Frontopolar activation during face-to-face conversation: an in situ study using near-infrared spectroscopy.
ABSTRACT Near-infrared spectroscopy (NIRS) is a functional brain imaging technique for monitoring brain activation in a natural setting using near-infrared light, and hence, is considered to have some advantages for studies of brain function during social interactions such as face-to-face conversation compared with functional magnetic resonance imaging and positron emission tomography, which have methodological constraints for studying brain mechanisms underlying social interactions: subjects have to lie down on a bed in a small gantry during examination. The purpose of this study was to validate the possible use of NIRS as a functional brain imaging technique for studying social interactions in a natural setting; therefore, we investigated frontal and temporal lobe activation during face-to-face conversation in healthy subjects in the sitting position. The frontal and superior temporal regions were activated during face-to-face conversation, with higher activity in the speaking segments than in the mute segments during conversation particularly in frontopolar NIRS channels. The magnitude of frontopolar activity negatively correlated with the cooperativeness score of the subjects assessed using the temperament and character inventory. These results demonstrated the successful monitoring of brain function during realistic social interactions using NIRS and interindividual differences in frontopolar activity during conversation in relation to the cooperativeness of an individual.
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ABSTRACT: Functional neuroimaging techniques are widely used to elucidate changes in brain activity, and various questionnaires are used to investigate psychopathological features in patients with eating disorders (ED). It is well known that social skills and interpersonal difficulties are strongly associated with the psychopathology of patients with ED. However, few studies have examined the association between brain activity and social relationships in patients with ED, particularly in patients with extremely low body weight.BMC Psychiatry 06/2014; 14(1):173. · 2.24 Impact Factor
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ABSTRACT: Major depressive disorder (MDD) and bipolar disorder (BD) patients show speech characteristics that vary greatly according to mood state. In a previous study, we found impaired temporal and right inferior frontal gyrus (IFG) activation in schizophrenia during face-to-face conversation; no study had, however, previously investigated mood disorders during face-to-face conversation. Here, we investigated frontal and temporal lobe activation during conversation in patients with MDD and BD. Frontal and temporal lobe activation was measured using near-infrared spectroscopy (NIRS) in 29 patients with MDD, 31 patients with BD, and 31 normal controls (NC). We compared continuous activation and rapid change of activation with talk/listen phase changes during the conversation and analyzed the correlation between these indices and clinical variables. Both the MDD and BD groups showed decreased continuous activation in the left dorsolateral prefrontal (DLPFC) and left frontopolar cortices (FPCs); they also showed decreased rapid change in bilateral FPC activation. In the MDD group, the rapid change of activation was positively correlated with Global Assessment of Functioning (GAF) scores. In the BD group, continuous activation was negatively correlated with age of onset. These results indicate that frontal activation during conversation decreases in both MDD and BD. However, both continuous activation and rapid change may reflect the pathophysiological character of MDD and BD; in particular, the reduced amount of rapid change in the right FPC may be related to impaired adaptive ability in MDD.Journal of Psychiatric Research 10/2014; · 4.09 Impact Factor
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ABSTRACT: The primary goal of our research is to investigate brain functions during human-human cooperative work. For this preliminary study, a human-machine system to investigate cooperative work was developed. Blood flow changes in the brain were examined using functional near-infrared spectroscopy (fNIRS) and a region of interest (ROI) was determined. The relationships between the difficulty in cooperation and brain activity were assessed. A tapping task between a person and a machine was performed as a cooperative task. The machine provided a sound stimulus and the person tapped in correspondence to this stimulus. The stimulus interval was fixed, but stimuli were presented with disturbances. We assumed that degree of this disturbance was equal to the difficulty of cooperation. Our results demonstrated that cerebral activation was observed near the inferior frontal gyrus when the stimulus disturbance increased. Thus, the inferior frontal gyrus was the cerebral region associated with cooperation.Proceedings of the 2013 IEEE International Conference on Systems, Man, and Cybernetics; 10/2013