Control of goal-directed and stimulus-driven attention in the brain

Whole-brain causal discovery using fMRI

Despite significant research, discovering causal relationships from fMRI remains a challenge. Popular methods such as Granger causality and dynamic causal modeling fall short in handling contemporaneous effects and latent common causes. Methods from causal structure learning literature can address these limitations but often scale poorly with network size and need acyclicity. In this study, we first provide a taxonomy of existing methods and compare their accuracy and efficiency on simulated fMRI from simple topologies. This analysis demonstrates a pressing need for more accurate and scalable methods, motivating the design of Causal discovery for Large-scale Low-resolution Time-series with Feedback (CaLLTiF). CaLLTiF is a constraint-based method that uses conditional independence between contemporaneous and lagged variables to extract causal relationships. On simulated fMRI from the macaque connectome, CaLLTiF achieves significantly higher accuracy and scalability than all tested alternatives. From resting-state human fMRI, CaLLTiF learns causal connectomes that are highly consistent across individuals, show clear top-down flow of causal effect from attention and default mode to sensorimotor networks, exhibit Euclidean distance dependence in causal interactions, and are highly dominated by contemporaneous effects. Overall, this work takes a major step in enhancing causal discovery from whole-brain fMRI and defines a new standard for future investigations.

Infant EEG microstate dynamics relate to fine-grained patterns of infant attention during naturalistic play with caregivers

As infants grow, they develop greater attentional control during interactions with others, shifting from patterns of attention primarily driven by caregivers (exogenous) to those that are also self-directed (endogenous). The ability to endogenously control attention during infancy is thought to reflect ongoing brain development and is influenced by patterns of joint attention between infant and caregiver. However, whether measures of infant attentional control and caregiver behavior during infant-caregiver interactions relate to patterns of infant brain activity is unknown and key for informing developmental models of attentional control. Using data from 43 infant-caregiver dyads, we quantified patterns of visual attention with dyadic, head-mounted eye tracking during infant-caregiver play and associated them with the duration of infant EEG microstate D/4 measured during rest. Importantly, microstate D/4 is a scalp potential topography thought to reflect the organization and function of attention-related brain networks. We found that microstate D/4 associated positively with infant-led joint attention rate but did not associate with caregiver-led joint attention rate, suggesting that infant-led coordination of joint attention during play may be critical for the neurobiological development of attentional control, or vice versa. Further, we found that microstate D/4 associated negatively with infant attention shift rate and positively with infant sustained attention duration, suggesting that increased stability of microstate D/4 may reflect maturation of attentional control and its underlying neural substrates. Together, our findings provide insights into how infant attentional control abilities and infant-caregiver visual behavior during play are associated with the spatial and temporal dynamics of infant brain activity.

The effect of expectancy on conditioned pain modulation: evidence from functional near-infrared spectroscopy

Background and objective

The psychological mechanisms that make Conditioned Pain Modulation (CPM) an effective non-pharmacological intervention are still not fully understood. Expectancy is believed to be a critical psychological factor affecting CPM effects, but its specific role has yet to be fully clarified. This study aims to explore the relationship between expectancy and CPM while providing physiological evidence using functional near-infrared spectroscopy (fNIRS).

Method

A standardized CPM induction paradigm was implemented, with verbal guidance used to induce expectancy. The Numeric Rating Scale (NRS) assessed the intensity of the test stimulus (TS), while an 11-point scale evaluated participants' attentional focus on the TS and the effect of expectancy. fNIRS was employed to monitor changes in prefrontal cortex (PFC) activity.

Results

Expectancy significantly amplified the CPM effect (p = 0.036) while markedly reducing attention to the experimental stimulus (p = 0.004). fNIRS findings indicated significant reductions in activity within the left frontal eye field, left dorsolateral prefrontal cortex, and left frontal pole regions. In the post-test, the control group demonstrated significantly higher cortical activity in the right frontal pole region compared to the expectancy group (p < 0.05). Within the expectancy group, bilateral frontal pole cortical activity was significantly lower in the post-test compared to the pre-test (p < 0.05).

Conclusion

Expectancy represents a key psychological mechanism underlying the CPM effect, potentially modulating its magnitude through attention regulation and accompanied by a reduction in oxygenated hemoglobin activity in the frontal pole region and introduced the Expectancy-Attention-CPM Modulation Model (ECAM).

Manipulating attention facilitates cooperation

Cooperation is essential for human societies, but not all individuals cooperate to the same degree. This is typically attributed to individual motives - for example, to be prosocial or to avoid risks. Here, we investigate whether cooperative behavior can, in addition, reflect what people pay attention to and whether cooperation may therefore be influenced by manipulations that direct attention. We first analyze the attentional patterns of participants playing one-shot Prisoner's Dilemma games and find that choices indeed relate systematically to attention to specific social outcomes, as well as to individual eye movement patterns reflecting attentional strategies. To test for the causal impact of attention independently of participants' prosocial and risk attitudes, we manipulate the task display and find that cooperation is enhanced when displays facilitate attention to others' outcomes. Machine learning classifiers trained on these attentional patterns confirm that attentional strategies measured using eye-tracking can accurately predict cooperation out-of-sample. Our findings demonstrate that theories of cooperation can benefit from incorporating attention and that attentional interventions can improve cooperative outcomes.

Placebo treatment entails resource-dependent downregulation of negative inputs

Clinical trials with antidepressants reveal significant improvements in placebo groups, with effects of up to 80% compared to real treatment. While it has been suggested that treatment expectations rely on cognitive control, direct evidence for affective placebo effects is sparse. Here, we investigated how cognitive resources at both the behavioral and neural levels influence the effects of positive expectations on emotional processing. Forty-nine healthy volunteers participated in a cross-over fMRI study where positive expectations were induced through an alleged oxytocin nasal spray and verbal instruction. Participants completed a spatial cueing task that manipulated attention to emotional face distractors while being scanned and were characterized regarding their general attention control ability. Placebo treatment improved mood and reduced distractibility from fearful compared to happy faces, particularly when more attentional resources were available for processing face distractors. This aligned with changes in activation and functional coupling within prefrontal-limbic networks, suggesting that expectations induce top-down regulation of aversive inputs. Additionally, neurobehavioral effects correlated with individual control ability. Our findings highlight the critical role of cognitive resources in verbally instructed placebo effects. This may be particularly relevant in patients with major depressive disorder, who often demonstrate enhanced negativity processing but have limited cognitive control capacity.

Altered resting-state network connectivity in internet gaming disorder

BACKGROUND

The growing popularity of internet gaming among adolescents and young adults has driven an increase in both casual and excessive gaming behavior. Nevertheless, it remains unclear how progressive increases in internet gaming engagement led to changes within and between brain networks. This study aims to investigate these connectivity alterations across varying levels of gaming involvement.

METHODS

In this cross-sectional study, 231 participants were recruited and classified into three groups according to Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria for Internet Gaming Disorder (IGD): IGD group, highly engaged gaming(HEG) group, and lowly engaged gaming (LEG) group. Resting-state fMRI data from 217 participants (143 males, 74 females) were included in the final analysis. Independent component analysis was used to examine differences in intra- and inter-network functional connectivity (FC)across the three groups.

RESULTS

No significant differences were found in intra-network FC across the three groups. However, significant inter-network differences between the dorsal attention network(dAN)and the visual network (VN) among the three groups were observed. The HEG group exhibited significantly higher dAN-VN functional network connectivity (FNC) compared to the LEG group. Linear correlation analyses showed no significant correlation between the dAN-VN FNC values and IGD-20T scores.

CONCLUSION

Throughout the development of IGD, increasing levels of engagement are associated with a rise and subsequent decline in FNC of DAN-VN. This pattern may reflect top-down attentional regulation in the early stages of addiction, followed by attentional bias as addiction progresses.

CDSE-UNet: Enhancing COVID-19 CT Image Segmentation With Canny Edge Detection and Dual-Path SENet Feature Fusion

Accurate segmentation of COVID-19 CT images is crucial for reducing the severity and mortality rates associated with COVID-19 infections. In response to blurred boundaries and high variability characteristic of lesion areas in COVID-19 CT images, we introduce CDSE-UNet: a novel UNet-based segmentation model that integrates Canny operator edge detection and a Dual-Path SENet Feature Fusion Block (DSBlock). This model enhances the standard UNet architecture by employing the Canny operator for edge detection in sample images, paralleling this with a similar network structure for semantic feature extraction. A key innovation is the DSBlock, applied across corresponding network layers to effectively combine features from both image paths. Moreover, we have developed a Multiscale Convolution Block (MSCovBlock), replacing the standard convolution in UNet, to adapt to the varied lesion sizes and shapes. This addition not only aids in accurately classifying lesion edge pixels but also significantly improves channel differentiation and expands the capacity of the model. Our evaluations on public datasets demonstrate CDSE-UNet's superior performance over other leading models. Specifically, CDSE-UNet achieved an accuracy of 0.9929, a recall of 0.9604, a DSC of 0.9063, and an IoU of 0.8286, outperforming UNet, Attention-UNet, Trans-Unet, Swin-Unet, and Dense-UNet in these metrics.

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.

The predictive nature of spontaneous brain activity across scales and species

Emerging research suggests the brain operates as a "prediction machine," continuously anticipating sensory, motor, and cognitive outcomes. Central to this capability is the brain's spontaneous activity-ongoing internal processes independent of external stimuli. Neuroimaging and computational studies support that this activity is integral to maintaining and refining mental models of our environment, body, and behaviors, akin to generative models in computation. During rest, spontaneous activity expands the variability of potential representations, enhancing the accuracy and adaptability of these models. When performing tasks, internal models direct brain regions to anticipate sensory and motor states, optimizing performance. This review synthesizes evidence from various species, from C. elegans to humans, highlighting three key aspects of spontaneous brain activity's role in prediction: the similarity between spontaneous and task-related activity, the encoding of behavioral and interoceptive priors, and the high metabolic cost of this activity, underscoring prediction as a fundamental function of brains across species.

Local Structural Indices Changes During Different Periods of Postherpetic Neuralgia: A Graphical Study in Structural Covariance Networks

Purpose

In this study, we aim to explore the changes in network graph theory indices of structural covariance networks (SCNs) in PHN patients with different disease durations.

Patients and Methods

High-resolution T1 magnetic resonance images were collected from 109 subjects. We constructed SCNs based on cortical thickness data and analyzed the changes in global and regional network measures of PHN patients and herpes zoster (HZ) patients, and get hubs of each group.

Results

(1) PHN patients with a disease duration >6 months had reduced global efficiency (P=0.035) and increased characteristic shortest path length (P=0.028). (2) Nodal efficiency of the right pars opercularis was greater in both HZ and PHN patients with a disease duration of 1 to 3 months (P<0.001); in PHN patients with a disease duration > 6 months, the nodal degree of the left pars triangularis and nodal efficiency of the right middle temporal gyrus were greater (P<0.001). (3) The right supramarginal gyrus was the common hub of healthy controls (HCs) and HZ patients, the right pars opercularis was the common hub of HZ patients and PHN patients with a disease duration of 1 to 3 months, and the bilateral superior frontal gyrus was the common hub of HZ patients and PHN patients with a disease duration >6 months.

Conclusion

There have changes in SCN indices in PHN patients with different disease durations. PHN patients with a disease duration >6 months had increased SCN integration and diminished information transfer capability between nodes, which complemented the topological properties of previous PHN networks. Eglobal and Lp can be considered as potential imaging markers for future clinical restaging of PHN.

Tired and out of control? Effects of total and partial sleep deprivation on response inhibition under threat and no-threat conditions

STUDY OBJECTIVES

Sleep deprivation may impair top-down inhibitory control over emotional responses (e.g. under threat). The current study examined the behavioral consequences of this phenomenon and manipulated the magnitude of individuals' sleep deficit to determine effect thresholds.

METHODS

Twenty-four healthy human participants were provided with 0, 2, 4, and 8 hours of sleep opportunity and, subsequently, performed a bimanual anticipatory response inhibition task under threat and no-threat conditions. Behavioral responses (button presses) and surface electromyography (EMG) from task effectors were collected to examine going and stopping processes.

RESULTS

Bayesian analyses revealed that compared to 8 hours of sleep, go-trial accuracy was reduced with 0 hours of sleep. Stopping speed was reduced with 0 and 2 hours of sleep, as evidenced by longer stop-signal delays, but only in a selective stopping context. None of the outcome measures were impacted by 4 hours of sleep. Under threat, go-trial accuracy was maintained, while responses were slightly delayed and characterized by amplified EMG bursts. Stopping speed was increased under threat across both stop-all and selective stopping contexts. No evidence was observed for interactions between sleep and threat.

CONCLUSIONS

Sleep deprivation negatively affected response inhibition in a selective stopping context, with stopping speed reduced following a single night of ≤2 hours of sleep. Performance-contingent threat improved response inhibition, possibly due to a prioritizing of stopping. No evidence was observed for increased threat-related responses after sleep deprivation, suggesting that sleep deprivation and threat may impact inhibitory control via independent mechanisms.

The hippocampus-IPL connectivity links to ADHD traits through sensory processing sensitivity

Accumulating evidence suggests that individuals with high sensory processing sensitivity often experience sensory overload and have difficulty sustaining attention, which can particularly resemble attention deficit symptoms of attention-deficit/hyperactivity disorder. However, due to the lack of understanding about the potential neural pathways involved in those processes, a comprehensive view of how sensory processing sensitivity and attention deficit are related is generally limited. Here, we quantified the sensory processing sensitivity and attention deficit using the Highly Sensitive Person Scale and the Adult Attention-deficit/Hyperactivity Disorder Self-Report Scale, respectively, to investigate the association between sensory processing sensitivity and attention deficit and further identify the corresponding neural substrates via the use of resting-state functional Magnetic Resonance Imaging (fMRI) analyses. On the behavioral level, the results indicated a significantly positive correlation between sensory processing sensitivity and attention deficit traits, while on the neural level, the sensory processing sensitivity score was positively correlated with functional connectivity between the rostral hippocampus and inferior parietal lobule, which is the core regions of the attention network. Mediation analysis revealed that hippocampus-Inferior Parietal Lobule (IPL) connectivity can further influence attention deficit through a mediating role of sensory processing sensitivity. Overall, these findings suggest that enhanced functional coupling between the hippocampus and attention network regions may heighten sensitivity to environmental stimuli, leading to increased distractibility and potentially contributing to attention deficit.

Hubs and interaction: the brain's meta-loop

We must reconcile the needs of the internal world and the demands of the external world to make decisions relevant to homeostasis, well-being, and flexible behavior. Engagement with the internal (eg interoceptive) world is linked to medial brain systems, whereas the extrapersonal space (eg exteroceptive) is associated with lateral brain systems. Using Human Connectome Project data, we found three association tracts connecting the action-related frontal lobe with perception-related posterior lobes. A lateral dorsal tract and a medial dorsal tract interact independently with a ventral tract at frontal and posterior hubs. The two frontal and the two posterior hubs are interconnected, forming a meta-loop that integrates lateral and medial brain systems. The four anatomical hubs correspond to the common nodes of the intrinsic cognitive brain networks such as the default mode network. These functional networks depend on the integration of both realms. Thus, the positioning of functional cognitive networks can be understood as the intersection of long anatomical association tracts. The strength of structural connectivity within lateral and medial brain systems correlates with performance on behavioral tests assessing theory of mind. The meta-loop provides an anatomical framework to associate neurological and psychiatric symptoms with functional and structural changes.

Modulation of thermal perception by VR-based visual stimulation to the embodied virtual body

Visual stimulation to the embodied virtual body could modulate human perception, however the associated neurophysiological mechanisms have not elucidated yet. The present study aimed to reveal the underlying neurophysiological mechanisms from a neurophysiological viewpoint. Fifteen healthy participants were subjected to three visual conditions (i.e., fire, water, and non-visual effect conditions) and psychological pain stimulation (thermal grill stimulation). Oscillatory neural activities during stimulation were measured with electroencephalogram. The association between accessory visual stimulation applied to the embodied virtual body, induced by virtual reality, and perception was examined through neuronal oscillatory analysis using electroencephalogram data. Regression analysis was performed to obtain data on brain regions contributing to sensory modulation with body illusion. The results of subjective measures under the fire and water conditions showed that thermal perception were modulated by a visual stimulus to the virtual hand. Furthermore, we found that the insula was commonly associated with thermal perception under the fire and water conditions. This result indicate that the insula may control sensory information as a gatekeeper as well as facilitate the access to human attention and cognition as a hub, suggesting the influence on perception and cognition.

Flash grab effect within the regions of modal and amodal completions

When a rotating grating reverses its direction and is accompanied by a briefly flashed stimulus on top, the flash's apparent position shifts in direction after the reversal. This phenomenon, termed the flash-grab effect, can induce an illusory position shift of several degrees of visual angle, prompting investigation into scenarios in which the expected position coincides with another visual event. We investigated two such situations: perceptual filling-in at the blind spot and amodal completion behind a visible occluder. By inducing a position shift in the flash presented just outside such completed patterns, we measured the perceived angular position of the flash in the perceptual matching paradigm. We found subjective localization within the completed region of the moving inducer. Consistent results were found even when the flash was presented at a less optimal time for the flash-grab effect. Illusion size had a certain dependency on stimulus configuration, suggesting that various sources of spatial referencing are involved in the position processing around the blind-spot/occluder region. These findings imply that the visual system does not necessarily avoid a region that is devoid of physical motion stimuli when determining perceived flash position, reaching a consistent perceptual solution that integrates the motion-induced position shift and perceptual completion.

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.

Functional Neuroanatomy of Tics: A Brain Network Perspective

Tourette syndrome is defined by motor and vocal tics, yet our understanding of the pathophysiology of tics remains limited. Functional MRI (fMRI) can localize brain function related to the clinical phenomenology of tics. Here, we review extant fMRI studies examining brain activity during the premonitory urge, tic release, and tic suppression. Results are placed in the context of large-scale functional networks, given recent advancements in understanding the brain's functional network organization. During tic-related phenomena, brain activity follows consistent patterns involving specific networks, largely centered around the cingulo-opercular action mode network. This network-level framework provides a novel avenue for targeted-treatment methods.

Exaggerated frontoparietal control over cognitive effort-based decision-making in young women with anorexia nervosa

Effortful tasks are generally experienced as costly, but the value of work varies greatly across individuals and populations. While most mental health conditions are characterized by amotivation and effort avoidance, individuals with anorexia nervosa (AN) persistently engage in effortful behaviors that most people find unrewarding (food restriction, excessive exercise). Current models of AN differentially attribute such extreme weight-control behavior to altered reward responding and exaggerated cognitive control. In a novel test of these theoretical accounts, we employed an established cognitive effort discounting paradigm in combination with fMRI in young acutely underweight female patients with AN (n = 48) and age-matched healthy controls (HC; n = 48). Contrary to the hypothesis that individuals with AN would experience cognitive effort (operationalized as N-back task performance) as less costly than HC participants, groups did not differ in the subjective value (SV) of discounted rewards or in SV-related activation of brain regions involved in reward valuation. Rather, all group differences in both behavior (superior N-back performance in AN and associated effort ratings) and fMRI activation (increased SV-related frontoparietal activation during decision-making in AN even for easier choices) were more indicative of increased control. These findings suggest that while effort discounting may be relatively intact in AN, effort investment is high both when performing demanding tasks and during effort-based decision-making; highlighting cognitive overcontrol as an important therapeutic target. Future research should establish whether exaggerated control during effort-based decision-making persists after weight-recovery and explore learning the value of effort in AN with tasks involving disorder-relevant effort demands and rewards.

Variation in brain aging: A review and perspective on the utility of individualized approaches to the study of functional networks in aging

Healthy aging is associated with cognitive decline across multiple domains, including executive function, memory, and attention. These cognitive changes can often influence an individual's ability to function and quality of life. However, the degree to which individuals experience cognitive decline, as well as the trajectory of these changes, exhibits wide variability across people. These cognitive abilities are thought to depend on the coordinated activity of large-scale networks. Like behavioral effects, large variation can be seen in brain structure and function with aging, including in large-scale functional networks. However, tracking this variation requires methods that reliably measure individual brain networks and their changes over time. Here, we review the literature on age-related cognitive decline and on age-related differences in brain structure and function. We focus particularly on functional networks and the individual variation that exists in these measures. We propose that novel individual-centered fMRI approaches can shed new light on patterns of inter- and intra-individual variability in aging. These approaches may be instrumental in understanding the neural bases of cognitive decline.

Switch cost in arithmetic operations and its relation to math anxiety

Math fluency is the ability to efficiently solve known arithmetic exercises, and it is one of the building blocks for academic achievements and daily use. Math fluency is assessed by how many exercises individuals can solve correctly in a limited time, requiring switching from one exercise to another. Switching is one of the executive functions and involves flexibility and adaptation to changing circumstances. Switching is measured through switch cost, which represents the difference in performance between executing the same task sequentially and switching between tasks. The current study examines the switch cost in math fluency. Participants, students from higher academic institutions, performed a math fluency test applied by the Ben-Gurion University Math Fluency (BGU-MF) tool, which included simple arithmetic exercises of addition, subtraction, multiplication and division. In Experiment 1, we examined the switch cost for each operation, and between pairs of operations, among 135 students (age 19 to 34). Results showed that the switch cost differs among different operations. Moreover, switch costs occur when alternating between complementary operations, but not between operations that rely on the same cognitive mechanisms, such as retrieval or calculation. In Experiment 2, we examined the switch cost in math fluency among 54 students (age 21 to 34) with high- vs. low- math anxiety. High math anxiety participants presented poorer performance in math fluency, as measured by accuracy rates and reaction times, and a larger switch cost. Our results fit the Attentional Control Theory (ACT) which suggests that anxiety impairs the executive functions. The effects of dominance, familiarity, difficulty, mental sets and executive functions on the switch cost in math fluency are discussed.

Studying decision making in rats using a contextual visual discrimination task: Detection and prevention of alternative behavioral strategies

BACKGROUND

The neural bases of decision-making and contextual sensory discriminations have traditionally been studied in primates, highlighting the role of the prefrontal cortex in cognitive control and flexibility. With the advent of molecular tools to manipulate and monitor neuronal activity, these processes have increasingly been studied in rodents. However, rodent tasks typically consist of two-alternative forced choice paradigms that usually feature coarse sensory discriminations and no contextual dependence, limiting prefrontal involvement in task performance.

NEW METHOD

To circumvent these limitations, we developed a novel contextual visual discrimination task that lends itself to rigorous psychophysical analyses. In this task, rats learn to detect left-right differences in one dimension (e.g. luminance or speed) depending on context while ignoring another (e.g. speed or luminance, respectively). Depending on trials, speed and luminance can be greater on the same side (congruent trials) or on opposite sides (incongruent trials).

RESULTS

Rats learned the task in four phases: nose-poking and lever-pressing (∼7 days), discriminating left-right differences in one dimension (∼20 days), discriminating left-right differences in a second dimension (∼10 days), and discriminating left-right differences in one of the two dimensions depending on context (∼2.5 months). A 20:80 ratio of congruent to incongruent trials is used to prevent rats from adopting alternative strategies.

COMPARISON WITH EXISTING METHODS

This task is comparable to contextual sensory discrimination tasks used in monkeys. Few equivalent tasks exist in rodents.

CONCLUSIONS

This task will allow investigators to use the full neuroscientific armamentarium to study contextual neural coding in the rat prefrontal cortex.

Individualized prediction of multi-domain intelligence quotient in bipolar disorder patients using resting-state functional connectivity

BACKGROUND

Although accumulating studies have explored the neural underpinnings of intelligence quotient (IQ) in patients with bipolar disorder (BD), these studies utilized a classification/comparison scheme that emphasized differences between BD and healthy controls at a group level. The present study aimed to infer BD patients' IQ scores at the individual level using a prediction model.

METHODS

We applied a cross-validated Connectome-based Predictive Modeling (CPM) framework using resting-state fMRI functional connectivity (FCs) to predict BD patients' IQ scores, including verbal IQ (VIQ), performance IQ (PIQ), and full-scale IQ (FSIQ). For each IQ domain, we selected the FCs that contributed to the predictions and described their distribution across eight widely-recognized functional networks. Moreover, we further explored the overlapping patterns of the contributed FCs for different IQ domains.

RESULTS

The CPM achieved statistically significant prediction performance for three IQ domains in BD patients. Regarding the contributed FCs, we observed a widespread distribution of internetwork FCs across somatomotor, visual, dorsal attention, and ventral attention networks, demonstrating their correspondence with aberrant FCs correlated to cognition deficits in BD patients. A convergent pattern in terms of contributed FCs for different IQ domains was observed, as evidenced by the shared-FCs with a leftward hemispheric dominance.

CONCLUSIONS

The present study preliminarily explored the feasibility of inferring individual IQ scores in BD patients using the FCs-based CPM framework. It is a step toward the development of applicable techniques for quantitative and objective cognitive assessment in BD patients and contributes novel insights into understanding the complex neural mechanisms underlying different IQ domains.

Neural correlates of choosing alcohol over a palatable food reward in humans

BACKGROUND

In a population of light and heavy, nontreatment seeking drinkers, we recently showed that choice for alcohol versus a concurrently available snack reward was sensitive to the relative cost of alcohol. Here, we examined the neural substrates of alcohol choice using functional magnetic resonance imaging (MRI) in a new sample of light and heavy drinkers.

METHODS

Participants were scanned during the Concurrent Alcohol Food Choice task, and collected points associated with the images of alcohol or snack rewards that they could redeem at the end of the experiment. As cost manipulation, point values were equal or varied so that they favored alcohol or the snack reward. Linear mixed-effects models were used for the analyses of behavioral and brain data.

RESULTS

In a replication of prior findings, alcohol choice was sensitive to the relative value of alcohol in both groups. Neural activations in, among others, orbitofrontal cortex and insula were associated to relative value during choice. In addition, we observed that choosing alcohol as opposed to snack engaged two separate sets of brain regions. We did not replicate our prior finding of increased choice preference for alcohol in heavy compared to light drinkers and found no between-group differences in brain activity.

CONCLUSIONS

Overall, we replicated intact sensitivity to relative costs of alcohol in heavy drinkers and found its associated brain activity regions involved in value and salience attribution. Alcohol choice engaged regions involved in value-based behavior while snack preference elicited activity in areas linked to externally oriented attention. The failure to replicate the between-group differences may be due to the artificial MRI environment or observed differences in personality traits.

Associations of Device-Measured Physical Activity and Sedentary Time With Neural Responses to Visual Food Cues in Adults: A Functional Magnetic Resonance Imaging Study

Self-reported physical activity is associated with lower brain food cue responsiveness in reward-related regions, but relationships utilizing objective physical activity measurement tools have not been explored. This cross-sectional study examined whether device-measured moderate-to-vigorous intensity physical activity and sedentary time are related to neural responses to visual food cues using functional magnetic resonance imaging. Fifty-one healthy adults (30 men, 21 women; mean ± SD: age 26 ± 6 years; body mass index 24.1 ± 3.0 kg/m2) underwent a functional magnetic resonance imaging scan after an overnight fast while viewing images of high/very high-energy density foods (HED), very low/low-energy density foods (LED) and non-food objects. Free-living moderate-to-vigorous intensity physical activity and sedentary time were measured for seven consecutive days using an ActiGraph wGT3X-BT and activPAL4 accelerometer, respectively. Associations of behavioural variables with brain food cue reactivity were examined in regression models controlling for physiological and behavioural covariates. After adjusting for age, sex, body mass index and device weartime, moderate-to-vigorous intensity physical activity was negatively associated with reactivity to LED versus non-food cues in the precentral gyrus, hippocampus, posterior insula, and amygdala, which may diminish inhibitory-related responses towards healthier lower energy value foods. Time spent in moderate-to-vigorous intensity physical activity was positively associated with reactivity to LED versus non-food cues in the dorsal striatum, a region implicated in food motivation. A positive association was identified between sedentary time and reactivity to HED versus non-food cues in the dorsal division of the posterior cingulate gyrus that has been implicated in attention allocation. These findings suggest that moderate-to-vigorous intensity physical activity may enhance the appeal of and motivation to consume LED foods, whereas sedentary time may promote attention towards HED foods, highlighting the potential for engaging in greater physical activity and less sedentary time to positively influence the central (brain) appetite control system.

High-definition transcranial direct-current stimulation of left primary motor cortices modulates beta and gamma oscillations serving motor control

Recent studies have linked non-invasive transcranial direct-current stimulation (tDCS) with altered neural processing near the site of stimulation and across a distributed network of brain regions, with some evidence for a possible therapeutic role. However, negative results also exist and the potential impacts on motor-related neural oscillations have rarely been studied. Herein, we applied high-definition tDCS to the left primary motor cortex of 62 healthy adults in three sessions (anodal, cathodal and sham). Participants then performed a motor task with two conditions (i.e. cognitive interference and no interference) during magnetoencephalography (MEG). The MEG data were imaged in the time-frequency domain and whole-brain, voxel-wise maps were probed for task condition and stimulation effects. Our results indicated the classic pattern of slower behavioural responses and stronger neural oscillations in frontal and parietal cortices during interference relative to no-interference trials. Importantly, we found task condition-by-stimulation interactions involving motor-related gamma oscillations, with weaker interference effects after cathodal stimulation relative to anodal and sham in the right prefrontal, left temporoparietal junction and left cerebellar cortices. Conversely, stronger gamma interference responses were found in the right motor and superior parietal cortices following anodal relative to cathodal and sham. Lastly, main effects of stimulation indicated stronger beta oscillations following anodal stimulation in the left supplementary motor area. Taken together, these data provide key mechanistic insight into the polarity-specific effects of tDCS on the neural oscillatory dynamics serving motor control. Such findings reflect the modulatory effects of tDCS on population-level neural oscillatory responses distant from the stimulation site. KEY POINTS: Neurophysiological studies have indicated that beta and gamma oscillations are critical to motor control and that their dynamics are modulated by higher-order features of the task. Recent investigations have shown that transcranial direct-current stimulation (tDCS) affects neural activity both locally and in brain regions distant from the stimulation site, but the mechanisms remain poorly understood. Sixty-two adults underwent anodal, cathodal and sham high-definition tDCS of the left motor cortices and completed a motor task with two levels of cognitive interference during magnetoencephalography (MEG). Task condition by stimulation-type interactions on movement-related gamma oscillations were observed across a distributed network of higher-order brain regions, including parietal cortices, right prefrontal and left temporoparietal junction. In sum, our results indicate polarity-specific effects on beta and gamma oscillations across a distributed network of brain regions that contribute to motor control in the context of interference and hold implications for understanding the therapeutic capacity of tDCS.

Effects of Frontal-Midline Theta Neurofeedback with Different Training Directions on Goal-Directed Attentional Control

As a significant component of executive function, goal-directed attentional control is crucial for cognitive processing and is closely linked to frontal-midline theta (FMT) rhythms. However, how up-regulation and down-regulation of FMT through neurofeedback training (NFT) impact goal-directed attention control remains unclear, especially for both short-term and long-lasting effects. Therefore, this study employed a single-blind sham-controlled between-subject design to answer this question. Forty-seven healthy adults were randomly assigned to the up-regulation, down-regulation, or sham control groups. Each group underwent one NFT session per day at the Fz electrode site for four consecutive days. All participants completed a visual search task before, immediately after the first, after the final, and one week following the last NFT session. The down-regulation group significantly reduced FMT activity during NFT and in the resting state (p < = 0.038), while the up-regulation group only showed an upward trend during the training phase (r = 0.721, p = 0.002). The behavioral performance showed no significant improvement in any group (p > 0.05). Importantly, the FMT learning efficacy in the up-regulation group revealed a significantly negative correlation with the change in switch cost (r = -0.602, p = 0.046). These findings suggest a close link between the up-regulation efficacy of FMT rhythms and goal-directed attentional control. In educational or clinical settings, it would be desirable to improve goal-directed attention through enhancement of FMT up-regulation efficacy of NFT in future work.

Specialization for different memory dimensions in brain activity evoked by cued recollection

Cued recollection involves the retrieval of different features of the encoded event. Previous research has shown that the recollection of complex events jointly recruits the Default Mode and the Frontoparietal Control networks, but the degree to which activity within these networks varies as a function of the particular memory dimension (e.g., the "when-what-where" information) remains largely unknown. In the present functional Magnetic Resonance Imaging (fMRI) study, human participants retrieved specific information about a previously encoded TV show to assess the veracity of detailed sentences along four memory dimensions (i.e., object and character details, spatial layouts, temporal sequences, verbal dialogues). A common activity for all dimensions was observed in a left-lateralized network of regions that largely overlaps with the Frontoparietal Control Network (FPCN), including the lateral prefrontal, lateral superior parietal, and lateral temporal cortex. Instead, a larger degree of specialization for different memory dimensions was observed within the Default Mode Network (DMN), particularly in its posterior nodes. Dimension-related specificity in both networks was associated with memory performance across subjects. Finally, a clear leftward asymmetry was observed in the DMN for all dimensions except for the temporal one, whereas the FPCN showed a bilateral activation across dimensions. The present results generally support the view that specific memory information is processed by a mosaic of regions within large portions of the associative cortex involved in higher-order mnemonic functions.

Cortical α4β2-nicotinic acetylcholine receptors and cognitive decline in Parkinson's disease

BackgroundAutopsy and in vivo molecular imaging studies suggest altered binding of the α4β2-nicotinic cholinergic receptor (α4β2-nAChR) with cognitive dysfunction in Parkinson's disease (PD).ObjectiveTo determine the relationship between cortical and hippocampal binding of the α4β2-nAChR with [18F]XTRA PET, a high-affinity radiotracer that enables quantification of α4β2-nAChR in these regions, and cognitive function in individuals with PD.MethodsIndividuals with PD (N = 32) and age-similar, controls without PD or dementia (N = 10) completed a cognitive assessment and one 90-min, [18F]XTRA PET scan. Metabolite-corrected arterial input function radioactivity time-activity curves were generated to obtain total distribution volume (VT) across 12 regions of interest (ROIs). [18F]XTRA binding was compared 1) between controls and people with PD and 2) between controls, persons with PD with normal cognition (PD-NC), and persons with PD with MCI (PD-MCI).Results[18F]XTRA binding was higher in the occipital cortex of the combined group of PD participants compared to age-similar controls. No regions showed lower binding in PD. VT with, but not without, partial volume correction was different between controls, PD-NC, and PD-MCI groups, and this was driven by higher binding in PD-MCI compared to controls. Regression of regional VT on cognitive domain T-scores, adjusting for age, showed that worse performance in visual-spatial memory tasks was associated with higher VT in the precuneus and the entire parietal cortex.ConclusionsHigher α4β2-nAChR binding in posterior cortical regions is found in PD and associated with worse visual perception and memory, possibly due to lower receptor occupancy by endogenous acetylcholine.

Association between the focus of attention and brain activation pattern during golf putting task in amateur and novice: A fNIRS study

PURPOSE

External focus of attention (FOA) has been shown to improve motor performance. However, recent research has found that the effectiveness of FOA is related to the level of expertise. Therefore, this study examined the effects of FOA on putting performance in golfers of different levels of expertise. The neural mechanisms behind FOA were explored in conjunction with fNIRS.

METHOD

A total of 30 participants, including 15 amateurs (Mage: 23.31(SD = 1.32)years; 15 males) and 15 novices (Mage: 22.69(SD = 1.55) years; 11 males; 4 females) were recruited. Participants completed EF and IF golf putting at a duration of 3s per time wearing fNIRS for 3 blocks of 30 s interspersed with 10-s rest blocks.

RESULT

Behavioral results showed a significant difference in the putting performance of the amateur group under the EF condition compared to the IF condition (P = 0.019), and relative to novices, the amateur group performed better under the EF condition (P = 0.003). fNIRS results revealed that the amateur group had higher activation levels in the right somatosensory association cortex (RSAC) and right motor cortex (RMC) under the IF condition. In contrast, for the novice group, higher activation levels were observed in the left prefrontal cortex and RMC under the EF condition.

CONCLUSIONS

Our results revealed SAC and MC over-activation in the amateur group under IF conditions with poor golf putting performance. Our findings suggest that the impairment of automated motor neural networks could be a possible mechanism by which IF affects motor performance with SAC and MC over-activation. Guiding novices to focus on task-related factors consciously could be a potential mechanism by which EF enhances motor performance.

The brain's action-mode network

The brain is always intrinsically active, using energy at high rates while cycling through global functional modes. Awake brain modes are tied to corresponding behavioural states. During goal-directed behaviour, the brain enters an action-mode of function. In the action-mode, arousal is heightened, attention is focused externally and action plans are created, converted to goal-directed movements and continuously updated on the basis of relevant feedback, such as pain. Here, we synthesize classical and recent human and animal evidence that the action-mode of the brain is created and maintained by an action-mode network (AMN), which we had previously identified and named the cingulo-opercular network on the basis of its anatomy. We discuss how rather than continuing to name this network anatomically, annotating it functionally as controlling the action-mode of the brain increases its distinctiveness from spatially adjacent networks and accounts for the large variety of the associated functions of an AMN, such as increasing arousal, processing of instructional cues, task general initiation transients, sustained goal maintenance, action planning, sympathetic drive for controlling physiology and internal organs (connectivity to adrenal medulla), and action-relevant bottom-up signals such as physical pain, errors and viscerosensation. In the functional mode continuum of the awake brain, the AMN-generated action-mode sits opposite the default-mode for self-referential, emotional and memory processing, with the default-mode network and AMN counterbalancing each other as yin and yang.

Decoding Visual Spatial Attention Control

In models of visual spatial attention control, it is commonly held that top-down control signals originate in the dorsal attention network, propagating to the visual cortex to modulate baseline neural activity and bias sensory processing. However, the precise distribution of these top-down influences across different levels of the visual hierarchy is debated. In addition, it is unclear whether these baseline neural activity changes translate into improved performance. We analyzed attention-related baseline activity during the anticipatory period of a voluntary spatial attention task, using two independent functional magnetic resonance imaging datasets and two analytic approaches. First, as in prior studies, univariate analysis showed that covert attention significantly enhanced baseline neural activity in higher-order visual areas contralateral to the attended visual hemifield, while effects in lower-order visual areas (e.g., V1) were weaker and more variable. Second, in contrast, multivariate pattern analysis (MVPA) revealed significant decoding of attention conditions across all visual cortical areas, with lower-order visual areas exhibiting higher decoding accuracies than higher-order areas. Third, decoding accuracy, rather than the magnitude of univariate activation, was a better predictor of a subject's stimulus discrimination performance. Finally, the MVPA results were replicated across two experimental conditions, where the direction of spatial attention was either externally instructed by a cue or based on the participants' free choice decision about where to attend. Together, these findings offer new insights into the extent of attentional biases in the visual hierarchy under top-down control and how these biases influence both sensory processing and behavioral performance.

Toward cognitive models of misophonia

Misophonia is a disorder in which specific common sounds such as another person breathing or chewing, or the ticking of a clock, cause an atypical negative emotional response. Affected individuals may experience anger, irritability, annoyance, disgust, and anxiety, as well as physiological autonomic responses, and may find everyday environments and contexts to be unbearable in which their 'misophonic stimuli' (often called 'trigger sounds') are present. Misophonia is gradually being recognized as a genuine problem that causes significant distress and has negative consequences for individuals and their families. It has only recently come under scientific scrutiny, as researchers and clinicians are establishing its prevalence, distinguishing it from other disorders of sensory sensitivity such as hyperacusis, establishing its neurobiological bases, and evaluating the effectiveness of potential treatments. While ideas abound as to the mechanisms involved in misophonia, few have coalesced into models. The aim of the present work is to summarize and extend recent thinking on the mechanistic basis of misophonia, with a focus on moving towards neurologically-informed cognitive models that can (a) account for extant findings, and (b) generate testable predictions. We hope this work will facilitate future refinements in our understanding of misophonia, and ultimately inform treatments.

Physically activated modes of attentional control

As we navigate through the day, our attentional control processes are constantly challenged by changing sensory information, goals, expectations, and motivations. At the same time, our bodies and brains are impacted by changes in global physiological state that can influence attentional processes. Based on converging lines of evidence from brain recordings in physically active humans and nonhumans, we propose a new framework incorporating at least two physically activated modes of attentional control in humans: altered gain control and differential neuromodulation of control networks. We discuss the implications of this framework for understanding a broader range of states and cognitive functions studied both in the laboratory and in the wild.

Aversive conditioning, anxiety, and the strategic control of attention

What we pay attention to is influenced by both reward learning and aversive conditioning. Although early attention tends to be biased toward aversively conditioned stimuli, sustained ignoring of such stimuli is also possible. How aversive conditioning influences how a person chooses to search, or the strategic control of attention, has not been explored. In the present study, participants learned an association between a colour and an aversive outcome during a training phase, and in a subsequent test phase searched for one of two targets presented on each trial; one target was rendered in the aversively conditioned colour (CS+) and the other in a neutral colour (CS-). Given the distribution of colour stimuli in the search array, it was more optimal to search for and report a target in one of the two colours on some trials. Our results demonstrate that participants were biased away from the CS+ target, which resulted in non-optimal search on some trials. Surprisingly, rather than accentuate this bias, greater state anxiety was associated with a stronger tendency to find and report the CS+ target. Our findings have implications for our understanding of the learning-dependent control of attention and abnormal attentional biases observed in high-anxious individuals.

Modulatory effects of goal relevance on emotional attention reveal that fear has a distinct value

Threat-related stimuli can capture attention. However, it remains debated whether this capture is automatic or not. To address this question, we compared attentional biases to emotional faces using a dot-probe task (DPT) where emotion was never goal-relevant (Experiment 1) or made directly task-relevant by means of induction trials (Experiments 2-3). Moreover, the contingency between the DPT and induction trials was either partial (Experiment 2) or full (Experiment 3). Eye-tracking was used to ascertain that the emotional cue and the subsequent target were processed with peripheral vision. Experiments 1 and 2 both showed that negative faces captured attention, with faster target processing when it appeared on the same side as the preceding fearful face (i.e. fear-valid trials) compared to the opposite side where the neutral face was shown (i.e. fear-invalid trials), but also when it appeared on the side of the preceding neutral face (i.e. happy-invalid trials) compared to the happy face (i.e. happy-valid trials). Importantly, this preferential spatial orienting to negative emotion was not observed in Experiment 3, where the goal relevance of emotion was high. However, in that experiment, fearful faces produced a specific attentional bias during the DPT, which was mostly driven by the induction trials themselves.

Youth Generalized Anxiety and Brain Activation States During Socioemotional Processing

Importance

The brain enters distinct activation states to support differential cognitive and emotional processes, but little is known about how brain activation states differ in youths with clinical anxiety.

Objective

To characterize brain activation states during socioemotional processing (movie stimuli) and assess associations between state characteristics and movie features and anxiety symptoms.

Design, Setting, and Participants

The Healthy Brain Network is an ongoing cross-sectional study of individuals aged 5 to 21 years experiencing difficulties in school, of whom approximately 45% met criteria for a lifetime anxiety disorder diagnosis. Data used in this study are from the first 9 releases (collected in a nonclinical research setting in the New York City metropolitan area from 2015 to 2020) and include 620 youths aged 5 to 15 years (53% of whom met criteria for a lifetime anxiety disorder diagnosis) who watched an emotional video during functional magnetic resonance imaging and completed questionnaires and clinical evaluation. Of those with functional magnetic resonance imaging data, 432 youths aged 7 to 15 years also self-reported on anxiety symptoms. Data were processed and analyzed between February 2020 and August 2024.

Main Outcomes and Measures

A hidden Markov model was trained to identify brain activation states across participants during video watching. Time spent in each state and the moment-to-moment probability of being in each state were extracted. Videos were annotated for emotion-specific and nonspecific information using the EmoCodes system. Self-reported anxiety symptoms were assessed using the Screen for Child Anxiety Related Disorders. Time spent in each state across the video and during and outside of peaks in negative content correlated with generalized and social anxiety scores.

Results

Among the 620 youths in the overall analysis, 369 were male and the mean (SD) age was 10.4 (2.8) years. In the anxiety symptom analysis, 263 of 432 youths were male and the mean (SD) age was 11.5 (2.2) years. Three brain activation states were identified: a high somatomotor activation state (state 1), a high cingulo-opercular network activation state (state 2), and a high ventral attention and default mode state (state 3). The probability of being in state 3 was correlated with video content that was more negative, quieter, and with less visual motion (ρ < 0.08; P < .001). Increased generalized anxiety was associated with greater time in state 3 (B, 0.10; 95% CI, 0.01 to 0.20; false discovery rate [FDR]-corrected P = .048) and less time in state 2 (B, -0.11; 95% CI, -0.21 to -0.02; FDR-corrected P = .048) when negative social cues were present.

Conclusions and Relevance

Youths entered 3 distinct brain activation states during movie watching, and youths with anxiety spent more time in a state with high ventral attention and default activation during negative socioemotional processing. Youths high in generalized anxiety may be more engaged in deeply processing negative emotional content, which may influence self-regulation. Interventions that focus on changing physiological and psychological state during negative social interactions in youths with anxiety should be considered.

Hemispheric co-lateralization of language and spatial attention reduces performance in dual-task

Hemispheric specialization of different functions is proposed to confer evolutionary benefits, yet the behavioral impacts of lateralization and its cognitive and neural mechanisms remain unclear. This study investigated the effect of lateralization pattern between language and spatial attention on dual-task performance and its association with callosal connectivity. Functional lateralization was assessed using fMRI verbal fluency and landmark tasks, and interhemispheric connections were evaluated through diffusion-weighted imaging. The typical lateralization pattern enhanced overall performance and reduced interference in dual-task compared to the co-lateralized pattern (both functions lateralized to one hemisphere). However, no differences were observed between the mirrored pattern (right language dominance and left attention dominance) and the co-lateralized pattern. While callosal connectivity did not significantly differ among groups, a negative correlation was observed between the lateralization degree and callosal connectivity. Our findings partially support the functional crowding hypothesis and offer insights into neurocognitive mechanisms underlying functional reorganization after brain lesions.

Connectivity of neural signals to the primary motor area during preparatory periods for movement following external and internal cues

PURPOSE

We investigated the connectivity of neural signals from movement-related cortical areas to the primary motor area (M1) in the hemisphere contralateral to the movement side during the period of movement-related magnetic fields before movement.

MATERIALS AND METHODS

Participants were 13 healthy adults, and nerual signals were recorded using magnetoencephalography. Spontaneous extension of the right wrist was performed at the participant's own pace and following a visual cue in internal (IC) and external (EC) cue tasks. The connectivity of neural signals to M1 from each movement-related motor area was assessed by Granger causality analysis (GCA). The GCA was performed on the neural activity elicited in a frequency band between 7.8 and 46.9 Hz during the pre-movement periods, which occurred durng the readiness field (RF) and the negative slope prime (NSp). F-values, as connectivity values obtained by GCA, were compared between the EC and IC cue tasks.

RESULTS

For NSp periods, the connectivity of neural signals from the left superior frontal area (SF-L) to M1 was dominant in the IC task, whereas that from the left superior parietal area (SP-L) to M1 was dominant in the EC task. The F value in the GCA from SP-L to M1 was greater in the EC task during RF than in the IC task during equivalent periods.

CONSLUSIONS

In the present study, there were differences in the connectivity of neural signals to M1 between IC and EC tasks. The present results suggested that the pattern of pre-movement neural activity that resulted in a movement was not uniform but differed between movement tasks just before the movement.

Early life brain network connectivity antecedents of executive function in children born preterm

Preterm birth is associated with an increased risk of executive function (EF) deficits, yet the underlying neural mechanisms remain unclear. We combine diffusion MRI, resting-state functional MRI, and graph theory analyses to examine how structural (SC) and functional connectivity (FC) at term-equivalent age (TEA) influence EF outcomes at 3 years corrected age in children born at or below 32 weeks' gestation. Here we show shorter average path length (a measure of efficient structural communication) in the insula is linked to better EF performance, implying that more direct structural pathways in this region facilitate critical cognitive processes. Additionally, higher betweenness centrality (a node-level metric of information flow) in parietal and superior temporal regions is associated with improved EF, reflecting these areas' prominent integrative roles in the whole-brain functional network. Importantly, our multimodal analyses reveal that regional structural efficiency helps shape functional organization, indicating a specific interplay between white-matter architecture and emergent functional hubs at TEA. These findings extend current knowledge by demonstrating how earlier disruptions in SC can alter subsequent FC patterns that support EF. By focusing on precise node-level metrics rather than broad within-network effects, our results clarify the contribution that SC has in guiding functional relationships essential for EF.

Distinct distributed brain networks dissociate self-generated mental states

Human cognition relies on two modes: a perceptually-coupled mode where mental states are driven by sensory input and a perceptually-decoupled mode featuring self-generated mental content. Past work suggests that imagined states are supported by the reinstatement of activity in sensory cortex, but transmodal systems within the canonical default network are also implicated in mind-wandering, recollection, and imagining the future. We identified brain systems supporting self-generated states using precision fMRI. Participants imagined different scenarios in the scanner, then rated their mental states on several properties using multi-dimensional experience sampling. We found that thinking involving scenes evoked activity within or near the default network, while imagining speech evoked activity within or near the language network. Imagining-related regions overlapped with activity evoked by viewing scenes or listening to speech, respectively; however, this overlap was predominantly within transmodal association networks, rather than adjacent unimodal sensory networks. The results suggest that different association networks support imagined states that are high in visual or auditory vividness.

Effects of startle on cognitive performance and physiological activity revealed by fNIRS and thermal imaging

Sudden and threatening stimuli can trigger a startle reflex, a stereotyped physiological response that may lead to a brief cognitive incapacitation. Better understanding this reaction would be beneficial to safety-critical occupational domains. We characterized some physiological correlates of the startle response while participants completed a difficult task (Toulouse N-back task) tapping executive functions. During the task, loud and threatening sounds were presented unpredictably to trigger a startle reflex. Brain activity and facial skin temperature were measured in 34 participants using functional near-infrared spectroscopy (fNIRS) and functional infrared thermal imaging (fITI), respectively. In the high difficulty condition, participants were generally less efficient, but their performance improved slightly following startle in the high difficulty condition. Brain activity in the right prefrontal cortex was also higher following startle, potentially reflecting a compensatory overactivation to sustain performance. Interestingly, higher trait-anxiety was associated with lower task performance, still following startle in the high difficulty condition. Finally, we found a decrease in temperature of the right eye and right cheek as well as an increase in the nose temperature following startle. These results underscore the complexity of startle-induced cognitive and physiological dynamics, which may have implications for occupational settings where managing sudden stressors is crucial.

Neural mechanisms of learned suppression uncovered by probing the hidden attentional priority map

Attentional capture by an irrelevant salient distractor is attenuated when the distractor appears more frequently in one location, suggesting learned suppression of that location. However, it remains unclear whether suppression is proactive (before attention is directed) or reactive (after attention is allocated). Here, we investigated this using a 'pinging' technique to probe the attentional distribution before search onset. In an EEG experiment, participants searched for a shape singleton while ignoring a color singleton distractor at a high-probability location. To reveal the hidden attentional priority map, participants also performed a continuous recall spatial memory task, with a neutral placeholder display presented before search onset. Behaviorally, search was more efficient when the distractor appeared at the high-probability location. Inverted encoding analysis of EEG data showed tuning profiles that decayed during memory maintenance but were revived by the placeholder display. Notably, tuning was most pronounced at the to-be-suppressed location, suggesting initial spatial selection followed by suppression. These findings suggest that learned distractor suppression is a reactive process, providing new insights into learned spatial distractor suppression mechanisms.

Accentuation and Attention: From Perceptual Organization to Consciousness

Background: This study investigates the complex relationship between accentuation and attention in visual perception, extending classical Gestalt principles by introducing dissimilarity as a complementary mechanism to similarity in perceptual organization. Objectives and Methods: Through a series of phenomenological experiments, we demonstrate how accentuation, driven by dissimilarity, plays a crucial role in shaping visual experience and guiding attention. Results: Our findings reveal that accentuation serves as a pre-attentive mechanism for highlighting salient features, influencing initial perceptual organization, and modulating the apparent shape and orientation of visual elements. We show that while accentuation operates rapidly and automatically, attention acts as a flexible, selective mechanism that can either reinforce or override accentuation-based percepts. This interplay suggests a two-stage process of visual perception, with implications for theories of consciousness and information processing in biological systems. This study also explores the evolutionary significance of accentuation in camouflage and sexual selection, providing insights into how perceptual mechanisms may have evolved to enhance adaptive fitness. Conclusions: Our results have broad implications for understanding visual cognition, design, and clinical applications related to attentional disorders.

Prestimulus functional connectivity reflects attention orientation in a prospective memory task: A magnetoencephalographic (MEG) study

Prospective Memory (PM) is the ability to encode an intention in memory and retrieve it at the right time in the future. After the intention is formed, it must be maintained in memory while simultaneously monitoring the environment until the occurrence of the stimulus associated with its retrieval. Therefore, monitoring and maintenance processes must work in conjunction to subserve PM processing (monitoring/maintenance phase). Several brain regions play a role in PM, such as the anterior prefrontal cortex, inferior parietal lobules, and precuneus. Notably, these regions belong to different brain networks and are differently involved depending on the memory and attentional requests of the PM task. In this study, we investigate the neural bases of PM from a network perspective, using functional connectivity (FC) analysis to identify the networks involved in the attentional and memory mechanisms underlying PM. To this end, we analyzed MEG data collected in two different PM conditions, enhancing either the monitoring (i.e., attention) or the maintenance (i.e., memory) loads of the PM task. To disentangle the neural correlates of these mechanisms from other processes occurring after stimulus presentation, the analysis focused on the prestimulus time window (monitoring/maintenance phase). The monitoring-load condition was characterized by increased inter-network FC of the Dorsal Attention Network (DAN) in the alpha band, a marker of increased top-down monitoring. In contrast, the maintenance-load condition was associated with increased connectivity of the Ventral Attention Network (VAN) with the FrontoParietal Control and the Default-Mode Networks (FPCN and DMN, respectively). Additionally, response times were found to correlate with prestimulus alpha connectivity of different networks in the two conditions. These differences in connectivity within and between networks support the hypothesis that different networks (DAN, or VAN and DMN) and mechanisms (top-down or bottom-up, respectively) are involved in PM processing depending on the features of the PM task.

Reshaped functional connectivity gradients in acute ischemic stroke

Ischemic brain stroke disrupts blood flow, leading to functional and structural changes associated with behavioral deficits. Importantly, despite this disruption occurring in localized regions, the resulting changes in the functional organization are both high-dimensional and widespread across the human cortex. However, the mechanisms with which these global patterns emerge and the subsequent behavioral deficits they entail, remain largely unexplored. Functional connectivity gradients provide consistent, reproducible, and robust low-dimensional representations of brain function that can be explored to reduce brain heterogeneity to a handful of axes along which brain function is organized. Here, we investigated how stroke disrupts this canonical gradient space by aligning each patient to a control-averaged gradient embedding and computing the distances to the "correct" positions to quantify functional deviations and their contribution to behavioral deficits. Importantly, we explicitly corrected these gradients for stroke-induced hemodynamic lags to further study their contribution. We found that lag correction enhanced the functional connectivity gradients most prominently in the second gradient, on which visual and somatomotor function is concentrated. Additionally, we identified significant functional deviations primarily within somatomotor, visual, and ventral attention networks, correlating with behavioral impairments. We studied the hemispheric asymmetries of these deviations finding that intact hemispheres preserve comparable patterns of asymmetry while damaged ones presented important changes. Lastly, right-sided lesions displayed more localized functional deviations than their contralateral lesions. Overall, we provide evidence that (1) correcting for hemodynamic lags improves gradient accuracy, as indicated by increased percentages of explained variance, and (2) behavioral impairments and hemispheric asymmetries result from a repositioning of region-based connectivity profiles in a low-dimensional interpretable space. This suggests that large-scale brain function alterations manifest in slight, predictable movements along a reduced set of brain axes that are not completely detached from white matter damage.

Reinstatement and transformation of memory traces for recognition

Episodic memory relies on the formation and retrieval of content-specific memory traces. In addition to their veridical reactivation, previous studies have indicated that traces may undergo substantial transformations. However, the exact time course and regional distribution of reinstatement and transformation during recognition memory have remained unclear. We applied representational similarity analysis to human intracranial electroencephalography to track the spatiotemporal dynamics underlying the reinstatement and transformation of memory traces. Specifically, we examined how reinstatement and transformation of item-specific representations across occipital, ventral visual, and lateral parietal cortices contribute to successful memory formation and recognition. Our findings suggest that reinstatement in temporal cortex and transformation in parietal cortex coexist and provide complementary strategies for recognition. Further, we find that generalization and differentiation of neural representations contribute to memory and probe memory-specific correspondence with deep neural network (DNN) model features. Our results suggest that memory formation is particularly supported by generalized and mnemonic representational formats beyond the visual features of a DNN.

Counteracting uncertainty: exploring the impact of anxiety on updating predictions about environmental states

Anxious emotional states disrupt decision-making and control of dexterous motor actions. Computational work has shown that anxiety-induced uncertainty alters the rate at which we learn about the environment, but the subsequent impact on the predictive beliefs that drive action control remains to be understood. In the present work we tested whether anxiety alters predictive (oculo)motor control mechanisms. Thirty participants completed an experimental task that consisted of manual interception of a projectile performed in virtual reality. Participants were subjected to conditions designed to induce states of high or low anxiety using performance incentives and social-evaluative pressure. We measured subsequent effects on physiological arousal, self-reported state anxiety, and eye movements. Under high pressure conditions we observed visual sampling of the task environment characterised by higher variability and entropy of position prior to release of the projectile, consistent with an active attempt to reduce uncertainty. Computational modelling of predictive beliefs, using gaze data as inputs to a partially observable Markov decision process model, indicated that trial-to-trial updating of predictive beliefs was reduced during anxiety, suggesting that updates to priors were constrained. Additionally, state anxiety was related to a less deterministic mapping of beliefs to actions. These results support the idea that organisms may attempt to counter anxiety-related uncertainty by moving towards more familiar and certain sensorimotor patterns.

Multiple brain activation patterns for the same perceptual decision-making task

Meaningful variation in internal states that impacts cognition and behavior remains challenging to discover and characterize. Here we leverage trial-to-trial fluctuations in the brain-wide signal recorded using functional MRI to test if distinct sets of brain regions are activated on different trials when accomplishing the same task. Across three different perceptual decision-making experiments, we estimate the brain activations for each trial. We then cluster the trials based on their similarity using modularity-maximization, a data-driven classification method. In each experiment, we find multiple distinct but stable subtypes of trials, suggesting that the same task can be accomplished in the presence of widely varying brain activation patterns. Surprisingly, in all experiments, one of the subtypes exhibits strong activation in the default mode network, which is typically thought to decrease in activity during tasks that require externally focused attention. The remaining subtypes are characterized by activations in different task-positive areas. The default mode network subtype is characterized by behavioral signatures that are similar to the other subtypes exhibiting activation with task-positive regions. These findings demonstrate that the same perceptual decision-making task is accomplished through multiple brain activation patterns.

Deficiency of histamine H2 receptors in parvalbumin-positive neurons leads to hyperactivity, impulsivity, and impaired attention

Attention deficit hyperactivity disorder (ADHD), affecting 4% of the population, is characterized by inattention, hyperactivity, and impulsivity; however, its neurophysiological mechanisms remain unclear. Here, we discovered that deficiency of histamine H2 receptor (H2R) in parvalbumin-positive neurons in substantia nigra pars recticulata (PVSNr) attenuates PV+ neuronal activity and induces hyperactivity, impulsivity, and inattention in mice. Moreover, decreased H2R expression was observed in PVSNr in patients with ADHD symptoms and dopamine-transporter-deficient mice, whose behavioral phenotypes were alleviated by H2R agonist treatment. Dysfunction of PVSNr efferents to the substantia nigra pars compacta dopaminergic neurons and superior colliculus differently contributes to H2R-deficiency-induced behavioral disorders. Collectively, our results demonstrate that H2R deficiency in PV+ neurons contributes to hyperactivity, impulsivity, and inattention by dampening PVSNr activity and involving different efferents in mice. It may enhance understanding of the molecular and circuit-level basis of ADHD and afford new potential therapeutic targets for ADHD-like psychiatric diseases.

Causal evidence for increased theta and gamma phase consistency in a parieto-frontal network during the maintenance of visual attention

Endogenous visuo-spatial attention is under the control of a fronto-parietal network of brain regions. One key node in this network, the intra-parietal sulcus (IPS), plays a crucial role in maintaining endogenous attention, but little is known about its ongoing physiology and network dynamics during different attentional states. Here, we investigated the reactivity of the left IPS in response to brain stimulation under different states of selective attention. We recorded electroencephalography (EEG) in response to single pulses of transcranial magnetic stimulation (TMS) of the IPS, while participants (N = 44) viewed bilateral random-dot motion displays. Individual MRI-guided TMS pulses targeted the left IPS, while the left primary somatosensory cortex (S1) served as an active control site. In separate blocks of trials, participants were cued to attend covertly to the motion display in one hemifield (left or right) and to report brief coherent motion targets. The perceptual load of the task was manipulated by varying the degree of motion coherence of the targets. Excitability, variability and information content of the neural responses to TMS were assessed by analysing TMS-evoked potential (TEP) amplitude and inter-trial phase clustering (ITPC), and by performing multivariate decoding of attentional state. Results revealed that a left posterior region displayed reduced variability in the phase of theta and gamma oscillations following TMS of the IPS, but not of S1, when attention was directed contralaterally, rather than ipsilaterally to the stimulation site. A right frontal cluster also displayed reduced theta variability and increased amplitude of TEPs when attention was directed contralaterally rather than ipsilaterally, after TMS of the IPS but not S1. Reliable decoding of attentional state was achieved after TMS pulses of both S1 and IPS. Taken together, our findings suggest that endogenous control of visuo-spatial attention leads to changes in the intrinsic oscillatory properties of the IPS and its associated fronto-parietal network.