Inhibition and the right inferior frontal cortex: one decade on

Relationship between overall right pre-frontal cortex activity and learning and retention of a visuomotor adaptation task: A continuous analysis

Learning a visuomotor adaptation task (VMA) is typically assessed by describing the behavioral changes during adaption (early-fast and late-slow phases) and retention (consolidation) tests. Few studies have concurrently examined behavioral and brain activity during this type of learning and therefore their time-dependent dynamics is unknown. It has been proposed that two distinct strategies can be used during such learning: a model-free and a model-based, which distinctively involved explicit and implicit learning strategies. It has also been proposed that prefrontal cortex (PFC) is more implicated when explicit processes are more relevant as it was observed in the early adaptation (Taylor & Ivry, 2014; Wolpe et al., 2020). Additionally, an explicit model-based strategy has been inferred when prefrontal (PFC) activity increases. Therefore, the study's aims were: (1) to examine the continuous temporal dynamics of behavior and right PFC activity during adaptation and retention of a VMA, and (2) to infer the implication of explicit processes during the learning of a VMA derived from right PFC activity. Eighteen young adults (24.22 ± 3.12 years) took part in this study. Continuous measures of the performance (the initial directional error, IDE, and the root mean square error, RMSE) of a rotational visuomotor adaptation task during an adaptation (AD) and two retention sets at 1 h (RT1) and 24 h (RT24) were collected. Concurrently, measures of the right PFC activity (relative changes of the oxyhemoglobin concentration, [ΔO2Hb]) were registered via a three-channel functional near-infrared spectroscopy device. General linear mixed models were run to explore differences across adaptation and retentions. Also, cross-correlations between performance (IDE and RMSE) and PFC activity were conducted to observe their relation during sets. The main results indicated that (1) initial fast behavioral improvement (decrease of IDE and RMSE) did not occur simultaneously with the largest increase of the [ΔO2Hb] in the PFC during the AD, and (2) there was similar performance in the RT1 and RT24 but possibly involving the PFC differently. While in both retentions the errors improved after the first trials, in RT1, the [ΔO2Hb] decreased from the very beginning, whereas the PFC activity initially increased in RT24. Our observations would suggest that various cooperating learning strategies, including model-free (i.e., exploratory) and model-based explicit (i.e., strategy) and implicit (i.e., sensory prediction errors), are coordinated in different timings to cooperate during the sensorimotor adaptation and consolidation processes. Furthermore, the involvement of these strategies during the retention may depend on the time elapsed from the end of the adaptation to the re-introduction of the task.

White matter properties in fronto-parietal tracts predict maladaptive functional activation and deficient response inhibition in ADHD

Response inhibition is a key characteristic of adaptive human behaviour. However, in attention deficit hyperactivity disorder (ADHD) it is often impaired. Previous neuroimaging investigations implicate a myriad of brain networks in response inhibition, making it more difficult to understand and overcome response inhibition difficulties. Recently, it has been suggested that a specific fronto-parietal functional circuitry between the inferior frontal gyrus (IFG) and the intraparietal sulcus (IPS), dictates the recruitment of the IPS during response inhibition in ADHD. To ascertain the critical role of the IFG-IPS functional circuit and its relevance to response inhibition in ADHD, it is crucial to understand the underlying structural architecture of this circuit so that the functional relevance could be interpreted correctly. Here we investigated the white matter pathways connecting the IFG and IPS using seed-based probabilistic tractography on diffusion data in 33 ADHD and 19 neurotypicals, assessing their impact on both IPS recruitment during response inhibition and on response inhibition performance in a Go/No-go task. Our results showed that individual differences in the structural properties of the IPS-IFG circuit, including tract volume and diffusivity, were linked to IPS activation and even predicted response inhibition performance outside the scanner. These findings highlight the structural-functional coupling within the IFG-IPS circuit in response inhibition in ADHD and suggest a structural basis for maladaptive functional top-down control in deficient inhibition in ADHD.

Conflict resolution and response inhibition: A simultaneous EEG-EMG-pupillometry study

Inhibition in cognitive control has many implications. Behaviorally, the stop signal task is supposedly capturing inhibition of already initiated responses (response inhibition). In contrast, the flanker paradigm supposedly captures the inhibition of several competing responses (competitive inhibition). As the neural mechanisms for these behavioral phenomena are not clear, it begs the question of whether both response inhibition and competitive inhibition draw from a similar inhibitory resource pool and to what extent they might interact. In the current study, the potential interplay between inhibitory mechanisms was investigated in a combined stop-signal flanker task where (in-)congruent flankers were occasionally followed by stop signals. A multimodal task-setup was implemented allowing for examination of behavior, electromyography (EMG), electroencephalography (EEG), and pupillometry to assess different inhibition-related outcome measures. Estimates of response inhibition speed (stop-signal reaction times; SSRTs) indicated an interaction with competitive inhibition, where stopping was faster in incongruent compared to congruent stop conditions. However, this was likely driven by differences at the short stop signal delays, which are susceptible to horse race model violations. Moreover, this interaction was not evident in physiological measures: neither stop-related EMG, EEG nor pupillometry measures showed such congruency modulations. Exploratory analyses showed that a larger pupillometry congruency effect was negatively associated with the congruency effect in SSRTs, suggesting that pupil dilation as a proxy for NE-LC activity might be linked to increased allocation of cognitive control. Taken together, our results do not provide clear evidence for an interaction between response inhibition and competitive inhibition.

Inhibitory control development from infancy to early childhood: A longitudinal fNIRS study

The developmental period from infancy to early childhood is one of substantial change - in advancements in cognitive skills, such as early executive functions, but also in the maturation of the prefrontal and parietal cortices that parallel such advances. The current study aims to investigate the emergence and development of inhibitory control, a core executive function, from infancy to early childhood. We collected longitudinal functional near-infrared spectroscopy (fNIRS) data from the same sample of participants at 10-months, 16-months, and 3½ years of age whilst they completed the Early Childhood Inhibitory Touchscreen Task. In our previous publications, we reported that 10-month-old infants recruited right lateralised regions of the prefrontal and parietal cortex when inhibition was required. Despite no change in response inhibition performance, 16-month-olds recruited broader and bilateral regions of the prefrontal and parietal cortex. Results of the current study found that 3½-year-olds activated regions of the right inferior parietal cortex and the right inferior frontal gyrus when inhibition was required. Response inhibition performance was significantly improved by early childhood, yet there was commonality in the brain regions recruited at 16-months and 3½ years. This could suggest that these brain regions are fundamental neural indices of inhibitory control, even from toddlerhood.

Hierarchical Organization of Bilateral Prefrontal-Basal Ganglia Circuits for Response Inhibition Control

Response inhibition control is primarily supported by the right inferior frontal gyrus (IFG) and the prefrontal-basal ganglia network, though the mechanisms behind right lateralization and regional interplay remain unclear. In this fMRI study, we explore the neural substrates supporting efficient inhibition control and examine whether the typical right lateralization of IFG activation can be modulated by stimulus properties (semantic features) and inhibitory demand (reaction times, RT). We chose a Go/No-Go lexical decision task, utilizing concrete and abstract words as Go stimuli and pseudo-word as No-Go stimuli. Behavioral results reveal that inhibition is more effective during concrete word sessions compared to abstract word sessions, suggesting a modulation of cognitive inhibition by semantic features. Neuroimaging results further demonstrate that successful inhibition activates bilateral IFG, indicating a flexible right lateralization pattern of IFG activation that varies with stimulus properties. To examine how varying inhibitory demands modulate neural activation patterns, we reclassified concrete and abstract sessions into fast and slow sessions based on RT, followed by within-group comparisons. Our study highlights the crucial role of the bilateral subthalamic nucleus (STN) in efficient inhibition, with increased activation associated with rapid response inhibition. Furthermore, we report enhanced neural coupling between the right IFG and multiple functionally connected regions, including bilateral insula, putamen, and pallidum, as well as between the right middle frontal gyrus and other prefrontal regions during rapid inhibitory responses, whereas no engagement of the left IFG was observed in efficient inhibition. These findings imply a hierarchical functional organization of the bilateral fronto-basal ganglia circuits, in which the right prefrontal regions play a dominant role in inhibition control, supported by basal ganglia regions, while the left IFG may serve a supplementary function. Stimulus properties can modulate right lateralization, underscoring the dynamic and flexible nature of the prefrontal-basal ganglia network in inhibition control.

Inhibitory control is related to fecal short-chain fatty acid concentrations in adults with overweight and obesity

Obesity is a pro-inflammatory condition with negative effects on executive functioning. Increased inflammation dysregulates gastrointestinal homeostasis and alters microbiota community composition. The gut microbiota produce immunomodulatory short-chain fatty acids (SCFA) that have been related to cognition in obesity, but the neural effects are not explored. Here, we hypothesized that greater fecal SCFA would be positively related to neuroelectric markers of inhibitory control and conflict monitoring in obesity. A cross-sectional cohort of 87 adults (35 ± 6 years, 53 females) with overweight and obesity (BMI = 32 ± 6 kg/m2) provided fresh fecal samples and participated in cognitive testing to assess response inhibition and conflict monitoring with electroencephalographic recording. Linear regressions, controlling for age, sex, BMI, and energy-adjusted dietary fiber intake, revealed positive relationships between NoGo N2 mean amplitude and fecal SCFA concentrations. Linear discriminant analysis effect size (LEfSe) revealed 16 amplicon sequence variants differentially abundant between high and low butyrate groups with Roseburia and Adlercreutzia individually related to NoGo N2 mean amplitude in MaAsLin2 modeling. Thus, greater fecal SCFA concentrations and SCFA producing microbiota (i.e., Roseburia) were related to markers of superior conflict monitoring in the NoGo task when adjusting for key covariates. These data highlight key associations between bacterial derived gut signaling molecules and neural regulation in cognitive domains particularly relevant to weight status that warrant further investigation.

Neural Tracking of Race-Related Information During Face Perception

Previous studies have identified two group-level processes, neural representations of interracial between-group difference and intraracial within-group similarity, that contribute to the racial categorization of faces. What remains unclear is how the brain tracks race-related information that varies across different faces as an individual-level neural process involved in race perception. In three studies, we recorded functional MRI signals when Chinese adults performed different tasks on morphed faces in which proportions of pixels contributing to perceived racial identity (Asian vs White) and expression (pain vs neutral) varied independently. We found that, during a pain expression judgment task, tracking other-race and same-race-related information in perceived faces recruited the ventral occipitotemporal cortices and medial prefrontal/anterior temporal cortices, respectively. However, neural tracking of race-related information tended to be weakened during explicit race judgments on perceived faces. During a donation task, the medial prefrontal activity also tracked race-related information that distinguished between two perceived faces for altruistic decision-making and encoded the Euclidean distance between the two faces that predicted decision-making speeds. Our findings revealed task-dependent neural mechanisms underlying the tracking of race-related information during face perception and altruistic decision-making.

Parietal cortex is recruited by frontal and cingulate areas to support action monitoring and updating during stopping

Recent evidence indicates that the intraparietal sulcus (IPS) may play a causal role in action stopping, potentially representing a novel neuromodulation target for inhibitory control dysfunctions. Here, we leverage intracranial recordings in human subjects to establish the timing and directionality of information flow between IPS and prefrontal and cingulate regions during action stopping. Prior to successful inhibition, information flows primarily from the inferior frontal gyrus (IFG), a critical inhibitory control node, to IPS. In contrast, during stopping errors the communication between IPS and IFG is lacking, and IPS is engaged by posterior cingulate cortex, an area outside of the classical inhibition network and typically associated with default mode. Anterior cingulate and orbitofrontal cortex also display performance-dependent connectivity with IPS. Our functional connectivity results provide direct electrophysiological evidence that IPS is recruited by frontal and anterior cingulate areas to support action plan monitoring and updating, and by posterior cingulate during control failures.

Brain mechanisms underlying the inhibitory control of thought

Controlling action and thought requires the capacity to stop mental processes. Over the past two decades, evidence has grown that a domain-general inhibitory control mechanism supported by the right lateral prefrontal cortex achieves these functions. However, current views of the neural mechanisms of inhibitory control derive largely from research into the stopping of action. Whereas action stopping is a convenient empirical model, it does not invoke thought inhibition and cannot be used to identify the unique features of this process. Here, we review research that addresses how organisms stop a key process that drives thoughts: memory retrieval. This work has shown that retrieval stopping shares right dorsolateral and ventrolateral prefrontal mechanisms with action stopping, consistent with a domain-general inhibitory control mechanism, but also recruits a distinct fronto-temporal pathway that determines the success of mental control. As part of this pathway, GABAergic inhibition within the hippocampus influences the efficacy of prefrontal control over thought. These unique elements of mental control suggest that hippocampal disinhibition is a transdiagnostic factor underlying intrusive thinking, linking the fronto-temporal control pathway to preclinical models of psychiatric disorders and fear extinction. We suggest that retrieval-stopping deficits may underlie the intrusive thinking that is common across many psychiatric disorders.

The benefit and neural mechanisms of computerized inhibitory control training for insomnia with short sleep duration phenotype: a rs-fMRI study

BACKGROUND

Inhibitory control (IC) impairment is characteristic of insomnia disorder with short sleep duration (ISSD), but not with normal sleep duration (INSD). IC is critical for sleep-wake regulation. This study evaluates whether computerized IC training can improve sleep in ISSD and explores related neural mechanisms using resting-state fMRI (rs-fMRI).

METHODS

Twenty ISSD patients participated in a three-week computerized IC training program (15 sessions), alongside a control group of 17 participants. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) and the Insomnia Severity Index (ISI), complemented by objective measures from overnight EEG recordings. Neuroimaging analyses focused on changes in regional homogeneity (ReHo), fractional amplitude of low-frequency fluctuations (fALFF), and functional connectivity (FC) in brain regions associated with IC.

RESULTS

Computerized IC training led to significant improvements in both subjective and objective sleep quality, demonstrated by reductions in PSQI and ISI scores, as well as decreased wake time during sleep. Neuroimaging revealed increased ReHo in the left medial orbitofrontal cortex (MOFC), elevated fALFF in the right middle frontal gyrus (MFG), and enhanced FC between the MOFC and the right rectus gyrus (RG), which correlated with improvements in sleep measures.

CONCLUSION

Computerized IC training appears to be an effective intervention for improving sleep in ISSD, likely by inducing functional changes in prefrontal cortex regions. These findings underscore the potential of IC-targeted treatments for ISSD and highlight the need for future research to evaluate the long-term effects of such interventions.

TRIAL REGISTRATION

The study was prospectively registered on May 30, 2024, in Chinese Clinical Trials registry (ChiCTR2400085063).

Association of spatiotemporal interaction of gamma oscillations with heart rate variability during response inhibition processing in patients with major depressive disorder: An MEG study

BACKGROUND

Impairment in response inhibition function is highly prevalent in patients with major depressive disorder (MDD), yet the spatiotemporal neural activity underlying response inhibition and its relationship with the autonomic nervous system (ANS) remains unclear.

METHODS

35 MDD participants and 35 healthy controls (HC) were included with magnetoencephalography (MEG) and electrocardiogram (ECG) data collecting during a go/no-go task. Heart rate variability (HRV) indices were calculated from the ECG data. Differences in functional connectivity (FC) of gamma oscillations (60-90 Hz) between 0-200 ms, 200-400 ms, and 400-600 ms in the two groups after no-go stimuli were analyzed, and the correlation between FC and HRV indices was examined.

RESULTS

The MDD group exhibited poorer task performance and lower HRV indices than the HC group. During the 200-400 ms period, compared to the HC group, the MDD group exhibited decreased FC between the left inferior frontal gyrus (opercular part) and right temporal pole (middle temporal gyrus) (t = 3.62, p < 0.05), and increased FC between the right superior frontal gyrus (orbital part) and right superior occipital gyrus (t = 3.68, p < 0.05). Additionally, a significant positive correlation was found between FC of the left inferior frontal gyrus (opercular part) and right middle temporal gyrus (temporal pole) and the HRV index RMSSD in the MDD group (r = 0.491, p < 0.05).

CONCLUSION

Abnormal spatiotemporal interactions in gamma oscillations related to response inhibition are observed in MDD patients and abnormal gamma oscillations showed task-dependent covariation with ANS indices, suggesting their potential interplay in MDD pathophysiology.

Shared neural correlates of interference control and response inhibition in adolescence and young adulthood

Inhibitory control (IC) is the ability to inhibit dominant or automatic behaviours, responses or thoughts, to allow for the selection of appropriate goal-directed responses. IC is a core executive function and has been associated with specific brain regions, such as the right inferior frontal gyrus (IFG) but also with a broader fronto-parietal network similar to the multiple demand network, which is thought to support the elaboration and maintenance of structured mental programs across a range of tasks. Here, functional magnetic resonance imaging data were collected from different IC tasks within the same participants to investigate similarities and differences in brain activation between tasks and age groups. Adolescents (11-15 years-old, n = 34) and adults (18-26, n = 33) completed block-design numerical Stroop and simple and complex Go/No-go (GNG) tasks. Univariate analyses showed large overlapping fronto-parietal activation in the Stroop and complex GNG tasks, with more limited activation in the simple GNG task. When compared to adolescents, adults showed greater increases in activation in the right IFG in the Stroop task and in temporo-parietal and precentral clusters in the complex GNG task. High multivariate similarity was observed across fronto-parietal regions between complex GNG and Stroop tasks, and between simple and complex GNG tasks, but was much lower between Stroop and simple GNG tasks. Adults showed greater similarity between complex GNG and Stroop tasks, suggesting increased reliance on shared neural processes across tasks, rather than increased specialisation of brain networks to specific aspects of IC over development.

The serotonin gene 5-HTTLPR and brain food-reward responses during sadness: a mood-induction neuroimaging study

BACKGROUND

High-calorie foods become particularly rewarding and difficult to resist under affective stressful circumstances. Individuals carrying the short allele variant of the serotonin transporter gene (s-allele 5-HTTLPR) often exhibit enhanced emotional and neuroendocrine stress responsiveness, which increases their risk to gain weight or to develop obesity.

OBJECTIVE

To explore whether homozygous S-allele 5-HTTLPR carriers are more sensitive to the rewarding effects of high- compared to low-calorie foods during sad mood.

METHODS

From a large (n = 827) DNA 5-HTTLPR database, a selected subgroup of homozygous S-allele and L-allele carriers were monitored for affective-motivational (mood, wanting-liking) and neural (fMRI) food-reward responsiveness during a food exposure task, before and after sad mood induction. Brain responsiveness was measured for high versus low calorie food pictures in a set of appetitive- and cognitive control ROIs, respectively.

RESULTS

Mood induction significantly increased sad mood in the majority of participants. Analyses revealed a genotype x mood induction interaction in cognitive control but not in affective ROIs. LL- compared to SS-carriers exhibited greater contrast value in the inferior frontal sulcus, dorsolateral PFC and superior parietal lob when viewing high- compared to low-calorie food pictures, which only in LL-genotypes significantly declined after sad mood induction.

CONCLUSION

LL- compared to SS-genotypes may have stronger high-calorie food responses in cognitive control brain areas in the absence of stress indicating better capacity to resist the rewarding effects of palatable foods.

Investigating brain network dynamics in state-dependent stimulation: A concurrent electroencephalography and transcranial magnetic stimulation study using hidden Markov models

BACKGROUND

Systems neuroscience studies have shown that baseline brain activity can be categorized into large-scale networks (resting-state-networks, RNSs), with influence on cognitive abilities and clinical symptoms. These insights have guided millimeter-precise selection of brain stimulation targets based on RSNs. Concurrently, Transcranial Magnetic Stimulation (TMS) studies revealed that baseline brain states, measured by EEG signal power or phase, affect stimulation outcomes. However, EEG dynamics in these studies are mostly limited to single regions or channels, lacking the spatial resolution needed for accurate network-level characterization.

OBJECTIVE

We aim at mapping brain networks with high spatial and temporal precision and to assess whether the occurrence of specific network-level-states impact TMS outcome. To this end, we will identify large-scale brain networks and explore how their dynamics relates to corticospinal excitability.

METHODS

This study leverages Hidden Markov Models to identify large-scale brain states from pre-stimulus source space high-density-EEG data collected during TMS targeting the left primary motor cortex in twenty healthy subjects. The association between states and fMRI-defined RSNs was explored using the Yeo atlas, and the trial-by-trial relation between states and corticospinal excitability was examined.

RESULTS

We extracted fast-dynamic large-scale brain states with unique spatiotemporal and spectral features resembling major RSNs. The engagement of different networks significantly influences corticospinal excitability, with larger motor evoked potentials when baseline activity was dominated by the sensorimotor network.

CONCLUSIONS

These findings represent a step forward towards characterizing brain network in EEG-TMS with both high spatial and temporal resolution and underscore the importance of incorporating large-scale network dynamics into TMS experiments.

Neural Associations between Inhibitory Control and Counterintuitive Reasoning in Science and Maths in Primary School Children

Emerging evidence suggests that inhibitory control (IC) plays a pivotal role in science and maths counterintuitive reasoning by suppressing incorrect intuitive concepts, allowing correct counterintuitive concepts to come to mind. Neuroimaging studies have shown greater activation in the ventrolateral and dorsolateral pFCs when adults and adolescents reason about counterintuitive concepts, which has been interpreted as reflecting IC recruitment. However, the extent to which neural systems underlying IC support science and maths reasoning remains unexplored in children. This developmental stage is of particular importance, as many crucial counterintuitive concepts are learned in formal education in middle childhood. To address this gap, fMRI data were collected while fifty-six 7- to 10-year-olds completed counterintuitive science and math problems, plus IC tasks of interference control (Animal Size Stroop) and response inhibition (go/no-go). Univariate analysis showed large regional overlap in activation between counterintuitive reasoning and interference control, with more limited activation observed in the response inhibition task. Multivariate similarity analysis, which explores fine-scale patterns of activation across voxels, revealed neural activation similarities between (i) science and maths counterintuitive reasoning and interference control tasks in frontal, parietal, and temporal regions, and (ii) maths reasoning and response inhibition tasks in the precuneus/superior parietal lobule. Extending previous research in adults and adolescents, this evidence is consistent with the proposal that IC, specifically interference control, supports children's science and maths counterintuitive reasoning, although further research will be needed to demonstrate the similarities observed do not reflect more general multidemand processes.

Left Ventral Caudate Functional Connectivity Mediates the Relationship Between Habitual Responding and Alcohol Use

Preclinical studies posit that habitual behaviour is an important mechanism in the development of alcohol use disorder (AUD), but human findings are unclear. The goals of this study were to test a behavioural measure of habit formation, the Slips of Action Task (SOAT), in humans and identify brain-based mechanisms explaining the relationship between habit and alcohol use. Thirty-six participants (63.9% female, mean age = 30.58, SD = 9.73, 69.4% White, 83.3% Not Hispanic/Latino) who endorsed heavy drinking completed self-report measures, the SOAT (lower scores = higher habit formation), a 2.5-h intravenous alcohol self-administration session, and a resting-state functional magnetic resonance imaging scan. Three seed regions-bilateral ventral caudate, nucleus accumbens and dorsal caudate-were assessed for significant whole brain functional connectivity (FC) associations with SOAT (cluster-level pFWE < 0.05 at a cluster-forming threshold p = 0.001). Two clusters survived Bonferroni correction (cluster pFWE = 0.008): FC between the left ventral caudate and the left middle frontal gyrus correlated negatively, while FC between the left NAc and the right central operculum correlated positively, with SOAT score. SOAT score was unrelated to drinking outcomes; however, there was a significant indirect relationship between SOAT and average drinks per drinking day through FC between the left ventral caudate and the left middle frontal gyrus. A similar trend seen with cumulative work for alcohol fell short of significance. Habit formation's relationship with alcohol use may function through neuroadaptations in the ventral caudate. More work is needed to better characterize objective habit formation in the human alcohol laboratory with additional laboratory-, alcohol-specific, imaging- and ambulatory-based alcohol use metrics.

Inhibitory control of speech production in the human premotor frontal cortex

Voluntary, flexible stopping of speech output is an essential aspect of speech motor control, especially during natural conversations. The cognitive and neural mechanisms of speech inhibition are not well understood. Here we have recorded direct high-density cortical activity while participants engaged in continuous speech production and were visually cued to stop speaking. Neural recordings revealed distinct activity in the premotor frontal cortex correlated with stopping speech. This activity was found in largely separate cortical sites from regions encoding vocal tract articulatory movements. Moreover, this activity primarily occurred with abrupt stopping in the middle of an utterance, rather than naturally completing a phrase. Electrocortical stimulation at many premotor sites with inhibitory stop activity caused involuntary speech arrest, which contradicts previous clinical interpretations of this effect as evidence for critical centres of speech production. Together, these results suggest a previously unknown premotor cortical network that supports the inhibitory control of speech, providing implications for understanding both natural and altered speech production.

Comparing level 1 and level 2 visuo-spatial perspective-taking in the brain: evidence from fMRI

Level 1 visuo-spatial perspective-taking (VSPT) refers to judging what other people can and cannot see. Previous research has suggested that this form of VSPT can be achieved relatively effortlessly. Level 2 VSPT, which refers to judgments about how an object appears from different viewpoints, is conceptually more complex and linked to higher-level social cognition and mentalizing. Despite growing neuroscientific evidence on VSPT, fMRI studies have not yet directly compared levels of perspective-taking. Study 1 collected fMRI data from a within-subject comparison of level 2 versus level 1 VSPT. We used a common activation contrast comparing inconsistent versus consistent perspectives between self and others. In Study 2, we further distinguished the brain regions associated with level 2 VSPT from those responsive to stimulus ambiguity and complexity. To achieve this, we asked participants to adopt different viewpoints on ambiguous and unambiguous stimuli. Results from both studies found that brain activation for level 2 VSPT was particularly high in areas of the dorsal attention network. Follow-up connectivity analysis found that level 2 VSPT is primarily carried out by the dorsal attention and the frontoparietal network. These results align with theories suggesting that VSPT can be achieved by engaging visuospatial attention and inhibitory control processes.

Common neural activations of creativity and exploration: A meta-analysis of task-based fMRI studies

Creativity is a common, complex, and multifaceted cognitive activity with significant implications for technological progress, social development, and human survival. Understanding the neurocognitive mechanisms underlying creative thought is essential for fostering individual creativity. While previous studies have demonstrated that exploratory behavior positively influences creative performance, few studies investigated the relationship between creativity and exploration at the neural level. To address this gap, we conducted a quantitative meta-analysis comprising 80 creativity experiments (1850 subjects) and 23 exploration experiments (646 subjects) to examine potential shared neural activations between creativity and exploration. Furthermore, we analyzed the neural similarities and differences among three forms of creative thinking-divergent thinking (DT), convergent thinking (CT), and artistic creativity-and their relationship with exploration. The conjunction analysis of creativity and exploration revealed significant activations in the bilateral IFJ and left preSMA. Further conjunction analyses revealed that both CT and artistic creativity exhibited common neural activations with exploration, with CT co-activating the left IFJ and artistic creativity co-activating both the right IFJ and left preSMA, while DT did not. Additionally, the conjunction analyses across the three forms of creativity did not identify shared neural activations. Further functional decoding analyses of the overlapping brain regions associated with CT and exploration, as well as artistic creativity and exploration, revealed correlations with inhibitory control mechanisms. These results enhance our understanding of the role of exploration in the creative thinking process and provide valuable insights for developing strategies to foster innovative thinking.

Whether or not to act is determined by distinct signals from motor thalamus and orbitofrontal cortex to secondary motor cortex

"To act or not to act" is a fundamental decision made in daily life. However, it is unknown how the relevant signals are transmitted to the secondary motor cortex (M2), which is the cortical origin of motor initiation. Here, we found that in a decision-making task in male mice, inputs from the thalamus to M2 positively regulated the action while inputs from the lateral part of the orbitofrontal cortex (LO) negatively regulated it. The motor thalamus that received the basal ganglia outputs transmitted action value-related signals to M2 regardless of whether the animal acted or not. By contrast, a large subpopulation of LO inputs showed decreased activity before and during the action, regardless of the action value. These results suggest that M2 integrates the positive signal of the action value from the motor thalamus with the negative action-biased signal from the LO to finally determine whether to act or not.

Delay- and Pressure-Dependent Neuromodulatory Effects of Transcranial Ultrasound Stimulation

OBJECTIVE

Despite the growing interest in transcranial focused ultrasound stimulation (TUS), our understanding of its underlying mechanisms remains limited. In this study, we aimed to investigate the effects of TUS on several functional magnetic resonance imaging metrics by considering their latency, duration, and relationship with applied acoustic pressure.

MATERIALS AND METHODS

We recruited 22 healthy volunteers and used a pre- vs post-TUS protocol. Half of the volunteers were stimulated in the right inferior frontal cortex and the other half in the right thalamus. The fractional amplitudes of low-frequency fluctuations, regional homogeneity, degree centrality, local functional connectivity density, and eigenvector centrality were considered. These metrics were compared before TUS and at three different time points in the first hour after TUS.

RESULTS

Our results showed that 1) TUS primarily alters functional connectivity metrics at both the local and global levels; 2) stronger alterations are observed when the delay after TUS increases and 3) when the applied acoustic pressure is close to the maximum.

CONCLUSION

These results suggest that some consequences of TUS might not be immediate, inviting us to revise the premise that TUS consequences are immediate and will progressively disappear.

The two sides of Phobos: Gray and white matter abnormalities in phobic individuals

Small animal phobia (SAP) is a subtype of specific phobia characterized by an intense and irrational fear of small animals, which has been underexplored in the neuroscientific literature. Previous studies often faced limitations, such as small sample sizes, focusing on only one neuroimaging modality, and reliance on univariate analyses, which produced inconsistent findings. This study was designed to overcome these issues by using for the first time advanced multivariate machine-learning techniques to identify the neural mechanisms underlying SAP. Specifically, we relied on the multimodal Canonical Correlation Analysis approach combined with Independent Component Analysis (ICA) to decompose the structural magnetic resonance images from 122 participants into covarying gray and white matter networks. Stepwise logistic regression and boosted decision trees were then used to extract a predictive model of SAP. Our results indicate that four covarying gray and white matter networks, IC19, IC14, IC21, and IC13, were critical in classifying SAP individuals from control subjects. These networks included brain regions, such as the Middle Temporal Gyrus, Precuneus, Insula, and Anterior Cingulate Cortex-all known for their roles in emotional regulation, cognitive control, and sensory processing. To test the generalizability of our results, we additionally ran a supervised machine-learning model (boosted decision trees), which achieved an 83.3% classification accuracy, with AUC of 0.9, indicating good predictive power. These findings provide new insights into the neurobiological underpinnings of SAP and suggest potential biomarkers for diagnosing and treating this condition. The study offers a more nuanced understanding of SAP, with implications for future research and clinical applications in anxiety disorders.

Effective Motor Skill Learning Induces Inverted-U Load-Dependent Activation in Contralateral Pre-Motor and Supplementary Motor Area

Motor learning involves complex interactions between the cognitive and sensorimotor systems, which are susceptible to different levels of task load. While the mechanism underlying load-dependent regulations in cognitive functions has been extensively investigated, their influence on downstream execution in motor skill learning remains less understood. The current study extends the understanding of whether and how learning alters the load-dependent activation pattern by a longitudinal functional near-infrared spectroscopy (fNIRS) study in which 30 healthy participants (15 females) engaged in extensive practice on a two-dimensional continuous hand tracking task with varying task difficulty. We proposed the index of difficulty (ID) as a quantitative measure of task difficulty, which was monotonically associated with a psychometric measure of subjective workload. As learning progressed, participants exhibited enhanced behavioral and metacognitive performance. Behavioral improvements were accompanied by plastic changes in the inferior prefrontal cortex, reflecting a shift in control strategy during motor learning. Most importantly, we found robust evidence of the learning-induced alteration in load-dependent cortical activation patterns, indicating that effective motor skill learning may lead to the emergence of an inverted-U relationship between cortical activation and load level in the contralateral pre-motor and supplementary motor areas. Our findings provide new insights into the learning-induced plasticity in brain and behavior, highlighting the load-dependent contributions in motor skill learning.

Reduced recruitment of inhibitory control regions in very young children with ADHD during a modified Kiddie Continuous Performance Task: A fMRI study

Attention-Deficit/Hyperactivity Disorder (ADHD) symptom profiles are known to undergo changes throughout development, rendering the neurobiological assessment of ADHD challenging across different developmental stages. Particularly in young children (ages 4- to 7-years), measuring inhibitory control network activity in the brain has been a formidable task due to the lack of child-friendly functional Magnetic Resonance Imaging (fMRI) paradigms. This study aims to address these difficulties by focusing on measuring inhibitory control in very young children within the MRI environment. A total of 56 children diagnosed with ADHD and 78 typically developing (TD) 4-7-year-old children were successfully examined using a modified version of the Kiddie-Continuous Performance Test (K-CPT) during BOLD fMRI to assess inhibitory control. We also evaluated their performance on the standardized K-CPT outside the MRI scanner. Our findings suggest that the modified K-CPT effectively elicited robust and expected brain activity related to inhibitory control in both groups who were successfully scanned. Comparisons between the two groups revealed differences in brain activity, primarily observed in inferior frontal gyrus, anterior insula, dorsal striatum, medial pre-supplementary motor area (pre-SMA), and cingulate cortex (p < .005, corrected). Notably, for both groups increased activity in the right anterior insula was associated with improved response time (RT) and reduced RT variability on the K-CPT administered outside the MRI environment, although this did not survive statistical correction for multiple comparisons. The study also revealed continuing challenges for scanning this population-an additional 51 TD children and 78 children with ADHD were scanned, but failed to provide useable data due to movement. In summary, for a subsample of children, we successfully overcame some of the challenges of measuring inhibitory control in very young children within the MRI environment by using a modified K-CPT during BOLD fMRI, but further challenges remain for scanning in this population. The findings shed light on the neurobiological correlates of inhibitory control in ADHD and TD children, provide valuable insights for understanding ADHD across development, and potentially inform ADHD diagnosis and intervention strategies. The research also highlights remaining challenges with task fMRI in very young clinical samples.

Annual Research Review: What processes are dysregulated among emotionally dysregulated youth? - a systematic review

Proliferation of the term "emotion dysregulation" in child psychopathology parallels the growing interest in processes that influence negative emotional reactivity. While it commonly refers to a clinical phenotype where intense anger leads to behavioral dyscontrol, the term implies etiology because anything that is dysregulated requires an impaired regulatory mechanism. Many cognitive, affective, behavioral, neural, and social processes have been studied to improve understanding of emotion dysregulation. Nevertheless, the defective regulatory mechanism that might underlie it remains unclear. This systematic review of research on processes that affect emotion dysregulation endeavors to develop an integrative framework for the wide variety of factors investigated. It seeks to ascertain which, if any, constitutes an impaired regulatory mechanism. Based on this review, we propose a framework organizing emotion-relevant processes into categories pertaining to stimulus processing, response selection and control, emotion generation, closed- or open-loop feedback-based regulation, and experiential influences. Our review finds scant evidence for closed-loop (automatic) mechanisms to downregulate anger arousal rapidly. Open-loop (deliberate) regulatory strategies seem effective for low-to-moderate arousal. More extensive evidence supports roles for aspects of stimulus processing (sensory sensitivity, salience, appraisal, threat processing, and reward expectancy). Response control functions, such as inhibitory control, show robust associations with emotion dysregulation. Processes relating to emotion generation highlight aberrant features in autonomic, endocrine, reward functioning, and tonic mood states. A large literature on adverse childhood experiences and family interactions shows the unique and joint effects of interpersonal with child-level risks. We conclude that the defective closed-loop regulatory mechanisms that emotion dysregulation implies require further specification. Integrating research on emotion-relevant mechanisms along an axis from input factors through emotion generation to corrective feedback may promote research on (a) heterogeneity in pathogenesis, (b) interrelationships between these factors, and (c) the derivation of better-targeted treatments that address specific pathogenic processes of affected youth.

Based on the resting-state functional magnetic resonance imaging reveals the causal relationship between the brain function network and the risk of tinnitus: a bidirectional Mendelian randomization analysis

OBJECTIVES

Tinnitus affects millions worldwide. Its neural mechanisms remain unclear. This study aimed to explore the causal relationships between brain functional networks and tinnitus risk using Mendelian randomization (MR) analyses.

METHODS

We performed MR analyses using brain activity data from resting-state functional magnetic resonance imaging (rs-fMRI) and genetic data from genome-wide association studies (GWAS). A total of 191 brain features, including amplitude traits and functional connectivity measures, were selected based on their genetic associations.

RESULTS

Forward MR analyses showed that increased activity in the parietal and inferior frontal regions was associated with a 41% reduction in tinnitus risk (OR = 0.59, p = 1.8 × 10-4). In contrast, increased activity in the precuneus, angular gyrus, and frontal areas was linked to a 49% increase in tinnitus risk (OR = 1.49, p = 8.9 × 10-4). Activities in the parietal and inferior frontal regions were negatively correlated with tinnitus risk (OR = 0.72, p = 0.0037). Additionally, higher activity in the parietal, frontal, and temporal regions doubled the risk (OR = 2.02, p = 0.015). Reverse MR showed that stronger connectivity between frontal and temporal regions was inversely related to tinnitus risk (beta = - 0.056, p = 0.049).

CONCLUSIONS

Specific brain activity and connectivity patterns are causally linked to tinnitus.

Variations in neuronal cytoskeletal integrity affect directed communication in distributed networks during inhibitory control

To ensure goal-directed behavior in daily life, the use of inhibitory control is of great importance. The aim of this study is to shed light on the underlying neuronal mechanisms of inhibitory control and the relevance of cytoarchitectonic integrity in it. We combine sophisticated EEG analysis techniques assessing directed communication between brain structures with measurements of neurofilaments as an index of cytoarchitectonic integrity. We show that an extensive theta band activity related neural network with fronto-temporal, parietal, and occipital brain regions is active during response inhibition. Importantly, cytoarchitectonic integrity as measured using neurofilaments modulates nonlinear directional connectivity, particularly when complex reconfiguration of perceptual and action mapping is required. The study thus shows an inter-relation between different levels of biological functioning-the level of cytoarchitectonic integrity and neurophysiological directed communication-for inhibitory control and emphasizes the role of nonlinear brain connectivity in cognitive control.

Mapping ADHD Heterogeneity and Biotypes through Topological Deviations in Morphometric Similarity Networks

Attention-deficit/hyperactivity disorder (ADHD) is characterized by considerable clinical heterogeneity. This study investigates whether normative modelling of topological properties derived from brain morphometry similarity networks can provide robust stratification markers for ADHD children. Leveraging multisite neurodevelopmental datasets (discovery: 446 ADHD, 708 controls; validation: 554 ADHD, 123 controls), we constructed morphometric similarity networks and developed normative models for three topological metrics: degree centrality, nodal efficiency, and participation coefficient. Through semi-supervised clustering, we delineated putative biotypes and examined their clinical profiles. We further contextualized brain profiles of these biotypes in terms of their neurochemical and functional correlates using large-scale databases, and assessed model generalizability in an independent cohort. ADHD exhibited atypical hub organization across all three topological metrics, with significant case-control differences primarily localized to a covarying multi-metric component in the orbitofrontal cortex. Three biotypes emerged: one characterized by severe overall symptoms and longitudinally persistent emotional dysregulation, accompanied by pronounced topological alterations in the medial prefrontal cortex and pallidum; a second by predominant hyperactivity/impulsivity accompanied by changes in the anterior cingulate cortex and pallidum; and a third by marked inattention with alterations in the superior frontal gyrus. These neural profiles of each biotype showed distinct neurochemical and functional correlates. Critically, the core findings were replicated in an independent validation cohort. Our comprehensive approach reveals three distinct ADHD biotypes with unique clinical-neural patterns, advancing our understanding of ADHD's neurobiological heterogeneity and laying the groundwork for personalized treatment.

Balancing postural control and motor inhibition during gait initiation

This study examines the relationship between stopping a planned gait initiation due to sudden environmental changes and maintaining body stability. Using a gait initiation version of the Stop Signal Task (SST), we studied changes in anticipatory postural adjustments (APAs) during gait initiation and suppression. We found that trial-level variables, such as the time to start or stop stepping, interacted with biomechanical factors like the center of mass displacement relative to the base of support affecting performance. A critical biomechanical threshold was identified, beyond which stopping movement was unlikely. These findings highlight the strong link between limb action control and body equilibrium, offering a framework within a motor control paradigm. By integrating biomechanical elements, the model effectively simulates real-life scenarios, identifying key variables for studying neural correlations between action and postural control, and aiding in the development of injury prevention and rehabilitation tools for individuals with movement and posture impairments.

The effect of high-intensity interval training on inhibitory function in overweight female college students: the mediating role of body composition

OBJECTIVE

To explore the inhibitory function characteristics of overweight female college students through two studies, and on this basis, to explore the effects of high-intensity interval training (HIIT) intervention on the inhibitory function of overweight female college students, as well as to test the mediating role of body composition.

METHODS

Study I recruited 34 overweight female college students and 38 normal-weight female college students, using the GO/NOGO task and the Flanker task to measure the participants' response inhibition and interference inhibition. Study II randomly divided the recruited 64 overweight female college students into an experimental group (n = 32) and a control group (n = 32), with the experimental group undergoing 8 weeks of Tabata-based HIIT and the control group not engaging in any form of exercise. The body composition of the participants was measured using a bioelectrical impedance body composition analyzer made in South Korea, the GAIA KIKO. Based on the SPSS 21.0 software, statistical techniques such as independent sample t-tests, Pearson correlation analysis, and mediation effect tests were used for analysis.

RESULTS

The reaction times of overweight female college students were significantly shorter than those of normal-weight female college students under the GO stimulus, consistent conditions, and inconsistent conditions (P < 0.05). 8 weeks of HIIT could effectively reduce the reaction times of overweight female college students under the GO stimulus, consistent conditions, and inconsistent conditions (P < 0.05), and effectively improve BMI, fat-free weight, fat content, muscle content, and basal metabolic rate (P < 0.05). There was a significant positive correlation between fat content and reaction times under the GO stimulus, consistent conditions, and inconsistent conditions (P < 0.05), and a significant negative correlation between waist-hip ratio and reaction times under the GO stimulus (P < 0.05). In addition, the mediation effect test found that fat content had a significant mediating effect in the reaction times under the consistent conditions after HIIT intervention (P < 0.01).

CONCLUSION

Overweight female college students have poorer inhibitory function, and HIIT can effectively improve their inhibitory function, with fat content playing a potential mediating role in the intervention process. It is recommended that HIIT be used as an important means to control the weight of overweight female college students and improve their inhibitory function.

Potential locations for non-invasive brain stimulation in treating ADHD: Results from a cross-dataset validation of functional connectivity analysis

Noninvasive brain stimulation (NIBS) has emerged as a promising therapeutic approach for attention-deficit/hyperactivity disorder (ADHD), yet the inaccurate selection of stimulation sites may constrain its efficacy. This study aimed to identify novel NIBS targets for ADHD by integrating meta-analytic findings with cross-dataset validation of functional connectivity patterns. A meta-analysis including 124 functional magnetic resonance imaging (fMRI) studies was first conducted to delineate critical brain regions associated with ADHD, which were defined as regions of interest (ROIs). Subsequently, functional connectivity (FC) analysis was performed using resting-state fMRI data from two independent databases comprising 116 patients with ADHD. Surface brain regions exhibiting consistent FC patterns with the ADHD-related ROIs across both datasets were identified as candidate NIBS targets. These targets were then translated to scalp-level stimulation sites using the 10-20 system and continuous proportional coordinates (CPC). Key regions mapped to the scalp included the bilateral dorsolateral prefrontal cortex, right inferior frontal gyrus, bilateral inferior parietal lobule, supplementary motor area (SMA), and pre-SMA. These findings propose a set of precise stimulation location for NIBS interventions in ADHD, potentially broadening the scope of neuromodulation strategies for this disorder. The study emphasized the utility of cross-dataset functional connectivity analysis in refining NIBS target selection and highlights novel brain targets that warrant further investigation in clinical trials.

Parietal cortex is recruited by frontal and cingulate areas to support action monitoring and updating during stopping

Recent evidence indicates that the intraparietal sulcus (IPS) may play a causal role in action stopping, potentially representing a novel neuromodulation target for inhibitory control dysfunctions. Here, we leverage intracranial recordings in human subjects to establish the timing and directionality of information flow between IPS and prefrontal and cingulate regions during action stopping. Prior to successful inhibition, information flows primarily from the inferior frontal gyrus (IFG), a critical inhibitory control node, to IPS. In contrast, during stopping errors the communication between IPS and IFG is lacking, and IPS is engaged by posterior cingulate cortex, an area outside of the classical inhibition network and typically associated with default mode. Anterior cingulate and orbitofrontal cortex also display performance-dependent connectivity with IPS. Our functional connectivity results provide direct electrophysiological evidence that IPS is recruited by frontal and anterior cingulate areas to support action plan monitoring/updating, and by posterior cingulate during control failures.

Genetic Correlation and Mendelian Randomization Analysis Revealed an Unidirectional Causal Relationship Between Left Caudal Middle Frontal Surface Area and Cigarette Consumption

OBJECTIVE

Previous studies have discovered a correlation between cigarette smoking and cortical thickness and surface area, but the causal relationship remains unclear. The objective of this investigation is to scrutinize the causal association between them.

METHODS

To derive summary statistics from a genome-wide association study (GWAS) on cortical thickness, surface area, and four smoking behaviors: 1) age of initiation of regular smoking (AgeSmk); 2) smoking initiation (SmkInit); 3) smoking cessation (SmkCes); 4) cigarettes per day (CigDay). Linkage disequilibrium score regression (LDSC) was employed to examine genetic association analysis. Furthermore, for traits with significant genetic associations, Mendelian randomization (MR) analyses were conducted.

RESULTS

The LDSC analysis revealed nominal genetic correlations between AgeSmk and right precentral surface area, left caudal anterior cingulate surface area, left cuneus surface area, left inferior parietal surface area, and right caudal anterior cingulate thickness, as well as between CigDay and left caudal middle frontal surface area, between SmkCes and left entorhinal thickness, and between SmkInit and left rostral anterior cingulate surface area, right rostral anterior cingulate thickness, and right superior frontal thickness (rg=-0.36-0.29, p<0.05). MR analysis showed a unidirectional causal association between left caudal middle frontal surface area and CigDay (βIVW=0.056, pBonferroni=2×10-4).

CONCLUSION

Left caudal middle frontal surface area has the potential to serve as a significant predictor of smoking behavior.

Neural circuit mapping of waiting impulsivity and proactive inhibition with convergent evidence from fMRI and TMS

BACKGROUND AND OBJECTIVES

Waiting and stopping are essential and distinct elements of motor response inhibition. Waiting impulsivity has been traditionally studied in humans with choice serial reaction time tasks. Proactive stopping is one form of stopping relevant to waiting impulsivity and the neural substrates underlying their interaction are not well defined.

METHODS

We conducted two separate, but hierarchical studies. In the first we used functional magnetic resonance imaging (fMRI), a choice reaction time task and a novel proactive stopping task, in N = 41 healthy volunteers to map the overlapping neural circuit involved in waiting impulsivity and proactive stopping. In the second study, we aimed to provide mechanistic and causal evidence that disruption of this circuit with continuous theta burst stimulation (cTBS; an inhibitory repetitive transcranial magnetic stimulation protocol) affected waiting impulsivity. We recruited N = 51 healthy, right-handed volunteers in a single-blind, randomized, between-subjects design who were randomly allocated to stimulation (N = 26) and sham (N = 25) groups and subsequently performed a choice reaction time task.

RESULTS

In the first study, we showed; 1. a shared neural network comprising the pre- supplementary motor area and bilateral anterior insula underlying both waiting impulsivity and proactive stopping, and 2. activity in dorsomedial prefrontal cortex and left inferior frontal gyrus negatively correlated with waiting impulsivity in trials with additional target onset delay. In the second study, we demonstrated that inactivation of the left inferior frontal gyrus using cTBS significantly increased waiting impulsivity in a choice reaction time task.

CONCLUSIONS

Our findings highlight the relevance of task design in assessing motor response inhibition and the role of the left inferior frontal gyrus integrity and related neural circuitry in waiting impulsivity and proactive stopping. We also leverage the use of convergent evidence from multi-modal investigation tools in addressing the causal neural areas underlying distinct forms of impulsivity.

Frontal localisation of a theory-based anxiety disorder biomarker - Goal conflict specific rhythmicity

PURPOSE

Anxiety disorders are a major global issue. Diagnosis via symptoms, not biological causes, delivers poor treatment outcomes. Our frontal EEG biomarker, Goal Conflict Specific Rhythmicity (GCSR; 4-12 Hz), developed from our long-standing detailed neuropsychological theory of anxiety processes, is reduced by all chemical types of selective anxiolytic and is high in cases across a range of currently diagnosed anxiety disorders.

METHODS

We assessed frontal sources of GCSR, recording scalp EEG at either low resolution (Experiment 1, 32 channels, University of Otago, ♀:33, ♂:16) or high resolution (Experiment 2, 128 channels, University of Auckland, ♀:10, ♂:8) in healthy participants performing a Stop Signal Task to generate GCSR as previously.

PRINCIPAL RESULTS

sLORETA demonstrated GCSR sources consistently in the right inferior frontal gyrus and, more strongly but less consistently, medial frontal gyrus. Variation was consistent with that of stopping in the same Stop Signal Task, depending on task demands.

MAJOR CONCLUSIONS

The sources of GCSR are consistent with our theory that hippocampal output receives goal information, detects conflict, and returns a negative biasing signal to the areas encoding goals in the current task. They match the variation in the control of stopping when response urgency changes. GCSR appears to index a biological type of anxiety unlike any current diagnosis and should help improve accuracy of diagnosis - anchored to actions of selective anxiolytic drugs. This task-related frontal "theta" rhythmicity provides proof-of-concept for further development of our theory of the neuropsychology of anxiety in direct human tests.

Saccadometry Findings in Migraine Patients Without Aura

INCLUDING

Migraine without aura is a common neurological disorder associated with structural and functional changes in the brain, which may lead to impairments in cognitive control and motor function. Functional magnetic resonance imaging (fMRI) has demonstrated changes in cortical gray matter volume associated with pain and ocular function in patients with migraine without aura.

OBJECTIVE

This study aims to evaluate prosaccade and antisaccade eye movements in patients with migraine without aura (MWOA) and determine whether the saccadometry test is an effective tool for identifying cognitive control and executive dysfunctions in these individuals.

METHODS

This study included 40 patients diagnosed with migraine without aura (MWOA) and 40 healthy controls. Prosaccade and anti-saccade eye movements were evaluated using a saccadometry test. The evaluation parameters were the latency, velocity, accuracy, overall error percentage, and directional error percentage.

RESULTS

The MWOA group performed worse on antisaccadic tasks compared to the control group. The MWOA group exhibited elevated overall and directional error rates, prolonged latency, and diminished accuracy (p = 0.0001) and velocity (p = 0.001) in comparison to the control group. No significant differences were seen in latency, velocity, and accuracy values for prosaccadic movements (p > 0.05), however general and directional error rates were significantly elevated (p = 0.014).

CONCLUSION

This study shows that migraine patients without aura experience difficulties in cognitive control and executive functions in antisaccadic eye movement tasks. Although prosaccade reflexive eye movements were generally preserved, significant difficulties were found in directional control and error suppression during the task. Our findings emphasize the potential for saccadometry to be an effective tool for assessing these impairments. The results may contribute to the development of more targeted treatment strategies for MWOA patients.

Separating neurocognitive mechanisms of maintenance and compensation to support financial ability in middle-aged and older adults: The role of language and the inferior frontal gyrus

This study investigated the role of brain regions involved in arithmetic processing in explaining individual differences in financial ability in 67 50-74-year-old cognitively normal adults. Structural integrity and resting-state functional connectivity measures were collected in the MRI scanner. Outside the scanner, participants performed financial ability and other cognitive tasks, and answered questionnaires to determine dementia risk, and financial risk and protective factors. Regions of interest involved in arithmetic processing were defined, focusing on language- and quantity-processing areas in temporo-frontal and parieto-frontal cortices, respectively. Our results showed that structural integrity and functional connectivity in brain regions associated with arithmetic retrieval were positively associated with financial ability, with language skill mediating left IFG structural integrity and financial ability. Connectivity patterns suggested that reliance on quantity mechanisms (i.e. calculation) was associated with poorer financial ability. Analyses revealed that reliance on these brain mechanisms did not depend on participants' age or risk of dementia and that protective factors such as household income or financial literacy supported the maintenance of connectivity related to financial abilities.

Neural Correlates of Different Randomization Tasks

In some cases, when we are making decisions, the available choices can appear to be equivalent. When this happens, our choices appear not to be constrained by external factors and, instead, we can believe to be selecting "randomly." Furthermore, randomness is sometimes even explicitly required by task conditions such as in random sequence generation tasks. This is a challenging task that involves the coordination of multiple cognitive processes, which can include the inhibition of habitual choice patterns and monitoring of the running choice sequence. It has been shown that random choices are strongly influenced by the way they are instructed. This raises the question whether the brain mechanisms underlying random selection also differ between different task instructions. To assess this, we measured brain activity while participants were engaging in three different variations of a sequence generation task: On the basis of previous work, participants were instructed to either (1) "generate a random sequence of choices," (2) "simulate a fair coin toss," or (3) "choose freely." Our results reveal a consistent frontoparietal activation pattern that is shared across all tasks. Specifically, increased activity was observed in bilateral inferior and right middle frontal gyrus, left pre-SMA, bilateral inferior parietal lobules, and portions of anterior insular cortex in both hemispheres. Activity in the mental coin toss condition was higher in right dorsolateral prefrontal cortex, left (pre-) SMA, a portion of right inferior frontal gyrus, bilateral superior parietal lobules, and bilateral anterior insula. In addition, our multivariate analysis revealed a distinct region in the right frontal pole to be predictive of the outcome of choices, but only when randomness was explicitly instructed. These results emphasize that different randomization tasks involve both shared and unique neural mechanisms. Thus, even seemingly similar randomization behavior can be produced by different neural pathways.

Neural Representation of Response Inhibition and Attentional Capture in the Right Inferior Frontal Gyrus

Inhibitory control requires individuals to suppress inappropriate behaviors while also engaging in attentional capture of response signals. Previous research has identified the right inferior frontal gyrus as a critical brain region for implementing inhibitory control; however, evidence regarding its role in attentional capture remains limited. Since the Stop trials in the stop signal task involve both attentional capture of salient stimuli and response inhibition, it is challenging to isolate the attentional capture process from inhibitory control. To address this issue, the present study modified the stop signal task by introducing Continue signals, allowing participants to execute Go responses upon seeing a Continue signal. Consequently, the processing of Continue signals involved attentional capture without engaging in response inhibition. Multivoxel pattern analysis revealed that the right inferior frontal gyrus is capable of representing both Stop and Continue signals, with a stronger neural representation for Stop signals compared to Continue signals. Thus, this study demonstrates that the right inferior frontal gyrus is involved in both attentional capture of stimulus signals and behavioral inhibition during the process of inhibitory control. This finding enhances our understanding of the specific functions of the right inferior frontal gyrus in the context of inhibitory control processing.

What Is Cognitive Control?

The last two decades have seen major advances in cognitive control research. In this paper, I provide an overview of this research. I next make a case that it might benefit from more reflection on its theoretical foundation. I end by suggesting that action theory might be of use with this.

The Effects of Transcranial Direct Current Stimulation (tDCS) on the Cognitive Functions: A Systematic Review and Meta-analysis

Previous studies have investigated the effect of transcranial direct current stimulation (tDCS) on cognitive functions. However, these studies reported inconsistent results due to differences in experiment design, measurements, and stimulation parameters. Nonetheless, there is a lack of meta-analyses and review studies on tDCS and its impact on cognitive functions, including working memory, inhibition, flexibility, and theory of mind. We performed a systematic review and meta-analysis of tDCS studies published from the earliest available data up to October 2021, including studies reporting the effects of tDCS on cognitive functions in human populations. Therefore, these systematic review and meta-analysis aim to comprehensively analyze the effects of anodal and cathodal tDCS on cognitive functions by investigating 69 articles with a total of 5545 participants. Our study reveals significant anodal tDCS effects on various cognitive functions. Specifically, we observed improvements in working memory reaction time (RT), inhibition RT, flexibility RT, theory of mind RT, working memory accuracy, theory of mind accuracy and flexibility accuracy. Furthermore, our findings demonstrate noteworthy cathodal tDCS effects, enhancing working memory accuracy, inhibition accuracy, flexibility RT, flexibility accuracy, theory of mind RT, and theory of mind accuracy. Notably, regarding the influence of stimulation parameters of tDCS on cognitive functions, the results indicated significant differences across various aspects, including the timing of stimulation (online vs. offline studies), population type (clinical vs. healthy studies), stimulation duration (< 15 min vs. > 15 min), electrical current intensities (1-1.5 m.A vs. > 1.5 m.A), stimulation sites (right frontal vs. left frontal studies), age groups (young vs. older studies), and different cognitive tasks in each cognitive functioning aspect. In conclusion, our results demonstrate that tDCS can effectively enhance cognitive task performance, offering valuable insights into the potential benefits of this method for cognitive improvement.

A longitudinal study on the effect of aerobic exercise intervention on the inhibitory control in college students with internet addiction

Objectives

This study aimed to investigate the effects of aerobic exercise on reactive inhibitory control in college students with internet addiction, examining both behavioral and electrophysiological changes over time.

Methods

A longitudinal study design was adopted, involving 48 male college students with internet addiction who were randomly assigned to either a control group or an experimental group. Participants in the experimental group engaged in 40 min aerobic cycling sessions three times per week for 12 weeks, while the control group maintained their usual physical activity levels without any intervention. A 3 × 2 × 3 mixed-factorial design was utilized, incorporating three time points (pre-experiment, 6 and 12 weeks), two groups (control and experimental), and three electrode sites (Fz, F3, F4). This design enabled the examination of the effects of aerobic exercise on reactive inhibitory control and its temporal dynamics in college students with internet addiction.

Results

A significant main effect of group was observed. Specifically, the experimental group demonstrated a significantly higher Nogo accuracy rate compared to the control group at both the mid-test (P < 0.01) and post-test (P < 0.001). Within the experimental group, the Nogo accuracy rate at the mid-test and post-test was significantly higher than at the pre-test (P < 0.001), with the post-test accuracy rate also significantly higher than the mid-test (P < 0.05). Time-frequency analysis revealed that, under the Nogo task, the energy values in the beta frequency band during the early (100-500 ms) and late (600-750 ms) time windows were significantly higher at the mid-test and post-test compared to the pre-test (P < 0.05), with the post-test values significantly exceeding those at the mid-test (P < 0.05).

Conclusion

(1) Moderate-intensity aerobic exercise significantly improves reactive inhibitory control in college students with internet addiction, with the magnitude of improvement increasing over the duration of the intervention. (2) Increased beta band energy during the early (100-500 ms) and late (600-750 ms) time windows serve as a key neurophysiological indicator of this enhancement.

Quebec French Version of the Hayling Sentence Completion Test: Error Scoring Guidelines, Normative Data for Adults and the Elderly and Validation Study in Mild Cognitive Impairment and Alzheimer's Disease

INTRODUCTION

Deficits in inhibition have been associated with various clinical conditions, including neurodegenerative diseases. The Hayling Sentence Completion Test (HSCT) is an assessment tool commonly used in clinical settings to measure verbal initiation and prepotent verbal response inhibition. Although it is used by numerous clinical and research groups in Quebec, normative data for the HSCT are not yet available for French-Quebec speakers.

OBJECTIVES

The aims of this study were to provide error scoring guidelines and normative data in the adult population of French Quebec for the HSCT-QC (Study 1) and to determine its known-group discriminant validity (Study 2).

RESULTS

The results of Study 1, based on a sample of 214 healthy individuals aged 50 to 89, indicated that age significantly affected test performance, while educational level and sex did not. As no transformations were able to normalize the score distribution, percentile ranks for HSCT-QC performance were calculated solely based on age. Results from Study 2 demonstrated that the HSCT-QC effectively distinguishes the performance of healthy participants from those with mild cognitive impairment or Alzheimer's disease.

CONCLUSION

Norms and psychometric data for the HSCT-QC will be highly beneficial for assessing inhibitory control in French-speaking adults in Quebec, Canada.

Suicidal risk is associated with hyper-connections in the frontal-parietal network in patients with depression

Suicide is a complex behavior strongly associated with depression. Despite extensive research, an objective biomarker for evaluating suicide risk precisely and timely is still lacking. Using the precision resting-state fMRI method, we studied 61 depressive patients with suicide ideation (SI) or suicide attempt (SA), and 35 patients without SI to explore functional biomarkers of suicide risk. Among them, 21 participants also completed electroconvulsive therapy (ECT) treatment, allowing the examination of functional changes across different risk states within the same individual. Functional networks were localized in each subject using resting-state fMRI and then an individualized connectome was constructed to represent the subject's functional brain organization. We identified a set of connections that track suicide risk (r = 0.41, p = 0.001) and found that these risk-associated connections were hyper-connected in the frontoparietal network (FPN, p = 0.008, Cohen's d = 0.58) in patients with suicide risk compared to those without. Moreover, ECT treatment significantly reduced (p = 0.001, Cohen's d = 0.56) and normalized these FPN hyper-connections. These findings suggest that connections involving FPN may constitute an important biomarker for evaluating suicide risk and may provide potential targets for interventions such as non-invasive brain stimulation.

Bifocal tACS over the primary sensorimotor cortices increases interhemispheric inhibition and improves bimanual dexterity

Concurrent application of transcranial alternating current stimulation over distant cortical regions has been shown to modulate functional connectivity between stimulated regions; however, the precise mechanisms remain unclear. Here, we investigated how bifocal transcranial alternating current stimulation applied over the bilateral primary sensorimotor cortices modulates connectivity between the left and right primary motor cortices (M1). Using a cross-over sham-controlled triple-blind design, 37 (27 female, age: 18 to 37 yrs) healthy participants received transcranial alternating current stimulation (1.0 mA, 20 Hz, 20 min) over the bilateral sensorimotor cortices. Before and after transcranial alternating current stimulation, functional connectivity between the left and right M1s was assessed using imaginary coherence measured via resting-state electroencephalography and interhemispheric inhibition via dual-site transcranial magnetic stimulation protocol. Additionally, manual dexterity was assessed using the Purdue pegboard task. While imaginary coherence remained unchanged after stimulation, beta (20 Hz) power decreased during the transcranial alternating current stimulation session. Bifocal transcranial alternating current stimulation but not sham strengthened interhemispheric inhibition between the left and right M1s and improved bimanual assembly performance. These results suggest that improvement in bimanual performance may be explained by modulation in interhemispheric inhibition, rather than by coupling in the oscillatory activity. As functional connectivity underlies many clinical symptoms in neurological and psychiatric disorders, these findings are invaluable in developing noninvasive therapeutic interventions that target neural networks to alleviate symptoms.

Disrupted functional connectivity of the emotion regulation network in major depressive disorder and its association with symptom improvement: A multisite resting-state functional MRI study

BACKGROUND

The emotion regulation network (ERN) in the brain provides a framework for understanding the neuropathology of affective disorders. Although previous neuroimaging studies have investigated the neurobiological correlates of the ERN in major depressive disorder (MDD), whether patients with MDD exhibit abnormal functional connectivity (FC) patterns in the ERN and whether the abnormal FC in the ERN can serve as a therapeutic response signature remain unclear.

METHODS

A large functional magnetic resonance imaging dataset comprising 709 patients with MDD and 725 healthy controls (HCs) recruited across five sites was analyzed. Using a seed-based FC approach, we first investigated the group differences in whole-brain resting-state FC of the 14 ERN seeds between participants with and without MDD. Furthermore, an independent sample (45 MDD patients) was used to evaluate the relationship between the aforementioned abnormal FC in the ERN and symptom improvement after 8 weeks of antidepressant monotherapy.

RESULTS

Compared to the HCs, patients with MDD exhibited aberrant FC between 7 ERN seeds and several cortical and subcortical areas, including the bilateral middle temporal gyrus, bilateral occipital gyrus, right thalamus, calcarine cortex, middle frontal gyrus, and the bilateral superior temporal gyrus. In an independent sample, these aberrant FCs in the ERN were negatively correlated with the reduction rate of the HAMD17 score among MDD patients.

CONCLUSIONS

These results might extend our understanding of the neurobiological underpinnings underlying unadaptable or inflexible emotional processing in MDD patients and help to elucidate the mechanisms of therapeutic response.

The hemispheric differences in prefrontal function of Internet game disorder and non-Internet game disorder: an activation likelihood estimation meta-analysis

This study explored the differences in brain activation between individuals with and without Internet gaming disorder (IGD) through activation likelihood estimation analysis. In total, 39 studies were included based on the inclusion and exclusion criteria by searching the literature in the PubMed and Web of Science databases, as well as reading other reviews. The analysis revealed that the activated brain regions in IGD were the right inferior frontal gyrus, left cingulate gyrus, and left lentiform nucleus. In comparison, the activated brain regions in non-IGD were the left middle frontal, left inferior frontal, left anterior cingulate, left precentral, and right precentral gyri. The results of the present study on differences in activation further confirm existing theoretical hypotheses. Future studies should explore hemispheric differences in prefrontal brain function between IGD and non-IGD.

Right inferior frontal cortex and preSMA in response inhibition: An investigation based on PTC model

Response inhibition is an essential component of cognitive function. A large body of literature has used neuroimaging data to uncover the neural architecture that regulates inhibitory control in general and movement cancelation. The presupplementary motor area (preSMA) and the right inferior frontal cortex (rIFC) are the key nodes in the inhibitory control network. However, how these two regions contribute to response inhibition remains controversial. Based on the Pause-then-Cancel Model (PTC), this study employed functional magnetic resonance imaging (fMRI) to investigate the functional specificity of two regions in the stopping process. The Go/No-Go task (GNGT) and the Stop Signal Task (SST) were administered to the same group of participants. We used the GNGT to dissociate the pause process and both the GNGT and the SST to investigate the inhibition mechanism. Imaging data revealed that response inhibition produced by both tasks activated the preSMA and rIFC. Furthermore, an across-participants analysis showed that increased activation in the rIFC was associated with a delay in the go response in the GNGT. In contrast, increased activation in the preSMA was associated with good inhibition efficiency via the striatum in both GNGT and SST. These behavioral and imaging findings support the PTC model of the role of rIFC and preSMA, that the former is involved in a pause process to delay motor responses, whereas the preSMA is involved in the stopping of motor responses.

Cerebral Small Vessel Disease Outperforms Brain Atrophy as an Imaging Biomarker in Diabetic Retinopathy

AIM

This study aimed to examine microvascular lesions and neurodegenerative changes in diabetic retinopathy (DR) compared to type 2 diabetes mellitus (T2DM) without DR (NDR) using structural MRI and to explore their associations with DR.

METHODS

243 patients with NDR and 122 patients with DR were included. Participants underwent conventional brain MRI scans, clinical measurements, and fundus examinations. Cerebral small vessel disease (CSVD) imaging parameters were obtained using AI-based software, manually verified, and corrected for accuracy. Volumes of major cortical and subcortical regions representing neurodegeneration were assessed using automated brain segmentation and quantitative techniques. Statistical analysis included T-test, chi-square test, Mann-Whitney U test, multivariate analysis of variance (MANCOVA), multivariate logistic regression, area under the receiver operating characteristic curve (AUC), and Delong test.

RESULTS

DR group exhibited significant differences in 11 CSVD features. Meanwhile, DR showed an atrophy trend in the frontal cortex, occipital cortex, and subcortical gray matter (GM) compared to NDR. After adjustment, DR patients exhibited greater perivascular spaces (PVS) numbers in the parietal lobe (OR = 1.394) and deep brain regions (OR = 1.066), greater dilated perivascular spaces (DPVS) numbers in the left basal ganglia (OR = 2.006), greater small subcortical infarcts (SSI) numbers in the right hemisphere (OR = 3.104), and decreased left frontal PVS (OR = 0.824), total left DPVS (OR = 0.714), and frontal cortex volume (OR = 0.959) compared to NDR. Further, the CSVD model showed a larger AUC (0.823, 95% CI: 0.781-0.866) than the brain atrophy model (AUC = 0.757, 95% CI: 0.706-0.808).

CONCLUSION

Microvascular and neurodegeneration are significantly associated with DR. CSVD is a better imaging biomarker for DR than brain atrophy.

Mediation of beneficial effects of an alcohol-specific inhibition training on drinking of patients with alcohol use disorder: The role of cognitive demands and inhibitory performance

BACKGROUND

A cognitively demanding, alcohol-specific inhibition training (Alc-IT) might enhance treatment success in patients with severe alcohol use disorder (AUD; Stein et al., 2023). An inhibitory working mechanism for Alc-IT has been discussed, but compelling evidence supporting this hypothesis is yet lacking. The present study investigates inhibitory performance during Alc-IT and examines whether inhibitory parameters mediate drinking outcome.

METHODS

Patients with AUD (N = 232) completed six sessions of either a standard or improved Alc-IT, differing in their inhibitory demands determined by Go/NoGo-ratios in a modified Go-NoGo-task, or a control training. During these training sessions, data on inhibitory performance was collected. To assess differences in inhibitory performance and its improvement, alcohol-related errors of commission and relative performance, integrating accuracy and speed, were analyzed with hierarchical linear contrast models. Mediation analyses tested whether inhibitory performance predicted drinking outcome (percent days abstinent at 3-month follow-up).

RESULTS

Patients in improved Alc-IT started with higher errors of commission (γ01(standard) =  -2.74, p < 0.001, R2 = 0.885) and a lower relative performance in the first training session compared to standard Alc-IT (γ01(standard) = 0.51, p = 0.004). They showed a steeper increase in relative performance until the final sixth session (γ1(s6),(standard) = -0.37, p = 0.024, R2 = 0.882). The effect of improved Alc-IT on drinking outcome was mediated by relative performance increase (bootstrap-CI [0.15, 7.11]).

CONCLUSION

Higher inhibitory demands enable larger improvements across sessions. Mediation analysis supports an inhibitory working mechanism. Tailoring inhibitory demands to individual performance capacity could optimize future Alc-IT.