Left Inferior Parietal Regions Research Articles

Alterations in cerebral glucose metabolism measured by FDG PET in subjects performing a meditation practice based on clitoral stimulation

Background The relationship between sexuality, or the libido, and spirituality or religion has long been debated in psychiatry. Recent studies have explored the neurophysiology of both sexual experiences and spiritual practices such as meditation or prayer. In the present study, we report changes in cerebral glucose metabolism in a unique meditation practice augmented by clitoral stimulation called, Orgasmic Meditation, in which a spiritual state is described to be attained by both male and female participants engaged in the practice as a pair. Methods Male (N=20) and female (N=20) subjects had an intravenous catheter connected to a bag of normal saline inserted prior to the practice. During the practice, men stimulated their partner’s clitoris for exactly 15 minutes (he received no sexual stimulation). Midway through the practice, researchers injected 18F-fluorodeoxyglucose so the scan would reflect cerebral metabolism during the practice. Positron emission tomography (PET) imaging was performed approximately 30 minutes later. Results In the female participants, the meditation state showed significant decreases in the left inferior frontal, inferior parietal, insula, middle temporal, and orbitofrontal regions as well as in the right angular gyrus, anterior cingulate and parahippocampus compared to a neutral state (p<0.01). Male subjects had significant decreases in the left middle frontal, paracentral, precentral, and postcentral regions as well as the right middle frontal and paracentral regions during meditation (p<0.01). Men also had significantly increased metabolism in the cerebellum and right postcentral and superior temporal regions (p<0.01). Conclusions These findings represent a distinct pattern of brain activity, for both men and women, that is a hybrid between that of other meditation practices and sexual stimulation. Such findings have potential psychotherapeutic implications and may deepen our understanding of the relationship between spiritual and sexual experience.

Longitudinal Patterns of Brain Changes in a Community Sample in Relation to Aging and Cognitive Status.

Aging and Alzheimer's disease (AD) are characterized by widespread cortical and subcortical atrophy. Though atrophy patterns between aging and AD overlap considerably, regional differences between these two conditions may exist. Few studies, however, have investigated these patterns in large community samples. Elaborate longitudinal changes in brain morphometry in relation to aging and cognitive status in a well-characterized community cohort. Clinical and neuroimaging data were compiled from 72 participants from the Cardiovascular Health Study-Cognition Study, a community cohort of healthy aging and probable AD participants. Two time points were identified for each participant with a mean follow-up time of 5.36 years. MRI post-processing, morphometric measurements, and statistical analyses were performed using FreeSurfer, Version 7.1.1. Cortical volume was significantly decreased in the bilateral superior frontal, bilateral inferior parietal, and left superior parietal regions, among others. Cortical thickness was significantly reduced in the bilateral superior frontal and left inferior parietal regions, among others. Overall gray and white matter volumes and hippocampal subfields also demonstrated significant reductions. Cortical volume atrophy trajectories between cognitively stable and cognitively declined participants were significantly different in the right postcentral region. Observed volume reductions were consistent with previous studies investigating morphometric brain changes. Patterns of brain atrophy between AD and aging may be different in magnitude but exhibit widespread spatial overlap. These findings help characterize patterns of brain atrophy that may reflect the general population. Larger studies may more definitively establish population norms of aging and AD-related neuroimaging changes.

Phonological and morphological literacy skills in English and Chinese: A cross-linguistic neuroimaging comparison of Chinese-English bilingual and monolingual English children.

Over the course of literacy development, children learn to recognize word sounds and meanings in print. Yet, they do so differently across alphabetic and character-based orthographies such as English and Chinese. To uncover cross-linguistic influences on children's literacy, we asked young Chinese-English simultaneous bilinguals and English monolinguals (N = 119, ages 5-10) to complete phonological and morphological awareness (MA) literacy tasks. Children completed the tasks in the auditory modality in each of their languages during functional near-infrared spectroscopy neuroimaging. Cross-linguistically, comparisons between bilinguals' two languages revealed that the task that was more central to reading in a given orthography, such as phonological awareness (PA) in English and MA in Chinese, elicited less activation in the left inferior frontal and parietal regions. Group comparisons between bilinguals and monolinguals in English, their shared language of academic instruction, revealed that the left inferior frontal was less active during phonology but more active during morphology in bilinguals relative to monolinguals. MA skills are generally considered to have greater language specificity than PA skills. Bilingual literacy training in a skill that is maximally similar across languages, such as PA, may therefore yield greater automaticity for this skill, as reflected in the lower activation in bilinguals relative to monolinguals. This interpretation is supported by negative correlations between proficiency and brain activation. Together, these findings suggest that both the structural characteristics and literacy experiences with a given language can exert specific influences on bilingual and monolingual children's emerging brain networks for learning to read.

Exploring the alteration of gut microbiota and brain function in gender-specific Parkinson's disease based on metagenomic sequencing.

The role of the microbiota-gut-brain axis in Parkinson's disease (PD) has received increasing attention. Although gender differences are known to an essential role in the epidemiology and clinical course of PD, there are no studies on the sex specificity of the microbiota-gut-brain axis in the development and progression of PD. Fresh fecal samples from 24 PD patients (13 males, 11 females) were collected for metagenomic sequencing. The composition and function of the gut microbiota were analyzed by resting-state functional magnetic resonance imaging (fMRI). Gender-dependent differences in brain ALFF values and their correlation with microbiota were further analyzed. The relative abundance of Propionivibrio, Thermosediminibacter, and Flavobacteriaceae_noname was increased in male PD patients. LEfse analysis showed that Verrucomicrobial, Akkermansiaceae, and Akkermansia were dominant in the males. In female patients, the relative abundance of Propionicicella was decreased and Escherichia, Escherichia_coli, and Lachnospiraceae were predominant. The expression of the sesquiterpenoid and triterpenoid biosynthesis pathways was increased in male PD patients and was statistically different from females. Compared to the Male PD patients, female patients showed decreased ALFF values in the left inferior parietal regions, and the relative abundance of Propionivibrio was positively correlated with the regional ALFF values. Our study provides novel clinical evidence of the gender-specific relationship between gut microbiota alterations and brain function in PD patients, highlighting the critical role of the microbiota-gut-brain axis in gender differences in PD.

Brain Areas Critical for Picture Naming: A Systematic Review and Meta-Analysis of Lesion-Symptom Mapping Studies.

Lesion-symptom mapping (LSM) studies have revealed brain areas critical for naming, typically finding significant associations between damage to left temporal, inferior parietal, and inferior fontal regions and impoverished naming performance. However, specific subregions found in the available literature vary. Hence, the aim of this study was to perform a systematic review and meta-analysis of published lesion-based findings, obtained from studies with unique cohorts investigating brain areas critical for accuracy in naming in stroke patients at least 1 month post-onset. An anatomic likelihood estimation (ALE) meta-analysis of these LSM studies was performed. Ten papers entered the ALE meta-analysis, with similar lesion coverage over left temporal and left inferior frontal areas. This small number is a major limitation of the present study. Clusters were found in left anterior temporal lobe, posterior temporal lobe extending into inferior parietal areas, in line with the arcuate fasciculus, and in pre- and postcentral gyri and middle frontal gyrus. No clusters were found in left inferior frontal gyrus. These results were further substantiated by examining five naming studies that investigated performance beyond global accuracy, corroborating the ALE meta-analysis results. The present review and meta-analysis highlight the involvement of left temporal and inferior parietal cortices in naming, and of mid to posterior portions of the temporal lobe in particular in conceptual-lexical retrieval for speaking.

Characterization of Longitudinal Brain Changes in a Community Cohort in Relation to Aging and Cognitive Impairment

AbstractBackgroundBrain atrophy in aging and Alzheimer’s Disease (AD) involve numerous cortical and subcortical regions. Though there is much overlap in atrophy patterns between aging and AD, there may be regional differences between these two conditions (Fjell et al., 2019). Few studies, however, have explored these patterns in large community samples. This study attempts to investigate longitudinal changes in brain volumes and thickness in relation to aging and cognitive impairment in a well‐characterized community cohort.MethodClinical and neuroimaging data were compiled from 72 participants from the Cardiovascular Health Study‐Cognition Study, a community cohort study of both healthy aging and probable AD patients. Two time points were investigated for each participant with a mean follow‐up time of 5.36 years. MRI post‐processing, cortical and subcortical volume measurements, including hippocampal subfields, and statistical analyses were performed using FreeSurfer, Version 7.1.1. Longitudinal changes were adjusted for multiple comparisons through cluster‐wise correction via the Monte Carlo Z simulation.ResultCortical volume was significantly decreased in the bilateral superior frontal (left: ‐2.322%, p = 0.0002; right: ‐3.03%, p = 0.0002), left superior parietal (‐3.451%, p = 0.0002) and bilateral inferior parietal (left: ‐3.129%, p = 0.0002; right: ‐3.656%, p = 0.003) regions. Cortical thickness was significantly reduced in the bilateral superior frontal (left: ‐1.435%, p = 0.006; right: ‐1.615%, p = 0.0002) and left inferior parietal regions (‐1.581%, p = 0.025). Overall gray and white matter volumes and hippocampal subfields, including the cornu ammonis regions, also demonstrated significant reductions. Cortical volume and thickness trajectories between cognitively declined and cognitively stable subjects were not significantly different.ConclusionObserved volume reductions were consistent with previous studies investigating patterns of brain atrophy (Salat et al., 2004). The magnitude of atrophy was comparable with MCI/AD changes than normal aging (Bakkour et al., 2013). As patterns of atrophy did not significantly differ regardless of cognitive decline, there exists significant overlap between AD‐vulnerable regions and effects of normal aging. These findings help characterize patterns of cortical atrophy that may be reflective of the general population. Larger studies replicating these results are important to more definitively establish population norms of aging and AD‐related neuroimaging changes.

Alterations in cerebral glucose metabolism measured by FDG PET in subjects performing a meditation practice based on clitoral stimulation

Background: The relationship between sexuality, or the libido, and spirituality or religion has long been debated in psychiatry. Recent studies have explored the neurophysiology of both sexual experiences and spiritual practices such as meditation or prayer. In the present study, we report changes in cerebral glucose metabolism in a unique meditation practice augmented by clitoral stimulation called, Orgasmic Meditation, in which a spiritual state is described to be attained by both male and female participants engaged in the practice as a pair. Methods: Male (N=20) and female (N=20) subjects had an intravenous catheter connected to a bag of normal saline inserted prior to the practice. During the practice, men stimulated their partner’s clitoris for exactly 15 minutes (he received no sexual stimulation). Midway through the practice, researchers injected 18F-fluorodeoxyglucose so the scan would reflect cerebral metabolism during the practice. Positron emission tomography (PET) imaging was performed approximately 30 minutes later. Results: In the female participants, the meditation state showed significant decreases in the left inferior frontal, inferior parietal, insula, middle temporal, and orbitofrontal regions as well as in the right angular gyrus, anterior cingulate and parahippocampus compared to a neutral state (p<0.01). Male subjects had significant decreases in the left middle frontal, paracentral, precentral, and postcentral regions as well as the right middle frontal and paracentral regions during meditation (p<0.01). Men also had significantly increased metabolism in the cerebellum and right postcentral and superior temporal regions (p<0.01). Conclusions: These findings represent a distinct pattern of brain activity, for both men and women, that is a hybrid between that of other meditation practices and sexual stimulation. Such findings have potential psychotherapeutic implications and may deepen our understanding of the relationship between spiritual and sexual experience.

Cortical neuroanatomical changes related to specific language impairments in primary progressive aphasia.

ObjectiveLanguage function test-specific neural substrates in Korean patients with primary progressive aphasia (PPA) might differ from those in other causes of dementia and English-speaking PPA patients. We investigated the correlation between language performance tests and cortical thickness to determine neural substrates in Korean patients with PPA.Materials and methodsNinety-six patients with PPA were recruited from the memory clinic. To acquire neural substrates, we performed linear regression using the scores of each language test as a predictor, cortical thickness as an outcome and age, sex, years of education, and intracranial volume as confounders.ResultsPoor performance in each language function test was associated with lower cortical thickness in specific cortical regions: (1) object naming and the bilateral anterior to mid-portion of the lateral temporal and basal temporal regions; (2) semantic generative naming and the bilateral anterior to mid-portion of the lateral temporal and basal temporal regions; (3) phonemic generative naming and the left prefrontal and inferior parietal regions; and (4) comprehension and the left posterior portion of the superior and middle temporal regions. In particular, the neural substrates of the semantic generative naming test in PPA patients, left anterior to mid-portion of the lateral and basal temporal regions, quite differed from those in patients with other causes of dementia.ConclusionOur findings provide a better understanding of the different pathomechanisms for language impairments among PPA patients from those with other causes of dementia.

Rapid learning of a phonemic discrimination in the first hours of life

Human neonates can discriminate phonemes, but the neural mechanism underlying this ability is poorly understood. Here we show that the neonatal brain can learn to discriminate natural vowels from backward vowels, a contrast unlikely to have been learnt in the womb. Using functional near-infrared spectroscopy, we examined the neuroplastic changes caused by 5 h of postnatal exposure to random sequences of natural and reversed (backward) vowels (T1), and again 2 h later (T2). Neonates in the experimental group were trained with the same stimuli as those used at T1 and T2. Compared with controls, infants in the experimental group showed shorter haemodynamic response latencies for forward vs backward vowels at T1, maximally over the inferior frontal region. At T2, neural activity differentially increased, maximally over superior temporal regions and the left inferior parietal region. Neonates thus exhibit ultra-fast tuning to natural phonemes in the first hours after birth.

Structured sparse multiset canonical correlation analysis of simultaneous fNIRS and EEG provides new insights into the human action-observation network

The action observation network (AON) is a network of brain regions involved in the execution and observation of a given action. The AON has been investigated in humans using mostly electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI), but shared neural correlates of action observation and action execution are still unclear due to lack of ecologically valid neuroimaging measures. In this study, we used concurrent EEG and functional Near Infrared Spectroscopy (fNIRS) to examine the AON during a live-action observation and execution paradigm. We developed structured sparse multiset canonical correlation analysis (ssmCCA) to perform EEG-fNIRS data fusion. MCCA is a generalization of CCA to more than two sets of variables and is commonly used in medical multimodal data fusion. However, mCCA suffers from multi-collinearity, high dimensionality, unimodal feature selection, and loss of spatial information in interpreting the results. A limited number of participants (small sample size) is another problem in mCCA, which leads to overfitted models. Here, we adopted graph-guided (structured) fused least absolute shrinkage and selection operator (LASSO) penalty to mCCA to conduct feature selection, incorporating structural information amongst the variables (i.e., brain regions). Benefitting from concurrent recordings of brain hemodynamic and electrophysiological responses, the proposed ssmCCA finds linear transforms of each modality such that the correlation between their projections is maximized. Our analysis of 21 right-handed participants indicated that the left inferior parietal region was active during both action execution and action observation. Our findings provide new insights into the neural correlates of AON which are more fine-tuned than the results from each individual EEG or fNIRS analysis and validate the use of ssmCCA to fuse EEG and fNIRS datasets.

Neural correlates of cognitive resilience differ between experiences of bilingualism and education: A cortical surface‐based morphometry study in dementia

AbstractBackgroundLife‐course experiences such as education and bilingualism can be protective against dementia. The cognitive effects of bilingualism are specific while education has a more pervasive effect on general cognitive abilities, indicating that there is a likelihood of a variability in mechanisms underlying resilience. India is characterised by educational diversity and bilingualism. Importantly, bilingualism is not always associated with confounding effects of education, socioeconomic class or immigration. This makes the population uniquely suited for the study of resilience and opens up the possibility to disentangle the independent effects of bilingualism and education. Recent evidence indicates that surface‐based morphometric features of the cortical thickness and surface area are significantly modulated by life course experiences. Therefore, in this study, the independent influence of bilingualism and education on cortical thickness and surface area in dementia were studied to investigate the mechanisms that underlie resilience.MethodForty‐five patients with Frontotemporal dementia (FTD) were enrolled. 27 bilinguals were matched with 18 monolinguals for demographic factors and clinical severity. We examined the independent associations of bilingualism and education with cortical thickness and surface area using a surface based morphometric approach.ResultBilinguals with FTD had greater cortical thickness and reduced surface area in bilateral dorsolateral and medial frontal areas, and right parietotemporal cortex, regions associated with executive control. Bilinguals also demonstrated lesser cortical thickness in the language processing areas of left superior temporal, inferior parietal and lateral occipital regions compared to monolinguals. On the other hand, higher education was associated with decreased cortical thickness and increased surface area in bilateral frontal, medial temporal, parietal, occipital, and left temporal regions.ConclusionThis study explores for the first‐time, associations of two different proxies of resilience with cortical thickness and surface area in FTD. Our findings indicate that the neural substrate underlying the protective effects of bilingualism differ from education in FTD, and can be related to their differential effects on cognition. Results indicate specific neural correlates of resilience for different life‐course experiences.

Multi-level decoding of task sets in neurophysiological data during cognitive flexibility

SummaryCognitive flexibility is essential to achieve higher level goals. Cognitive theories assume that the activation/deactivation of goals and task rules is central to understand cognitive flexibility. However, how this activation/deactivation dynamic is implemented on a neurophysiological level is unclear. Using EEG-based multivariate pattern analysis (MVPA) methods, we show that activation of relevant information occurs parallel in time at multiple levels in the neurophysiological signal containing aspects of stimulus-related processing, response selection, and motor response execution, and relates to different brain regions. The intensity with which task sets are activated and processed dynamically decreases and increases. The temporal stability of these activations could, however, hardly explain behavioral performance. Instead, task set deactivation processes associated with left orbitofrontal regions and inferior parietal regions selectively acting on motor response task sets are relevant. The study shows how propositions from cognitive theories stressing the importance task set activation/deactivation during cognitive flexibility are implemented on a neurophysiological level.

The influence of methadone on cerebral gray matter and functional connectivity.

Methadone maintenance treatment (MMT) is widely used for heroin use disorder. Although its curative effect is remarkable, there are problems associated with its use. While previous studies have found that methadone use may have certain effects on cerebral white matter, its effect on gray matter (GM) and its related neural networks is unclear. This study aimed to observe the effects of long-term methadone use on cerebral GM and the changes in related neural networks. Patients receiving MMT treatment for heroin use disorder (N=50) were recruited. Longitudinal self-control was adopted, and the voxel-based morphometry (VBM) was used to compare the difference in cerebral GM volume before and after 1 year of methadone use, then we select the brain region where the GM volume changed as the region of interest (ROI), and use the DPARSF software for the whole brain function connection, and the differences in brain function connections before and after 1year MMT treatment were compared. Our results demonstrated that, after 1 year of MMT, patients showed smaller GM volume in the bilateral insula, occipital lingual gyrus, right cingulate gyrus, middle temporal gyrus, left inferior parietal lobule, caudate nucleus, temporal, and occipital regions, and the resting neural network of the brain also changed. We speculate that long-term methadone use can lead to damage to GM structure and adaptive changes in the neural network of patients with heroin use disorder, mainly involving emotional perception, spatial localization, working memory, and other related functions.

Distinct Neural Substrates Support Phonological and Orthographic Working Memory: Implications for Theories of Working Memory.

Prior behavioral and neuroimaging evidence supports a separation between working memory capacities in the phonological and orthographic domains. Although these data indicate distinct buffers for orthographic and phonological information, prior neural evidence does indicate that nearby left inferior parietal regions support both of these working memory capacities. Given that no study has directly compared their neural substrates based on data from the same individuals, it is possible that there is a common left inferior parietal region shared by both working memory capacities. In fact, those endorsing an embedded processes account of working memory might suggest that parietal involvement reflects a domain-general attentional system that directs attention to long-term memory representations in the two domains, implying that the same neural region supports the two capacities. Thus, in this work, a multivariate lesion-symptom mapping approach was used to assess the neural basis of phonological and orthographic working memory using behavioral and lesion data from the same set of 37 individuals. The results showed a separation of the neural substrates, with regions in the angular gyrus supporting orthographic working memory and with regions primarily in the supramarginal gyrus supporting phonological working memory. The results thus argue against the parietal involvement as supporting a domain-general attentional mechanism and support a domain-specific buffer account of working memory.

The neurocognitive basis of morphological processing in typical and impaired readers.

Morphological awareness, or sensitivity to units of meaning, is an essential component of reading comprehension development. Current neurobiological models of reading and dyslexia have largely been built upon phonological processing models, yet reading for meaning is as essential as reading for sound. To fill this gap, the present study explores the relation between children's neural organization for morphological awareness and successful reading comprehension in typically developing and impaired readers. English-speaking children ages 6-11 (N = 97; mean age = 8.6years, 25% reading impaired) completed standard literacy assessments as well as an auditory morphological awareness task during functional near-infrared spectroscopy (fNIRS) neuroimaging, which included root (e.g., PERSON + al) and derivational (e.g., quick + LY) morphology. Regression analyses revealed that children's morphological awareness predicted unique variance in reading comprehension above and beyond demographic factors, vocabulary knowledge, and decoding ability. Neuroimaging analyses further revealed that children with stronger reading comprehension showed greater engagement of brain regions associated with integrating sound and meaning, including left inferior frontal, middle temporal, and inferior parietal regions. This effect was especially notable for the derivational morphology condition that involved manipulating more analytically demanding and semantically abstract units (e.g., un-, -ly, -ion). Together, these findings suggest that successful reading comprehension, and its deficit in dyslexia, may be related to the ability to manipulate morpho-phonological units of word meaning and structure. These results inform theoretical perspectives on literacy and children's neural architecture for learning to read.

Morphology of the criminal brain: gray matter reductions are linked to antisocial behavior in offenders

Aggression and psychopathy are multifaceted conditions determined interpersonal and antisocial factors. Only a few studies analyze the link between these separate factors and specific brain morphology distinctively. A voxel-based morphometry (VBM) analysis was performed on 27 violent offenders and 27 controls aiming to associate sub-features of aggressive and psychopathic behavior with specific gray matter volumes. Trait aggression was assessed using two self-report tests (Aggression Questionnaire, AQ, and Reactive–Proactive–Aggression Questionnaire, RPQ) and psychopathy with the Psychopathy Checklist-Revised (PCL-R). Total and sub-scale scores of these tests were correlated to the brain morphometry of the offenders group in separate analyses. It was found that psychopathic behavior was negatively correlated with prefrontal gray matter volume and that this result was primarily driven by the antisocial behavior sub-scale of the PCL-R. Furthermore, less gray matter in right superior frontal and left inferior parietal regions with increasing antisocial behavior could be observed. One cluster comprising the right middle and superior temporal gyrus was negatively correlated with both, reactive aggression and antisocial behavior. These results outline (1) the importance of distinctively analyzing sub-features that contribute to aggressive and psychopathic behavior, given that the negative correlation of psychopathy global scores with prefrontal volume was driven by one single facet of the PCL-R scale (antisocial behavior). Moreover, these results indicate (2) fronto-temporo-parietal network deficits in antisocial, criminal offenders, with a particular strong effect in the temporal lobe.

S164. HIPPOCAMPAL CONNECTIVITY IN YOUTH WITH SCHIZOPHRENIA: COMPARISON WITH PATIENTS WITH NMDA RECEPTOR ENCEPHALITIS AND HEALTHY VOLUNTEERS

BackgroundThe N-methyl-D-aspartate receptor (NMDAR) hypofunction model of schizophrenia suggests that dysfunction of these receptors could underlie the brain functional abnormalities characterising these patients. In NMDAR encephalitis (NMDARE), which holds clinical similarities with schizophrenia, autoantibodies target NMDARs, predominantly located in the hippocampal region, leading to disrupted glutamatergic transmission. One study so far has described abnormal connectivity between the medial temporal lobe and posterior default mode network regions in patients with NMDARE (Peer et al., 2017), however no study so far has examined brain functional correlates of schizophrenia and NMDARE comparatively.MethodsPatients with schizophrenia (N=16) and with NMDARE shortly after clinical stabilisation (N=15) were recruited within a tertiary setting, and compared with age and sex-matched healthy volunteers (N=20). All individuals were scanned with a 3T Siemens scanner including a functional resting state sequence, during which individuals were instructed to view a fixation cross. A seed-based analysis was performed using a spherical seed of 4mm located in the left hippocampus (MNI coordinates x =-32, y=-24, x=-14). Only grey matter voxels were considered to obtain the seed average signal. BOLD signal was preprocessed including slice timing, motion correction, spatial smoothing, and frequency filtering, and regressed taken into account movement parameters (rigid transformation, frame displacement, and DVARS). Statistics was performed between the correlation maps including age and sex as covariates. Family-wise error (FWE) was used to correct for multiple comparisons.ResultsSeed to voxel analyses revealed connectivity between the seed and the bilateral thalamus, parahippocampus, precuneus, posterior cingulate, right hippocampus and lateral temporal regions (threshold Fisher’s z > 0.28). We first examined differences in connectivity between both patient groups combined and healthy volunteers, which revealed greater connectivity in patients than in controls between the left hippocampus and the left inferior parietal, postcentral and posterior cingulate gyri (pFWE< 0.05). When examining patient groups individually, patients with schizophrenia continued to exhibit significantly greater connectivity between the left hippocampus and left inferior parietal and postcentral region (pFWE< 0.05) and at near trend level in the posterior cingulate (pFWE= 0.15). NMDARE patients also presented near trend level increased connectivity in the posterior cingulate and postcentral gyri (pFWE= 0.10). There were no differences in functional connectivity of the left hippocampus between patients with schizophrenia and with NMDARE.DiscussionTo our knowledge, this is the first study to compare patients with schizophrenia with patients with NMDARE using measures of brain function. We found that, for both conditions, the left hippocampus showed greater connectivity with areas belonging to the posterior default mode network. Connectivity between these regions has been associated with psychotic symptoms in schizophrenia (Lefebvre et al., 2016). Our findings suggest that this alteration could also underlie neuropsychiatric symptoms in NMDARE, and provides further evidence that NMDAR dysfunction may underpin the pathophysiology of schizophrenia.

Daily-life affective instability in emotional distress disorders is associated with function and structure of posterior parietal cortex

Affective instability (i.e., large and frequent shifts in negative emotions) is a key emotion dysregulation symptom in emotional distress disorders and can be reliably and validly assessed using ambulatory assessment. However, no study has examined whether affective instability is associated with brain function and structure. Using multimodal neuroimaging and ambulatory assessment, we examined associations between functional activation and cortical structure with ambulatory-assessed affective instability in emotional distress disorders (n = 27). Increased daily life-affective instability was associated with decreased neural activation on an emotion regulation task in a left inferior parietal region consistently associated with emotion regulation. Daily-life affective instability was also associated with hypogyria in this same left inferior parietal region, with hypogyria extending into additional posterior parietal regions. This study found evidence that daily-life affective instability was associated with both functionstructure of the posterior parietal cortex, a key attentional control region involved in emotion regulation.

Building the multitasking brain: An integrated perspective on functional brain activation during task-switching and dual-tasking

Multitasking behavior is associated with well-known performance costs, but the question of why individuals falter when attempting to manage multiple streams of information remains difficult to answer. One reason for this difficulty may be that multitasking costs are often characterized by isolating component processes that are studied largely independently. In this study, we instead integrate two commonly studied substrates of multitasking, task-switching and dual-tasking, within the same procedural context. This method allows not only a direct comparison of performance costs associated with different demand types but also examination of their interaction. We measured functional brain activation in thirty healthy young adults as they completed a block-design version of the task, observing consistent and separable patterns of frontoparietal activation as a function of demand type. Broadly, task-switching was associated with activation of left premotor and inferior parietal regions, and dual-tasking was associated with activation in regions of right prefrontal and inferior parietal cortex. In the interaction condition, we observed a distributed bilateral pattern of activation across the areas associated with each demand in isolation. These results provide both behavioral and neuroimaging evidence that task-switching and dual-tasking demands can be dissociated and contribute to multitasking costs in unique and separable ways.

Connectivity between the visual word form area and the parietal lobe improves after the first year of reading instruction: a longitudinal MRI study in children.

Shortly after reading instruction, a region in the ventral occipital temporal cortex (vOTC) of the left hemisphere, the Visual Word Form Area (VWFA), becomes specialized for written words. Its reproducible location across scripts suggests important anatomical constraints, such as specific patterns of connectivity, notably to spoken language areas. Here, we explored the structural connectivity of the emerging VWFA in terms of its specificity relative to other ventral visual regions and its stability throughout the process of reading instruction in ten children studied longitudinally over 2years. Category-specific regions for words, houses, faces, and tools were identified in the left vOTC of each subject with functional MRI. With diffusion MRI and tractography, we reconstructed the connections of these regions at two time points (mean age ± standard deviation: 6.2 ± 0.3, 7.2 ± 0.4years). We first showed that the regions for each visual category harbor their own specific connectivity, all of which precede reading instruction and remain stable throughout development. The most specific connections of the VWFA were to the dorsal posterior parietal cortex. We then showed that microstructural changes in these connections correlated with improvements in reading scores over the first year of instruction but not 1 year later in a subsample of eight children (age: 8.4 ± 0.3years). These results suggest that the VWFA location depends on its connectivity to distant regions, in particular, the left inferior parietal region which may play a crucial role in visual field maps and eye movement dynamics in addition to attentional control in letter-by-letter reading and disambiguation of mirror-letters during the first stages of learning to read.