1. The inhibition/excitation ratio related to task-induced oscillatory modulations during a working memory task: A multtimodal-imaging study using MEG and MRS.
- Author
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Takei, Yuichi, Fujihara, Kazuyuki, Tagawa, Minami, Hironaga, Naruhito, Near, Jamie, Kasagi, Masato, Takahashi, Yumiko, Motegi, Tomokazu, Suzuki, Yusuke, Aoyama, Yoshiyuki, Sakurai, Noriko, Yamaguchi, Miho, Tobimatsu, Shozo, Ujita, Koichi, Tsushima, Yoshito, Narita, Kosuke, and Fukuda, Masato more...
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SHORT-term memory , *MEDICAL imaging systems , *MAGNETOENCEPHALOGRAPHY , *NUCLEAR magnetic resonance spectroscopy , *NEUROTRANSMITTERS - Abstract
Detailed studies on the association between neural oscillations and the neurotransmitters gamma-aminobutyric acid (GABA) and glutamate have been performed in vitro . In addition, recent functional magnetic resonance imaging studies have characterized these neurotransmitters in task-induced deactivation processes during a working memory (WM) task. However, few studies have investigated the relationship between these neurotransmitters and task-induced oscillatory changes in the human brain. Here, using combined magnetoencephalography (MEG) and magnetic resonance spectroscopy (MRS), we investigated the modulation of GABA and glutamate + glutamine (Glx) concentrations related to task-induced oscillations in neural activity during a WM task. We first acquired resting-state MRS and MEG data from 20 healthy male volunteers using the n-back task. Time-frequency analysis was employed to determine the power induced during the encoding and retention phases in perigenual anterior cingulate cortex (pg-ACC), mid-ACC, and occipital cortex (OC). Statistical analysis showed that increased WM load was associated with task-induced oscillatory modulations (TIOMs) of the theta-gamma band relative to the zero-back condition (TIOM 0B ) in each volume of interest during the encoding phase of the n-back task. The task-induced oscillatory modulations in the two-back condition relative to the zero-back condition (TIOM 2B-0B ) were negatively correlated with the percent rate change of the correct hit rate for 2B-0B, but positively correlated with GABA/Glx. The positive correlation between TIOM 2B-0B and GABA/Glx during the WM task indicates the importance of the inhibition/excitation ratio. In particular, a low inhibition/excitation ratio is essential for the efficient inhibition of irrelevant neural activity, thus producing precise task performance. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
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