- Email: [email protected]
P8-7 Effects of aging on activity of the prefrontal cortex during shiritori task
S148
Posters
significant activity only in association to passive listening of bi-syllabic words. Particularly, they were found activated channels located on left superior temporal gyrus (p = 0.008), left supramarginal gyrus (p = 0.007) and left posterior inferior parietal lobe (p = 0.007). No significant HbO2 variations were observed in association to syllables listening. In a sample of right handed, adult Italian native speakers, we found a significant activation in the left hemisphere during passive listening of bi-syllabic words in areas already known to be involved in speech comprehension. OT proved to be a promising alternative to Wada test for a noninvasive assessment of hemispheric language lateralization. This may be particularly relevant since it was obtained with a testing procedure, requiring minimal subject involvement, designed for future applications with less cooperative subjects (young children or patients with cognitive deficits, mental retardation or behavioural disorders). P8-4 Changes in task-associated cerebral blood induced by Role lettering: Measurement by multichannel near-infrared spectroscopy 1
1,2
3
2
4
Y. Okamoto , K. Morita , A. Yamamoto , Y. Shoji , N. Haruguchi 1 Cognitive and Molecular Research Institute of Brain Diseases, Kurume University, Fukuoka, Japan, 2 Department of Neuropsychiatry, Kurume University, Japan, 3 Cognitive and Molecular Research Institute of Brain Diseases, Kurume University, Fukuoka, Japan, 4 Oita Yuai Hospital, Japan Objective: Role lettering shows promise as an effective treatment for problems resulting from psychological defenses and resistance, because it addresses patients’ paradoxical desires for self-disclosure and confidentiality in the therapy sessions, and this therapeutic exercise is useful in promoting objective self-assessment and personal security by relating oneself to others and others to oneself. Using optical topography (near-infrared spectroscopy: NIRS), relative changes in oxidized hemoglobin (oxy-Hb) were measured before and after the introduction of Role lettering. Methods: Subjects included 16 junior high school students (age, 12.1±0.8; boys, 13; girls, 3). No subject had a psychiatric illness or a motor system disease. The subject wrote the mukashi banashi (‘once a upon a time . . . ’) as a resting state, and ‘from me to five kind of persons’ (friend, mother, father, teacher, special friend) as antegrade, and ‘from five kind of persons to me’ as retrograde tasks with 30-second resting intervals, respectively. The averaged waveforms in the 5 tasks were measured, changes from the resting-state. The ethics committee of Kurume University approved the present study. Results: With the antegrade writing task, no significant difference was observed throughout the study; with the retrograde writing task, oxyHb level decreased significantly in right lateral ROI after 6 months; the decrease persisted at 1 year. The number of words produced after Role lettering increased significantly in both antegrade and retrograde writing tasks at 1 year. Conclusions: Oxy-Hb decreased significantly only in right recording regions, suggesting that subjects became more able to an objectively observe and describe themselves while thinking about themselves as viewed by other person as they practiced Role lettering. By training and continuation, people become able to readily think and perform the task, suggesting that plasticity of the cortical network for emotionally related imaging may contribute to adaptations leading to Role lettering practice. P8-5 Amplitudes of rTMS-evoked NIRS responses correlate with changes in heart rate aki1,2 , K. Kotilahti1,2 , I. Nissil¨ a1 , R.J. Ilmoniemi1 T. N¨ asi1,2 , H. M¨ 1 Department of Biomedical Engineering and Computational Science (BECS), Finland, 2 BioMag Laboratory, HUSLAB, Helsinki University Central Hospital, Helsinki, Finland Objective: Near-infrared spectroscopy (NIRS) can be used to measure concentration changes of total hemoglobin (HbT) due to repetitive transcranial magnetic stimulation (rTMS). In previous studies, TMS-evoked NIRS responses are thought to reflect brain activity. However, NIRS signals are also affected by changes in global hemodynamics. To address this issue, we studied similarities in rTMS-evoked HbT amplitudes and heart rate changes. Methods: We delivered rTMS trains to the left primary motor cortex of eight healthy subjects and recorded corresponding HbT responses over
the stimulation site and measured the heart rate with a pulse oximeter attached to the subject’s finger. The 8-s rTMS trains had an intensity of 75% of the resting motor threshold of the right abductor pollicis brevis, pulse frequencies of 0.5, 1, and 2 Hz in randomized order, and a randomized 20 30 s rest period between them. The NIRS grid had four short (1.3 cm), four intermediate (2.8 cm) and six long (3.8 cm) sourceto-detector (SD) distances. The HbT responses and changes in heart rate were averaged time-locked to the rTMS train onsets. Results: The rTMS produced HbT decreases at all SD distances and heart rate increases. The HbT responses to 0.5- and 2-Hz rTMS had larger amplitudes than the responses to 1-Hz rTMS. The HbT decreases of the subjects correlated with their increases in heart rate. Conclusions: HbT responses evoked by rTMS and changes in the heart rate of subjects are related. Thus, changes in global hemodynamics should be taken into account when analyzing and interpreting TMS-evoked NIRS responses. P8-6 Multichannel NIRS revealed frontal cortex activation associated with speeded processing of visuospatial working memory T. Nakahachi1 , R. Ishii1 , M. Iwase1 , L. Canuet1 , H. Takahashi1 , R. Kurimoto1 , K. Ikezawa1 , M. Azechi1 , Y. Aoki1 , O. Kajimoto2,3 , M. Takeda1 1 Department of Psychiatry, Osaka University Graduate School of Medicine, Japan, 2 Department of Biomarker and Molecular Biophysics, Osaka City University Graduate School of Medicine, Japan, 3 Soiken Incorporated, Japan Objective: Visuospatial working memory (VSWM) is commonly used during speeded and rather unconscious memory processing in daily life. The purpose of this study is to measure frontal cortex activation in a style mimicking VSWM performance in daily life activities using multichannel near-infrared spectroscopy (NIRS). Methods: Twenty-six healthy volunteers were enrolled in this study. We measured relative changes in concentration of oxygenated hemoglobin ([oxy-Hb]) by NIRS, as index of frontal activation, during a VSWM task, namely the Advanced Trail Making Test (ATMT). This task consists of Task R and Task F: the former is believed to measure motor factors only, and the latter is thought to measure motor and cognitive factors, which are involved in speeded and rather unconscious VSWM operations. Results: Changes in [oxy-Hb] during the ATMT were determined in fifty-two measurement points (channels) on the frontal area. Activated channels during Task F performance were distributed bilaterally over the dorsolateral and ventrolateral prefrontal cortices. This cortical activation might reflect central executive function of working memory. On the other hand, the channels activated by Task R were observed only over the left ventrolateral prefrontal cortex which was also activated during Task F performance and presumably represents subvocal articulatory rehearsal or task-related motor factors activation. Conclusions: It was confirmed that application of multichannel NIRS during ATMT performance is feasible to measure VSWM-induced cortical activation in a similar way that VSWM is used in daily activities. P8-7 Effects of aging on activity of the prefrontal cortex during shiritori task A. Yamamoto1 , K. Morita1 , Y. Shoji1,2 , Y. Nakashima1 , Y. Okamoto1 , N. Uchimura2 1 Cognitive and Molecular Research Institute of Brain Diseases, Fukuoka, Japan, 2 Department of Neuropsychiatry Kurume University School of Medicine, Fukuoka, Japan Changes in oxy-Hb during performing a shiritori (Japanese word-chain game) task were compared among generations in healthy subjects using optic topography (NIRS). The subjects were junior high school students (age: 12.9±0.67 years), adults (age: 30.7±11.32 years), and elderly persons (age: 70.7±3.03 years). They alternately performed control (6 times) and shiritori (5 times) tasks every 30 seconds, and the total number of words produced during the shiritori task was regarded as the result. Changes in oxy-Hb during performing the task were measured via a 44 channel set on the bilateral sides using an NIRS system (ETG4000, Hitachi). The task result was not significantly different among the 3 generation groups, but significant differences in oxy-Hb changes were noted in the left measurement region during performing the shiritori task between the junior high school student and adult groups and between the
29th International Congress of Clinical Neurophysiology adult and elderly groups. The smallest increase in oxy-Hb was noted in the adult group, and the increase was significantly smaller than those in the junior high school student and elderly groups. In contrast, no significant difference was noted in the right measurement region between the junior high school student and adult groups or between the adult and elderly groups. The task result and increase in oxy-Hb were not significantly correlated in the junior high school student and adult groups, but a significant positive correlation was noted in the elderly group. Measurement of increases in oxy-Hb by NIRS detects age-related changes in brain activity, which may serve as a useful psychophysiological index. P8-8 Consideration on fluctuation in NIRS measurement N. Matsushiro1 , K. Yamashita1 , Y. Kasagi2 , K. Nakazawa3 , I. Shimoyama2 Graduate School of Medicine, Chiba University, Chiba, Japan, 2 Human Neurophysiology, Frontier Medical Eng., Chiba University, Chiba, Japan, 3 Integrative Neurophysiology, Graduate School of Medicine, Chiba University, Chiba, Japan 1
The oxygen dynamic monitoring using NIRS which have relatively short history is still in debate over the reliability of its absolute value and the interpretation of the measurement result. The difficulty of the reliability problem lies in the fluctuation problem. Not only NIRS but also EEG, the effect of the fluctuation of neural activities has not been clarified up until now. It is difficult to quantify the amount of the fluctuation. In this study, fluctuation is evaluated based on correlation between two pair of measurements: EEG and NIRS at alpha-blocking phenomena, and oxy-Hb and deox-Hb (NIRS) at rest. Larger fluctuation in the two pair of signals leads smaller correlation coefficients. Experiments have been performed with five volunteers. Simultaneous measurement of EEG and NIRS have been performed for the eyes opening and closing alternative task and the rest task. Based on the correlation coefficients, we can conclude that fluctuations do not disturb meanings included in signals of NIRS for the tasks employed in this paper. P8-9 Auditory delayed feedback and learning: near infrared spectroscopy on the forehead. K. Yamashita1,2 , I. Shimoyama1,2 , Y. Kasagi1 , N. Matsushiro1,2 , R. Okamoto1 , K. Yoshizaki1 , A. Yoshida1 , F. Hayashi1 1 Department of Human Neurophysiology, Graduate School of Medicine, Chiba University, Japan, 2 Human Neurophysiology, Frontier Medical Engineering, Chiba University, Japan Objective: To study auditory learning, the effect of delayed auditory feedback on the activity of the bilateral prefrontal region of the brain was investigated by near-infrared light spectroscopy (NIRS). Methods: Ten volunteers read aloud one of Aesop’s Fables written in Japanese as they listened to their own voices through headphones. They read aloud the story and alternatively listened to their self-voice with no delay or a designated 200-ms delay repeating 5 times each. Changes in cerebral blood oxygenation of the bilateral prefrontal region were monitored by measuring the oxygenated and deoxygenated hemoglobin levels every 1/6 s using two-channel NIRS (NIRO-200, Hamamatsu, Japan). Blood flow was measured over the mid forehead at 10 Hz (CDF-2000, CyberMed, NEC Infrontia, Japan). The voice was recorded with a voice recorder at 22.1 kHz. Results: The oxygenated hemoglobin levels on the bilateral prefrontal region were significantly increased at the first reading with no delay and the delay (p < 0.05). However, the oxygenated hemoglobin levels varied within each repeated reading set. The forehead cutaneous blood flow did not change significantly. The duration in reading time with delayed feedback is more decreased over time compared with no delay (p < 0.05). Conclusion: With or without delayed feedback of self-voice, oxygenated hemoglobin levels in the bilateral prefrontal region were increased at the first reading of a story. The reading time when there was delayed feedback decreased over time most likely due to the learning effect.
S149 P8-10 Effects of transcranial direct current stimulation on movement associated cortical activation T. Ogino1 , S. Obayashi1 , S. Ogawa1 , Y. Hara1 , S. Kobayashi2 1 Nippon Medical School, Chiba Hokusoh Hospital, Department of Rehabilitation Medicine, Japan, 2 Nippon Medical School, Chiba Hokusoh Hospital, Department of Neurosurgery, Japan Transcranial direct current stimulation (tDCS) is a non-invasive technique with which motor function of healthy adults and stroke survivors is expected to improve. However, the effects of tDCS on cortical motor activity remain poorly defined. Here the purpose of present study is to research the effect of tDCS on the cortical activation during movement using near infrared spectroscopy (NIRS). Ten right-handed healthy subjects participated in this study. We studied cortical activation changes under the electrodes induced by tDCS using NIRS. tDCS applied to the scalp over the left sensorimotor cortex (C3 area by international 10/20 EEG system) with the stimulation methods of anode, cathode or sham. NIRS recordings were also made during tDCS stimulation. These three different stimulation sessions were examined under the motor tasks and rest. The motor tasks were pinch movements which performed 50% maximal voluntary contraction using the right hand. Cortical activation changes were measured by the concentration of oxygenated hemoglobin (oxy-Hb) around the location of C3 area. Under the active condition, oxyHb concentration decreased in the anodal stimulation and increased as for the cathodal stimulation, in comparison with sham stimulation. Under the resting condition, neither anodal nor cathodal stimulation changed the oxy-Hb concentration compared with ones of sham stimulation. Therefore, our results suggest that tDSC contributes to the movement associated change of cortical activation. P8-11 Developmental change of prefrontal activity in Go/Nogo task revealed by Near Infrared-Spectroscopy T. Mizutani1 , H. Ozaki2 , T. Koike3 1 The Graduate School of Psychology, Rissho University, Tokyo, Japan, 2 College of Education, Ibaraki University, Ibaraki, Japan, 3 Comprehensive Educational Sceience, Tokyo Gakugei University, Tokyo, Japan Objective: It is known that development of executive process relates with maturation of prefrontal cortex during childhood. To examine the developmental change of motor execution/inhibition, cerebral blood flow in prefrontal cortices was measured during Go/Nogo task. Methods: 23 children from 6 to 13 years old had participated. Visual target or nontarget was presented with equal probability at one of four quadrants of CRT for 0.5 sec with 1 sec interval. All participants were asked to press the key as soon as possible when target appeared during Go/Nogo task for 2 min. As baseline condition, simple reaction tasks with 100% probability of target were executed for 1 min before and after Go/Nogo task. 16-ch NIRS (OEG-100, Spectratech inc, Japan) was used to measure concentration of Oxy-Hb and Deoxy-Hb. 2×6 array was placed over the forehead and the center of bottom row was placed at Fpz according to international 10/20 system. Results: The behavioral reaction was accelerated according to development. In lateral part of prefrontal cortex, remarkable increase of Oxy-Hb was observed both in younger and older children. The increase of Oxy-Hb was grater in younger children than that in older children. In medial part of prefrontal cortex, remarkable increase of Oxy-Hb was also observed in younger children, but not in older children. Discussion: The brain activity enhanced more extensively at medial and lateral parts in prefrontal cortex in younger children. However, prefrontal activation was localized to lateral part of prefrontal cortex in older children. Motor response might be inhibited when nontarget appeared in both groups. Therefore, lateral part of prefrontal cortex which might concern to motor inhibition was activated. According to maturation of motor control, little attentional demands will be enough to discriminate stimuli in older children. Absence of medial activation of prefrontal cortex in older children might be concerned with lesser attentional resource to control motor behavior.
Posters
significant activity only in association to passive listening of bi-syllabic words. Particularly, they were found activated channels located on left superior temporal gyrus (p = 0.008), left supramarginal gyrus (p = 0.007) and left posterior inferior parietal lobe (p = 0.007). No significant HbO2 variations were observed in association to syllables listening. In a sample of right handed, adult Italian native speakers, we found a significant activation in the left hemisphere during passive listening of bi-syllabic words in areas already known to be involved in speech comprehension. OT proved to be a promising alternative to Wada test for a noninvasive assessment of hemispheric language lateralization. This may be particularly relevant since it was obtained with a testing procedure, requiring minimal subject involvement, designed for future applications with less cooperative subjects (young children or patients with cognitive deficits, mental retardation or behavioural disorders). P8-4 Changes in task-associated cerebral blood induced by Role lettering: Measurement by multichannel near-infrared spectroscopy 1
1,2
3
2
4
Y. Okamoto , K. Morita , A. Yamamoto , Y. Shoji , N. Haruguchi 1 Cognitive and Molecular Research Institute of Brain Diseases, Kurume University, Fukuoka, Japan, 2 Department of Neuropsychiatry, Kurume University, Japan, 3 Cognitive and Molecular Research Institute of Brain Diseases, Kurume University, Fukuoka, Japan, 4 Oita Yuai Hospital, Japan Objective: Role lettering shows promise as an effective treatment for problems resulting from psychological defenses and resistance, because it addresses patients’ paradoxical desires for self-disclosure and confidentiality in the therapy sessions, and this therapeutic exercise is useful in promoting objective self-assessment and personal security by relating oneself to others and others to oneself. Using optical topography (near-infrared spectroscopy: NIRS), relative changes in oxidized hemoglobin (oxy-Hb) were measured before and after the introduction of Role lettering. Methods: Subjects included 16 junior high school students (age, 12.1±0.8; boys, 13; girls, 3). No subject had a psychiatric illness or a motor system disease. The subject wrote the mukashi banashi (‘once a upon a time . . . ’) as a resting state, and ‘from me to five kind of persons’ (friend, mother, father, teacher, special friend) as antegrade, and ‘from five kind of persons to me’ as retrograde tasks with 30-second resting intervals, respectively. The averaged waveforms in the 5 tasks were measured, changes from the resting-state. The ethics committee of Kurume University approved the present study. Results: With the antegrade writing task, no significant difference was observed throughout the study; with the retrograde writing task, oxyHb level decreased significantly in right lateral ROI after 6 months; the decrease persisted at 1 year. The number of words produced after Role lettering increased significantly in both antegrade and retrograde writing tasks at 1 year. Conclusions: Oxy-Hb decreased significantly only in right recording regions, suggesting that subjects became more able to an objectively observe and describe themselves while thinking about themselves as viewed by other person as they practiced Role lettering. By training and continuation, people become able to readily think and perform the task, suggesting that plasticity of the cortical network for emotionally related imaging may contribute to adaptations leading to Role lettering practice. P8-5 Amplitudes of rTMS-evoked NIRS responses correlate with changes in heart rate aki1,2 , K. Kotilahti1,2 , I. Nissil¨ a1 , R.J. Ilmoniemi1 T. N¨ asi1,2 , H. M¨ 1 Department of Biomedical Engineering and Computational Science (BECS), Finland, 2 BioMag Laboratory, HUSLAB, Helsinki University Central Hospital, Helsinki, Finland Objective: Near-infrared spectroscopy (NIRS) can be used to measure concentration changes of total hemoglobin (HbT) due to repetitive transcranial magnetic stimulation (rTMS). In previous studies, TMS-evoked NIRS responses are thought to reflect brain activity. However, NIRS signals are also affected by changes in global hemodynamics. To address this issue, we studied similarities in rTMS-evoked HbT amplitudes and heart rate changes. Methods: We delivered rTMS trains to the left primary motor cortex of eight healthy subjects and recorded corresponding HbT responses over
the stimulation site and measured the heart rate with a pulse oximeter attached to the subject’s finger. The 8-s rTMS trains had an intensity of 75% of the resting motor threshold of the right abductor pollicis brevis, pulse frequencies of 0.5, 1, and 2 Hz in randomized order, and a randomized 20 30 s rest period between them. The NIRS grid had four short (1.3 cm), four intermediate (2.8 cm) and six long (3.8 cm) sourceto-detector (SD) distances. The HbT responses and changes in heart rate were averaged time-locked to the rTMS train onsets. Results: The rTMS produced HbT decreases at all SD distances and heart rate increases. The HbT responses to 0.5- and 2-Hz rTMS had larger amplitudes than the responses to 1-Hz rTMS. The HbT decreases of the subjects correlated with their increases in heart rate. Conclusions: HbT responses evoked by rTMS and changes in the heart rate of subjects are related. Thus, changes in global hemodynamics should be taken into account when analyzing and interpreting TMS-evoked NIRS responses. P8-6 Multichannel NIRS revealed frontal cortex activation associated with speeded processing of visuospatial working memory T. Nakahachi1 , R. Ishii1 , M. Iwase1 , L. Canuet1 , H. Takahashi1 , R. Kurimoto1 , K. Ikezawa1 , M. Azechi1 , Y. Aoki1 , O. Kajimoto2,3 , M. Takeda1 1 Department of Psychiatry, Osaka University Graduate School of Medicine, Japan, 2 Department of Biomarker and Molecular Biophysics, Osaka City University Graduate School of Medicine, Japan, 3 Soiken Incorporated, Japan Objective: Visuospatial working memory (VSWM) is commonly used during speeded and rather unconscious memory processing in daily life. The purpose of this study is to measure frontal cortex activation in a style mimicking VSWM performance in daily life activities using multichannel near-infrared spectroscopy (NIRS). Methods: Twenty-six healthy volunteers were enrolled in this study. We measured relative changes in concentration of oxygenated hemoglobin ([oxy-Hb]) by NIRS, as index of frontal activation, during a VSWM task, namely the Advanced Trail Making Test (ATMT). This task consists of Task R and Task F: the former is believed to measure motor factors only, and the latter is thought to measure motor and cognitive factors, which are involved in speeded and rather unconscious VSWM operations. Results: Changes in [oxy-Hb] during the ATMT were determined in fifty-two measurement points (channels) on the frontal area. Activated channels during Task F performance were distributed bilaterally over the dorsolateral and ventrolateral prefrontal cortices. This cortical activation might reflect central executive function of working memory. On the other hand, the channels activated by Task R were observed only over the left ventrolateral prefrontal cortex which was also activated during Task F performance and presumably represents subvocal articulatory rehearsal or task-related motor factors activation. Conclusions: It was confirmed that application of multichannel NIRS during ATMT performance is feasible to measure VSWM-induced cortical activation in a similar way that VSWM is used in daily activities. P8-7 Effects of aging on activity of the prefrontal cortex during shiritori task A. Yamamoto1 , K. Morita1 , Y. Shoji1,2 , Y. Nakashima1 , Y. Okamoto1 , N. Uchimura2 1 Cognitive and Molecular Research Institute of Brain Diseases, Fukuoka, Japan, 2 Department of Neuropsychiatry Kurume University School of Medicine, Fukuoka, Japan Changes in oxy-Hb during performing a shiritori (Japanese word-chain game) task were compared among generations in healthy subjects using optic topography (NIRS). The subjects were junior high school students (age: 12.9±0.67 years), adults (age: 30.7±11.32 years), and elderly persons (age: 70.7±3.03 years). They alternately performed control (6 times) and shiritori (5 times) tasks every 30 seconds, and the total number of words produced during the shiritori task was regarded as the result. Changes in oxy-Hb during performing the task were measured via a 44 channel set on the bilateral sides using an NIRS system (ETG4000, Hitachi). The task result was not significantly different among the 3 generation groups, but significant differences in oxy-Hb changes were noted in the left measurement region during performing the shiritori task between the junior high school student and adult groups and between the
29th International Congress of Clinical Neurophysiology adult and elderly groups. The smallest increase in oxy-Hb was noted in the adult group, and the increase was significantly smaller than those in the junior high school student and elderly groups. In contrast, no significant difference was noted in the right measurement region between the junior high school student and adult groups or between the adult and elderly groups. The task result and increase in oxy-Hb were not significantly correlated in the junior high school student and adult groups, but a significant positive correlation was noted in the elderly group. Measurement of increases in oxy-Hb by NIRS detects age-related changes in brain activity, which may serve as a useful psychophysiological index. P8-8 Consideration on fluctuation in NIRS measurement N. Matsushiro1 , K. Yamashita1 , Y. Kasagi2 , K. Nakazawa3 , I. Shimoyama2 Graduate School of Medicine, Chiba University, Chiba, Japan, 2 Human Neurophysiology, Frontier Medical Eng., Chiba University, Chiba, Japan, 3 Integrative Neurophysiology, Graduate School of Medicine, Chiba University, Chiba, Japan 1
The oxygen dynamic monitoring using NIRS which have relatively short history is still in debate over the reliability of its absolute value and the interpretation of the measurement result. The difficulty of the reliability problem lies in the fluctuation problem. Not only NIRS but also EEG, the effect of the fluctuation of neural activities has not been clarified up until now. It is difficult to quantify the amount of the fluctuation. In this study, fluctuation is evaluated based on correlation between two pair of measurements: EEG and NIRS at alpha-blocking phenomena, and oxy-Hb and deox-Hb (NIRS) at rest. Larger fluctuation in the two pair of signals leads smaller correlation coefficients. Experiments have been performed with five volunteers. Simultaneous measurement of EEG and NIRS have been performed for the eyes opening and closing alternative task and the rest task. Based on the correlation coefficients, we can conclude that fluctuations do not disturb meanings included in signals of NIRS for the tasks employed in this paper. P8-9 Auditory delayed feedback and learning: near infrared spectroscopy on the forehead. K. Yamashita1,2 , I. Shimoyama1,2 , Y. Kasagi1 , N. Matsushiro1,2 , R. Okamoto1 , K. Yoshizaki1 , A. Yoshida1 , F. Hayashi1 1 Department of Human Neurophysiology, Graduate School of Medicine, Chiba University, Japan, 2 Human Neurophysiology, Frontier Medical Engineering, Chiba University, Japan Objective: To study auditory learning, the effect of delayed auditory feedback on the activity of the bilateral prefrontal region of the brain was investigated by near-infrared light spectroscopy (NIRS). Methods: Ten volunteers read aloud one of Aesop’s Fables written in Japanese as they listened to their own voices through headphones. They read aloud the story and alternatively listened to their self-voice with no delay or a designated 200-ms delay repeating 5 times each. Changes in cerebral blood oxygenation of the bilateral prefrontal region were monitored by measuring the oxygenated and deoxygenated hemoglobin levels every 1/6 s using two-channel NIRS (NIRO-200, Hamamatsu, Japan). Blood flow was measured over the mid forehead at 10 Hz (CDF-2000, CyberMed, NEC Infrontia, Japan). The voice was recorded with a voice recorder at 22.1 kHz. Results: The oxygenated hemoglobin levels on the bilateral prefrontal region were significantly increased at the first reading with no delay and the delay (p < 0.05). However, the oxygenated hemoglobin levels varied within each repeated reading set. The forehead cutaneous blood flow did not change significantly. The duration in reading time with delayed feedback is more decreased over time compared with no delay (p < 0.05). Conclusion: With or without delayed feedback of self-voice, oxygenated hemoglobin levels in the bilateral prefrontal region were increased at the first reading of a story. The reading time when there was delayed feedback decreased over time most likely due to the learning effect.
S149 P8-10 Effects of transcranial direct current stimulation on movement associated cortical activation T. Ogino1 , S. Obayashi1 , S. Ogawa1 , Y. Hara1 , S. Kobayashi2 1 Nippon Medical School, Chiba Hokusoh Hospital, Department of Rehabilitation Medicine, Japan, 2 Nippon Medical School, Chiba Hokusoh Hospital, Department of Neurosurgery, Japan Transcranial direct current stimulation (tDCS) is a non-invasive technique with which motor function of healthy adults and stroke survivors is expected to improve. However, the effects of tDCS on cortical motor activity remain poorly defined. Here the purpose of present study is to research the effect of tDCS on the cortical activation during movement using near infrared spectroscopy (NIRS). Ten right-handed healthy subjects participated in this study. We studied cortical activation changes under the electrodes induced by tDCS using NIRS. tDCS applied to the scalp over the left sensorimotor cortex (C3 area by international 10/20 EEG system) with the stimulation methods of anode, cathode or sham. NIRS recordings were also made during tDCS stimulation. These three different stimulation sessions were examined under the motor tasks and rest. The motor tasks were pinch movements which performed 50% maximal voluntary contraction using the right hand. Cortical activation changes were measured by the concentration of oxygenated hemoglobin (oxy-Hb) around the location of C3 area. Under the active condition, oxyHb concentration decreased in the anodal stimulation and increased as for the cathodal stimulation, in comparison with sham stimulation. Under the resting condition, neither anodal nor cathodal stimulation changed the oxy-Hb concentration compared with ones of sham stimulation. Therefore, our results suggest that tDSC contributes to the movement associated change of cortical activation. P8-11 Developmental change of prefrontal activity in Go/Nogo task revealed by Near Infrared-Spectroscopy T. Mizutani1 , H. Ozaki2 , T. Koike3 1 The Graduate School of Psychology, Rissho University, Tokyo, Japan, 2 College of Education, Ibaraki University, Ibaraki, Japan, 3 Comprehensive Educational Sceience, Tokyo Gakugei University, Tokyo, Japan Objective: It is known that development of executive process relates with maturation of prefrontal cortex during childhood. To examine the developmental change of motor execution/inhibition, cerebral blood flow in prefrontal cortices was measured during Go/Nogo task. Methods: 23 children from 6 to 13 years old had participated. Visual target or nontarget was presented with equal probability at one of four quadrants of CRT for 0.5 sec with 1 sec interval. All participants were asked to press the key as soon as possible when target appeared during Go/Nogo task for 2 min. As baseline condition, simple reaction tasks with 100% probability of target were executed for 1 min before and after Go/Nogo task. 16-ch NIRS (OEG-100, Spectratech inc, Japan) was used to measure concentration of Oxy-Hb and Deoxy-Hb. 2×6 array was placed over the forehead and the center of bottom row was placed at Fpz according to international 10/20 system. Results: The behavioral reaction was accelerated according to development. In lateral part of prefrontal cortex, remarkable increase of Oxy-Hb was observed both in younger and older children. The increase of Oxy-Hb was grater in younger children than that in older children. In medial part of prefrontal cortex, remarkable increase of Oxy-Hb was also observed in younger children, but not in older children. Discussion: The brain activity enhanced more extensively at medial and lateral parts in prefrontal cortex in younger children. However, prefrontal activation was localized to lateral part of prefrontal cortex in older children. Motor response might be inhibited when nontarget appeared in both groups. Therefore, lateral part of prefrontal cortex which might concern to motor inhibition was activated. According to maturation of motor control, little attentional demands will be enough to discriminate stimuli in older children. Absence of medial activation of prefrontal cortex in older children might be concerned with lesser attentional resource to control motor behavior.