広汎性発達障害におけるプロソディ理解力の生理学的指標の確立

金沢大学医学系幼児期は言語発達が目覚ましい時期である。就学以降の人を対象とした研究では、広汎性発達障害や言語障害がある人とない人では、音や人の声などの刺激によって引き起こされる脳の反応が、異なったパターンを示すことが言われている。我々は幼児期の段階で、それらの聴覚刺激による子どもの脳の反応を捉えることができれば、子どもの音や声の処理能力や言語能力に関わる発達の指標となりえる可能性があるのではないかと考えた。平成23年度は、我々は3-5歳の定型発達児を対象とするこれまでの研究をさらにすすめ、被験者数を59人にまで増やし、小児用MEG(脳磁図)を用いて「音声」に対する子どもの聴覚刺激による脳反応を測定し、言語能力との関係を調べた。「ね」という呼びかけや共感を表す日本語音声を聴覚刺激とし、等価電流双極子(equivalent current dipole ; ECD)法で聴覚野の反応のIntensityについて解析を行った。さらに、各子どもの聴覚野の反応とK-ABC (Kaufman assessment battery for children)の下位検査である言語課題『なぞなぞ』の得点と比較した。その結果、両半球において100-200msの時間幅で明らかなIntensityのピークが得られた。スピアマン順位相関において、子どもの左半球のIntensityと『なぞなぞ』の得点に有意な相関が認められた。この関係は、月齢や、非言語性の認知機能で、コントロールして(重回帰分析)も、有意な結果であった。これは子どもの言語発達と聴覚野の反応は深く関係している可能性を示唆している。この成果は、査読つき国際論文に発表した(Eur J Neurosci.2012)。研究課題/領域番号:22591277, 研究期間(年度):2010-10-20 – 2013-03-31出典：研究課題「広汎性発達障害におけるプロソディ理解力の生理学的指標の確立」課題番号22591277（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-22591277/）を加工して作

A custom magnetoencephalography device reveals brain connectivity and high reading/decoding ability in children with autism

A subset of individuals with autism spectrum disorder (ASD) performs more proficiently on certain visual tasks than may be predicted by their general cognitive performances. However, in younger children with ASD (aged 5 to 7), preserved ability in these tasks and the neurophysiological correlates of their ability are not well documented. In the present study, we used a custom child-sized magnetoencephalography system and demonstrated that preserved ability in the visual reasoning task was associated with rightward lateralisation of the neurophysiological connectivity between the parietal and temporal regions in children with ASD. In addition, we demonstrated that higher reading/decoding ability was also associated with the same lateralisation in children with ASD. These neurophysiological correlates of visual tasks are considerably different from those that are observed in typically developing children. These findings indicate that children with ASD have inherently different neural pathways that contribute to their relatively preserved ability in visual tasks

Somatosensory Evoked Field in Response to Visuotactile Stimulation in 3- to 4-Year-Old Children

A child-customized magnetoencephalography system was used to investigate somatosensory evoked field (SEF) in 3- to 4-year-old children. Three stimulus conditions were used in which the children received tactile-only stimulation to their left index finger or visuotactile stimulation. In the two visuotactile conditions, the children received tactile stimulation to their finger while they watched a video of tactile stimulation applied either to someone else’s finger (the finger-touch condition) or to someone else’s toe (the toe-touch condition). The latencies and source strengths of equivalent current dipoles (ECDs) over contralateral (right) somatosensory cortex were analyzed. In the preschoolers who provided valid ECDs, the stimulus conditions induced an early-latency ECD occurring between 60 and 68 ms mainly with an anterior direction. We further identified a middle-latency ECD between 97 and 104 ms, which predominantly had a posterior direction. Finally, initial evidence was found for a late-latency ECD at about 139–151 ms again more often with an anterior direction. Differences were found in the source strengths of the middle-latency ECDs among the stimulus conditions. For the paired comparisons that could be formed, ECD source strength was more pronounced in the finger-touch condition than in the tactile-only and the toe-touch conditions. Although more research is necessary to expand the data set, this suggests that visual information modulated preschool SEF. The finding that ECD source strength was higher when seen and felt touch occurred to the same body part, as compared to a different body part, might further indicate that connectivity between visual and tactile information is indexed in preschool somatosensory cortical activity, already in a somatotopic way

The brain's response to the human voice depends on the incidence of autistic traits in the general population.

Optimal brain sensitivity to the fundamental frequency (F0) contour changes in the human voice is important for understanding a speaker's intonation, and consequently, the speaker's attitude. However, whether sensitivity in the brain's response to a human voice F0 contour change varies with an interaction between an individual's traits (i.e., autistic traits) and a human voice element (i.e., presence or absence of communicative action such as calling) has not been investigated. In the present study, we investigated the neural processes involved in the perception of F0 contour changes in the Japanese monosyllables "ne" and "nu." "Ne" is an interjection that means "hi" or "hey" in English; pronunciation of "ne" with a high falling F0 contour is used when the speaker wants to attract a listener's attention (i.e., social intonation). Meanwhile, the Japanese concrete noun "nu" has no communicative meaning. We applied an adaptive spatial filtering method to the neuromagnetic time course recorded by whole-head magnetoencephalography (MEG) and estimated the spatiotemporal frequency dynamics of event-related cerebral oscillatory changes in beta band during the oddball paradigm. During the perception of the F0 contour change when "ne" was presented, there was event-related de-synchronization (ERD) in the right temporal lobe. In contrast, during the perception of the F0 contour change when "nu" was presented, ERD occurred in the left temporal lobe and in the bilateral occipital lobes. ERD that occurred during the social stimulus "ne" in the right hemisphere was significantly correlated with a greater number of autistic traits measured according to the Autism Spectrum Quotient (AQ), suggesting that the differences in human voice processing are associated with higher autistic traits, even in non-clinical subjects

Anterior prefrontal hemodynamic connectivity in conscious 3- to 7-year-old children with typical development and autism spectrum disorder.

Socio-communicative impairments are salient features of autism spectrum disorder (ASD) from a young age. The anterior prefrontal cortex (aPFC), or Brodmann area 10, is a key processing area for social function, and atypical development of this area is thought to play a role in the social deficits in ASD. It is important to understand these brain functions in developing children with ASD. However, these brain functions have not yet been well described under conscious conditions in young children with ASD. In the present study, we focused on the brain hemodynamic functional connectivity between the right and the left aPFC in children with ASD and typically developing (TD) children and investigated whether there was a correlation between this connectivity and social ability. Brain hemodynamic fluctuations were measured non-invasively by near-infrared spectroscopy (NIRS) in 3- to 7-year-old children with ASD (n = 15) and gender- and age-matched TD children (n = 15). The functional connectivity between the right and the left aPFC was assessed by measuring the coherence for low-frequency spontaneous fluctuations (0.01-0.10 Hz) during a narrated picture-card show. Coherence analysis demonstrated that children with ASD had a significantly higher inter-hemispheric connectivity with 0.02-Hz fluctuations, whereas a power analysis did not demonstrate significant differences between the two groups in terms of low frequency fluctuations (0.01-0.10 Hz). This aberrant higher connectivity in children with ASD was positively correlated with the severity of social deficit, as scored with the Autism Diagnostic Observation Schedule. This is the first study to demonstrate aberrant brain functional connectivity between the right and the left aPFC under conscious conditions in young children with ASD

Statistical parametric mapping analyses revealed significant correlation between beta band ERD and AQ score for the “nu” syllable.

<p>A, The AQ score is negatively correlated with differences in beta band ERD (high falling F0 contour “nu” – flat F0 contour “nu”) in the four time windows 100–300 ms (in the left temporal and occipital areas), 200–400 ms (in the left occipital areas), 300–500 ms (in the right frontal areas), and 400–600 ms (in the right temporal areas). B, Scatter plot of the AQ scores and differences in beta band ERD (high falling F0 contour/Nu/− flat F0 contour/nu/) during a time window of 400–600 ms in the right fusiform gyrus (one voxel) in all participants. Higher values in beta band ERD (/Nu/−/nu/) suggest a prominent decrease in the beta band oscillation after the auditory stimuli/Nu/compared with/nu/.</p