- Email: [email protected]
P1-27. Influence of stimulus direction on the efficacy of continuous theta burst stimulation
Abstracts / Clinical Neurophysiology 128 (2017) e171–e177
evoked potentials (FMEPs) elicited by transcranial electrical stimulation during microvascular decompression (MVD) in 26 patients with hemifacial spasm. In the orbicularis oculi muscle, the AMRs disappeared in 11 patients before MVD, in six after MVD, and in three during dural closure. The AMRs persisted in six patients. FMEP amplitudes decreased to less than 50% in two patients before MVD, in four after MVD, and in six during dural closure. FMEP amplitudes did not decrease in 14 patients (p < 0.005). In the mentalis muscle, the AMRs disappeared in eight patients before MVD, in five after MVD, and in four during dural closure. AMRs persisted in nine patients. FMEPs decreased in two patients before MVD and in two during dural closure, although the remaining 22 patients did not have decreased FMEPs (p < 0.001). The differences between the time-dependent changes in AMR and FMEP are likely attributable to the different origins of the two responses. AMRs mainly occur around the compression site of the facial nerve and FMEPs mainly originate in the facial nucleus in the brainstem. doi:10.1016/j.clinph.2017.06.012
O3-7-17. Detection of Resting state network activity using eLORETA-ICA in Dementia with Lewy Bodies—Yasunori Aoki, Hiroaki Kazui, Roberto D. Pascual-Marqui, Ryouhei Ishii, Kenji Yoshiyama, Hideki Kanemoto, Yukiko Suzuki, Shunsuke Sato, Shunichiro Ikeda, Masahiro Hata, Masao Iwase (Osaka University, Osaka, Japan) Dementia with Lewy bodies (DLB) is the second most common type of dementia and characterized by progressive cognitive decline, fluctuating cognition, visual hallucinations and Parkinsonism. However, pathophysiological mechanism of these symptoms remain poorly understood. In this study, using exact low resolution brain electromagnetic tomography-independent component analysis (eLORETAICA), we assessed activities of five electroencephalography-resting state networks (EEG-RSNs) in 49 DLB patients who were not administered acetylcholinesterase inhibitors. The results were that DLB patients had significantly decreased activities in the occipital visual network and memory perception network, and significantly enhanced activities in the visual perception network and self-referential network compared to 80 healthy controls. Furthermore, we found correlations between these network activities and DLB symptoms. In particular, enhanced visual perception network activity correlated with severe delusions. Enhanced self-referential network activity correlated with worse working memory. Decreased memory perception network activity correlated with worse semantic memory. In addition, sensorimotor network activity correlated with milder delusions, aberrant motor behavior and fluctuating cognition as well as with more severe Parkinsonism. These results indicate that eLORETA-ICA can sensitively detect EEG-RSN activity changes in DLB related to symptoms. Therefore, eLORETA-ICA with EEG data will be a powerful tool for understanding of neurophysiological mechanisms underlying this disease. doi:10.1016/j.clinph.2017.06.013
P1-06. Two CIDP patients with anti-CNTN1 IgG4 antibodies and nephrotic syndrome—Norito Kokubun, Takahide Nagashima, Kei Funakoshi, Tomoko Komagamine, Koichi Hirata, Nobuhiro Yuki (Dokkyo Medical University, Tochigi, Japan) Previous studies showed that CIDP patients with anti-CNTN1 IgG4 antibodies form a specific subtype, which shows subacute progression and poor prognosis. In contrast, nephropathy has been recognized as a rare complication in CIDP and other immune-mediated neuropathies.
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We here describe two CIDP patients with anti-CNTN1 IgG4 antibodies and nephrotic syndrome. The patients were 35- (P1) and 69-year-old (P2) males. Both patients developed subacute course of sensory and motor neuropathy. In parallel with neuropathy course, nephrotic syndrome was present. Nerve conduction studies revealed severe demyelinating polyneuropathy. The disease showed resistance to IVIg, cortico steroids, plasma exchange and cyclosporine, and the severe sensory disturbance and muscle atrophies were left. High titer of anti-CNTN1 IgG4 antibodies was detected in their serum. Renal biopsy in P1 showed membranous nephropathy with the deposition of IgG1 and IgG4 on the glomerular-basement membrane. These findings arise a possibility of existence of shared antigen between peripheral nerve and renal glomerular-basement membrane. doi:10.1016/j.clinph.2017.06.014
P1-12. L-DOPA may modify function of the sensory cortex in Parkinson’s disease—Nobuyuki Ishii, Hitoshi Mochizuki, Kazutaka Shiomi, Masamitsu Nakazato (University of Miyazaki, Miyazaki, Japan) Sensory disturbance is occasionally accompanied with parkinsonism and is sometimes improved by L-DOPA treatment. The abnormalities in cerebral somatosensory neurons were already revealed by neurophysiological methods. However, whether L-DOPA influences the cerebral somatosensory functions is unknown. We evaluated the effect of L-DOPA on the sensory cortex in Parkinson disease (PD) using neurophysiological technique such as highfrequency oscillations (HFOs) and somatosensory evoked potential recovery functions (SEP-Rs), which could detect slight functional abnormalities of cerebral somatosensory interneurons. We examined ten drug-naïve PD patients in pre- and post-L-DOPA treatment. HFOs were obtained by digitally filtering raw SEPs from 500 to 1000 Hz. For SEP-Rs study, paired-pulse stimuli at various interstimulus intervals (ISIs; 20–200 ms) were given. There were no significant differences in the HFO study. The SEP-Rs study demonstrated that patients with disease duration of more than one year (n = 6) had a significant disinhibition (P = 0.003) in P25-N33 of posttreatment compared with pre-treatment. L-DOPA may have some effects on the abnormal GABAergic interneuron function in sensory cortex, which could improve sensory disturbance by L-DOPA therapy in PD patients. doi:10.1016/j.clinph.2017.06.015
P1-27. Influence of stimulus direction on the efficacy of continuous theta burst stimulation—Takuya Sasaki, Masashi Hamada, Shin-ichi Tokushige, Satomi Inomata-Terada, Yasuo Terao, Yoshikazu Ugawa (The University of Tokyo, Tokyo, Japan) Continuous theta burst stimulation (cTBS) is a method commonly used to induce long term depression (LTD)-like plasticity in human motor cortex. However, its after-effects are likely to be highly variable between individuals. In this study, we hypothesized that the direction of stimulus current may have a role in the efficacy of cTBS, as cTBS is usually applied using a biphasic stimulus pulse which preferentially induces anterior-to-posterior (AP) current in the second depolarizing phase in the brain. To test this, we investigated changes of motor evoked potentials (MEPs) after cTBS carried out with rotating the stimulation coil 45° clockwise from the conventional position, which preferentially induces medial-to-lateral current in the brain. Nine healthy volunteers participated in the study and transcranial magnetic stimulation (TMS) was given to the M1 representation of the right first dorsal interosseous muscle.
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Abstracts / Clinical Neurophysiology 128 (2017) e171–e177
We found that the modified cTBS with rotated coil tented to show better responder rate compared with the conventional cTBS (66.7% vs. 33.3%) though there were no statistical differences. We concluded that the after-effects of cTBS were highly variable irrespective of direction of stimulus current. doi:10.1016/j.clinph.2017.06.016
P1-41. Verification of stimulation site in bulbocavernous reflex (BCR) monitoring—Kunio Sugiyama, Shunpei Ando, Hiroyuki Masuda, Kosuke Kondo, Akihito Wada, Naoyuki Harada, Masaaki Nemoto, Hiroshi Takahashi, Nobuo Sugo (Toho University, Tokyo, Japan) Bulbocavernosus reflex (BCR) monitoring is useful for lumbar and cauda surgery. However, in some cases BCR may be difficult to record. We report verification of the stimulation site of BCR monitoring. The subjects were 24 patients undergoing BCR monitoring from 2010 to 2015 (0–79 years old, 14 males, 10 females). In all cases, BCR was recorded from the needle electrode of the anal sphincter. An adult male stimulated the dorsal side of the penis. The boy stimulated the dorsal and ventral side of the penis. Women were classified into three types: clitoral and labia stimulation, left and right side stimulation of the clitoris, clitoris and pubis stimulation. An adult male was able to record in all cases. An adult female could record with a type that stimulated the clitoris and labia. Childhood cases were difficult to record in all cases. Women’s BCR stimulation needs to directly stimulate the clitoris. Children may be involved in neuropathy due to congenital diseases or underdeveloped nerve. doi:10.1016/j.clinph.2017.06.017
P1-46. Types of F-wave waveform during rest in healthy subjects—Naoko Komatsu, Maki Yamada, Kaito Takamori, Keisuke Akamatsu, Toshihiro Ohnuma, Hirofumi Watanabe, Toshiaki Suzuki (Rokujizo General Hospital, Kyoto, Japan) We investigated types of F-waves during rest in healthy subjects. We measured F-waves from the thenar muscles on the nondominant side after stimulating the median nerve at the wrist in healthy subjects. We calculated the correlation coefficient for each type of F-wave using Microsoft Excel, as recommended by Suzuki et al. (2015), and identified F-waves as those with a value greater than or equal to 0.995. The number of different F-wave types was determined from the number of individual waveforms. The results showed that all F-wave types had different waveforms. Suzuki (2015) reported that F-wave waveform values increased with improvement in voluntary movement in patients with cerebrovascular disease. Therefore, we suggest that evaluation of the type of F-wave waveform be used as a component of motor function assessment. doi:10.1016/j.clinph.2017.06.018
P2-03. An electrophysiological severity classification system for diabetic polyneuropathy and small fiber dysfunction—Chieko Suzuki 1, Masayuki Baba 1, Tomoya Kon 1, Yukihisa Funamizu 1, Tatsuya Ueno 1, Rie Haga 1, Haruo Nishijima 1, Akira Arai 1, Jinichi Nunomura 1, Masahiko Tomiyama 1, Hiroki Mizukami 2, Soroku Yagihashi 2 (1 Aomori Prefectural Central Hospital, Japan , 2 Hirosaki University School of Medicine, Aomori, Japan) We reported an electrophysiological severity classification for diabetic polyneuropathy (DPN) using a nerve conduction study
(NCS). This new classification system combines of the amplitude and velocity of NCS and classifies DPN into five stages. Stage 0 is the mildest stage, while Stage IV is the most severe. Here, we clarified the association of this classification system with small fiber abnormalities. We measured intra-epidermal nerve fiber densities (IENFD) and pain threshold using intra-epidermal electrical stimulation (IES) to evaluate the function of small fibers. We recruited 65 patients with diabetes, and performed NCS, skin biopsy and pain threshold using IES. The mean IENFD observed in the skin biopsies were 8.27 n/mm in Stage 0, 7.79 n/mm in Stage I, 4.49 n/mm in Stage II, 2.85 n/mm in Stage III, and 0 n/mm in Stage IV. The mean pain thresholds were 0.05 mA in Stage 0, 0.11 mA in Stage I, 0.08 mA in Stage II, 0.27 mA in Stage III, and 0.59 mA in Stage IV. In summary, the abnormalities of IENFD and pain threshold correlated with electrophysiological severity. The present results indicate that the large fiber dysfunction in DPN progresses in parallel with the small fiber abnormalities. doi:10.1016/j.clinph.2017.06.019
P2-23. GABA predicts resting-state functional connectivity in cingulate cortex—Kazuyuki Fujihara, Kosuke Narita, Yusuke Suzuki, Masato Kasagi, Tomokazu Motegi, Yuichi Takei, Minami Tagawa, Koichi Ujita, Jamie Near, Masato Fukuda (Gunma University Hospital, Gunma, Japan) Anterior cingulate cortex (ACC) is one of the key components of default mode network (DMN). Recent studies have shown that local concentrations of gamma-amino butyric acid (GABA), the major inhibitory neurotransmitter in central nervous system, modulate activities of specific neuronal networks at rest. But the relationship between GABA level of ACC and the functional connectivity within DMN is largely unknown. In this study, we performed magnetic resonance spectroscopy (MRS) using MEGA-PRESS sequence to measure the amount of GABA in ACC and resting-state functional magnetic resonance imaging to evaluate intrinsic neuronal activity at rest in twenty-five healthy subjects. This experiment demonstrates that GABA/ Creatine (Cr) ratio is not correlated with the functional connectivity between ACC and other DMN regions. On the other hand, GABA/Cr ratio in ACC is significantly correlated with the functional connectivity between ACC and posterior-mid cingulate cortex (pMCC). These results suggests that local GABA level in ACC is a predictor of synchronized activity within cingulate cortex, rather than within DMN. doi:10.1016/j.clinph.2017.06.020
P2-28. Single-event-related changes in Oxy-Hb during verbal discrimination tasks in schizophrenic patients: Correlation with the symptom—Youhei Ishii, Kiichiro Morita, Yoshihisa Shoji, Mamoru Sato, Hiroko Yanagimoto, Naohisa Uchimura (Kurume University, Kurume, Japan) Schizophrenic patients have been associated with cognitive dysfunction including attention and executive functions. ‘‘Shiritori” is a very popular word chain game in Japan. This game requires players to generate a word that begins with the last syllable of the preceding word. The present study assessed the difference of hemodynamic changes between schizophrenic patients and healthy controls during a Japanese word production task (shiritori) based on a single-eventrelated design measured by a multi-channel NIRS system. Relationships between brain activation and clinical symptoms were also examined. The subjects were 30 schizophrenic patients and 30 age- and sex-matched healthy native-Japanese speakers. Two
evoked potentials (FMEPs) elicited by transcranial electrical stimulation during microvascular decompression (MVD) in 26 patients with hemifacial spasm. In the orbicularis oculi muscle, the AMRs disappeared in 11 patients before MVD, in six after MVD, and in three during dural closure. The AMRs persisted in six patients. FMEP amplitudes decreased to less than 50% in two patients before MVD, in four after MVD, and in six during dural closure. FMEP amplitudes did not decrease in 14 patients (p < 0.005). In the mentalis muscle, the AMRs disappeared in eight patients before MVD, in five after MVD, and in four during dural closure. AMRs persisted in nine patients. FMEPs decreased in two patients before MVD and in two during dural closure, although the remaining 22 patients did not have decreased FMEPs (p < 0.001). The differences between the time-dependent changes in AMR and FMEP are likely attributable to the different origins of the two responses. AMRs mainly occur around the compression site of the facial nerve and FMEPs mainly originate in the facial nucleus in the brainstem. doi:10.1016/j.clinph.2017.06.012
O3-7-17. Detection of Resting state network activity using eLORETA-ICA in Dementia with Lewy Bodies—Yasunori Aoki, Hiroaki Kazui, Roberto D. Pascual-Marqui, Ryouhei Ishii, Kenji Yoshiyama, Hideki Kanemoto, Yukiko Suzuki, Shunsuke Sato, Shunichiro Ikeda, Masahiro Hata, Masao Iwase (Osaka University, Osaka, Japan) Dementia with Lewy bodies (DLB) is the second most common type of dementia and characterized by progressive cognitive decline, fluctuating cognition, visual hallucinations and Parkinsonism. However, pathophysiological mechanism of these symptoms remain poorly understood. In this study, using exact low resolution brain electromagnetic tomography-independent component analysis (eLORETAICA), we assessed activities of five electroencephalography-resting state networks (EEG-RSNs) in 49 DLB patients who were not administered acetylcholinesterase inhibitors. The results were that DLB patients had significantly decreased activities in the occipital visual network and memory perception network, and significantly enhanced activities in the visual perception network and self-referential network compared to 80 healthy controls. Furthermore, we found correlations between these network activities and DLB symptoms. In particular, enhanced visual perception network activity correlated with severe delusions. Enhanced self-referential network activity correlated with worse working memory. Decreased memory perception network activity correlated with worse semantic memory. In addition, sensorimotor network activity correlated with milder delusions, aberrant motor behavior and fluctuating cognition as well as with more severe Parkinsonism. These results indicate that eLORETA-ICA can sensitively detect EEG-RSN activity changes in DLB related to symptoms. Therefore, eLORETA-ICA with EEG data will be a powerful tool for understanding of neurophysiological mechanisms underlying this disease. doi:10.1016/j.clinph.2017.06.013
P1-06. Two CIDP patients with anti-CNTN1 IgG4 antibodies and nephrotic syndrome—Norito Kokubun, Takahide Nagashima, Kei Funakoshi, Tomoko Komagamine, Koichi Hirata, Nobuhiro Yuki (Dokkyo Medical University, Tochigi, Japan) Previous studies showed that CIDP patients with anti-CNTN1 IgG4 antibodies form a specific subtype, which shows subacute progression and poor prognosis. In contrast, nephropathy has been recognized as a rare complication in CIDP and other immune-mediated neuropathies.
e173
We here describe two CIDP patients with anti-CNTN1 IgG4 antibodies and nephrotic syndrome. The patients were 35- (P1) and 69-year-old (P2) males. Both patients developed subacute course of sensory and motor neuropathy. In parallel with neuropathy course, nephrotic syndrome was present. Nerve conduction studies revealed severe demyelinating polyneuropathy. The disease showed resistance to IVIg, cortico steroids, plasma exchange and cyclosporine, and the severe sensory disturbance and muscle atrophies were left. High titer of anti-CNTN1 IgG4 antibodies was detected in their serum. Renal biopsy in P1 showed membranous nephropathy with the deposition of IgG1 and IgG4 on the glomerular-basement membrane. These findings arise a possibility of existence of shared antigen between peripheral nerve and renal glomerular-basement membrane. doi:10.1016/j.clinph.2017.06.014
P1-12. L-DOPA may modify function of the sensory cortex in Parkinson’s disease—Nobuyuki Ishii, Hitoshi Mochizuki, Kazutaka Shiomi, Masamitsu Nakazato (University of Miyazaki, Miyazaki, Japan) Sensory disturbance is occasionally accompanied with parkinsonism and is sometimes improved by L-DOPA treatment. The abnormalities in cerebral somatosensory neurons were already revealed by neurophysiological methods. However, whether L-DOPA influences the cerebral somatosensory functions is unknown. We evaluated the effect of L-DOPA on the sensory cortex in Parkinson disease (PD) using neurophysiological technique such as highfrequency oscillations (HFOs) and somatosensory evoked potential recovery functions (SEP-Rs), which could detect slight functional abnormalities of cerebral somatosensory interneurons. We examined ten drug-naïve PD patients in pre- and post-L-DOPA treatment. HFOs were obtained by digitally filtering raw SEPs from 500 to 1000 Hz. For SEP-Rs study, paired-pulse stimuli at various interstimulus intervals (ISIs; 20–200 ms) were given. There were no significant differences in the HFO study. The SEP-Rs study demonstrated that patients with disease duration of more than one year (n = 6) had a significant disinhibition (P = 0.003) in P25-N33 of posttreatment compared with pre-treatment. L-DOPA may have some effects on the abnormal GABAergic interneuron function in sensory cortex, which could improve sensory disturbance by L-DOPA therapy in PD patients. doi:10.1016/j.clinph.2017.06.015
P1-27. Influence of stimulus direction on the efficacy of continuous theta burst stimulation—Takuya Sasaki, Masashi Hamada, Shin-ichi Tokushige, Satomi Inomata-Terada, Yasuo Terao, Yoshikazu Ugawa (The University of Tokyo, Tokyo, Japan) Continuous theta burst stimulation (cTBS) is a method commonly used to induce long term depression (LTD)-like plasticity in human motor cortex. However, its after-effects are likely to be highly variable between individuals. In this study, we hypothesized that the direction of stimulus current may have a role in the efficacy of cTBS, as cTBS is usually applied using a biphasic stimulus pulse which preferentially induces anterior-to-posterior (AP) current in the second depolarizing phase in the brain. To test this, we investigated changes of motor evoked potentials (MEPs) after cTBS carried out with rotating the stimulation coil 45° clockwise from the conventional position, which preferentially induces medial-to-lateral current in the brain. Nine healthy volunteers participated in the study and transcranial magnetic stimulation (TMS) was given to the M1 representation of the right first dorsal interosseous muscle.
e174
Abstracts / Clinical Neurophysiology 128 (2017) e171–e177
We found that the modified cTBS with rotated coil tented to show better responder rate compared with the conventional cTBS (66.7% vs. 33.3%) though there were no statistical differences. We concluded that the after-effects of cTBS were highly variable irrespective of direction of stimulus current. doi:10.1016/j.clinph.2017.06.016
P1-41. Verification of stimulation site in bulbocavernous reflex (BCR) monitoring—Kunio Sugiyama, Shunpei Ando, Hiroyuki Masuda, Kosuke Kondo, Akihito Wada, Naoyuki Harada, Masaaki Nemoto, Hiroshi Takahashi, Nobuo Sugo (Toho University, Tokyo, Japan) Bulbocavernosus reflex (BCR) monitoring is useful for lumbar and cauda surgery. However, in some cases BCR may be difficult to record. We report verification of the stimulation site of BCR monitoring. The subjects were 24 patients undergoing BCR monitoring from 2010 to 2015 (0–79 years old, 14 males, 10 females). In all cases, BCR was recorded from the needle electrode of the anal sphincter. An adult male stimulated the dorsal side of the penis. The boy stimulated the dorsal and ventral side of the penis. Women were classified into three types: clitoral and labia stimulation, left and right side stimulation of the clitoris, clitoris and pubis stimulation. An adult male was able to record in all cases. An adult female could record with a type that stimulated the clitoris and labia. Childhood cases were difficult to record in all cases. Women’s BCR stimulation needs to directly stimulate the clitoris. Children may be involved in neuropathy due to congenital diseases or underdeveloped nerve. doi:10.1016/j.clinph.2017.06.017
P1-46. Types of F-wave waveform during rest in healthy subjects—Naoko Komatsu, Maki Yamada, Kaito Takamori, Keisuke Akamatsu, Toshihiro Ohnuma, Hirofumi Watanabe, Toshiaki Suzuki (Rokujizo General Hospital, Kyoto, Japan) We investigated types of F-waves during rest in healthy subjects. We measured F-waves from the thenar muscles on the nondominant side after stimulating the median nerve at the wrist in healthy subjects. We calculated the correlation coefficient for each type of F-wave using Microsoft Excel, as recommended by Suzuki et al. (2015), and identified F-waves as those with a value greater than or equal to 0.995. The number of different F-wave types was determined from the number of individual waveforms. The results showed that all F-wave types had different waveforms. Suzuki (2015) reported that F-wave waveform values increased with improvement in voluntary movement in patients with cerebrovascular disease. Therefore, we suggest that evaluation of the type of F-wave waveform be used as a component of motor function assessment. doi:10.1016/j.clinph.2017.06.018
P2-03. An electrophysiological severity classification system for diabetic polyneuropathy and small fiber dysfunction—Chieko Suzuki 1, Masayuki Baba 1, Tomoya Kon 1, Yukihisa Funamizu 1, Tatsuya Ueno 1, Rie Haga 1, Haruo Nishijima 1, Akira Arai 1, Jinichi Nunomura 1, Masahiko Tomiyama 1, Hiroki Mizukami 2, Soroku Yagihashi 2 (1 Aomori Prefectural Central Hospital, Japan , 2 Hirosaki University School of Medicine, Aomori, Japan) We reported an electrophysiological severity classification for diabetic polyneuropathy (DPN) using a nerve conduction study
(NCS). This new classification system combines of the amplitude and velocity of NCS and classifies DPN into five stages. Stage 0 is the mildest stage, while Stage IV is the most severe. Here, we clarified the association of this classification system with small fiber abnormalities. We measured intra-epidermal nerve fiber densities (IENFD) and pain threshold using intra-epidermal electrical stimulation (IES) to evaluate the function of small fibers. We recruited 65 patients with diabetes, and performed NCS, skin biopsy and pain threshold using IES. The mean IENFD observed in the skin biopsies were 8.27 n/mm in Stage 0, 7.79 n/mm in Stage I, 4.49 n/mm in Stage II, 2.85 n/mm in Stage III, and 0 n/mm in Stage IV. The mean pain thresholds were 0.05 mA in Stage 0, 0.11 mA in Stage I, 0.08 mA in Stage II, 0.27 mA in Stage III, and 0.59 mA in Stage IV. In summary, the abnormalities of IENFD and pain threshold correlated with electrophysiological severity. The present results indicate that the large fiber dysfunction in DPN progresses in parallel with the small fiber abnormalities. doi:10.1016/j.clinph.2017.06.019
P2-23. GABA predicts resting-state functional connectivity in cingulate cortex—Kazuyuki Fujihara, Kosuke Narita, Yusuke Suzuki, Masato Kasagi, Tomokazu Motegi, Yuichi Takei, Minami Tagawa, Koichi Ujita, Jamie Near, Masato Fukuda (Gunma University Hospital, Gunma, Japan) Anterior cingulate cortex (ACC) is one of the key components of default mode network (DMN). Recent studies have shown that local concentrations of gamma-amino butyric acid (GABA), the major inhibitory neurotransmitter in central nervous system, modulate activities of specific neuronal networks at rest. But the relationship between GABA level of ACC and the functional connectivity within DMN is largely unknown. In this study, we performed magnetic resonance spectroscopy (MRS) using MEGA-PRESS sequence to measure the amount of GABA in ACC and resting-state functional magnetic resonance imaging to evaluate intrinsic neuronal activity at rest in twenty-five healthy subjects. This experiment demonstrates that GABA/ Creatine (Cr) ratio is not correlated with the functional connectivity between ACC and other DMN regions. On the other hand, GABA/Cr ratio in ACC is significantly correlated with the functional connectivity between ACC and posterior-mid cingulate cortex (pMCC). These results suggests that local GABA level in ACC is a predictor of synchronized activity within cingulate cortex, rather than within DMN. doi:10.1016/j.clinph.2017.06.020
P2-28. Single-event-related changes in Oxy-Hb during verbal discrimination tasks in schizophrenic patients: Correlation with the symptom—Youhei Ishii, Kiichiro Morita, Yoshihisa Shoji, Mamoru Sato, Hiroko Yanagimoto, Naohisa Uchimura (Kurume University, Kurume, Japan) Schizophrenic patients have been associated with cognitive dysfunction including attention and executive functions. ‘‘Shiritori” is a very popular word chain game in Japan. This game requires players to generate a word that begins with the last syllable of the preceding word. The present study assessed the difference of hemodynamic changes between schizophrenic patients and healthy controls during a Japanese word production task (shiritori) based on a single-eventrelated design measured by a multi-channel NIRS system. Relationships between brain activation and clinical symptoms were also examined. The subjects were 30 schizophrenic patients and 30 age- and sex-matched healthy native-Japanese speakers. Two