Neural representation of phonological information during Chinese character reading

Previous studies have revealed that phonological processing of Chinese characters elicited activation in the left prefrontal cortex, bilateral parietal cortex, and occipitotemporal regions. However, it is controversial what role the left middle frontal gyrus plays in Chinese character reading, and whether the core regions (e.g., the left superior temporal gyrus and supramarginal gyrus) for phonological processing of alphabetic languages are also involved in Chinese character reading. To address these questions, the present study used both univariate and multivariate analysis (i.e., representational similarity analysis, RSA) to explore neural representations of phonological information during Chinese character reading. Participants were scanned while performing a reading aloud task. Univariate activation analysis revealed a widely distributed network for word reading, including the bilateral inferior frontal gyrus, middle frontal gyrus, lateral temporal cortex, and occipitotemporal cortex. More importantly, RSA showed that the left prefrontal (i.e., the left middle frontal gyrus and left inferior frontal gyrus) and bilateral occipitotemporal areas (i.e., the left inferior and middle temporal gyrus and bilateral fusiform gyrus) represented phonological information of Chinese characters. These results confirmed the importance of the left middle frontal gyrus and regions in ventral pathway in representing phonological information of Chinese characters.     

Headache-related circuits and high frequencies evaluated by EEG,MRI, PET as potential biomarkers to differentiate chronic and episodic migraine: Evidence from a systematic review

BackgroundThe diagnosis of migraine is mainly clinical and self-reported, which makes additional examinations unnecessary in most cases. Migraine can be subtyped into chronic (CM) and episodic (EM). Despite the very high prevalence of migraine, there are no evidence-based guidelines for differentiating between these subtypes other than the number of days of migraine headache per month. Thus, we consider it timely to perform a systematic review to search for physiological evidence from functional activity (as opposed to anatomical structure) for the differentiation between CM and EM, as well as potential functional biomarkers. For this purpose, Web of Science (WoS), Scopus, and PubMed databases were screened.FindingsAmong the 24 studies included in this review, most of them (22) reported statistically significant differences between the groups of CM and EM. This finding is consistent regardless of brain activity acquisition modality, ictal stage, and recording condition for a wide variety of analyses. That speaks for a supramodal and domain-general differences between CM and EM that goes beyond a differentiation based on the days of migraine per month. Together, the reviewed studies demonstrates that electro- and magneto-physiological brain activity (M/EEG), as well as neurovascular and metabolic recordings from functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), show characteristic patterns that allow to differentiate between CM and EM groups.ConclusionsAlthough a clear brain activity-based biomarker has not yet been identified to distinguish these subtypes of migraine, research is approaching headache specialists to a migraine diagnosis based not only on symptoms and signs reported by patients. Future studies based on M/EEG should pay special attention to the brain activity in medium and fast frequency bands, mainly the beta band. On the other hand, fMRI and PET studies should focus on neural circuits and regions related to pain and emotional processing.     

Altruistic acting caused by a touching hand: neural underpinnings of the Midas touch effect

Giving and receiving touch are some of the most important social stimuli we exchange in daily life. By touching someone, we can communicate various types of information. Previous studies have also demonstrated that interpersonal touch may affect our altruistic behavior. A classic study showed that customers give bigger tips when they are lightly touched by a waitress, which has been called the Midas touch effect. Numerous studies reported similar effects of touch on different kinds of helping or prosocial behaviors. Here, we aim to examine the neural underpinnings of this effect by employing a functional magnetic resonance imaging approach. While lying in the scanner, participants played different rounds of the dictator game, a measure of prosocial behavior. Before each round, participants were touched (or not touched in the control condition) by an experimenter. We found that touching the hand increased the likeliness to behave prosocial (but not the general liking of control stimuli), thereby confirming the Midas touch effect. The effect was predicted by activity in the primary somatosensory cortex, indicating that the somatosensory cortex here plays a causal role in prosocial behavior. We conclude that the tactile modality in social life may be much more important than previously thought.     

The effect of learning to drum on behavior and brain function in autistic adolescents

This current study aimed to investigate the impact of drum training on behavior and brain function in autistic adolescents with no prior drumming experience. Thirty-six autistic adolescents were recruited and randomly assigned to one of two groups. The drum group received individual drum tuition (two lessons per week over an 8-wk period), while the control group did not. All participants attended a testing session before and after the 8-wk period. Each session included a drumming assessment, an MRI scan, and a parent completing questionnaires relating to the participants’ behavioral difficulties. Results showed that improvements in drumming performance were associated with a significant reduction in hyperactivity and inattention difficulties in drummers compared to controls. The fMRI results demonstrated increased functional connectivity in brain areas responsible for inhibitory control, action outcomes monitoring, and self-regulation. In particular, seed-to-voxel analyses revealed an increased functional connectivity in the right inferior frontal gyrus and the right dorsolateral prefrontal cortex. A multivariate pattern analysis demonstrated significant changes in the medial frontal cortex, the left and right paracingulate cortex, the subcallosal cortex, the left frontal pole, the caudate, and the left nucleus accumbens. In conclusion, this study investigates the impact of a drum-based intervention on neural and behavioral outcomes in autistic adolescents. We hope that these findings will inform further research and trials into the potential use of drum-based interventions in benefitting clinical populations with inhibition-related disorders and emotional and behavioral difficulties.

Autism spectrum disorder (ASD) is a lifelong neurodevelopmental disorder characterized by deficits in social communication and social interactions as well as a range of restricted, repetitive interests, activities, and behaviors (1). Over recent decades, incidence estimates for ASD have increased (2), with a prevalence of 1 in 59 children in the United States (3) and over 600,000 people in the United Kingdom, which is equivalent to a population prevalence of ∼1% (4, 5). In this context of increased autism prevalence, there is an existing need to develop interventions that offer new insights and perspectives and help address the specifically high demand for services for autistic adolescents and young adults (6). [The term “autistic” is used throughout this paper because of a large percentage of the UK autism community’s preference for the identity-first construction (e.g., “autistic person”) over the person-first phrase (e.g., “person with autism”) (7).] Indeed, autistic young people often face discontinuity in care provision in the transitionary period from child and adolescent services to adult services, just when their care needs are most pressing, making their transition into adulthood particularly difficult (8). In particular, mismatches across services, such as differences in eligibility criteria or age cutoffs, mean that many autistic young adults fall through the care gap after exiting high school (8). Autistic individuals are particularly vulnerable during this period because they often face high unemployment rates, increased levels of comorbid psychiatric diagnoses such as anxiety and depression, and, more broadly, greater reliance on assistance from others when it comes to carrying out adulthood-related daily activities (9–11).A growing body of research suggests that key social domains of the ASD symptomatology may be related to atypical executive functioning (12, 13). Inhibitory control, one of the core executive functions (EFs), corresponds to the ability to delay the onset of behavioral responses, or withhold behaviors that are prepotent but contextually inappropriate (14, 15). It works in concert with other EFs, such as cognitive flexibility and working memory, to exert top-down control on behavioral responses, enable self-regulation, and help navigate social relationships, therefore supporting transition into adulthood and independent living (16, 17). More specifically, it is thought that atypical inhibitory control in autism may underlie significant strengths but may also exacerbate key features of the ASD symptomatology, such as struggling with change and uncertainty, or having difficulty interpreting social cues (18–21). Impaired performance on inhibitory control tasks is frequent in autistic individuals (12, 13, 22, 23). In particular, it has been associated with severe restricted and repetitive behaviors (19, 24, 25), as well as a deficit in proactive response slowing [the ability to slow the initiation of a behavioral response in preparation for stopping during conditions of uncertainty (19)]. At the neuroimaging level, prior studies have revealed atypical recruitment of frontal regions in autistic adolescents (20), and impaired functional connectivity (FC) of the inferior frontal junction, key regions for inhibitory control, in autistic children (26).Autistic individuals often report being preoccupied with certain topics (27) and struggling with anxiety and anger management (28, 29). In a study by Van Hees et al. (30), higher-education autistic students described feeling overwhelmed by the demands placed on them while facing significant difficulties with planning, information processing, time management, organizational skills, and sensory overload. These difficulties may reflect impaired attention and inhibition abilities, complementary processes that allow individuals to pursue the achievement of a particular goal while remaining flexibly responsive to environmental demands (21, 31). A research study on a population-based twin sample of 17,000 children (9 y to 12 y old) concluded that the vast majority of children with ASD traits also exhibit cooccurring attention deficit and hyperactivity disorder (ADHD) traits (32). More specifically, the authors demonstrated that 82% of the boys and 95% of the girls with high ASD traits on all three ASD domains (social impairments, communication impairments, and restricted repetitive behaviors and interests) exhibited difficulties on at least one of the three ADHD domains (attentional difficulties, hyperactivity, and impulsivity). Additionally, they reported that repetitive and restricted behaviors in ASD correlated with ADHD domains, particularly with impulsivity and attentional difficulties. This is in line with a previous twin study in adults, which reported the highest phenotypic and genetic overlap between ADHD traits and “nonsocial” autistic-like traits such as attention switching difficulties (33).Music has long been known to promote cognitive and emotional wellbeing in both clinical and healthy populations (34, 35). Rhythm-based musical training, in particular, has been shown to enhance higher-order cognition and motor control (31). There is growing evidence that activities designed to improve beat synchronization skills may provide an effective approach to developing neurological processes that underpin self-regulation and EF skills (36). Indeed, EF deficits have been linked with poor rhythm perception in children (37) and poor sensorimotor synchronization in young adults (38). Using the Integrated Visual and Auditory Plus Continuous Performance Test (39), Slater et al. (31) highlighted that drumming practice is associated with better scores in inhibitory control and selective attention in adult percussionists compared to nonmusicians.More specifically, learning to drum requires error monitoring and temporal accuracy and therefore both attentional and inhibitory control (31, 40). In a recent study, Lowry et al. (40) used a mixed-methods analysis to investigate behavioral changes in children with emotional and behavioral difficulties, after learning to drum. Following drum training, the participants displayed enhanced attentional focus and reduced hyperactivity and peer problems (40). These results concur with Draper et al.’s (41) recent findings showing that drumming improves motor control and attentional focus and reduces emotional and peer problems in autistic children. It is important to note that motor control is particularly relevant in the context of ASD. Indeed, recent studies have consistently demonstrated motor impairments across the autism spectrum (42, 43), including gross and fine motor difficulties (44, 45) and delays with motor planning (46). Sokhadze et al. (47) showed that ∼80% of autistic individuals also present with clumsiness or motor dyspraxia, which can manifest as having difficulty with motor coordination as well as concentration, planning, and organization. These difficulties may impact the individual’s ability to carry out daily activities, which, in turn, can lead to rejection from peers and social isolation (48). Similarly, motor impairments in balance, motor accuracy, and object manipulation scores have been reported to be predictive of social dysfunction in young autistic boys (49). In this context, learning to drum could be regarded as particularly beneficial because it involves not only musicality but also the development of multimodal skills such as body coordination, sensorimotor integration, and cardiovascular exercise processes (50). Additionally, it is appealing and accessible to everyone regardless of age, gender, ethnicity, or musical background (51, 52).In our proof-of-concept study, Amad et al. (53) showed that the brain is capable of neuroplastic modifications through drum-based practice in neurotypical adolescents. In particular, changes in FC were observed post drum training in brain regions known to exhibit atypical functioning in autism, such as areas associated with motor skills and the mirror neuron system.In the present study, we investigated the impact of drum training on brain function in 36 autistic adolescents who were split into two age- and gender-matched groups: a drum group (n = 19), who were evaluated before and after learning to drum, and a control group (n = 17), who were also evaluated longitudinally but with no intervention. We explored behavioral outcomes related to drum practice in this clinical population and examined their association with changes in FC between the two groups (i.e., drum group vs. control group) over time (i.e., before vs. after drum training).We hypothesized that drumming performance would improve in the drum group over time, while no improvement would be observed in the control group. Furthermore, we hypothesized that changes in hyperactivity, attentional difficulties, problem behaviors, and repetitive and restricted behaviors would be observed in the drum group. We also hypothesized that cooccurring changes in FC in brain areas responsible for attentional focus and inhibitory control would be identified following drum training.     

Accumulation System: Distributed Neural Substrates of Perceptual Decision Making Revealed by fMRI Deconvolution

Neural substrates of evidence accumulation have been a central issue in decision-making studies because of the prominent success of the accumulation model in explaining a wide range of perceptual decision making. Since accumulation-shaped activities have been found in multiple brain regions, which are called accumulators, questions regarding functional relations among these accumulators are emerging. This study employed the deconvolution method of functional magnetic resonance imaging (fMRI) signals from human male and female participants during object-category decision tasks, taking advantage of the whole-brain coverage of fMRI with improved availability of temporal information of the deconvolved activity. We detected the accumulation activity in many non-category-selective regions (NCSRs) over the frontal, parietal, and temporal lobes as well as category-selective regions (CSRs) of the categorization task. Importantly, the frontal regions mostly showed activity peaks matching the decision timing (classified as “type-A accumulator”), while activity peaks of the parietal and temporal regions were behind the decision (classified as “type-B accumulator”). The CSRs showed activity peaks whose timing depended on both region and stimulus preference, plausibly reflecting the competition among the alternative choices (classified as “type-C accumulator”). The results suggest that these functionally heterogeneous accumulators form a system for evidence accumulation in which the type-A accumulator regions make decisions in a general manner while the type-B and type-C accumulator regions are employed depending on the modality and content of decision tasks. The concept of the accumulation system may provide a key to understanding the universality of the accumulation model over various kinds of decision tasks.SIGNIFICANCE STATEMENT Perceptual decision making, such as deciding to walk or stop on seeing the signal colors, has been explained theoretically by the accumulation model, in which sensory information is accumulated to reach a certain threshold for making decisions. Neural substrates of this model, however, are still under elucidation among candidate regions found over the brain. We show here that, taking advantage of the whole-brain coverage of functional magnetic resonance imaging (fMRI) with improving availability of temporal information by deconvolution method, the accumulation is conducted by a system comprising many regions in different abstraction levels and only a part of these regions in the frontal cortex make decisions. The system concept may provide a key to explaining the universality of the accumulation model.     

The functional dissociation of posterior parietal regions during multimodal memory formation

The incidental acquisition of multimodal associations is a key memory function for everyday life. While the posterior parietal cortex has been frequently shown to be involved for these memory functions, ventral and dorsal regions revealed differences in their functional recruitment and the precise difference in multimodal memory processing with respect to the associative process has not been differentiated. Using an incidental multimodal learning task, we isolated the associative process during multimodal learning and recollection. The result of the present functional magnetic resonance imaging (fMRI) study demonstrated that during both learning and recollection a clear functional differentiation between ventral and dorsal posterior parietal regions was found and can be related directly to the associative process. The recruitment of a ventral region, the angular gyrus, was specific for learning and recollection of multimodal associations. In contrast, a dorsal region, the superior parietal lobule, could be attributed to memory guided attentional processing. Independent of the memory stage, we assumed a general role for the angular gyrus in the generation of associative representations and updating of fixed association, episodic memory.     

The impact of depression on mothers’ neural processing of their adolescents’ affective behavior

Depression affects neural processing of emotional stimuli and could, therefore, impact parent–child interactions. However, the neural processes with which mothers with depression process their adolescents’ affective interpersonal signals and how this relates to mothers’ parenting behavior are poorly understood. Mothers with and without depression (N = 64 and N = 51, respectively; M_age = 40 years) from low-income families completed an interaction task with their adolescents (M_age = 12.8 years), which was coded for both individuals’ aggressive, dysphoric, positive and neutral affective behavior. While undergoing fMRI, mothers viewed video clips from this task of affective behavior from their own and an unfamiliar adolescent. Relative to non-depressed mothers, those with depression showed more aggressive and less positive affective behavior during the interaction task and more activation in the bilateral insula, superior temporal gyrus and striatum but less in the lateral prefrontal cortex while viewing aggressive and neutral affect. Findings were comparable for own and unfamiliar adolescents’ affect. Heightened limbic, striatal and sensory responses were associated with more aggressive and dysphoric parenting behavior during the interactions, while reduced lateral prefrontal activation was associated with less positive parenting behavior. These results highlight the importance of depressed mothers’ affective information processing for understanding mothers’ behavior during interactions with their adolescents.     

Frontostriatal functional connectivity underlies self-enhancement during social evaluation

Self-enhancement, the tendency to view oneself positively, is a pervasive social motive widely investigated in the psychological sciences. Relatively little is known about the neurocognitive mechanisms underlying this motive, specifically in social-evaluative situations. To investigate whether positive emotion regulation circuitry, circuitry involved in modulating positive affect, relates to the self-enhancement motive in social contexts, we conducted an functional magnetic resonance imaging (fMRI) study in a healthy young adult sample. We hypothesized that self-enhancement indices (state and trait self-esteem) would relate to greater functional connectivity between right ventrolateral prefrontal cortex (RVLPFC), a region implicated in emotion regulation, and the ventral striatum (VS), a region associated with reward-related affect, during a social feedback task. Following social evaluation, participants experienced stable or decreased state self-esteem. Results showed that stable state self-esteem from pre- to post-scan and higher trait self-esteem related to greater RVLPFC–VS connectivity during positive evaluation. Stable-state self-esteem also related to greater RVLPFC–VS connectivity during negative evaluation. Moreover, RVLPFC activation during all types of feedback processing and left VS activation during negative feedback processing was greater for participants with stable-state self-esteem. These findings implicate neurocognitive mechanisms underlying emotion regulation in the self-enhancement motive and highlight a pathway through which self-enhancement may restore feelings of self-worth during threatening situations.     

The architecture of the colour centre in the human visual brain: new results and a review

We have used the technique of functional magnetic resonance imaging (fMRI) and a variety of colour paradigms to activate the human brain regions selective for colour. We show here that the region defined previously [Lueck et al. (1989) Nature, 340, 386-389; Zeki et al. (1991) J. Neurosci., 11, 641-649; McKeefry & Zeki (1997) Brain, 120, 2229-2242] as the human colour centre consists of two subdivisions, a posterior one, which we call V4 and an anterior one, which we refer to as V4alpha, the two together being part of the V4-complex. The posterior area is retinotopically organized while the anterior is not. We discuss our new findings in the context of previous studies of the cortical colour processing system in humans and monkeys. Our new insight into the organization of the colour centre in the human brain may also account for the variability in both severity and degree of recovery from lesions producing cerebral colour blindness (achromatopsia).