title: Influence of Pleasant and Unpleasant Auditory Stimuli on Cerebral Blood Flow and Physiological Changes in Normal Subjects.
abstract: The prefrontal cortex (PFC) plays an important role in emotion and emotional regulation. The valence asymmetry hypothesis, proposes that the left/right asymmetry of the PFC activity is correlated with specific emotional responses to stressors. However, this hypothesis still seems to leave room for clarifying neurophysiological mechanisms. The purpose of the present study was to investigate the effects of stimuli with positive and negative valence sounds (hereafter PS, NS) selected from the International Affective Digitized Sounds-2 on physiological and physiological responses, including PFC activity in normal participants. We studied the effect of both stimuli using 12 normal subjects (mean age 26.8 years) on cerebral blood oxygenation in the bilateral PFC by a multi-channel NIRS, alpha wave appearance rate in theta, alpha, beta by EEG, autonomic nervous function by heart rate, and emotional conditions by the State-Trait Anxiety Inventory (STAI) and the visual analogue scale (VAS). PS was selected over 7.00 and NS were fewer than 3.00 in the Pleasure values. Sounds were recorded during 3 s and reproduced at random using software. Every task session was designed in a block manner: seven rests with Brown Noise (30 s) and six tasks (30 s) blocks. All participants performed each session in random order with eyes closed. A paired Student's t-test was used for comparisons (P<0.05). PFC activity showed increases bilaterally during both stimuli with a greater activation of the left side in PS and a tendency of more activation by NS in the right PFC. Significantly greater alpha wave intensity was obtained in PS. Heart rate tended to show smaller values in PS. The STAI level tended to show smaller values in PS, and a significantly greater VAS score was obtained in PS which indicated 'pleasant'. Despite the limitations of this study such as the low numbers of the subjects, the present study indicated that PS provided pleasant psychological and physiological responses and NS unpleasant responses. The PFC was activated bilaterally, implying a valence effect with the possibility of a dominant side.
authors.affiliation: Department of Oral Health and Clinical Science, Division of Sports Dentistry, Tokyo Dental College, 2-9-18, Misaki, Thiyoda, Tokyo, 101-0061, Japan. ttakeda@tdc.ac.jp.
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Takeda
authors.affiliation: Department of Oral Health and Clinical Science, Division of Sports Dentistry, Tokyo Dental College, 2-9-18, Misaki, Thiyoda, Tokyo, 101-0061, Japan.
authors.forename: Michiyo
authors.initials: M
authors.lastname: Konno
authors.affiliation: Department of Oral Health and Clinical Science, Division of Sports Dentistry, Tokyo Dental College, 2-9-18, Misaki, Thiyoda, Tokyo, 101-0061, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kawakami
authors.affiliation: Department of Oral Health and Clinical Science, Division of Sports Dentistry, Tokyo Dental College, 2-9-18, Misaki, Thiyoda, Tokyo, 101-0061, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: Department of Oral Health and Clinical Science, Division of Sports Dentistry, Tokyo Dental College, 2-9-18, Misaki, Thiyoda, Tokyo, 101-0061, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kawano
authors.affiliation: Department of Oral Health and Clinical Science, Division of Sports Dentistry, Tokyo Dental College, 2-9-18, Misaki, Thiyoda, Tokyo, 101-0061, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Nakajima
authors.affiliation: Department of Oral Health and Clinical Science, Division of Sports Dentistry, Tokyo Dental College, 2-9-18, Misaki, Thiyoda, Tokyo, 101-0061, Japan.
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Ozawa
authors.affiliation: Department of Oral Health and Clinical Science, Division of Sports Dentistry, Tokyo Dental College, 2-9-18, Misaki, Thiyoda, Tokyo, 101-0061, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Ishigami
authors.affiliation: Department of Electrical and Electronics Engineering, Nihon University, NEWCAT Institute, College of Engineering, Fukushima, Japan.
authors.forename: Naohiro
authors.initials: N
authors.lastname: Takemura
authors.affiliation: Department of Electrical and Electronics Engineering, Nihon University, NEWCAT Institute, College of Engineering, Fukushima, Japan.|School of Medicine, Department of Neurological Surgery, Nihon University, Tokyo, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Sakatani
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D002560:Cerebrovascular Circulation; D006801:Humans; D017397:Prefrontal Cortex / Q000502:physiology; D064232:Visual Analog Scale
keywords: Electroencephalogram; International Affective Digitized Sounds-2; Near-infrared spectroscopy; Prefrontal cortex; Stress