Hidetsugu Komeda

Neural basis of individualistic and collectivistic views of self

Individualism and collectivism refer to cultural values that influence how people construe themselves and their relation to the world. Individualists perceive themselves as stable entities, autonomous from other people and their environment, while collectivists view themselves as dynamic entities, continually defined by their social context and relationships. Despite rich understanding of how individualism and collectivism influence social cognition at a behavioral level, little is known about how these cultural values modulate neural representations underlying social cognition. Using cross‐cultural functional magnetic resonance imaging (fMRI), we examined whether the cultural values of individualism and collectivism modulate neural activity within medial prefrontal cortex (MPFC) during processing of general and contextual self judgments. Here, we show that neural activity within the anterior rostral portion of the MPFC during processing of general and contextual self judgments positively predicts how individualistic or collectivistic a person is across cultures. These results reveal two kinds of neural representations of self (eg, a general self and a contextual self) within MPFC and demonstrate how cultural values of individualism and collectivism shape these neural representations. Hum Brain Mapp, 2009.

Dynamic cultural influences on neural representations of the self

People living in multicultural environments often encounter situations which require them to acquire different cultural schemas and to switch between these cultural schemas depending on their immediate sociocultural context. Prior behavioral studies show that priming cultural schemas reliably impacts mental processes and behavior underlying self-concept. However, less well understood is whether or not cultural priming affects neurobiological mechanisms underlying the self. Here we examined whether priming cultural values of individualism and collectivism in bicultural individuals affects neural activity in cortical midline structures underlying self-relevant processes using functional magnetic resonance imaging. Biculturals primed with individualistic values showed increased activation within medial prefrontal cortex (MPFC) and posterior cingulate cortex (PCC) during general relative to contextual self-judgments, whereas biculturals primed with collectivistic values showed increased response within MPFC and PCC during contextual relative to general self-judgments. Moreover, degree of cultural priming was positively correlated with degree of MPFC and PCC activity during culturally congruent self-judgments. These findings illustrate the dynamic influence of culture on neural representations underlying the self and, more broadly, suggest a neurobiological basis by which people acculturate to novel environments.

The effect of a protagonist's emotional shift on situation model construction.

We examined whether readers monitored protagonists’ emotional shifts and whether reader engagement influenced situation model construction. Participants read narratives that included an emotional shift in the middle of the story. In Experiment 1, participants were instructed to read stories appreciatively and to empathize with the protagonists. In Experiment 2, readers were instructed to read the stories normally, as if they were reading novels. The results from the two experiments suggest that readers monitor temporal and causal shifts as well as protagonists’ emotional shifts in stories. Moreover, in Experiment 1 readers detected temporal and causal shifts regardless of the degree of their engagement during the empathetic reading, while in Experiment 2 the high ego involvement group detected causal shifts during the normal reading. Thus, these results show both that readers monitor protagonists’ emotional states and that reader emotional engagement can influence situation model construction with normal reading.

Hard to "tune in": neural mechanisms of live face-to-face interaction with high-functioning autistic spectrum disorder

Persons with autism spectrum disorders (ASD) are known to have difficulty in eye contact (EC). This may make it difficult for their partners during face to face communication with them. To elucidate the neural substrates of live inter-subject interaction of ASD patients and normal subjects, we conducted hyper-scanning functional MRI with 21 subjects with autistic spectrum disorder (ASD) paired with typically-developed (normal) subjects, and with 19 pairs of normal subjects as a control. Baseline EC was maintained while subjects performed real-time joint-attention task. The task-related effects were modeled out, and inter-individual correlation analysis was performed on the residual time-course data. ASD–Normal pairs were less accurate at detecting gaze direction than Normal–Normal pairs. Performance was impaired both in ASD subjects and in their normal partners. The left occipital pole (OP) activation by gaze processing was reduced in ASD subjects, suggesting that deterioration of eye-cue detection in ASD is related to impairment of early visual processing of gaze. On the other hand, their normal partners showed greater activity in the bilateral occipital cortex and the right prefrontal area, indicating a compensatory workload. Inter-brain coherence in the right IFG that was observed in the Normal-Normal pairs (Saito et al., 2010) during EC diminished in ASD–Normal pairs. Intra-brain functional connectivity between the right IFG and right superior temporal sulcus (STS) in normal subjects paired with ASD subjects was reduced compared with in Normal–Normal pairs. This functional connectivity was positively correlated with performance of the normal partners on the eye-cue detection. Considering the integrative role of the right STS in gaze processing, inter-subject synchronization during EC may be a prerequisite for eye cue detection by the normal partner.

Differences between estimating protagonists' emotions and evaluating readers' emotions in narrative comprehension

We examined the differences between estimating the emotions of protagonists and evaluating those of readers in narrative comprehension. Half of the participants read stories and rated the emotional states of the protagonists, while the other half of the participants rated their own emotional states while reading the stories. The results showed that reading comprehension was facilitated when highly extraverted participants read stories about, and rated the emotional experiences of, extraverted protagonists, with personalities similar to their own. However, the same facilitative effect was not observed for less extraverted participants, nor was it observed for either type of participants under the condition in which participants rated their own emotional experiences. Thus, at least for highly extraverted participants, readers both facilitated the construction of a situation model and correctly estimated the emotional states of protagonists who were similar to themselves, perhaps due to empathy.

Transient neural activation in human amygdala involved in aversive conditioning of face and voice

Elucidating the neural mechanisms involved in aversive conditioning helps find effective treatments for psychiatric disorders such as anxiety disorder and phobia. Previous studies using fMRI and human subjects have reported that the amygdala plays a role in this phenomenon. However, the noxious stimuli that were used as unconditioned stimuli in previous studies (e.g., electric shock) might have been ecologically invalid because we seldom encounter such stimuli in daily life. Therefore, we investigated whether a face stimulus could be conditioned by using a voice that had negative emotional valence and was collected from a real-life environment. A skin conductance response showed that healthy subjects were conditioned by using these stimuli. In an fMRI study, there was greater amygdala activation in response to the faces that had been paired with the voice than to those that had not. The right amygdala showed transient activity in the early stage of acquisition. A psychophysiological interaction analysis indicated that the subcortical pathway from the medial geniculate body to the amygdala played a role in conditioning. Modulation of the subcortical pathway by voice stimuli preceded the transient activity in the amygdala. The finding that an ecologically valid stimulus elicited the conditioning and amygdala response suggests that our brain is automatically processing unpleasant stimuli in daily life.

Autistic empathy toward autistic others

Individuals with autism spectrum disorder (ASD) are thought to lack self-awareness and to experience difficulty empathizing with others. Although these deficits have been demonstrated in previous studies, most of the target stimuli were constructed for typically developing (TD) individuals. We employed judgment tasks capable of indexing self-relevant processing in individuals with and without ASD. Fourteen Japanese men and 1 Japanese women with high-functioning ASD (17–41 years of age) and 13 Japanese men and 2 TD Japanese women (22–40 years of age), all of whom were matched for age and full and verbal intelligence quotient scores with the ASD participants, were enrolled in this study. The results demonstrated that the ventromedial prefrontal cortex was significantly activated in individuals with ASD in response to autistic characters and in TD individuals in response to non-autistic characters. Although the frontal–posterior network between the ventromedial prefrontal cortex and superior temporal gyrus participated in the processing of non-autistic characters in TD individuals, an alternative network was involved when individuals with ASD processed autistic characters. This suggests an atypical form of empathy in individuals with ASD toward others with ASD.

Similarity hypothesis: understanding of others with autism spectrum disorders by individuals with autism spectrum disorders.

Individuals with an autism spectrum disorder (ASD) are generally thought to lack empathy. However, according to recent empirical and self-advocacy studies, individuals with ASD identify with others with ASD. Based on mutual understanding, individuals with ASD respond empathically to others with these disorders. Results have shown that typically developing (TD) adults identify with TD fictional characters, and that such identification plays a critical role in social cognition. TD individuals retrieve episodes involving TD individuals faster than they retrieve episodes involving ASD individuals. Individuals with ASD also show a “similarity effect” whereby they retrieve stories involving ASD individuals more effectively when the stories have consistent outcomes than when they have inconsistent outcomes. In this context, I hypothesized that similarities between a perceiver and a target facilitate cognitive processing. This hypothesis was named the “similarity hypothesis”. Perceivers empathize with targets similar to themselves, which facilitates subsequent cognitive processing. Behavioral and neuroimaging studies are reviewed based on the similarity hypothesis.

Episodic memory retrieval for story characters in high-functioning autism.

BackgroundThe objective of this study was to examine differences in episodic memory retrieval between individuals with autism spectrum disorder (ASD) and typically developing (TD) individuals. Previous studies have shown that personality similarities between readers and characters facilitated reading comprehension. Highly extraverted participants read stories featuring extraverted protagonists more easily and judged the outcomes of such stories more rapidly than did less extraverted participants. Similarly, highly neurotic participants judged the outcomes of stories with neurotic protagonists more rapidly than did participants with low levels of neuroticism. However, the impact of the similarity effect on memory retrieval remains unclear. This study tested our ‘similarity hypothesis’, namely that memory retrieval is enhanced when readers with ASD and TD readers read stories featuring protagonists with ASD and with characteristics associated with TD individuals, respectively.MethodsEighteen Japanese individuals (one female) with high-functioning ASD (aged 17 to 40 years) and 17 age- and intelligence quotient (IQ)-matched Japanese (one female) TD participants (aged 22 to 40 years) read 24 stories; 12 stories featured protagonists with ASD characteristics, and the other 12 featured TD protagonists. Participants read a single sentence at a time and pressed a spacebar to advance to the next sentence. After reading all 24 stories, they were asked to complete a recognition task about the target sentence in each story.ResultsTo investigate episodic memory in ASD, we analyzed encoding based on the reading times for and readability of the stories and retrieval processes based on the accuracy of and response times for sentence recognition. Although the results showed no differences between ASD and TD groups in encoding processes, they did reveal inter-group differences in memory retrieval. Although individuals with ASD demonstrated the same level of accuracy as did TD individuals, their patterns of memory retrieval differed with respect to response times.ConclusionsIndividuals with ASD more effectively retrieved ASD-congruent than ASD-incongruent sentences, and TD individuals retrieved stories with TD more effectively than stories with ASD protagonists. Thus, similarity between reader and story character had different effects on memory retrieval in the ASD and TD groups.

Decision making processes based on social conventional rules in early adolescents with and without autism spectrum disorders.

Autism spectrum disorder (ASD) is characterized by problems with reciprocal social interaction, repetitive behaviours/narrow interests, and impairments in the social cognition and emotional processing necessary for intention-based moral judgements. The aim of this study was to examine the information used by early adolescents with and without ASD when they judge story protagonists as good or bad. We predicted that adolescents with ASD would use protagonists’ behaviour, while typically developing (TD) adolescents would use protagonists’ characteristics when making the judgements. In Experiment 1, we measured sentence by sentence reading times and percentages for good or bad judgements. In Experiment 2, two story protagonists were presented and the participants determined which protagonist was better or worse. Experiment 1 results showed that the adolescents with ASD used protagonist behaviours and outcomes, whereas the TD adolescents used protagonist characteristics, behaviours, and outcomes. In Experiment 2, TD adolescents used characteristics information when making “bad” judgements. Taken together, in situations in which participants cannot go back and assess (Experiment 1), and in comparable situations in which all information is available (Experiment 2), adolescents with ASD do not rely on information about individual characteristics when making moral judgements.