Fine Motor Skills, a Surrogate of Motor Planning Ability, at Age 2 Predict Social Skills at Age 6.

OBJECTIVES: Motor planning is the cognitive process of planning necessary steps for achieving a purposeful movement and is specifically reflected through object manipulation. This study aimed to investigate whether fine motor skills, a surrogate of the motor planning ability of object manipulation, in early childhood are associated with later social skills, in a general-population birth cohort. METHODS: A total of 913 children, participating in the Hamamatsu Birth Cohort for Mothers and Children, were enrolled. Social skills were measured using the Vineland Adaptive Behavior Scales-II, Socialization domain, at age 6 years. Fine motor skills were measured using the Mullen Scales of Early Learning at 14, 24, and 32 months. The associations between fine motor skills at ages 14, 24, and 32 months and social skills at age 6 years were tested separately through multivariable linear regression after adjusting for covariates, including gross motor and language skills at the contemporaneous age, autistic symptoms at age 6 years, and demographic factors. RESULTS: Fine motor skills at 24 and 32 months were significantly associated with social skills at age 6 years (at 24 months: nonstandardized regression coefficient = 1.38 [95% CI, 0.50-2.26], p = 0.002; at 32 months: 1.47 [0.56-2.38], p = 0.001). CONCLUSION: Fine motor skills in early childhood predicted social skills at age 6 years, indicating an association between the complex motor planning ability of object manipulation and later social skills. Children who demonstrate fine motor delay at as early an age as 2 years should be closely monitored by child professionals.

Physical Therapists Use Different Motivational Strategies for Stroke Rehabilitation Tailored to an Individual's Condition: A Qualitative Study.

OBJECTIVE: Various strategies are used to motivate individuals with stroke during rehabilitation. However, how physical therapists select the motivational strategies that they use for each individual is yet to be established. Therefore, this study aimed to explore how physical therapists use different motivational strategies for individuals in stroke rehabilitation programs. METHODS: A criterion sample of 15 physical therapists who have worked in rehabilitation for over 10 years and were interested in an individual's motivation participated in one-on-one semi-structured online interviews. The interviews explored their perspectives and experiences regarding the motivational strategies used depending on each individual's condition. The collected data were analyzed with thematic analysis. RESULTS: A total of 9 themes emerged from the data upon thematic analysis and inductive coding. Participants used different strategies to encourage individuals' active participation in physical therapy depending on (1) their mental health, (2) their physical difficulties, (3) their level of cognitive function, (4) their personality, (5) their activities and participation, (6) their age, (7) their human environment, and (8) the type of rehabilitation service where the individual underwent treatment. For example, in cases where an individual lost self-confidence, participants offered practice tasks that the individual could achieve with little effort to make them experience success. The interviews also revealed (9) motivational strategies used regardless of the individual's condition. For instance, patient-centered communication was used to build rapport with individuals, irrespective of their condition. CONCLUSION: This qualitative study suggests that physical therapists use different strategies depending on the individual's mental health conditions, physical problems, level of cognitive function, personality, activities and participation, age, human environment, and the type of rehabilitation service where the individual undergoes treatment to motivate individuals with stroke during physical therapy. IMPACT: The findings of this study can provide experience-based recommendations regarding the selection of motivational strategies for stroke rehabilitation.

Brief Reports: Influence of Friendship on Loneliness Among Adolescents with Autism Spectrum Disorders in Japan.

PURPOSE: Previous studies have reported that people with autism spectrum disorder (ASD) have higher levels of loneliness than neurotypical (NTP) people, most likely because of their difficulties in social communication with their predominantly NTP peers. However, direct investigations on the causal influence of friendship on their feelings of loneliness is scarce. METHODS: In the current study, using the causal mediation analysis, we investigated whether friendship among ASD individuals influences their feelings of loneliness, especially during adolescence when the importance of friendship is typically most elevated. Furthermore, we examined whether individual differences in autistic behavioral features or age affect feelings of loneliness or the qualities of friendship with linear regression analyses. RESULTS: The results demonstrated that the higher levels of loneliness in adolescents with ASD were mediated by one aspect of friendship, companionship. We also found that positive aspects of friendship, but not negative aspects, influence the feelings of loneliness in both ASD and NTP populations. One subcategory of the measured autistic trait, difficulty in imagination, which is associated the ability to consider another's perspective, had a negative relationship with the positive aspects of friendship in the ASD group, but not in the NTP group. CONCLUSION: These findings indicate that the quality of the positive aspects of friendship is similarly important for both adolescents with ASD and NTP adolescents, but the autistic behavioral features could interfere with the experience of such positive friendships.

The Role of the Left Inferior Frontal Gyrus in Introspection during Verbal Communication.

Conversation enables the sharing of our subjective experiences through verbalizing introspected thoughts and feelings. The mentalizing network represents introspection, and successful conversation is characterized by alignment through imitation mediated by the mirror neuron system (MNS). Therefore, we hypothesized that the interaction between the mentalizing network and MNS mediates the conversational exchange of introspection. To test this, we performed hyperscanning functional magnetic resonance imaging during structured real-time conversations between 19 pairs of healthy participants. The participants first evaluated their preference for and familiarity with a presented object and then disclosed it. The control was the object feature identification task. When contrasted with the control, the preference/familiarity evaluation phase activated the dorso-medial prefrontal cortex, anterior cingulate cortex, precuneus, left hippocampus, right cerebellum, and orbital portion of the left inferior frontal gyrus (IFG), which represents introspection. The left IFG was activated when the two participants' statements of introspection were mismatched during the disclosure. Disclosing introspection enhanced the functional connectivity of the left IFG with the bilateral superior temporal gyrus and primary motor cortex, representing the auditory MNS. Thus, the mentalizing system and MNS are hierarchically linked in the left IFG during a conversation, allowing for the sharing of introspection of the self and others.

Neural underpinning of Japanese particle processing in non-native speakers.

Grammar acquisition by non-native learners (L2) is typically less successful and may produce fundamentally different grammatical systems than that by native speakers (L1). The neural representation of grammatical processing between L1 and L2 speakers remains controversial. We hypothesized that working memory is the primary source of L1/L2 differences, by considering working memory within the predictive coding account, which models grammatical processes as higher-level neuronal representations of cortical hierarchies, generating predictions (forward model) of lower-level representations. A functional MRI study was conducted with L1 Japanese speakers and highly proficient Japanese learners requiring oral production of grammatically correct Japanese particles. We assumed selecting proper particles requires forward model-dependent processes of working memory as their functions are highly context-dependent. As a control, participants read out a visually designated mora indicated by underlining. Particle selection by L1/L2 groups commonly activated the bilateral inferior frontal gyrus/insula, pre-supplementary motor area, left caudate, middle temporal gyrus, and right cerebellum, which constituted the core linguistic production system. In contrast, the left inferior frontal sulcus, known as the neural substrate of verbal working memory, showed more prominent activation in L2 than in L1. Thus, the working memory process causes L1/L2 differences even in highly proficient L2 learners.

Context-prosody interaction in sarcasm comprehension: A functional magnetic resonance imaging study.

During conversation, sarcasm is perceived as an incongruity between the context, content, and prosody of the utterance. We hypothesized that prosody modifies the context‒content incongruity effect. Thus, we conducted a functional magnetic resonance imaging study with an auditory sarcasm detection task in 22 healthy adult participants. The participants listened to a short conversation according to which they had done either a good or bad deed, about which their conversational partner made a positive comment. When the context was positive (congruent with the content of utterance), positive prosody lessened the sarcasm rating, whereas negative prosody enhanced this rating. When the context was negative, the positive prosody effect disappeared, while negative prosody increased the sarcasm rating. Thus, context‒content incongruity is the primary determinant of sarcasm comprehension; and is modified by prosody in a context-dependent manner. Neuroimaging results showed that the context‒content incongruity effect was notable in the cerebellum and the mentalizing network, representing what was uttered in a particular context. The content‒prosody incongruity effect was observed in the bilateral amygdala, representing the manner of utterance. The interaction between these incongruity effects was found in the bilateral dorsolateral prefrontal cortex, extending to the inferior frontal gyrus and the salience network, including the anterior insular cortex and the caudal part of the dorso-medial prefrontal cortex. These findings indicate that two distinct incongruity detection systems for sarcasm comprehension are integrated in the prefrontal cortices through the salience network.

Coexistence of sensory qualities and value representations in human orbitofrontal cortex.

Despite the multiple regions and neural networks associated with value-based decision-making, the orbitofrontal cortex (OFC) is possible a particularly important one. Although the role of the OFC in reinforcer devaluation tasks, which assess the ability to represent identity, sensory qualities, and subjective values of the expected outcomes, has been established, the specific aspect represented in this area remains unclear. In this study, using functional magnetic resonance imaging, wherein participants rated the palatability of 128 food items using photographs, we investigated whether the human OFC represents object identity, sensory qualities, or value. Employing many items helped us dissociate object identity from sensory qualities and values; the inferred sensory qualities of identical items were manipulated by a change in metabolic state. Moreover, value differences between items were analytically controlled by employing a technique similar to age adjustment. The palatability ratings for food items significantly decreased after a meal. Using representational similarity analysis, we confirmed that the OFC represents value. Moreover, identical items were represented similarly in the lateral OFC in a given metabolic state; however, these representations were altered post-feeding. Importantly, this change was not explained by subjective value, suggesting that the OFC represents sensory quality and value, but not object identity.

Neural substrates of shared visual experiences: a hyperscanning fMRI study.

Sharing experience is a fundamental human social cognition. Since visual experience is a mental state directed toward the world, we hypothesized that sharing visual experience is mediated by joint attention (JA) for sharing directedness and mentalizing for mental state inferences. We conducted a hyperscanning functional magnetic resonance imaging with 44 healthy adult volunteers to test this hypothesis. We employed spoken-language-cued spatial and feature-based JA tasks. The initiator attracts the partner's attention by a verbal command to a spatial location or an object feature to which the responder directs their attention. Pair-specific inter-individual neural synchronization of task-specific activities was found in the right anterior insular cortex (AIC)-inferior frontal gyrus (IFG) complex, the core node of JA and salience network, and the right posterior superior temporal sulcus, which represents the shared categories of the target. The right AIC-IFG also showed inter-individual synchronization of the residual time-series data, along with the right temporoparietal junction and dorsomedial prefrontal cortex-the core components for mentalization and the default mode network (DMN). This background synchronization represents sharing the belief of sharing the situation. Thus, shared visual experiences are represented by coherent coordination between the DMN and salience network linked through the right AIC-IFG.

Neural substrates for sharing intention in action during face-to-face imitation.

Face-to-face imitation is a unique social interaction wherein a shared action is executed based on the feedback of the partner. Imitation by the partner is the feedback to the imitatee's action, resulting in sharing actions. The neural mechanisms of the shared representation of action during face-to-face imitation, the core of inter-subjectivity, are not well-known. Here, based on the predictive coding account, we hypothesized that the pair-specific forward internal model is the shared representation of action which is represented by the inter-individual synchronization of some portion of the mirror neuron system. Hyperscanning functional magnetic resonance imaging was conducted during face-to-face interaction in 16 pairs of participants who completed an immediate imitation task of facial expressions. Paired participants were alternately assigned to either an imitator or an imitatee who was prompted to express a happy, sad, or non-emotional face. While neural activation elicited by imitating and being imitated were distinct with little overlap, on-line imitative interaction enhanced inter-brain synchronization in the right inferior parietal lobule that correlated with the similarity in facial movement kinematic profile. This finding indicates a critical role of the right inferior parietal lobule in sharing representation of action as a pair-specific forward internal model through imitative interaction.

Frequency-specific task modulation of human brain functional networks: A fast fMRI study.

How coherent neural oscillations are involved in task execution is a fundamental question in neuroscience. Although several electrophysiological studies have tackled this issue, the brain-wide task modulation of neural coherence remains uncharacterized. Here, with a fast fMRI technique, we studied shifts of brain-wide neural coherence across different task states in the ultraslow frequency range (0.01-0.7 Hz). First, we examined whether the shifts of the brain-wide neural coherence occur in a frequency-dependent manner. We quantified the shift of a region's average neural coherence by the inter-state variance of the mean coherence between the region and the rest of the brain. A clustering analysis based on the variance's spatial correlation between frequency components revealed four frequency bands (0.01-0.15 Hz, 0.15-0.37 Hz, 0.37-0.53 Hz, and 0.53-0.7 Hz) showing band-specific shifts of the brain-wide neural coherence. Next, we investigated the similarity of the inter-state variance's spectra between all pairs of regions. We found that regions showing similar spectra correspond to those forming functional modules of the brain network. Then, we investigated the relationship between identified frequency bands and modules' inter-state variances. We found that modules showing the highest variance are those made up of parieto-occipital regions at 0.01-0.15 Hz, while it is replaced with another consisting of frontal regions above 0.15 Hz. Furthermore, these modules showed specific shifting patterns of the mean coherence across states at 0.01-0.15 Hz and above 0.15 Hz, suggesting that identified frequency bands differentially contribute to neural interactions during task execution. Our results highlight that usage of the fast fMRI enables brain-wide investigation of neural coherence up to 0.7 Hz, which opens a promising track for assessment of the large-scale neural interactions in the ultraslow frequency range.

The Neural Correlates of Semantic and Grammatical Encoding During Sentence Production in a Second Language: Evidence From an fMRI Study Using Structural Priming.

Japanese English learners have difficulty speaking Double Object (DO; give B A) than Prepositional Object (PO; give A to B) structures which neural underpinning is unknown. In speaking, syntactic and phonological processing follow semantic encoding, conversion of non-verbal mental representation into a structure suitable for expression. To test whether DO difficulty lies in linguistic or prelinguistic process, we conducted functional magnetic resonance imaging. Thirty participants described cartoons using DO or PO, or simply named them. Greater reaction times and error rates indicated DO difficulty. DO compared with PO showed parieto-frontal activation including left inferior frontal gyrus, reflecting linguistic process. Psychological priming in PO produced immediately after DO and vice versa compared to after control, indicated shared process between PO and DO. Cross-structural neural repetition suppression was observed in occipito-parietal regions, overlapping the linguistic system in pre-SMA. Thus DO and PO share prelinguistic process, whereas linguistic process imposes overload in DO.

The neural network underpinning social feedback contingent upon one's action: An fMRI study.

Praise enhances motor performance; however, the underlying feedback pathway is unknown. Here, we hypothesized that the social evaluation feedback to the motor system is modified by the top-down effect of the social contingency valuation system, such as the anterior rostral medial prefrontal cortex (arMPFC). We developed a pseudo-interactive task that simplified a conversational student-teacher interaction and conducted a functional magnetic resonance imaging study with 33 participants (13 men, 20 women; mean age = 21.7 years; standard deviation = 2.0 years). The participant inside the scanner uttered the pseudo-English word to the English teacher outside the scanner. The teacher provided feedback of acceptance or rejection by either gestures or words, through video. As a control condition, the pseudo-word was read aloud by a computer. Approval from the teacher enhanced the participants' pleasure rate. Feedback to the participants' utterance, either rejection or acceptance, activated the arMPFC. Irrespective of the preceding utterance by self or computer, acceptance compared with rejection activated the right primary visual cortex (V1), and the reverse activated the left V1. This valence-dependent laterality of V1 activation indicates that the effect is not the domain-general modulation of visual processing. Instead, the early visual cortices are part of the valence-specific representation of the social signal. Physio-physiological interaction analysis with the seed regions in the right and left V1 and the modulator region in the arMPFC showed enhanced connectivity with the bilateral primary motor cortex. These findings indicate that the socially contingent, self-relevant signals from others act as feedback to the motor control system, and this process is mediated by the early visual cortex.

Surprise Acts as a Reducer of Outcome Value in Human Reinforcement Learning.

Surprise occurs because of differences between a decision outcome and its predicted outcome (prediction error), regardless of whether the error is positive or negative. It has recently been postulated that surprise affects the reward value of the action outcome; studies have indicated that increasing surprise as an absolute value of prediction error decreases the value of the outcome. However, how surprise affects the value of the outcome and subsequent decision making is unclear. We suggest that, on the assumption that surprise decreases the outcome value, agents will increase their risk-averse choices when an outcome is often surprising. Here, we propose the surprise-sensitive utility model, a reinforcement learning model that states that surprise decreases the outcome value, to explain how surprise affects subsequent decision making. To investigate the properties of the proposed model, we compare the model with previous reinforcement learning models on two probabilistic learning tasks by simulations. As a result, the proposed model explains the risk-averse choices like the previous models, and the risk-averse choices increase as the surprise-based modulation parameter of outcome value increases. We also performed statistical model selection by using two experimental datasets with different tasks. The proposed model fits these datasets better than the other models with the same number of free parameters, indicating that the model can better capture the trial-by-trial dynamics of choice behavior.

Achieving affective human-virtual agent communication by enabling virtual agents to imitate positive expressions.

Affective communication, communicating with emotion, during face-to-face communication is critical for social interaction. Advances in artificial intelligence have made it essential to develop affective human-virtual agent communication. A person's belief during human-virtual agent interaction that the agent is a computer program affects social-cognitive processes. Whether this belief interferes with affective communication is an open question. We hypothesized that the imitation of a positive emotional expression by a virtual agent induces a positive emotion, regardless of the belief. To test this hypothesis, we conducted an fMRI study with 39 healthy volunteers, who were made to believe that a virtual agent was either a person or a computer. They were instructed to smile, and immediately afterwards, the virtual agent displayed a positive, negative, or neutral expression. The participants reported a positive emotion only when their smile was imitated by the agent's positive expression regardless of their belief. This imitation activated the participants' medial prefrontal cortex and precuneus, which are involved in anthropomorphism and contingency, respectively. These results suggest that a positive congruent response by a virtual agent can overcome the effect of believing that the agent is a computer program and thus contribute to achieving affective human-virtual agent communication.

Attenuated activation of the anterior rostral medial prefrontal cortex on self-relevant social reward processing in individuals with autism spectrum disorder.

The social motivation hypothesis posits that people with autism spectrum disorder (ASD) find social stimuli less rewarding and are therefore less motivated towards social interaction than people with neuro-typical development (TD). However, the less rewarding social stimuli characteristics during social interaction for people with ASD are largely unknown. The contingent positive responsiveness of others relevant to self-action motivates the early development of social interaction, thus representing a social reward. As individuals with ASD often exhibit atypical responses to self-relevant stimuli in their early life, we hypothesized that the self-relevant responses of others are less rewarding for individuals with ASD. To test this hypothesis, we conducted a functional magnetic resonance imaging study using a social contingency task. During the task, the participants attempted to make the audience laugh by telling funny jokes and thus activating the anterior rostral medial prefrontal cortex (arMPFC) of TD individuals (Sumiya et al., 2017). We explicitly predicted that the atypical activation of the arMPFC is related to the reduced reward value of self-relevant responses to others in individuals with ASD. Thirty-one adults with ASD and 24 age- and intelligence quotient-matched TD adults participated in the study. Participants with ASD reported significantly lower pleasure after the audience's responses to their own actions than those in the TD group. Correspondingly, the self-related activation of the arMPFC, defined by the results of our previous study, was attenuated in the ASD group compared to the TD group. The present findings indicate that weak self-relevant outcome processing mediated by the arMPFC of individuals with ASD dampens the rewarding nature of social interaction.

What Makes Eye Contact Special? Neural Substrates of On-Line Mutual Eye-Gaze: A Hyperscanning fMRI Study.

Automatic mimicry is a critical element of social interaction. A salient type of automatic mimicry is eye contact characterized by sharing of affective and mental states among individuals. We conducted a hyperscanning functional magnetic resonance imaging study involving on-line (LIVE) and delayed off-line (REPLAY) conditions to test our hypothesis that recurrent interaction through eye contact activates the limbic mirror system, including the anterior cingulate cortex (ACC) and anterior insular cortex (AIC), both of which are critical for self-awareness. Sixteen pairs of human adults participated in the experiment. Given that an eye-blink represents an individual's attentional window toward the partner, we analyzed pairwise time-series data for eye-blinks. We used multivariate autoregression analysis to calculate the noise contribution ratio (NCR) as an index of how a participant's directional attention was influenced by that of their partner. NCR was greater in the LIVE than in the REPLAY condition, indicating mutual perceptual-motor interaction during real-time eye contact. Relative to the REPLAY condition, the LIVE condition was associated with greater activation in the left cerebellar hemisphere, vermis, and ACC, accompanied by enhanced functional connectivity between ACC and right AIC. Given the roles of the cerebellum in sensorimotor prediction and ACC in movement initiation, ACC-cerebellar activation may represent their involvement in modulating visual input related to the partner's movement, which may, in turn, involve the limbic mirror system. Our findings indicate that mutual interaction during eye contact is mediated by the cerebellum and limbic mirror system.

TMS Motor Thresholds Correlate With TDCS Electric Field Strengths in Hand Motor Area.

Transcranial direct current stimulation (TDCS) modulates cortical activity and influences motor and cognitive functions in both healthy and clinical populations. However, there is large inter-individual variability in the responses to TDCS. Computational studies have suggested that inter-individual differences in cranial and brain anatomy may contribute to this variability via creating varying electric fields in the brain. This implies that the electric fields or their strength and orientation should be considered and incorporated when selecting the TDCS dose. Unfortunately, electric field modeling is difficult to perform; thus, a more-robust and practical method of estimating the strength of TDCS electric fields for experimental use is required. As recent studies have revealed a relationship between the sensitivity to TMS and motor cortical TDCS after-effects, the aim of the present study was to investigate whether the resting motor threshold (RMT), a simple measure of transcranial magnetic stimulation (TMS) sensitivity, would be useful for estimating TDCS electric field strengths in the hand area of primary motor cortex (M1). To achieve this, we measured the RMT in 28 subjects. We also obtained magnetic resonance images from each subject to build individual three-dimensional anatomic models, which were used in solving the TDCS and TMS electric fields using the finite element method (FEM). Then, we calculated the correlation between the measured RMT and the modeled TDCS electric fields. We found that the RMT correlated with the TDCS electric fields in hand M1 (R2 = 0.58), but no obvious correlations were identified in regions outside M1. The found correlation was mainly due to a correlation between the TDCS and TMS electric fields, both of which were affected by individual's anatomic features. In conclusion, the RMT could provide a useful tool for estimating cortical electric fields for motor cortical TDCS.

Emotions surrounding friendships of adolescents with autism spectrum disorder in Japan: A qualitative interview study.

Emotions are embedded in culture and play a pivotal role in making friends and interacting with peers. To support the social participation of students with autism spectrum disorders (ASD) it is essential to understand their emotional life in the context of ethnic and school cultures. We are particularly interested in how anxiety and loneliness are experienced in developing and maintaining friendships in the daily encounters of adolescents with ASD in the specific context of Japanese schools, because these emotions could serve either as facilitators or barriers to social interaction, depending on how individuals manage them. The present qualitative study investigated perceptions of emotions related to friendship in the everyday school life of 11 adolescents with ASD in Japan. Data were collected by means of semi-structured individual interviews, which revealed a wide range of motivations for socialization, limited future prospects to deepen friendships, robust self-awareness of one's own social challenges, and conscious efforts to cope with these challenges. An inductive approach to data analysis resulted in four themes: social motivation, loneliness, anxiety, and distress. To our knowledge this is the first study to uncover the rich emotional life of adolescents with ASD in the context of their friendships in an Asian culture.

Brain networks of social action-outcome contingency: The role of the ventral striatum in integrating signals from the sensory cortex and medial prefrontal cortex.

Social interactions can be facilitated by action-outcome contingency, in which self-actions result in relevant responses from others. Research has indicated that the striatal reward system plays a role in generating action-outcome contingency signals. However, the neural mechanisms wherein signals regarding self-action and others' responses are integrated to generate the contingency signal remain poorly understood. We conducted a functional MRI study to test the hypothesis that brain activity representing the self modulates connectivity between the striatal reward system and sensory regions involved in the processing of others' responses. We employed a contingency task in which participants made the listener laugh by telling jokes. Participants reported more pleasure when greater laughter followed their own jokes than those of another. Self-relevant listener's responses produced stronger activation in the medial prefrontal cortex (mPFC). Laughter was associated with activity in the auditory cortex. The ventral striatum exhibited stronger activation when participants made listeners laugh than when another did. In physio-physiological interaction analyses, the ventral striatum showed interaction effects for signals extracted from the mPFC and auditory cortex. These results support the hypothesis that the mPFC, which is implicated in self-related processing, gates sensory input associated with others' responses during value processing in the ventral striatum.