TITLE:
Females with schizophrenia have abnormal functional cortical connectivity in the gamma frequency during an auditory oddball task using magnetoencephalography
AUTHORS:
Toshiro Fujimoto, Eiichi Okumura, Kouzou Takeuchi, Atsushi Kodabashi, Toshiaki Otsubo, Katsumi Nakamura, Masaki Sekine, Shinichiro Kamiya, Yuji Higashi, Susumu Shimooki, Toshiyo Tamura
KEYWORDS:
Schizophrenia; Female; Gamma Band; Coherence; Functional Connectivity Oddball; Magnetoencephalography
JOURNAL NAME:
Open Journal of Psychiatry,
Vol.4 No.1,
January
7,
2014
ABSTRACT: We studied differences in imaginary coherence (IC)
of the gamma band between brain regions of female schizophrenia patients during
the auditory oddball task using magnetoencephalography (MEG). Subjects were 12
right-handed female schizophrenia patients, who were evaluated by the Positive
and Negative Syndrome Scales (PANSS). Functional connectivity during an
auditory oddball task was reconstructed in low gamma (30 - 50 Hz) and high
gamma (50 - 100 Hz and 100 - 150 Hz) bands, and represented by IC using seeds
determined by the significant oscillatory power changes obtained by
event-related synchronization (ERS) and event-related desynchronization (ERD)
power measurements. Gamma ERS (30 - 50 Hz) power was decreased in the left
precuneus at 500 - 750 ms and in the right precuneus at 750 - 1000 ms. IC in
the gamma band (50 - 100 Hz) was decreased between the right precuneus (seed)
and right paracentral lobule (target) and between the right precuneus and right
hypothalamus at 0 - 250 ms. IC in the gamma band (100 - 150 Hz) was increased
between the left precuneus and right cuneus (Brodmann area 7) at 250 - 500 ms,
between the left precuneus and right culmen at 500 - 750 ms, and between the
left precuneus and right cuneus (Brodmann area 17), between the left precuneus
and right posterior cingulate cortex, and between the left precuneus and right
caudate nucleus at 750 - 1000 ms. In the high gamma band (50 - 100 Hz) at 0 - 250
ms, significant positive correlations were shown between IC and conceptual
disorganization in PANSS scores, between IC and unusual thought content score,
and between IC and positive scale score. IC within the high gamma band in
female schizophrenia patients showed two types of functional disconnection,
intrahemispheric and interhemispheric. IC between the right or left precuneus
and other specific cortical areas showed dysfunction, suggesting that the
parietal lobe plays an important role in dysfunction in connectivity in the
gamma band during the oddball task.