Publications by authors named "Ryuta Kawashima"

351 Publications

Lead exposure is associated with functional and microstructural changes in the healthy human brain.

Commun Biol 2021 Jul 26;4(1):912. Epub 2021 Jul 26.

Division of Developmental Cognitive Neuroscience, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.

Lead is a toxin known to harm many organs in the body, particularly the central nervous system, across an individual's lifespan. To date, no study has yet investigated the associations between body lead level and the microstructural properties of gray matter areas, and brain activity during attention-demanding tasks. Here, utilizing data of diffusion tensor imaging, functional magnetic resonance imaging and cognitive measures among 920 typically developing young adults, we show greater hair lead levels are weakly but significantly associated with (a) increased working memory-related activity in the right premotor and pre-supplemental motor areas, (b) lower fractional anisotropy (FA) in white matter areas near the internal capsule, (c) lower mean diffusivity (MD) in the dopaminergic system in the left hemisphere and other widespread contingent areas, and (d) greater MD in the white matter area adjacent to the right fusiform gyrus. Higher lead levels were also weakly but significantly associated with lower performance in tests of high-order cognitive functions, such as the psychometric intelligence test, greater impulsivity measures, and higher novelty seeking and extraversion. These findings reflect the weak effect of daily lead level on the excitability and microstructural properties of the brain, particularly in the dopaminergic system.
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http://dx.doi.org/10.1038/s42003-021-02435-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8313694PMC
July 2021

Ventral-Dorsal Subregions in the Posterior Cingulate Cortex Represent Pay and Interest, Two Key Attributes of Job Value.

Cereb Cortex Commun 2021 9;2(2):tgab018. Epub 2021 Mar 9.

Institute of Development, Aging and Cancer, Tohoku University, Sendai 980-8575, Japan.

Career choices affect not only our financial status but also our future well-being. When making these choices, individuals evaluate their willingness to obtain a job (i.e., job values), primarily driven by simulation of future pay and interest. Despite the importance of these decisions, their underlying neural mechanisms remain unclear. In this study, we examined the neural representation of pay and interest. Forty students were presented with 80 job names and asked to evaluate their job values while undergoing functional magnetic resonance imaging (fMRI). Following fMRI, participants rated the jobs in terms of pay and interest. The fMRI data revealed that the ventromedial prefrontal cortex (vmPFC) was associated with job value representation, and the ventral and dorsal regions of the posterior cingulate cortex (PCC) were associated with pay and interest representations, respectively. These findings suggest that the neural computations underlying job valuation conform to a multi-attribute decision-making framework, with overall value signals represented in the vmPFC and the attribute values (i.e., pay and interest) represented in specific regions outside the vmPFC, in the PCC. Furthermore, anatomically distinct representations of pay and interest in the PCC may reflect the differing roles of the two subregions in future simulations.
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http://dx.doi.org/10.1093/texcom/tgab018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8152834PMC
March 2021

Brain Activation during Thoughts of One's Own Death and Its Linear and Curvilinear Correlations with Fear of Death in Elderly Individuals: An fMRI Study.

Cereb Cortex Commun 2021 28;2(1):tgab003. Epub 2021 Jan 28.

Institute of Development, Aging and Cancer, Tohoku University, Sendai 980-8575, Japan.

Facing one's own death and managing the fear of death are important existential issues, particularly in older populations. Although recent functional magnetic resonance imaging (fMRI) studies have investigated brain responses to death-related stimuli, none has examined whether this brain activation was specific to one's own death or how it was related to dispositional fear of death. In this study, during fMRI, 34 elderly participants (aged, 60-72 years) were presented with either death-related or death-unrelated negative words and asked to evaluate the relevance of these words to the "self" or the "other." The results showed that only the left supplementary motor area (SMA) was selectively activated during self-relevant judgments of death-related words. Regression analyses of the effect of fear of death on brain activation during death-related thoughts identified a significant negative linear correlation in the right supramarginal gyrus (SMG) and an inverted-U-shaped correlation in the posterior cingulate cortex (PCC) only during self-relevant judgments. Our results suggest potential involvement of the SMA in the existential aspect of thoughts of death. The distinct fear-of-death-dependent responses in the SMG and PCC may reflect fear-associated distancing of the physical self and the processing of death-related thoughts as a self-relevant future agenda, respectively.
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http://dx.doi.org/10.1093/texcom/tgab003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8152848PMC
January 2021

Neural Evidence of Language Membership Control in Bilingual Word Recognition: An fMRI Study of Cognate Processing in Chinese-Japanese Bilinguals.

Front Psychol 2021 7;12:643211. Epub 2021 Jun 7.

Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.

This study aims to examine the neural mechanisms of resolving response competition during bilingual word recognition in the context of language intermixing. During fMRI scanning, Chinese-Japanese unbalanced bilinguals were required to perform a second-language (L2) lexical decision task composed of cognates, interlingual homographs, matched control words from both Chinese (first language) and Japanese (L2), and pseudowords. Cognate word processing showed longer reaction times and greater activation in the supplementary motor area (SMA) than L2 control word processing. In light of the orthographic and semantic overlap of cognates, these results reflect the cognitive processing involved in resolving response conflicts enhanced by the language membership of non-target language during bilingual word recognition. A significant effect of L2 proficiency was also observed only in the SMA, which is associated with the task decision system. This finding supports the bottom-up process in the BIA+ model and the Multilink model. The task/decision system receives the information from the word identification system, making appropriate responses during bilingual word recognition.
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http://dx.doi.org/10.3389/fpsyg.2021.643211DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8215659PMC
June 2021

Repeated Exposure to Illusory Sense of Body Ownership and Agency Over a Moving Virtual Body Improves Executive Functioning and Increases Prefrontal Cortex Activity in the Elderly.

Front Hum Neurosci 2021 31;15:674326. Epub 2021 May 31.

Department of Advanced Brain Science, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.

We previously showed that the illusory sense of ownership and agency over a moving body in immersive virtual reality (displayed in a first-person perspective) can trigger subjective and physiological reactions on the real subject's body and, therefore, an acute improvement of cognitive functions after a single session of high-intensity intermittent exercise performed exclusively by one's own virtual body, similar to what happens when we actually do physical activity. As well as confirming previous results, here, we aimed at finding in the elderly an increased improvement after a longer virtual training with similar characteristics. Forty-two healthy older subjects (28 females, average age = 71.71 years) completed a parallel-group randomized controlled trial (RCT; UMIN000039843, umin.ac.jp) including an adapted version of the virtual training previously used: while sitting, participants observed the virtual body in a first-person perspective (1PP) or a third-person perspective (3PP) performing 20 min of virtual high-intensity intermittent exercise (vHIE; the avatar switched between fast and slow walking every 2 min). This was repeated twice a week for 6 weeks. During the vHIE, we measured the heart rate and administered questionnaires to evaluate illusory body ownership and agency. Before the beginning of the intervention, immediately after the first session of vHIE, and at the end of the entire intervention, we evaluated the cognitive performance at the Stroop task with online recording of the hemodynamic activity over the left dorsolateral prefrontal cortex. While we confirm previous results regarding the virtual illusion and its physiological effects, we did not find significant cognitive or neural improvement immediately after the first vHIE session. As a novelty, in the 1PP group only, we detected a significant decrease in the response time of the Stroop task in the post-intervention assessment compared to its baseline; coherently, we found an increased activation on left dorsolateral prefrontal cortex (lDLPFC) after the entire intervention. While the current results strengthen the impact of the virtual full-body illusion and its physiological consequences on the elderly as well, they might have stronger and more established body representations. Perhaps, a longer and increased exposure to those illusions is necessary to initiate the cascade of events that culminates to an improved cognitive performance.
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http://dx.doi.org/10.3389/fnhum.2021.674326DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8200494PMC
May 2021

Magnetoencephalography to confirm epileptiform discharges mimicking small sharp spikes in temporal lobe epilepsy.

Clin Neurophysiol 2021 Aug 8;132(8):1785-1789. Epub 2021 May 8.

Department of Epileptology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan; Department of Collaborative Laboratory of Electromagnetic Neurophysiology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.

Objective: To determine whether magnetoencephalography (MEG) can identify epileptiform discharges mimicking small sharp spikes (SSSs) on scalp electroencephalography (EEG) in patients with temporal lobe epilepsy (TLE).

Methods: We retrospectively reviewed simultaneous scalp EEG and MEG recordings of 83 consecutive patients with TLE and 49 with extra-TLE (ETLE).

Results: SSSs in scalp EEG were detected in 15 (18.1%) of 83 TLE patients compared to only two (4.1%) of 49 ETLE patients (p = 0.029). Five of the 15 TLE patients had MEG spikes with concurrent SSSs in EEG, but neither of the 2 ETLE patients. Three of these 5 TLE patients had additional interictal epileptiform discharges (IEDs) in EEG and MEG. Equivalent current dipoles (ECDs) of MEG spikes with concurrent SSSs and IEDs showed no difference in temporal lobe localization and horizontal orientation, whereas ECD moments were smaller in MEG spikes with concurrent SSSs than those with IEDs.

Conclusions: SSSs were more common in TLE than in ETLE. At least some morphologically diagnosed SSSs are true but low-amplitude epileptiform discharges in TLE which can be identified with simultaneous MEG.

Significance: Simultaneous MEG is useful to identify epileptiform discharges mimicking SSSs in patients with TLE.
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http://dx.doi.org/10.1016/j.clinph.2021.03.049DOI Listing
August 2021

Lutein Has a Positive Impact on Brain Health in Healthy Older Adults: A Systematic Review of Randomized Controlled Trials and Cohort Studies.

Nutrients 2021 May 21;13(6). Epub 2021 May 21.

Smart Aging Research Center, Tohoku University, Seiryo-machi 4-1, Sendai 980-8575, Japan.

A previous systematic review revealed that lutein intake leads to improved cognitive function among older adults. However, the association between lutein intake and brain health remains unclear.

Methods: We searched the Web of Science, PubMed, PsycInfo, and Cochrane Library for research papers. The criteria were (1) an intervention study using oral lutein intake or a cross-sectional study that examined lutein levels and the brain, (2) participants were older adults, and (3) brain activities or structures were measured using a brain imaging technique (magnetic resonance imaging (MRI) or electroencephalography (EEG)).

Results: Seven studies using MRI (brain activities during rest, cognitive tasks, and brain structure) and two studies using EEG were included. We mainly focused on MRI studies. Three intervention studies using MRI indicated that 10 mg lutein intake over 12 months had a positive impact on healthy older adults' brain activities during learning, resting-state connectivity, and gray matter volumes. Four cross-sectional studies using MRI suggested that lutein was positively associated with brain structure and neural efficiency during cognitive tasks.

Conclusion: Although only nine studies that used similar datasets were reviewed, this systematic review indicates that lutein has beneficial effects on healthy older adults' brain health.
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http://dx.doi.org/10.3390/nu13061746DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8223987PMC
May 2021

Brain Microstructural Properties Related to Subjective Well-Being: Diffusion Tensor Imaging Analysis.

Soc Cogn Affect Neurosci 2021 May 14. Epub 2021 May 14.

Division of Developmental Cognitive Neuroscience, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.

Although it is known that health is not merely the absence of disease, the positive aspects of mental health have been less comprehensively researched compared with its negative aspects. Subjective well-being is one of the indicators of positive psychology, and high subjective well-being is considered to benefit individuals in multiple ways. However, the neural mechanisms underlying individual differences in subjective well-being remain unclear, particularly in terms of brain microstructural properties as detected by diffusion tensor imaging. The present study aimed to investigate the relationship between measurements of diffusion tensor imaging (mean diffusivity and fractional anisotropy) and the degree of subjective well-being as measured using a questionnaire. Voxel-based analysis was used to investigate the association between mean diffusivity and subjective well-being scores in healthy young adults (age, 20.7 ± 1.8 years; 695 males and 514 females). Higher levels of subjective well-being were found to be associated with lower mean diffusivity in areas surrounding the right putamen, insula, globus pallidus, thalamus, and caudate. These results indicated that individual subjective well-being is associated with variability in brain microstructural properties.
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http://dx.doi.org/10.1093/scan/nsab063DOI Listing
May 2021

Childhood socioeconomic status is associated with psychometric intelligence and microstructural brain development.

Commun Biol 2021 04 29;4(1):470. Epub 2021 Apr 29.

Division of Developmental Cognitive Neuroscience, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.

Childhood socioeconomic status is robustly associated with various children's cognitive factors and neural mechanisms. Here we show the association of childhood socioeconomic status with psychometric intelligence and mean diffusivity and fractional anisotropy using diffusion tensor imaging at the baseline experiment (N = 285) and longitudinal changes in these metrics after 3.0 ± 0.3 years (N = 223) in a large sample of normal Japanese children (mean age = 11.2 ± 3.1 years). After correcting for confounding factors, cross-sectional and longitudinal analyses show that higher childhood socioeconomic status is associated with greater baseline and baseline to follow-up increase of psychometric intelligence and mean diffusivity in areas around the bilateral fusiform gyrus. These results demonstrate that higher socioeconomic status is associated with higher psychometric intelligence measures and altered microstructural properties in the fusiform gyrus which plays a key role in reading and letter recognition and further augmentation of such tendencies during development. Definitive conclusions regarding the causality of these relationships requires intervention and physiological studies. However, the current findings should be considered when developing and revising policies regarding education.
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http://dx.doi.org/10.1038/s42003-021-01974-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8084976PMC
April 2021

Intrinsic hippocampal functional connectivity underlying rigid memory in children and adolescents with autism spectrum disorder: A case-control study.

Autism 2021 Mar 28:13623613211004058. Epub 2021 Mar 28.

Tohoku University, Japan.

Lay Abstract: Atypical learning and memory in early life can promote atypical behaviors in later life. Specifically, less relational learning and inflexible retrieval in childhood may enhance restricted and repeated behaviors in patients with autism spectrum disorder. The purpose of this study was to elucidate the mechanisms of atypical memory in children with autism spectrum disorder. We conducted picture-name pair learning and delayed-recognition tests with two groups of youths: one group with high-functioning autism spectrum disorder children (aged 7-16,  = 41) and one group with typically developing children ( = 82) that matched the first group's age, sex, and full-scale IQ. We examined correlations between successful recognition scores and neural connectivity during resting in the magnetic resonance imaging scanner without thinking about anything. Although both learning and retrieval performances were comparable between the two groups, we observed significantly fewer memory gains in the autism spectrum disorder group than in the typically developing group. The memory network was involved in successful memory retrieval in youths with typically developing, while the other memory systems that do not depend to a great degree on networks may be involved in successful memory in youths with autism spectrum disorder. Context-independent and less relational memory processing may be associated with fewer memory gains in autism spectrum disorder. In other words, autism spectrum disorder youths might benefit from non-relational memory. These atypical memory characteristics in autism spectrum disorder may exaggerate their inflexible behaviors in some situations, or-vice versa-their atypical behaviors may result in rigid and less connected memories.
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http://dx.doi.org/10.1177/13623613211004058DOI Listing
March 2021

Association Between Gene SNP rs1059004 and Negative Self-Schema Constructing Trait Factors Underlying Susceptibility to Depression.

Front Psychiatry 2021 8;12:631475. Epub 2021 Mar 8.

Department of Psychiatry, Tohoku University Hospital, Sendai, Japan.

Recent evidence has indicated that the disruption of oligodendrocytes may be involved in the pathogenesis of depression. Genetic factors are likely to affect trait factors, such as characteristics, rather than state factors, such as depressive symptoms. Previously, a negative self-schema had been proposed as the major characteristic of constructing trait factors underlying susceptibility to depression. Thus, the association between a negative self-schema and the functional single nucleotide polymorphism (SNP) rs1059004 in the gene, which influences gene expression, white matter integrity, and cerebral blood flow, was evaluated. A total of 546 healthy subjects were subjected to genotype and psychological evaluation using the Beck Depression Inventory-II (BDI-II) and the Brief Core Schema Scale (BCSS). The rs1059004 SNP was found to be associated with the self-schema subscales of the BCSS and scores on the BDI-II in an allele dose-dependent manner, and to have a predictive impact on depressive symptoms via a negative-self schema. The results suggest the involvement of a genetic factor regulating oligodendrocyte function in generating a negative-self schema as a trait factor underlying susceptibility to depression.
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http://dx.doi.org/10.3389/fpsyt.2021.631475DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7983671PMC
March 2021

Effects of β-Lactolin on Regional Cerebral Blood Flow within the Dorsolateral Prefrontal Cortex during Working Memory Task in Healthy Adults: A Randomized Controlled Trial.

J Clin Med 2021 Jan 28;10(3). Epub 2021 Jan 28.

Institute of Development, Aging and Cancer (IDAC), Tohoku University, 4-1 Seiryo, Aoba-ku, Sendai 980-8575, Japan.

Epidemiological studies have reported that consumption of dairy products rich in β-lactolin is beneficial for cognitive decline among elderly individuals. Although previous studies have shown that β-lactolin supplementation improves memory function and attention in healthy adults, the mechanism through which β-lactolin affects human brain function has yet to be elucidated. This placebo-controlled randomized double-blind study therefore examined the effects of β-lactolin on human regional cerebral blood flow (rCBF) using near-infrared spectroscopy (NIRS) according to the Consolidated Standards of Reporting Trials guidelines. A total of 114 healthy participants aged between 50 and 75 years with relatively low cognition were randomly allocated into the β-lactolin or placebo groups ( = 57 for both groups) and received supplementation for 6 weeks. After the 6 weeks of supplementation, total hemoglobin during cognitive tasks (Kraepelin and 2-back tasks) was measured using two-channel NIRS to determine rCBF. Accordingly, the β-lactolin group had significantly higher changes in total hemoglobin at the left dorsolateral prefrontal cortex (DLPFC) area measured using the left-side channel during the 2-back tasks ( = 0.027) compared to the placebo group. The present study suggests that β-lactolin supplementation increases rCBF and DLPFC activity during working memory tasks.
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http://dx.doi.org/10.3390/jcm10030480DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7865841PMC
January 2021

Brain Training and Sulforaphane Intake Interventions Separately Improve Cognitive Performance in Healthy Older Adults, Whereas a Combination of These Interventions Does Not Have More Beneficial Effects: Evidence from a Randomized Controlled Trial.

Nutrients 2021 Jan 25;13(2). Epub 2021 Jan 25.

Smart Aging Research Center (S.A.R.C.), Tohoku University, Seiryo-Machi 4-1, Sendai 980-8575, Japan.

Background: Earlier studies have demonstrated that a single-domain intervention, such as a brain-training (BT) game alone and a sulforaphane (SFN) intake, positively affects cognition. This study examined whether a combined BT and SFN intake intervention has beneficial effects on cognitive function in older adults.

Methods: In a 12-week double-blinded randomized control trial, 144 older adults were randomly assigned to one of four groups: BT with SFN (BT-S), BT with placebo (BT-P), active control game (AT) with SFN (AT-S), and active control game with placebo (AT-P). We used Brain Age in BT and Tetris in AT. Participants were asked to play BT or AT for 15 min a day for 12 weeks while taking a supplement (SFN or placebo). We measured several cognitive functions before and after the intervention period.

Results: The BT (BT-S and BT-P) groups showed more improvement in processing speed than the active control groups (AT-S and AT-P). The SFN intake (BT-S and AT-S) groups recorded significant improvements in processing speed and working memory performance unlike the placebo intake groups (BT-P and AT-P). However, we did not find any evidence of the combined intervention's beneficial effects on cognition.

Discussion: We discussed a mechanism to improve cognitive functions in the BT and SFN alone interventions.
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http://dx.doi.org/10.3390/nu13020352DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7912304PMC
January 2021

General Intelligence Is Associated with Working Memory-Related Functional Connectivity Change: Evidence from a Large-Sample Study.

Brain Connect 2021 03 5;11(2):89-102. Epub 2021 Feb 5.

Division of Developmental Cognitive Neuroscience, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.

Psychometric intelligence is closely related to working memory (WM) and the associated brain activity. We aimed to clarify the associations between psychometric intelligence and WM-induced functional connectivity changes. Here we determined the associations between psychometric intelligence measured by nonverbal reasoning (using the Raven's Advanced Progressive Matrices) and WM-induced changes in functional connectivity during the N-back paradigm, in a large cohort of 1221 young adults. We observed that the measures of general intelligence showed a significant positive correlation with WM-induced changes in the functional connectivity with the key nodes of the frontoparietal network, such as the bilateral premotor cortices and the presupplementary motor area. Those significant correlations were observed for (1) areas showing a WM-induced increase of the functional connectivity with the abovementioned key nodes, such as the lateral parietal cortex; (2) areas showing a WM-induced decrease of the functional connectivity with the abovementioned key nodes (2-a) such as left perisylvian areas and cuneus, the fusiform gyrus, and the lingual gyrus, which play key roles in language processing, (2-b) hippocampus and parahippocampal gyrus, which play key roles in memory processing, and (2-c) the key node of the default mode network such as the medial prefrontal cortex; as well as (3) the border areas between (1) and (2). Psychometric intelligence is associated with WM-induced changes in functional connectivity, influencing the way in which WM key nodes dynamically modulate the interaction with other brain nodes in response to WM.
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http://dx.doi.org/10.1089/brain.2020.0769DOI Listing
March 2021

Brain activity predicts future learning success in intensive second language listening training.

Brain Lang 2021 Jan 30;212:104839. Epub 2020 Nov 30.

Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan; International Research Institute for Disaster Science, Tohoku University, Sendai, Japan.

This study explores neural mechanisms underlying how prior knowledge gained from pre-listening transcript reading helps comprehend fast-rate speech in a second language (L2) and applies to L2 learning. Top-down predictive processing by prior knowledge may play an important role in L2 speech comprehension and improving listening skill. By manipulating the pre-listening transcript effect (pre-listening transcript reading [TR] vs. no transcript reading [NTR]) and type of languages (first language (L1) vs. L2), we measured brain activity in L2 learners, who performed fast-rate listening comprehension tasks during functional magnetic resonance imaging. Thereafter, we examined whether TR_L2-specific brain activity can predict individual learning success after an intensive listening training. The left angular and superior temporal gyri were key areas responsible for integrating prior knowledge to sensory input. Activity in these areas correlated significantly with gain scores on subsequent training, indicating that brain activity related to prior knowledge-sensory input integration predicts future learning success.
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http://dx.doi.org/10.1016/j.bandl.2020.104839DOI Listing
January 2021

Neural mechanisms of language learning from social contexts.

Brain Lang 2021 Jan 18;212:104874. Epub 2020 Nov 18.

Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.

Humans learn languages in real-life situations by integrating multiple signals, including linguistic forms, their meanings, and the actions and intentions of speakers. However, little is known about the neural bases underlying the social learning of a second language (L2) in adults. In this study, 36 adults were asked to learn two sets of L2 spoken words through translation versus simulated social interactive videos (social learning). Brain activation during word learning was measured using fMRI. Greater activation was observed in the bilateral superior temporal sulcus, posterior middle temporal gyri, and right inferior parietal lobule during social learning as compared with translation learning. Furthermore, higher activity in the right temporal parietal junction, right hippocampus, and motor areas was observed during the initial stage of social learning, with the more successful performance being at the time of overnight testing. We argue that social learning may strengthen the link from new L2 forms to rich L2 semantic representations wherein memory properties are embodied, multimodal, and richly contextualized.
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http://dx.doi.org/10.1016/j.bandl.2020.104874DOI Listing
January 2021

N100m latency shortening caused by selective attention.

Brain Res 2021 01 26;1751:147177. Epub 2020 Oct 26.

Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.

The N100m response to a specific same-sound stimulus may be altered by the degree of attention paid to the stimulus. When participants selectively pay attention to the stimulus, the N100m amplitude increases; however, minimal effects are observed on the N100m latency. In this study, we examined the effects of selective special attention (motivation) to extract the frequency (or pitch) information from a probe tone on the N100m response to the probe tone. We compared the N100m latencies and amplitudes using magnetoencephalography, with the following three experimental conditions: 1) vocalization task protocol (vocalize in tune with the pitch of the probe tone after the presentation of the probe tone), 2) hearing task protocol (just listen to the probe tone), and 3) imagining (just imagine the vocalization in tune with the probe tone). The results indicated that the N100m latency in response to the probe tone was significantly shortened in the vocalization and imagining tasks compared with the hearing task in the right hemisphere of the brain. The amplitude was significantly increased in the vocalization task compared with the imagining and hearing tasks in the right hemisphere, and in the vocalization task compared with the hearing task in the left hemisphere of the brain; that is, the attention and/or motivation required to extract the information from the stimulus tones may have caused N100m latency shortening. To our knowledge, this study is the first to demonstrate that the N100m latency may be shortened under particular attentional conditions in response to a simple tone.
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http://dx.doi.org/10.1016/j.brainres.2020.147177DOI Listing
January 2021

β-lactolin increases cerebral blood flow in dorsolateral prefrontal cortex in healthy adults: a randomized controlled trial.

Aging (Albany NY) 2020 Sep 29;12(18):18660-18675. Epub 2020 Sep 29.

Institute of Development, Aging and Cancer (IDAC), Tohoku University, Aoba-ku, Sendai 980-0872, Japan.

The number of elderly individuals with age-related cognitive decline or dementia is rapidly increasing. Dairy product consumption, including β-lactolin, is beneficial for their cognitive function. The underlying mechanism of β-lactolin's effects on human brain activity is yet to be investigated. We examined the β-lactolin effects on human cerebral blood flow (CBF) using near-infrared spectroscopy (NIRS) in a placebo-controlled randomized double-blind study, which reported according to the CONSORT guidelines. Fifty healthy participants (aged 45-60 years) were randomly allocated into the β-lactolin or the placebo group (n = 25 each) and supplemented for 6 weeks. During the 6 week, oxy-hemoglobin during the working memory tasks was measured using 34-channels (CHs) NIRS. The changes of oxy-hemoglobin, which represents the CBF, in CH 23 located at the left dorsolateral prefrontal cortex (DLPFC) during the spatial working memory task showed higher statistical significance (false discovery rate () = 0.045) in the β-lactolin than in the placebo group. The oxy-Hb changes in CH23 have a co-relationship with the working memory task reaction time. This clinical trial showed an increase in the CBF in the left DLPFC area during the 6-week β-lactolin supplementation. This study contributes to elucidating the underlying mechanisms of β-lactolin on cognitive performance.
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http://dx.doi.org/10.18632/aging.103951DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7585116PMC
September 2020

Awake state-specific suppression of primary somatosensory evoked response correlated with duration of temporal lobe epilepsy.

Sci Rep 2020 09 28;10(1):15895. Epub 2020 Sep 28.

Department of Epileptology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan.

Epilepsy is a network disease. The primary somatosensory cortex (S1) is usually considered to be intact, but could be subclinically disturbed based on abnormal functional connectivity in patients with temporal lobe epilepsy (TLE). We aimed to investigate if the S1 of TLE is abnormally modulated. Somatosensory evoked magnetic fields (SEFs) evoked by median nerve stimulation were recorded in each hemisphere of 15 TLE patients and 28 normal subjects. All responses were separately averaged in the awake state and light sleep using background magnetoencephalography. Latency and strength of the equivalent current dipole (ECD) was compared between the groups for the first (M1) and second peaks. Latencies showed no significant differences between the groups in either wakefulness or light sleep. ECD strengths were significantly lower in TLE patients than in controls only during wakefulness. The reduction of M1 ECD strength in the awake state is significantly correlated with duration of epilepsy. SEFs of TLE patients showed pure ECD strength reduction without latency delay. The phenomenon occurred exclusively during wakefulness, suggesting that a wakefulness-specific modulator of S1 is abnormal in TLE. Repetitive seizures may gradually insult the modulator of S1 distant from the epileptogenic network.
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http://dx.doi.org/10.1038/s41598-020-73051-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7523010PMC
September 2020

Sex-Dependent Effects of the APOE ɛ4 Allele on Behavioral Traits and White Matter Structures in Young Adults.

Cereb Cortex 2021 Jan;31(1):672-680

Division of Developmental Cognitive Neuroscience, Institute of Development, Aging and Cancer, Tohoku University, Sendai 980-8575, Japan.

The APOE ɛ4 allele is associated with a risk of Alzheimer's disease in the elderly, with the association being pronounced in females. Conversely, findings of the effects of the APOE ɛ4 allele in young adults are mixed. Here, we investigated the sex-genotype interaction effects of the APOE ɛ4 allele on cognitive functions as well as brain structures among 1258 young adults. After adjusting for multiple comparisons, there were significant effects of the interaction between sex and the number of APOE ɛ4 allele on some speed tasks (e.g., simple processing speed tasks and the reverse Stroop task) as well as on regional white matter volume (rWMV). The observed sex-genotype interaction conferred better cognitive performance and greater rWMV in the anterior frontal and precentral white matter areas in females having more APOE ɛ4 alleles and reduced rWMV in the same areas in male having more APOE ɛ4 alleles. These findings support the long-debated antagonistic pleiotropic effects of the APOE ɛ4 allele in females.
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http://dx.doi.org/10.1093/cercor/bhaa251DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7727389PMC
January 2021

The Role of Cognitive Control in Age-Related Changes in Well-Being.

Front Aging Neurosci 2020 9;12:198. Epub 2020 Jul 9.

Institute of Development, Aging, and Cancer (IDAC), Tohoku University, Sendai, Japan.

Maintaining emotional well-being in late life is crucial for achieving successful and healthy aging. While previous research from Western cultures has documented that emotional well-being improves as individuals get older, previous research provided mixed evidence on the effects of age on well-being in Eastern Asian cultures. However, previous studies in East Asia do not always take into account the effects of cognitive control-an ability which has been considered as a key to enable older adults to regulate their emotions. In the current study, we tested whether cognitive control abilities interact with age in determining individuals' well-being in 59 Japanese females (age range: 26-79; = 64.95). Participants' mental health and mental fatigue were tracked for 5 years together with their cognitive control abilities. We found that as individuals became older, they showed improved mental health and decreased mental fatigue. In addition, we found a quadratic effect of age on mental fatigue, which was further qualified by baseline cognitive control abilities. Specifically, in those who had a lower level of cognitive control abilities, mental fatigue declined until the mid-60s, at which point it started increasing (a U-shape effect). In contrast, in those who had a higher level of cognitive control ability, mental fatigue showed a steady decrease with age even after their mid-60s. These results suggest that whether advancing age is associated with positive vs. negative changes in well-being depends on cognitive control abilities, and that preserved cognitive control is a key to maintain well-being in late life.
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http://dx.doi.org/10.3389/fnagi.2020.00198DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7396630PMC
July 2020

Virtual training leads to physical, cognitive and neural benefits in healthy adults.

Neuroimage 2020 11 21;222:117297. Epub 2020 Aug 21.

Smart Aging International Research Center (SAIRC), Tohoku University, 4-1 Seiryocho, Aobaku, Sendai 980-8575, Japan; Institute of Development, Aging and Cancer (IDAC), Tohoku University, 4-1 Seiryocho, Aobaku, Sendai 980-8575, Japan.

Physical activity, such as high-intensity intermittent aerobic exercise (HIE), can improve executive functions. Although performing strength or aerobic training might be problematic or not feasible for someone. An experimental situation where there is no actual movement, but the body shows physiological reactions, is during the illusion through immersive virtual reality (IVR). We aimed to demonstrate whether a virtual HIE-based intervention (vHIE) performed exclusively by the own virtual body has physical, cognitive, and neural benefits on the real body. 45 healthy young adults (cross-over design) experienced HIE training in IVR (i.e., the virtual body performed eight sets of 30 s of running followed by 30 s of slow walking, while the subject is completely still) in two random-ordered conditions (administered in two sessions one week apart): the virtual body is displayed in first-person perspective (1PP) or third-person perspective (3PP). During the vHIE, we recorded the heart rate and subjective questionnaires to confirm the effectiveness of the illusion; before and after vHIE, we measured cortical hemodynamic changes in the participants' left dorsolateral prefrontal cortex (lDLPFC) using the fNIRS device during the Stroop task to test our main hypothesis. Preliminary, we confirmed that the illusion was effective: during the vHIE in 1PP, subjects' heart rate increased coherently with the virtual movements, and they reported subjective feelings of ownership and agency. Primarily, subjects were faster in executing the Stroop task after the vHIE in 1PP; also, the lDLPFC activity increased coherently. Clinically, these results might be exploited to train cognition and body simultaneously. Theoretically, we proved that the sense of body ownership and agency can affect other parameters, even in the absence of actual movements.
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http://dx.doi.org/10.1016/j.neuroimage.2020.117297DOI Listing
November 2020

Dorsolateral Prefrontal Cortex Activity during a Brain Training Game Predicts Cognitive Improvements after Four Weeks' Brain Training Game Intervention: Evidence from a Randomized Controlled Trial.

Brain Sci 2020 Aug 15;10(8). Epub 2020 Aug 15.

Smart Aging Research Center (S.A.R.C.), Tohoku University, Seiryo-machi 4-1, Sendai 980-8575, Japan.

Background: Recent studies have demonstrated that brain activities using NIRS (near-infrared spectroscopy) at baseline during cognitive tasks (e.g., N-back task) can predict the cognitive benefits of a cognitive training. In this study, we investigated whether brain activities during brain training game (BT) at baseline would predict benefits to cognitive functions after the intervention period.

Methods: In a four-week double-blinded randomized control trial (RCT) 72 young adults were randomly assigned to one of the two groups: participants in the BT group played specific game, called the Brain Age. Participants in an active control group (ACT) played the puzzle game Tetris. We measured brain activity during the training games using two channel NIRS before the intervention period. Cognitive functions were tested before and after the four-week intervention period.

Results: The BT showed significant improvements in inhibition, processing speed, and working memory performance compared to ACT. The left and right DLPFC (dorsolateral prefrontal cortex) brain activities during the BT at baseline were associated with improvements in inhibition and processing speed.

Discussion: This randomized control trial first provides scientific evidence that DLPFC activities during BT at baseline can predict cognitive improvements after a four-week intervention period.
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http://dx.doi.org/10.3390/brainsci10080560DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7464011PMC
August 2020

The associations of BMI with mean diffusivity of basal ganglia among young adults with mild obesity and without obesity.

Sci Rep 2020 07 28;10(1):12566. Epub 2020 Jul 28.

Division of Developmental Cognitive Neuroscience, Institute of Development, Aging and Cancer (IDAC), Tohoku University, 4-1 Seiryo-cho, Aoba-ku, Sendai, 980-8575, Japan.

Obesity causes a wide range of systemic diseases and is associated with mood and anxiety disorders. It is also associated with dopaminergic reward system function. However, the relationships between microstructural properties of the dopaminergic system and body mass index (BMI) have not been investigated. In this study, we investigated the associations of BMI with mean diffusivity (MD), diffusion tensor imaging measure in areas of the dopaminergic system (MDDS) in 435 healthy young adults with mild obesity and without obesity (BMI < 40). We detected the association between greater BMI and lower MD of the right globus pallidus and the right putamen. These results suggest that the property of the dopaminergic system is associated with BMI among young adults with mild obesity and without obesity.
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http://dx.doi.org/10.1038/s41598-020-69438-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7387490PMC
July 2020

Effects of training of shadowing and reading aloud of second language on working memory and neural systems.

Brain Imaging Behav 2021 Jun;15(3):1253-1269

Faculty of Medicine, Tohoku University, Sendai, Japan.

Shadowing and reading aloud both involve multiple complex cognitive processes, and both are considered effective methods for second-language learning. The working memory system, particularly the phonological loop, has been suggested to be involved in shadowing and reading aloud. The purpose of this study was to investigate the effects of a 4-week intensive adaptive training including shadowing and reading aloud of second language on working-memory capacity, regional gray matter volume (rGMV), and functional activation related to the n-back working-memory task in young adults. The results showed that compared with the training groups without speaking (listening to compressed speech and active control involving the second language), the training groups with speaking (shadowing and reading aloud) showed a tendency for greater test-retest increases in digit-span scores, and significantly greater test-retest decreases in N-back task reaction time (increase in working memory performance). Imaging analyses revealed compared with the active control group, shadowing group exhibited decreases in rGMV and brain activity during the working memory task (2-back task), in the left cerebellum and reading group exhibited decreases in them in the right anterior insula. These regions are parts of the phonological loop, suggesting the presence of training-induced neural plasticity in these neurocognitive mechanisms.
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http://dx.doi.org/10.1007/s11682-020-00324-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8286220PMC
June 2021

Succeeding in deactivating: associations of hair zinc levels with functional and structural neural mechanisms.

Sci Rep 2020 07 23;10(1):12364. Epub 2020 Jul 23.

Division of Developmental Cognitive Neuroscience, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-cho, Aoba-ku, Sendai, 980-8575, Japan.

Zinc is a biologically essential element and involved in a wide range of cellular processes. Here, we investigated the associations of zinc levels in hair with brain activity during the n-back working memory task using functional magnetic resonance imaging, fractional anisotropy (FA) of diffusion tensor imaging, and cognitive differences in a study cohort of 924 healthy young adults. Our findings showed that greater hair zinc levels were associated with lower brain activity during working memory in extensive areas in the default mode network (i.e., greater task-induced deactivation) as well as greater FA in white matter areas near the hippocampus and posterior limbs of the internal capsule. These findings advance previous non-neuroimaging findings of zinc's associations with excitability, excitability-associated disorders, and myelination.
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http://dx.doi.org/10.1038/s41598-020-69277-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7378227PMC
July 2020

Differential roles of amygdala and posterior superior temporal sulcus in social scene understanding.

Soc Neurosci 2020 10 21;15(5):516-529. Epub 2020 Jul 21.

Institute of Development, Aging and Cancer, Tohoku University , Sendai, Japan.

Neuropsychology and neuroimaging studies provide distinct views on the key neural underpinnings of social scene understanding (SSU): the amygdala and multimodal neocortical areas such as the posterior superior temporal sulcus (pSTS), respectively. This apparent incongruity may stem from the difference in the assumed cognitive processes of the situation-response association and the integrative or creative processing of social information. To examine the neural correlates of different SSU types using functional magnetic resonance imaging (fMRI), we devised a clothing recommendation task in three types of client's standpoint. Situation-response association was induced by a situation-congruent standpoint (ecological SSU), whereas the integrative and creative processing of social information was elicited by a lack and situation incongruence of the standpoint (perceptual and elaborative SSUs, respectively). Activation characteristic of the ecological SSU was identified in the right amygdala, while that of the perceptual SSU and elaborative SSU demand was identified in the right pSTS and left middle temporal gyrus (MTG), respectively. Thus, the current results provide evidence for the conceptual and neural distinction of the three types of SSU, with basic ecological SSU being supported by a limbic structure while sophisticated integrative or creative SSUs being developed in humans by multimodal association cortices.
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http://dx.doi.org/10.1080/17470919.2020.1793811DOI Listing
October 2020

A Single 30 Minutes Bout of Combination Physical Exercises Improved Inhibition and Vigor-Mood in Middle-Aged and Older Females: Evidence From a Randomized Controlled Trial.

Front Aging Neurosci 2020 24;12:179. Epub 2020 Jun 24.

Smart Aging Research Center, Tohoku University, Sendai, Japan.

Background: Long-term combination of physical exercises has reported benefits for cognitive functions and mood states. However, it remains unclear whether a single bout of combination exercise training has acute positive effects on cognitive functions and mood states in middle-aged and older women. It is important to investigate acute effect of physical exercise because it would help to understand a mechanism of benefits of physical exercise. The purpose of this study was to investigate 30 min of a single bout of combination exercise training on cognition and mood states in middle-aged and older females.

Methods: In this single-blinded randomized control trial (RCT), middle-aged and older females were assigned randomly to two groups: a combination exercise group and a no-exercise control group. The former group did the combination exercise training (aerobic, strength, and stretching exercises) for 30 min. Meanwhile, the latter group did not do any exercise and waited for 30 min. We measured cognitive functions and mood performance states before and after the exercise or control interventions.

Results: Our main results demonstrated that, compared to the control group, the combination exercise improved inhibition (reverse Stroop and Stroop) and increased vigor-activity mood scores in both middle-aged and older groups. We also found that the only combination exercise group showed the significant positive correlations between improved inhibition performance and improved vigor-activity mood.

Discussion: This randomized controlled trial revealed the acute benefits of combination exercise on inhibition in executive functions and vigor-activity in the healthy middle-aged and older females. Our results provided the scientific evidence related to acute effects of the single bout of the combination exercise training. It suggests that we would be better to do the 30 min physical exercise for our health.

Clinical Trial Registration: This trial was registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN000029681). Registered 24 October 2017, https://upload.umin.ac.jp/cgi-bin/ctr/ctr_view_reg.cgi?recptno=R000033922.
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http://dx.doi.org/10.3389/fnagi.2020.00179DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7326951PMC
June 2020

Association Between Resting-State Functional Connectivity and Reading in Two Writing Systems in Japanese Children With and Without Developmental Dyslexia.

Brain Connect 2020 08 20;10(6):254-266. Epub 2020 Jul 20.

Division of Developmental Cognitive Neuroscience, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.

Japanese is unique, as it features two distinct writing systems that share the same sound and meaning: syllabic Hiragana and logographic Kanji scripts. Acquired reading difficulties in Hiragana and Kanji have been examined in older patients with brain lesions. However, the precise mechanisms underlying deficits in developmental dyslexia (DD) remain unclear. The neural signatures of Japanese children with DD were examined by using resting-state functional magnetic resonance imaging. We examined 22 dyslexic and 46 typically developing (TD) children, aged 7-14 years. Reading performance in each writing system was correlated with neural connectivity in TD children. In contrast, in children with DD, weak associations between neural connectivity and reading performance were observed. In TD children, Hiragana-reading fluency was positively correlated with the left fusiform gyrus network. No significant correlations between Hiragana fluency and neural connectivity were observed in children with DD. Correspondingly, there were fewer correlations between Kanji accuracy and strength of reading-related connectivity in children with DD, whereas positive correlations with the bilateral fronto-parietal network and negative correlations with the left fusiform network were found in TD children. These data suggest that positive and negative coupling with neural connectivity is associated with developing Japanese reading skills. Further, different neural connectivity correlations between Hiragana fluency and Kanji accuracy were detected in TD children but less in children with DD. The two writing systems may exert differential effects and deficits on reading in healthy children and in children with DD, respectively.
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http://dx.doi.org/10.1089/brain.2020.0759DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7465633PMC
August 2020

Originality of divergent thinking is associated with working memory-related brain activity: Evidence from a large sample study.

Neuroimage 2020 08 25;216:116825. Epub 2020 Apr 25.

Division of Developmental Cognitive Neuroscience, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan; Smart Aging Research Center, Tohoku University, Sendai, Japan; Department of Advanced Brain Science, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan; Department of Ubiquitous Sensing, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.

The originality of creativity measured by divergent thinking (CMDT) is a unique variable that is positively correlated with psychometric intelligence and other psychological measures. Here, we aimed to determine the associations of CMDT originality/fluency scores and brain activity associated with working memory (WM) and simple cognitive processes during the N-back paradigm in a cohort of 1221 young adults. We observed that originality/fluency scores were associated with greater brain activity during the 0-back simple cognitive task and 2-back WM task in key nodes of the ventral attention system in the right hemisphere. Further, subjects with higher originality/fluency scores showed lower task-induced deactivations in areas of the default mode network, especially during the 2-back task. Psychological analyses revealed the associations of originality/fluency scores with both psychometric intelligence and systemizing. We also observed the effects of interaction between sex and originality/fluency scores on functional activity during the 0-back task in posterior parts of the default mode network together with other areas as well as simple processing speed. These results indicate that the originality of CMDT is associated with (a) greater activation of the ventral attention system, which is involved in reorienting attention and (b) reduced task-induced deactivation of the default mode network, which is indicative of alterations in attentional reallocation, and (c) cognitive correlates of originality of CMDT and revealed sex differences in these associations.
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http://dx.doi.org/10.1016/j.neuroimage.2020.116825DOI Listing
August 2020
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