, more dominant in the hemisphere contralateral to the moving hand (button-pressing in response to target stimuli).


CONCLUSIONS
Prefrontal theta and alpha ERS, and frontocentral-parietal delta ERS are functionally engaged in auditory attention and memory updating process.


CONCLUSIONS
Spatially filtered MEG is valuable for detection and source localization of task-related changes in the ongoing oscillatory activity during oddball tasks.
Ishii
Ryouhei
R
Department of Psychiatry, Osaka University Graduate School of Medicine, D3 2-2 Yamada-oka, Suita, 565-0871 Osaka, Japan. ishii@psy.med.osaka-u.ac.jp
Canuet
Leonides
L
Herdman
Anthony
A
Gunji
Atsuko
A
Iwase
Masao
M
Takahashi
Hidetoshi
H
Nakahachi
Takayuki
T
Hirata
Masayuki
M
Robinson
Stephen E
SE
Pantev
Christo
C
Takeda
Masatoshi
M
D000161:Acoustic Stimulation; D000328:Adult; D001288:Attention / Q000502:physiology*; D001683:Biological Clocks / Q000502:physiology*; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000502:physiology*; D003071:Cognition / Q000502:physiology; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D008297:Male; D008568:Memory / Q000502:physiology*; D009415:Nerve Net / Q000033:anatomy & histology / Q000502:physiology; D009434:Neural Pathways / Q000033:anatomy & histology / Q000502:physiology; D009483:Neuropsychological Tests; D012815:Signal Processing, Computer-Assisted; D013017:Sound Localization / Q000502:physiology