Inhibitory Control Network Research Articles

Distinct functional connectivity phenotypes in preadolescent children with binge eating disorder by BMI status.

The neurobiological mechanisms underpinning binge eating disorder (BED) in children remain largely unclear, as the alterations that have been identified to date may be attributable to BED, obesity, or compound effects. This study aimed to delineate functional connectivity (FC) patterns in inhibitory control and reward networks in preadolescent children with and without BED from the Adolescent Brain Cognitive Development (ABCD) Study according to BMI. Resting-state FC was examined in the inhibitory control network by using seeds in the dorsolateral prefrontal cortex, the anterior cingulate cortex, and the posterior cingulate cortex, whereas the reward network included seeds in the orbitofrontal cortex, nucleus accumbens, and amygdala. Seed-to-voxel analyses characterized FC differences between preadolescent children with BED with a high BMI and those with BED with a low BMI. We identified that BED was characterized by reduced connectivity between the reward network and regions in the default mode network, irrespective of weight status. Participants with BED also presented with hypoconnectivity in fronto-amygdalar circuits, which has been consistently associated with impaired emotion regulation capacity. Our findings support that FC alterations between the reward network and the default mode network may be specifically impacted by the presence of BED as opposed to weight status.

Neural mechanisms of inhibitory control in preadolescent irritability: Insights from the ABCD study

ObjectiveElevated pediatric irritability is a transdiagnostic symptom that predicts multiple mental health problems in adolescence and adulthood. Altered top-down regulatory networks, such as inhibitory control networks that suppress an impulse in favor of goal-directed behavior, are thought to contribute to high levels of youth irritability. Nevertheless, little work has examined links between youth irritability and neural processes supporting inhibitory control in large diverse samples, nor have they focused on the key period ramping up to adolescence (i.e., preadolescence). MethodFunctional MRI data from 5380 preadolescents (age M=9.97 years, SD=0.62) in the baseline Adolescent Brain and Cognitive Development (ABCD) Study were analyzed. Parents reported on their preadolescent’s irritability. The stop signal task (SST) was leveraged to probe successful and failed inhibitory control. Activation and functional connectivity with amygdala, ventral striatum, and prefrontal seed regions were calculated during the SST and used in whole brain and region of interest (ROI) group-level analyses evaluating irritability effects. ResultsPreadolescents with higher levels of irritability displayed decreases in functional connectivity among amygdala, ventral striatum, and prefrontal cortex regions during both successful and failed inhibitory control conditions. These results remained after adjusting for co-occurring anxiety, depression, and attention-deficit/hyperactivity symptoms. ConclusionsFindings suggest neural aberrations in inhibitory control play a role in the pathophysiology of preadolescent irritability and associations are not merely due to co-occurring symptoms. Neural mechanisms of inhibitory control associated with irritability may provide novel intervention targets.

White matter fibre density in the brain's inhibitory control network is associated with falling in low activity older adults.

Recent research has indicated that the relationship between age-related cognitive decline and falling may be mediated by the individual's capacity to quickly cancel or inhibit a motor response. This longitudinal investigation demonstrates that higher white matter fibre density in the motor inhibition network paired with low physical activity was associated with falling in elderly participants. We measured the density of white matter fibre tracts connecting key nodes in the inhibitory control network in a large sample (n = 414) of older adults. We modelled their self-reported frequency of falling over a 4-year period with white matter fibre density in pathways corresponding to the direct and hyperdirect cortical-subcortical loops implicated in the inhibitory control network. Only connectivity between right inferior frontal gyrus and right subthalamic nucleus was associated with falling as measured cross-sectionally. The connectivity was not, however, predictive of future falling when measured 2 and 4 years later. Higher white matter fibre density was associated with falling, but only in combination with low levels of physical activity. No such relationship existed for selected control brain regions that are not implicated in the inhibitory control network. Albeit statistically robust, the direction of this effect was counterintuitive (more dense connectivity associated with falling) and warrants further longitudinal investigation into whether white matter fibre density changes over time in a manner correlated with falling, and mediated by physical activity.

Passive exercise provides a simultaneous and postexercise executive function benefit

IntroductionPassive exercise involves limb movement via an external force and is an intervention providing an immediate postexercise executive function (EF) benefit. It is, however, unknown whether EF is improved simultaneous with passive exercise—a salient question given the advent of passive (and active) exercise workstations designed to enhance productivity and wellbeing for individuals engaged in sedentary occupations.MethodsHere, participants (N = 23) completed separate 20-min conditions involving active (i.e., via volitional muscle activation) and passive (i.e., via mechanically driven cycle ergometer) cycle ergometry and a non-exercise control condition. EF was assessed prior to (i.e., preintervention), simultaneous with, and immediately after (post-intervention) each condition via the antipointing task. Antipointing involves a goal-directed limb movement mirror-symmetrical to a target and is an ideal tool for the current investigation given that the task is mediated via EF inhibitory control networks that show response-dependent changes following a single bout of exercise.Results and discussionResults showed that passive exercise produced a simultaneous and post-intervention reduction in antipointing reaction time (RT), whereas active exercise selectively produced a post-intervention—but not simultaneous—RT reduction. Thus, passive and active exercise elicited a postexercise EF benefit; however, only passive exercise produced a simultaneous benefit. That passive—but not active—exercise produced a simultaneous benefit may reflect that the intervention provides the necessary physiological or psychological changes to elicit improved EF efficiency without the associated dual-task cost(s) of volitional muscle activity.

Functional connectivity and complexity analyses of resting-state fMRI in pre-adolescents demonstrating the behavioral symptoms of ADHD

Attention deficit hyperactivity disorder (ADHD) has been characterized by impairments among distributed functional brain networks, e.g., the frontoparietal network (FPN), default mode network (DMN), reward and motivation-related circuits (RMN), and salience network (SAL). In the current study, we evaluated the complexity and functional connectivity (FC) of resting state fMRI (rsfMRI) in pre-adolescents with the behavioral symptoms of ADHD, for pathology-relevant networks.We leveraged data from the Adolescent Brain and Cognitive Development (ABCD) Study. The final study sample included 63 children demonstrating the behavioral features of ADHD and 92 healthy control children matched on age, sex, and pubertal development status. For selected regions in the relevant networks, ANCOVA compared multiscale entropy (MSE) and FC between the groups. Finally, differences in the association between MSE and FC were evaluated.We found significantly reduced MSE along with increased FC within the FPN of pre-adolescents demonstrating the behavior symptoms of ADHD compared to matched healthy controls. Significant partial correlations between MSE and FC emerged in the FPN and RMN in the healthy controls however the association was absent in the participants demonstrating the behavior symptoms of ADHD.The current findings of complexity and FC in ADHD pathology support hypotheses of altered function of inhibitory control networks in ADHD.

What happens to the inhibitory control functions of the right inferior frontal cortex when this area is dominant for language?

A low number of individuals show an atypical brain control of language functions that differs from the typical lateralization in the left cerebral hemisphere. In these cases, the neural distribution of other cognitive functions is not fully understood. Although there is a bias towards a mirrored brain organization consistent with the Causal hypothesis, some individuals are found to be exceptions to this rule. However, no study has focused on what happens to the homologous language areas in the right frontal inferior cortex. Using an fMRI-adapted stop-signal task in a healthy non right-handed sample (50 typically lateralized and 36 atypically lateralized for language production), our results show that atypical lateralization is associated with a mirrored brain organization of the inhibitory control network in the left hemisphere: inferior frontal cortex, presupplementary motor area, and subthalamic nucleus. However, the individual analyses revealed a large number of cases with a noteworthy overlap in the inferior frontal gyrus, which shared both inhibitory and language functions. Further analyses showed that atypical lateralization was associated with stronger functional interhemispheric connectivity and larger corpus callosum. Importantly, we did not find task performance differences as a function of lateralization, but there was an association between atypical dominance in the inferior frontal cortex and higher scores on schizotypy and autistic spectrum traits, as well as worse performance on a reading accuracy test. Together, these results partially support the Causal hypothesis of hemispheric specialization and provide further evidence of the link between atypical hemispheric lateralization and increased interhemispheric transfer through the corpus callosum.

What happens to the inhibitory control functions of the right inferior frontal cortex when this area is dominant for language?

A low number of individuals show an atypical brain control of language functions that differs from the typical lateralization in the left cerebral hemisphere. In these cases, the neural distribution of other cognitive functions is not fully understood. Although there is a bias towards a mirrored brain organization consistent with the Causal hypothesis, some individuals are found to be exceptions to this rule. However, no study has focused on what happens to the homologous language areas in the right frontal inferior cortex. Using an fMRI-adapted stop-signal task in a healthy non right-handed sample (50 typically lateralized and 36 atypically lateralized for language production), our results show that atypical lateralization is associated with a mirrored brain organization of the inhibitory control network in the left hemisphere: inferior frontal cortex, presupplementary motor area, and subthalamic nucleus. However, the individual analyses revealed a large number of cases with a noteworthy overlap in the inferior frontal gyrus, which shared both inhibitory and language functions. Further analyses showed that atypical lateralization was associated with stronger functional interhemispheric connectivity and larger corpus callosum. Importantly, we did not find task performance differences as a function of lateralization, but there was an association between atypical dominance in the inferior frontal cortex and higher scores on schizotypy and autistic spectrum traits, as well as worse performance on a reading accuracy test. Together, these results partially support the Causal hypothesis of hemispheric specialization and provide further evidence of the link between atypical hemispheric lateralization and increased interhemispheric transfer through the corpus callosum.

A unified account of simple and response-selective inhibition

Response inhibition is a key attribute of human executive control. Standard stop-signal tasks require countermanding a single response; the speed at which that response can be inhibited indexes the efficacy of the inhibitory control networks. However, more complex stopping tasks, where one or more components of a multi-component action are cancelled (i.e., response-selective stopping) cannot be explained by the independent-race model appropriate for the simple task (Logan and Cowan 1984). Healthy human participants (n=28; 10 male; 19–40 years) completed a response-selective stopping task where a ‘go’ stimulus required simultaneous (bimanual) button presses in response to left and right pointing green arrows. On a subset of trials (30%) one, or both, arrows turned red (constituting the stop signal) requiring that only the button-press(es) associated with red arrows be cancelled. Electromyographic recordings from both index fingers (first dorsal interosseous) permitted the assessment of both voluntary motor responses that resulted in overt button presses, and activity that was cancelled prior to an overt response (i.e., partial, or covert, responses). We propose a simultaneously inhibit and start (SIS) model that extends the independent race model and provides a highly accurate account of response-selective stopping data. Together with fine-grained EMG analysis, our model-based analysis offers converging evidence that the selective-stop signal simultaneously triggers a process that stops the bimanual response and triggers a new unimanual response corresponding to the green arrow. Our results require a reconceptualisation of response-selective stopping and offer a tractable framework for assessing such tasks in healthy and patient populations.Significance StatementResponse inhibition is a key attribute of human executive control, frequently investigated using the stop-signal task. After initiating a motor response to a go signal, a stop signal occasionally appears at a delay, requiring cancellation of the response. This has been conceptualised as a ‘race’ between the go and stop processes, with the successful (or failed) cancellation determined by which process wins the race. Here we provide a novel computational model for a complex variation of the stop-signal task, where only one component of a multicomponent action needs to be cancelled. We provide compelling muscle activation data that support our model, providing a robust and plausible framework for studying these complex inhibition tasks in both healthy and pathological cohorts.

Investigating Cerebellar Modulation of Premovement Beta-Band Activity during Motor Adaptation.

Enhancing cerebellar activity influences motor cortical activity and contributes to motor adaptation, though it is unclear which neurophysiological mechanisms contributing to adaptation are influenced by the cerebellum. Pre-movement beta event-related desynchronization (β-ERD), which reflects a release of inhibitory control in the premotor cortex during movement planning, is one mechanism that may be modulated by the cerebellum through cerebellar-premotor connections. We hypothesized that enhancing cerebellar activity with intermittent theta burst stimulation (iTBS) would improve adaptation rates and increase β-ERD during motor adaptation. Thirty-four participants were randomly assigned to an active (A-iTBS) or sham cerebellar iTBS (S-iTBS) group. Participants performed a visuomotor task, using a joystick to move a cursor to targets, prior to receiving A-iTBS or S-iTBS, following which they completed training with a 45° rotation to the cursor movement. Behavioural adaptation was assessed using the angular error of the cursor path relative to the ideal trajectory. The results showed a greater adaptation rate following A-iTBS and an increase in β-ERD, specific to the high β range (20-30 Hz) during motor planning, compared to S-iTBS, indicative of cerebellar modulation of the motor cortical inhibitory control network. The enhanced release of inhibitory activity persisted throughout training, which suggests that the cerebellar influence over the premotor cortex extends beyond adaptation to other stages of motor learning. The results from this study further understanding of cerebellum-motor connections as they relate to acquiring motor skills and may inform future skill training and rehabilitation protocols.

Dual-site beta tACS over rIFG and M1 enhances response inhibition: A parallel multiple control and replication study

Response inhibition is a core component of cognitive control. Past electrophysiology and neuroimaging studies have identified beta oscillations and inhibitory control cortical regions correlated with response inhibition, including the right inferior frontal gyrus (rIFG) and primary motor cortex (M1). Hence, increasing beta activity in multiple brain regions is a potential way to enhance response inhibition. Here, a novel dual-site transcranial alternating current stimulation (tACS) method was used to modulate beta activity over the rIFG-M1 network in a sample of 115 (excluding 2 participants) with multiple control groups and a replicated experimental design. In Experiment 1, 70 healthy participants were randomly assigned to three dual-site beta-tACS groups, including in-phase, anti-phase or sham stimulation. During and after stimulation, participants were required to complete the stop-signal task, and electroencephalography (EEG) was collected before and after stimulation. The Barratt Impulsiveness Scale was completed before the experiment to evaluate participants' impulsiveness. In addition, we conducted an active control experiment with a sample size of 20 to exclude the potential effects of the dual-site tACS “return” electrode. To validate the behavioural findings of Experiment 1, 25 healthy participants took part in Experiment 2 and were randomized into two groups, including in-phase and sham stimulation groups. We found that compared to the sham group, in-phase but not anti-phase beta-tACS significantly improved both response inhibition performance and beta synchronization of the inhibitory control network in Experiment 1. Furthermore, the increased beta synchronization was correlated with enhanced response inhibition. In an independent sample of Experiment 2, the enhanced response inhibition performance observed in the in-phase group was replicated. After combining the data from the above two experiments, the time dynamics analysis revealed that the in-phase beta-tACS effect occurred in the post-stimulation period but not the stimulation period. The state-dependence analysis showed that individuals with poorer baseline response inhibition or higher attentional impulsiveness had greater improvement in response inhibition for the in-phase group. These findings strongly support that response inhibition in healthy adults can be improved by in-phase dual-site beta-tACS of the rIFG-M1 network, and provide a new potential treatment targets of synchronized cortical network activity for patients with clinically deficient response inhibition.

Altered effective connectivity between reward and inhibitory control networks in people with binge eating episodes: A spectral dynamic causal modeling study

BackgroundConverging evidence points to the crucial role of brain connectivity involved in aberrant behavioral control and reward reactivity in the onset and maintenance of binge eating. However, the directional interaction pattern between brain's reward and inhibitory control systems in people with binge eating episodes is largely unknown. MethodsResting-state fMRI data were collected from 36 adults with binge eating episodes (age: 19.05 ± 0.90) and 36 well-matched controls (age: 18.88 ± 0.78). We applied spectral dynamic causal modeling approach to estimate effective connectivity of the executive control network (ECN) and reward network (RN) with 15 predefined regions of interest, and investigate the between-group differences in directional connectivity. ResultsCompared with controls, the positive connections within the ECN were significantly strengthened in individuals with binge eating episodes, while the negative connections from the ECN to RN and from the RN to ECN were significantly weakened. In adults with binge eating episodes, the RN→ECN connectivity was positively related to binge frequency even controlling for age, sex, and body mass index. ConclusionThis study represents an important first step in addressing the role of directional integration between reward and inhibitory control networks in binge eating, and provides novel evidence that the ability of people with binge eating episodes to maintain a balance between inhibitory control and reward reactivity is decreased, as reflected by diminished bidirectional negative effects of prefrontal-subcortical circuitry at rest.

Sleep loss and lack of social interaction: a summary interview

Sleep loss is popular in modern society, and this health problem may further lead to social dysfunctions. In this article, we present some interesting behavioral and fMRI studies in the field of sleep and social functions. In light of these studies, we provide a dynamic framework for understanding the relationship between sleep loss and social interaction. In this framework, four sequential stages construct a life circle of interaction. The effects of sleep loss have distinct functions in each stage and correspond to different brain networks. These functions include the desire for social interaction, social withdrawal, subjective perceptions of social relationships, and loneliness. More importantly, we identify the core behavioral factors may be sleepiness, social-emotional processing, memory control, and rumination. For the brain networks, default mode network, negative affective network, inhibitory control network, and near-space networks may contribute to the relation between sleep loss and social interaction. In the future, experiments based on ecological sampling, and tracking studies based on the life cycle of interaction may be helpful for our understanding of this framework. The applications of some new technologies such as brain stimulation and neural feedback can be taken at different stages of social interactions.

Negative impact of daily screen use on inhibitory control network in preadolescence: A two-year follow-up study

The COVID-19 pandemic has made an unprecedented shift in children’s daily lives. Children are increasingly spending time with screens to learn and connect with others. As the online environment rapidly substitutes in-person experience, understanding children’s neuropsychological trajectories associated with screen experiences is important. Previous findings suggest that excessive screen use can lead children to prefer more immediate rewards over delayed outcomes. We hypothesized that increased screen time delays a child’s development of inhibitory control system in the brain (i.e., fronto-striatal circuitry). By analyzing neuropsychological data from 8324 children (9–11ys) from the ABCD Study, we found that children who had more screen time showed a higher reward orientation and weaker fronto-striatal connectivity. Importantly, we found that the daily screen exposure mediated the effect of reward sensitivity on the development of the inhibitory control system in the brain over a two year period. These findings suggest possible negative long-term impacts of increased daily screen time on children’s neuropsychological development. The results further demonstrated that screen time influences dorsal striatum connectivity, which suggests that the effect of daily screen use is a habitual seeking behavior. The study provides neural and behavioral evidence for the negative impact of daily screen use on developing children.

Aberrant functional connectivity between reward and inhibitory control networks in pre-adolescent binge eating disorder.

Behavioral features of binge eating disorder (BED) suggest abnormalities in reward and inhibitory control. Studies of adult populations suggest functional abnormalities in reward and inhibitory control networks. Despite behavioral markers often developing in children, the neurobiology of pediatric BED remains unstudied. 58 pre-adolescent children (aged 9-10-years) with BED (mBMI = 25.05; s.d. = 5.40) and 66 age, BMI and developmentally matched control children (mBMI = 25.78; s.d. = 0.33) were extracted from the 3.0 baseline (Year 0) release of the Adolescent Brain Cognitive Development (ABCD) Study. We investigated group differences in resting-state functional MRI functional connectivity (FC) within and between reward and inhibitory control networks. A seed-based approach was employed to assess nodes in the reward [orbitofrontal cortex (OFC), nucleus accumbens, amygdala] and inhibitory control [dorsolateral prefrontal cortex, anterior cingulate cortex (ACC)] networks via hypothesis-driven seed-to-seed analyses, and secondary seed-to-voxel analyses. Findings revealed reduced FC between the dlPFC and amygdala, and between the ACC and OFC in pre-adolescent children with BED, relative to controls. These findings indicating aberrant connectivity between nodes of inhibitory control and reward networks were corroborated by the whole-brain FC analyses. Early-onset BED may be characterized by diffuse abnormalities in the functional synergy between reward and cognitive control networks, without perturbations within reward and inhibitory control networks, respectively. The decreased capacity to regulate a reward-driven pursuit of hedonic foods, which is characteristic of BED, may in part, rest on this dysconnectivity between reward and inhibitory control networks.

Prefrontal Cortical Connectivity Mediates Locus Coeruleus Noradrenergic Regulation of Inhibitory Control in Older Adults.

Response inhibition is a core executive function enabling adaptive behavior in dynamic environments. Human and animal models indicate that inhibitory control and control networks are modulated by noradrenaline, arising from the locus coeruleus. The integrity (i.e., cellular density) of the locus coeruleus noradrenergic system can be estimated from magnetization transfer (MT)-sensitive magnetic resonance imaging (MRI), in view of neuromelanin present in noradrenergic neurons of older adults. Noradrenergic psychopharmacological studies indicate noradrenergic modulation of prefrontal and frontostriatal stopping-circuits in association with behavioral change. Here, we test the noradrenergic hypothesis of inhibitory control, in healthy adults. We predicted that locus coeruleus integrity is associated with age-adjusted variance in response inhibition, mediated by changes in connectivity between frontal inhibitory control regions. In a preregistered analysis, we used MT MRI images from N = 63 healthy humans aged above 50 years (of either sex) who performed a Stop-Signal Task (SST), with atlas-based measurement of locus coeruleus contrast. We confirm that better response inhibition is correlated with locus coeruleus integrity and stronger connectivity between presupplementary motor area (preSMA) and right inferior frontal gyrus (rIFG), but not volumes of the prefrontal cortical regions. We confirmed a significant role of prefrontal connectivity in mediating the effect of individual differences in the locus coeruleus on behavior, where this effect was moderated by age, over and above adjustment for the mean effects of age. Our results support the hypothesis that in normal populations, as in clinical settings, the locus coeruleus noradrenergic system regulates inhibitory control.SIGNIFICANCE STATEMENT We show that the integrity of the locus coeruleus, the principal source of cortical noradrenaline, is related to the efficiency of response inhibition in healthy older adults. This effect is in part mediated by its effect on functional connectivity in a prefrontal cortical stopping-network. The behavioral effect, and its mediation by connectivity, are moderated by age. This supports the psychopharmacological and genetic evidence for the noradrenergic regulation of behavioral control, in a population-based normative cohort. Noradrenergic treatment strategies may be effective to improve behavioral control in impulsive clinical populations, but age, and locus coeruleus integrity, are likely to be important stratification factors.

Regional gray matter abnormalities in pre-adolescent binge eating disorder: A voxel-based morphometry study

BackgroundBinge eating disorder (BED) is a pernicious psychiatric disorder which is linked with an array of multisystemic organ morbidity, broad psychiatric morbidity, and obesity. Despite behavioral markers often developing in early childhood, the neurobiological markers of early-onset BED remain understudied, and developmental pathophysiology remains poorly understood. Methods71 preadolescent children (aged 9–10-years) with BED and 74 age, BMI and developmentally matched control children were extracted from the 3.0 baseline (Year 0) release of the Adolescent Brain Cognitive Development (ABCD) Study. We investigated group differences in gray matter density (GMD) via voxel-based morphometry (VBM). We additionally performed region of interest analyses, assessing the association between GMD in nodes of the reward (orbitofrontal cortex; OFC) and inhibitory control (dorsolateral prefrontal cortex; dlPFC) networks, and parent-reported behavioral inhibition and approach tendencies. ResultsDiffuse elevations in cortical GMD were noted in those with BED, which spanned prefrontal, parietal, and temporal regions. No areas of reduced GMD were noted in those with BED. No alterations in subcortical GMD were noted. Brain-behavioral associations suggest a distinct and negative relationship between GMD in the OFC and dlPFC, respectively, and self-reported markers of hedonic behavioral approach tendencies. ConclusionsEarly-onset BED may be characterized by diffuse morphological abnormalities in gray matter density, suggesting alterations in cortical architecture which may reflect decreased synaptic pruning and arborization, or decreased myelinated fibers and therefore inter-regional afferents.

Negative Impact of Daily Screen Use on Inhibitory Control Network in Preadolescence: A Two Year Follow-Up Study

Negative Impact of Daily Screen Use on Inhibitory Control Network in Preadolescence: A Two Year Follow-Up Study

Atypical development of Broca's area in a large family with inherited stuttering.

Developmental stuttering is a condition of speech dysfluency, characterized by pauses, blocks, prolongations and sound or syllable repetitions. It affects around 1% of the population, with potential detrimental effects on mental health and long-term employment. Accumulating evidence points to a genetic aetiology, yet gene-brain associations remain poorly understood due to a lack of MRI studies in affected families. Here we report the first neuroimaging study of developmental stuttering in a family with autosomal dominant inheritance of persistent stuttering. We studied a four-generation family, 16 family members were included in genotyping analysis. T1-weighted and diffusion-weighted MRI scans were conducted on seven family members (six male; aged 9-63 years) with two age and sex matched controls without stuttering (n = 14). Using Freesurfer, we analysed cortical morphology (cortical thickness, surface area and local gyrification index) and basal ganglia volumes. White matter integrity in key speech and language tracts (i.e. frontal aslant tract and arcuate fasciculus) was also analysed using MRtrix and probabilistic tractography. We identified a significant age by group interaction effect for cortical thickness in the left hemisphere pars opercularis (Broca's area). In affected family members this region failed to follow the typical trajectory of age-related thinning observed in controls. Surface area analysis revealed the middle frontal gyrus region was reduced bilaterally in the family (all cortical morphometry significance levels set at a vertex-wise threshold of P < 0.01, corrected for multiple comparisons). Both the left and right globus pallidus were larger in the family than in the control group (left P = 0.017; right P = 0.037), and a larger right globus pallidus was associated with more severe stuttering (rho = 0.86, P = 0.01). No white matter differences were identified. Genotyping identified novel loci on chromosomes 1 and 4 that map with the stuttering phenotype. Our findings denote disruption within the cortico-basal ganglia-thalamo-cortical network. The lack of typical development of these structures reflects the anatomical basis of the abnormal inhibitory control network between Broca's area and the striatum underpinning stuttering in these individuals. This is the first evidence of a neural phenotype in a family with an autosomal dominantly inherited stuttering.

Sleep Loss Gives Rise to Intrusive Thoughts

We propose a framework in which top-down inhibitory control networks are impaired by sleep deprivation, giving rise to intrusive thoughts and, consequently, emotion dysregulation. This process leads to a vicious cycle of sleeplessness, persistent unwanted thoughts, and heightened anxiety, ultimately increasing the risk of mental illness.

Reward-related neural correlates in adolescents with excess body weight

The functional and connectivity reward processing in adults with excessive body weight is well documented, though is relatively less researched during adolescence. Given that reward and inhibition may be highly malleable during adolescence, it is unknown how impulsive behaviors, potentially stemming from impaired inhibitory control and heightened sensitivity to rewarding cues, relate to increases in body weight in adolescents. Adolescents (N = 76; mean age = 14.10 years, SD = 1.92) with varied body mass index (BMI) performed a child-friendly monetary incentive delay task during functional magnetic resonance imaging, to study reward processing during the anticipation of rewards (cue) and reactions to feedback about rewards (feedback). Our results show that adolescents with greater BMI z-score show neural activation and ventral striatum connectivity alterations in networks implicated in reward, salience detection, and inhibitory control. These bottom-up reward and top-down inhibitory control networks, as well as interactions between these networks were prevalent during the anticipation period (when the cue is presented) as well as when receiving feedback about whether one has received a reward. Specifically, our results were mainly driven by failure to receive a reward in the feedback period, and the anticipation of a potential reward in the anticipation period. Overall, we provide evidence for heightened reward salience as well as inhibitory control deficits that, in combination, may contribute to the impulsive behaviors that lead to higher BMI in adolescents.