Kotoe Sakihara

Self-face recognition in children with autism spectrum disorders : A near-infrared spectroscopy study

It is assumed that children with autism spectrum disorders (ASD) have specificities for self-face recognition, which is known to be a basic cognitive ability for social development. In the present study, we investigated neurological substrates and potentially influential factors for self-face recognition of ASD patients using near-infrared spectroscopy (NIRS). The subjects were 11 healthy adult men, 13 normally developing boys, and 10 boys with ASD. Their hemodynamic activities in the frontal area and their scanning strategies (eye-movement) were examined during self-face recognition. Other factors such as ASD severities and self-consciousness were also evaluated by parents and patients, respectively. Oxygenated hemoglobin levels were higher in the regions corresponding to the right inferior frontal gyrus than in those corresponding to the left inferior frontal gyrus. In two groups of children these activities reflected ASD severities, such that the more serious ASD characteristics corresponded with lower activity levels. Moreover, higher levels of public self-consciousness intensified the activities, which were not influenced by the scanning strategies. These findings suggest that dysfunction in the right inferior frontal gyrus areas responsible for self-face recognition is one of the crucial neural substrates underlying ASD characteristics, which could potentially be used to evaluate psychological aspects such as public self-consciousness.

Reduced prefrontal hemodynamic response in children with ADHD during the Go/NoGo task: a NIRS study.

The current study examined the hemodynamic response during the Go/NoGo task in children with/without attention deficit/hyperactivity disorder (ADHD). Using near-infrared spectroscopy, oxy-Hb and deoxy-Hb concentration changes in the frontal areas were compared during the conditions with/without inhibitory demand. Compared with typically developing children, children with ADHD showed significantly reduced activation during the conditions with inhibitory demand (NoGo-condition) in the frontal areas. However, no significant differences in activation during the conditions without inhibitory demand (Go-condition) were found between the two groups. The current findings revealed that children with ADHD exhibit an altered hemodynamic response specifically during response inhibition, but not during response execution, and suggested the clinical usefulness of near-infrared spectroscopy for the evaluation of response inhibition deficits in children with ADHD.

Effects of the emotional connotations in words on the frontal areas--a spatially filtered MEG study.

The objective of this study was to elucidate how and where emotional connotations in words influenced linguistic processing in the language-related areas. We recorded neuromagnetic signals in nine right-handed and one left-handed healthy volunteers while they silently read emotional and emotionless words written in Japanese kanji characters, and investigated the distribution of the cerebral oscillatory changes using synthetic aperture magnetometry. Event-related desynchronizations (ERDs) in the beta-low gamma bands were observed in the anterior cingulate cortex (ACC) that were specific to the reading of emotional words in seven of nine right-handers. Beta-low gamma band ERDs were also detected in the left inferior or middle frontal gyrus (IFG or MFG) in nine right-handers regardless of the tasks. The magnitude of the ERDs in the IFG or MFG was significantly greater during emotional-word reading than during emotionless-word reading in nine right-handers. Left-dominant ERDs in the beta and gamma bands were observed in the prefrontal cortex (PFC) when negative emotional words were read (i.e. sadness), while right-dominant ERDs were observed for positive emotional words (i.e. happiness) in seven of nine right-handers (p=0.012, corrected). In one left-hander, the ERD in the ACC and the greater ERD that occurred in the IFG that was specific to emotional-word reading were also observed, but their lateralities in the IFG and PFC were reversed. These results suggest that emotional connotations in words facilitated the ERDs in the frontal language-related areas, and that these facilitations might be modulated by emotional processing in the ACC. Furthermore, negative and positive emotional words may be processed by different mechanisms.

Gamma-band desynchronization in language areas reflects syntactic process of words

The aim of this study was to verify the relation between gamma-band activity and process of function words. We recorded the neuromagnetic signals in six healthy volunteers during silent reading of verbs (verb task) and forming of the past tenses (past-tense task) and investigated the spatio-temporal distribution of event-related desynchronization (ERD) and synchronization using synthetic aperture magnetometry. In both tasks, ERDs were observed simultaneously at multiple language-related areas. The left junctional area of inferior frontal sulcus and precentral sulcus and the left supramarginal gyrus showed stronger and/or longer-lasting ERDs in past-tense task than in verb task. This result suggests that the gamma-activities reflect the syntactic process of words.

Transcranial magnetic stimulation over the cerebellum evokes late potential in the soleus muscle

Transcranial magnetic stimulation (TMS) with a double cone coil placed over the left lateral side of the basal occiput was able to elicit late electromyographic (EMG) responses at the bilateral soleus muscles (SOL) averaged over 30 stimulation events, with a mean latency of approximately 100 ms. These EMG responses were detected using a low frequency bandpass filter with 0.05 Hz magnetic stimulation on ten healthy subjects in standing posture. As magnetic stimulation over the left basal occiput with a double cone coil can stimulate cerebellar structure, this late response seems to be conducted from the cerebellar structure to the SOL via an as yet unknown descending pathway. Here, we report new late EMG responses in relation to cerebellum or cerebellum related structures.

Scanning Strategies Do Not Modulate Face Identification: Eye-Tracking and Near-Infrared Spectroscopy Study

Background During face identification in humans, facial information is sampled (seeing) and handled (processing) in ways that are influenced by the kind of facial image type, such as a self-image or an image of another face. However, the relationship between seeing and information processing is seldom considered. In this study, we aimed to reveal this relationship using simultaneous eye-tracking measurements and near-infrared spectroscopy (NIRS) in face identification tasks. Methodology/Principal Findings 22 healthy adult subjects (8 males and 14 females) were shown facial morphing movies in which an initial facial image gradually changed into another facial image (that is, the subjects own face was changed to a familiar face). The fixation patterns on facial features were recorded, along with changes in oxyhemoglobin (oxyHb) levels in the frontal lobe, while the subjects identified several faces. In the self-face condition (self-face as the initial image), hemodynamic activity around the right inferior frontal gyrus (IFG) was significantly greater than in the familiar-face condition. On the other hand, the scanning strategy was similar in almost all conditions with more fixations on the eyes and nose than on other areas. Fixation time on the eye area did not correlate with changes in oxyHb levels, and none of the scanning strategy indices could estimate the hemodynamic changes. Conclusions/Significance We conclude that hemodynamic activity, i.e., the means of processing facial information, is not always modulated by the face-scanning strategy, i.e., the way of seeing, and that the right IFG plays important roles in both self-other facial discrimination and self-evaluation.

Facial identity recognition in children with autism spectrum disorders revealed by P300 analysis: A preliminary study

BACKGROUND To reveal the neural substrate of communication difficulties in children with autism spectrum disorders (ASDs), we investigated the P300 component of event-related potentials (ERPs) as represented by the average of electroencephalography findings time-locked to events and behavior. Because the P300 amplitude influences attentional resource allocation during discrimination, the component elicited during perception of known and unknown faces should indicate familiarity processing. METHODS AND RESULTS Nine typically developing children (TD) and nine children with ASDs participated in this study (Experiment 1). The P300 amplitude in TD children was significantly larger during familiar face perception than during unfamiliar face perception (p<0.01). However, there was no evidence of familiarity effect in children with ASDs. In three children with ASDs, we also assessed the P300 amplitude during perception of a therapists face one month before (baseline), a few days before and after social skills training (SST) sessions (Experiment 2). To evaluate the effect of familiarity on facial identity processing, we analyzed the therapist/unknown ratio of P300 amplitudes related to the face discrimination task as an index. The ratio was larger after SST sessions than before, but there was no difference in the ratio between baseline and before SST assessments. CONCLUSION The P300 might be influenced by attentional resource allocation depending on the stage of learning face identification in children with ASDs. We speculate that this approach to evaluating brain responses during facial identity recognition could be used as a tool to clarify childrens communication difficulties.

Late response evoked by cerebellar stimuli: effect of optokinetic stimulation.

We previously demonstrated that late electromyographic responses with a latency of 100 ms were evoked bilaterally in soleus muscles following transcranial magnetic stimulation over the left cerebellum. Efferent fibers from the left cerebellum modulate vestibulospinal tract influences on the extensor muscles of the left hindlimb. Here, we investigated whether the vestibulospinal tract mediates this late response. We activated the vestibulospinal tract by optokinetic stimulation. Our results show that the latency of the soleus electromyographic response is shortened by optokinetic stimulation, but the latency of the motor response evoked by the corticospinal tract is unchanged. These findings support our hypothesis that vestibulospinal tracts mediate late electromyographic responses, and allow the development of techniques to assess the human vestibulospinal system function.

Applicability of the Movement Assessment Battery for Children-Second Edition to Japanese children: A study of the Age Band 2

BACKGROUND The diagnosis of Developmental Coordination Disorder (DCD) requires a precise assessment of motor skills via a standardized tool such as the Movement Assessment Battery for Children-Second Edition (MABC-2). Although the MABC-2 has been widely used in English-speaking countries, to the best of our knowledge, no studies have examined its applicability to Japanese children. Thus, it has been difficult to diagnose DCD in Japan. AIMS As a preliminary investigation preceding its formal standardization in Japan, we examined the applicability of the MABC-2. METHODS AND PROCEDURES Participants comprised 132 typically developing Japanese children who completed a test set of the MABC-2 for Age Band 2. We analyzed both internal consistency and factorial validity for our Japanese sample. We also included a comparison between our sample of Japanese children and the normative sample of the MABC-2, as well as an examination of gender differences. OUTCOMES AND RESULTS Our results indicated acceptable internal consistency and scale homogeneity. High factorial validity, which has not been examined in other populations, was also confirmed for the test set. Moreover, we found differences in component scores between the Japanese and normative children with respect to Manual Dexterity and Balance. We also found that girls obtained superior Manual Dexterity and Balance scores compared with boys. CONCLUSIONS AND IMPLICATIONS The present findings represent the first step towards the standardization of the MABC-2 in a Japanese population.

Mu rhythm desynchronization by tongue thrust observation

We aimed to investigate the mu rhythm in the sensorimotor area during tongue thrust observation and to obtain an answer to the question as to how subtle non-verbal orofacial movement observation activates the sensorimotor area. Ten healthy volunteers performed finger tap execution, tongue thrust execution, and tongue thrust observation. The electroencephalogram (EEG) was recorded from 128 electrodes placed on the scalp, and regions of interest were set at sensorimotor areas. The event-related desynchronization (ERD) and event-related synchronization (ERS) for the mu rhythm (8–13 Hz) and beta (13−25 Hz) bands were measured. Tongue thrust observation induced mu rhythm ERD, and the ERD was detected at the left hemisphere regardless whether the observed tongue thrust was toward the left or right. Mu rhythm ERD was also recorded during tongue thrust execution. However, temporal analysis revealed that the ERD associated with tongue thrust observation preceded that associated with execution by approximately 2 s. Tongue thrust observation induces mu rhythm ERD in sensorimotor cortex with left hemispheric dominance.