Prefrontal hemodynamic response to verbal-fluency task and hyperventilation in bipolar disorder measured by multi-channel near-infrared spectroscopy

Matsuo, Koji; Watanabe, Akira; Onodera, Yoichi; Kato, Nobumasa; Kato, Tadafumi

doi:10.1016/j.jad.2003.10.004

« Previous Next »Journal of Affective Disorders
Volume 82, Issue 1 , Pages 85-92, 1 October 2004

Prefrontal hemodynamic response to verbal-fluency task and hyperventilation in bipolar disorder measured by multi-channel near-infrared spectroscopy

Koji Matsuo
- Corresponding author. Department of Neuropsychiatry, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. Tel.: +81-3-5800-9263; fax: +81-3-5800-6894.
- Department of Neuropsychiatry, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
- Laboratory for Molecular Dynamics of Mental Disorders, Brain Science Institute, RIKEN, Japan
Akira Watanabe
- Kujira Hospital, Japan
Yoichi Onodera
- Laboratory for Molecular Dynamics of Mental Disorders, Brain Science Institute, RIKEN, Japan
Nobumasa Kato
- Department of Neuropsychiatry, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
Tadafumi Kato
- Laboratory for Molecular Dynamics of Mental Disorders, Brain Science Institute, RIKEN, Japan

Received 26 December 2002; accepted 1 October 2003.

Abstract

Background: Many neuroimaging studies of patients with bipolar disorder have demonstrated functional hypofrontality (reduced activation of the frontal cortex), although this finding is still controversial. We previously found hypoactivation of the left prefrontal region in remitted subjects with bipolar disorder measured by one-channel near-infrared spectroscopy (NIRS). The aim of the present study was to clarify whether or not this finding was due to altered cerebral lateralization or caused by reduced cerebrovascular reactivity. Methods: We enrolled nine remitted patients with bipolar disorder and nine normal controls. Hemodynamic responses in the prefrontal cortex during the verbal-fluency and hyperventilation tasks were monitored by 24-channel NIRS, which can measure oxygenated hemoglobin (OxyHb), deoxygenated hemoglobin, and total hemoglobin (TotalHb). Results: The increases of OxyHb and TotalHb in the bipolar group were significantly smaller than that in the controls during the verbal-fluency task. The response of TotalHb during hyperventilation in the bipolar group was weaker than that in the controls. Limitations: The sample size was small. Conclusions: These findings suggest that the bilateral hypofrontality to a cognitive task is seen in remitted subjects with bipolar disorder, which may be related to vascular function as measured by the response to hyperventilation.

Keywords: Mood disorder, NIRS, Cognition, Physiological task, Hypofrontality