Large-scale reconfiguration of connectivity patterns among attentional networks during context-dependent adjustment of cognitive control

Changes in effective connectivity during the visual-motor integration tasks: a preliminary f-NIRS study

BACKGROUND

Visual-motor integration (VMI) is an essential skill in daily life. The present study aimed to use functional near-infrared spectroscopy (fNIRS) technology to explore the effective connectivity (EC) changes among brain regions during VMI activities of varying difficulty levels.

METHODS

A total of 17 healthy participants were recruited for the study. Continuous Performance Test (CPT), Behavior Rating Inventory of Executive Function-Adult Version (BRIEF-A), and Beery VMI test were used to evaluate attention performance, executive function, and VMI performance. Granger causality analysis was performed for the VMI task data to obtain the EC matrix for all participants. One-way ANOVA analysis was used to identify VMI load-dependent EC values among different task difficulty levels from brain network and channel perspectives, and partial correlation analysis was used to explore the relationship between VMI load-dependent EC values and behavioral performance.

RESULTS

We found that the EC values of dorsal attention network (DAN) → default mode network (DMN), DAN → ventral attention network (VAN), DAN → frontoparietal network (FPN), and DAN → somatomotor network (SMN) in the complex condition were higher than those in the simple and moderate conditions. Further channel analyses indicated that the EC values of the right superior parietal lobule (SPL) → right superior frontal gyrus (SFG), right middle occipital gyrus (MOG) → left SFG, and right MOG → right postcentral gyrus (PCG) in the complex condition were higher than those in the simple and moderate conditions. Subsequent partial correlation analysis revealed that the EC values from DAN to DMN, VAN, and SMN were positively correlated with executive function and VMI performance. Furthermore, the EC values of right MOG → left SFG and right MOG → right PCG were positively correlated with attention performance.

CONCLUSIONS

The DAN is actively involved during the VMI task and thus may play a critical role in VMI processes, in which two key brain regions (right SPL, right MOG) may contribute to the EC changes in response to increasing VMI load. Meanwhile, bilateral SFG and right PCG may also be closely related to the VMI performance.

Face masks degrade our ability to remember face-name associations more than predicted by judgments of learning

In response to the COVID-19 pandemic, face masks became required attire. Face masks obstruct the bottom portion of faces, restricting face processing. The present study examined the influence face masks have on memory predictions and memory performance for new face-name associations. Participants studied face-name pairs presented for 8 s (Experiment 1) or 10 s (Experiment 2). Half of the face-name pairs included a face mask obstructing the nose and mouth of the pictured face, counterbalanced across participants. Participants provided item-by-item judgements of learning (JOLs) and completed subsequent cued recall and associative recognition memory tests. Both experiments demonstrated that face masks impaired memory for newly-learned names, however, the magnitude of the mask impact was under-predicted by JOLs. The presence of a face mask negatively influenced memory performance to a greater degree than participants' JOLs predicted. Results have implications for name learning during pandemics, as well as in settings where face masks are common (e.g., medical field).

Large-scale networks changes in Wilson's disease associated with neuropsychiatric impairments: a resting-state functional magnetic resonance imaging study

BACKGROUND

In Wilson's disease (WD) patients, network connections across the brain are disrupted, affecting multidomain function. However, the details of this neuropathophysiological mechanism remain unclear due to the rarity of WD. In this study, we aimed to investigate alterations in brain network connectivity at the whole-brain level (both intra- and inter-network) in WD patients through independent component analysis (ICA) and the relationship between alterations in these brain network functional connections (FCs) and clinical neuropsychiatric features to understand the underlying pathophysiological and central compensatory mechanisms.

METHODS

Eighty-five patients with WD and age- and sex-matched 85 healthy control (HC) were recruited for resting-state functional magnetic resonance imaging (rs-fMRI) scanning. We extracted the resting-state networks (RSNs) using the ICA method, analyzed the changes of FC in these networks and the correlation between alterations in FCs and clinical neuropsychiatric features.

RESULTS

Compared with HC, WD showed widespread lower connectivity within RSNs, involving default mode network (DMN), frontoparietal network (FPN), somatomotor network (SMN), dorsal attention network (DAN), especially in patients with abnormal UWDRS scores. Furthermore, the decreased FCs in the left medial prefrontal cortex (L_ MPFC), left anterior cingulate gyrus (L_ACC), precuneus (PCUN)within DMN were negatively correlated with the Unified Wilson's Disease Rating Scale-neurological characteristic examination (UWDRS-N), and the decreased FCs in the L_MPFC, PCUN within DMN were negatively correlated with the Unified Wilson's Disease Rating Scale-psychiatric symptoms examination (UWDRS-P). We additionally discovered that the patients with WD exhibited significantly stronger FC between the FPN and DMN, between the DAN and DMN, and between the FPN and DAN compared to HC.

CONCLUSIONS

We have provided evidence that WD is a disease with widespread dysfunctional connectivity in resting networks in brain, leading to neurological features and psychiatric symptoms (e.g. higher-order cognitive control and motor control impairments). The alter intra- and inter-network in the brain may be the neural underpinnings for the neuropathological symptoms and the process of injury compensation in WD patients.

Brief mindfulness meditation intervention improves attentional control of athletes in virtual reality shooting competition: Evidence from fNIRS and eye tracking

Attentional control is a crucial cognitive ability for sports performance. The current research aimed to investigate whether a brief (20-min) pre-competition mindfulness meditation (MM) intervention enhances athletes' attentional control during competitions and alters the activity of brain regions related to attentional control. We created a virtual reality shooting competition to compare the eye-gaze indicators and functional near-infrared spectroscopy (fNIRS) parameters of 78 university athletes after 20 min of MM or 20 min of mind wandering (MW). Participants' average fixation durations (AFDs) on task-relevant information (targets) were significantly longer in the MM group. In contrast, both average fixation counts (AFCs) and AFDs on task-irrelevant information (the ranking screen) were significantly lower in the MM group than in the MW group. Additionally, the MM group exhibited significantly stronger activation of the left and right dorsolateral prefrontal cortex (dlPFC) as well as higher levels of oxygenated haemoglobin [HbO] and greater functional connectivity (FC) of the right dlPFC, which was considered evidence of recruitment for attentional control. Moreover, the MM group achieved significantly better shooting performance than the MW group. Overall, the findings suggest that one session 20-min MM practice pre-competition facilitates focus during competition and improves athletic performance. We recommend the application of brief mindfulness practice in sports, especially in closed-skill sports that require high attention participation (e.g., shooting, archery, darts, golf, gymnastics, skating etc.).

Flexible integration and segregation of large-scale networks during adaptive control

Adaptive control characterizes the dynamic adjustment of cognitive control to changing environmental demand, and has obtained growing interests in its neural mechanism for the past two decades. Recent years, interpreting network reconfiguration in terms of integration and segregation has been proved to shed light on neural structure underlying various cognitive tasks. However, the relationship between network architecture and adaptive control remains unclear. Here, we quantified the network integration (global efficiency, participation coefficient, inter-subnetwork efficiency) and segregation (local efficiency, modularity) in the whole-brain and analyzed how these graph theory metrics were modulated by adaptive control. The results showed that the integration of the cognitive control network (the fronto-parietal network, FPN), the visual network (VIN) and the sensori-motor network (SMN) was significantly improved when conflict was rare, so as to cope with the incongruent trials of high cognitive control demands. Additionally, as the conflict proportion increased, the segregation of the cingulo-opercular network (CON) and the default mode network (DMN) significantly enhanced, which may contribute to specialized functioning or automatic processing, and help to solve conflict in a less resource-intensive mode. Finally, using graph metrics as features, the multivariate classifier reliably predicted the context condition. These results demonstrate how large-scale brain networks support adaptive control through flexible integration and segregation.

Learning of irrelevant stimulus-response associations modulates cognitive control

It has been shown that manipulating the proportion of congruent to incongruent trials in conflict tasks (e.g., Stroop, Simon, and flanker tasks) can vary the size of conflict effects, however, by two different mechanisms. One theory is the control learning account (the brain learns the probability of conflict and uses it to proactively adjust the control demand for future trials). The other is the irrelevant stimulus-response learning account (the brain learns the probability of irrelevant stimulus-response associations and uses it to prepare responses). Previous fMRI studies have detected the brain regions that contribute to the control-learning-modulated conflict effects, but it is less known what neural substrates underlie the conflict effects modulated by irrelevant S-R learning. We here investigated this question with a model-based fMRI study, in which the proportion of congruent to incongruent trials changed dynamically in the Simon task and the models learned the probability of irrelevant S-R associations quantitatively. Behavioral analyses showed that the unsigned prediction errors (PEs) of responses generated by the learning models correlated with reaction times irrespective of congruent and incongruent trials, indicating that large unsigned PEs associated with slow responses. The fMRI results showed that the regions of fronto-parietal and cingulo-opercular network involved in cognitive control were significantly modulated by the unsigned PEs, also irrespective of congruent and incongruent trials, indicating that large unsigned PEs associated with transiently increased activity in these regions. These results together suggest that learning of irrelevant S-R associations modulates reactive control, which demonstrates a new way to modulate cognitive control compared to the control learning account.

Conflict Experience Regulates the Neural Encoding of Cognitive Conflict

Cognitive control is adaptive in that it rapidly adjusts attention in response to changing contexts and shifting goals. Research provides evidence that cognitive control can rapidly adjust attention to focus on task-relevant information based on prior conflict experience. Neural encoding of goal-related information is critical for goal-directed behaviour; however, the empirical evidence on how conflict experience affects the encoding of cognitive conflict in the brain is rather weak. In the present fMRI study, a Stroop task with different proportions of incongruent trial was used to investigate the neural encoding of cognitive conflict in the environment with changing conflict experience. The results showed that the anterior cingulate cortex, dorsolateral prefrontal cortex, and intraparietal sulcus played a pivotal role in the neural encoding of cognitive conflict. The classification in anterior cingulate cortex was significantly above chance in the high-proportion, moderate-proportion, and low-proportion conflict conditions conducted separately, suggesting that neural encoding of cognitive conflict in this region was not altered based on proportion of conflict. The dorsolateral prefrontal cortex and intraparietal sulcus showed significant above-chance classification in the moderate-proportion and low-proportion conflict conditions, but not in the high-proportion conflict condition. These findings provide direct evidence that conflict experience modulates the neural encoding of cognitive conflict.

Functional connectivity of brain networks with three monochromatic wavelengths: a pilot study using resting-state functional magnetic resonance imaging

Exposure to certain monochromatic wavelengths can affect non-visual brain regions. Growing research indicates that exposure to light can have a positive impact on health-related problems such as spring asthenia, circadian rhythm disruption, and even bipolar disorders and Alzheimer’s. However, the extent and location of changes in brain areas caused by exposure to monochromatic light remain largely unknown. This pilot study (N = 7) using resting-state functional magnetic resonance shows light-dependent functional connectivity patterns on brain networks. We demonstrated that 1 min of blue, green, or red light exposure modifies the functional connectivity (FC) of a broad range of visual and non-visual brain regions. Largely, we observed: (i) a global decrease in FC in all the networks but the salience network after blue light exposure, (ii) a global increase in FC after green light exposure, particularly noticeable in the left hemisphere, and (iii) a decrease in FC on attentional networks coupled with a FC increase in the default mode network after red light exposure. Each one of the FC patterns appears to be best arranged to perform better on tasks associated with specific cognitive domains. Results can be relevant for future research on the impact of light stimulation on brain function and in a variety of health disciplines.

Temporal dynamics of conflict adaptation across different conflict strengths

Conflict adaptation is considered to reflect the adjustment of cognitive control, and it is critical for adaptive behavior. Despite intensive investigations on conflict adaptation, straightforward evidence on how changes in conflict strength influence the behavioral and neural dynamics of conflict adaptation remains scarce. To address this issue, we manipulated conflict strength by varying distractor-target congruency to investigate whether conflict strength per se or the expectancy of conflict strength triggers the adjustment of cognitive control. Behavioral and electroencephalographic (EEG) measures were recorded while participants performed a variant four-choice flanker task without feature repetitions. The behavioral results showed that reaction times increased with increasing conflict strength. Importantly, there were conflict adaptations between the congruent and incongruent-low, congruent and incongruent-high, and incongruent-low and incongruent-high conditions. Consistent with the behavioral results, the EEG results revealed that N2 and P3 were sensitive to conflict strength. Critically, there were typical conflict adaptations between every two conflict conditions on the early P3 amplitude related to the adjustment of attentional strategies. However, there were no differences among these conflict adaptation effects, both on reaction times and the early P3 amplitude, demonstrating that the expectancy of conflict strength rather than conflict strength per se may play a crucial role in conflict adaptation. Altogether, these results emphasize the functional role of expectancy based on previous conflict strength in the exertion of cognitive control, which is in accordance with the repetition expectation theory than with the conflict monitoring theory.

Intensity-dependent acute aerobic exercise: Effect on reactive control of attentional functions in acclimatized lowlanders at high altitude

Human attentional function is sensitive to hypoxia. However, little is known about whether and how attentional function is altered after acute aerobic exercise at high altitude, especially for acclimatized lowlanders. In this study, we used the Attention Network Test (ANT) to measure alerting, orienting, and executive control functions and the Stroop Color and Word Test (SCWT) with a different proportion of incongruent trials to investigate proactive and reactive control of executive function. We randomly divided the sample of 160 Tibetan lowlanders who had lived in the highlands for more than two years into four groups. Each of three groups performed 20 min of low-, moderate-, or high-intensity acute aerobic exercise, separately, and a control group watched a 20-min documentary. The ANT and SCWT were conducted before and after exercise or watching the documentary. The results indicated that the executive control effects of the three experimental groups significantly decreased and, in the posttest, the executive control effects of the high-intensity group were lower than those of the low-intensity group. Furthermore, the accuracy of the moderate- and high-intensity groups was increased significantly in the blocks containing 25% incongruent trials of SCWT task. These results suggest that the acute aerobic exercise at high altitude will improve the reactive control of attentional functions in acclimatized lowlanders, and the intensity may play an important role in the exercise-cognition interaction at high altitude.

Longitudinal effects of cannabis use on attentional processes in patients with first episode of psychosis

BACKGROUND

Attention deficits have been considered to be a central characteristic of schizophrenia-spectrum disorders. However, the specific interactions with, and longitudinal effects of, cannabis use at the different stages of the disorder remain unknown. Due to the high percentage of patients who are cannabis users at the onset of the disease, our objective was to explore this relationship and how it evolves in the first three years of the disease.

METHOD

A total of 461 patients with a first episode of psychosis (FEP) and 187 healthy controls were studied. The differences between cannabis users and non-users at baseline were explored based on both sociodemographic variables and performance in neuropsychological tests of attention. The interaction between cannabis, attentional, and clinical variables was followed up at 3 years.

RESULTS

Of the 648 participants included in this study, 229 (35.34%) were cannabis users. Of them, 187 (40.6%) were patients and 42 (22.5%) were healthy controls. At baseline, control groups [cannabis users (N = 42); non-users (N = 145)] outperformed the patient groups [cannabis users (N = 187); non-users (N = 274)] in all attention tasks. Longitudinal analyses showed significant improvements in the attentional domains at 3-year follow-up, mainly in the group of patients who had never used cannabis (N = 238), followed by ex-users (N = 105), and persistent users (N = 43). At 3-year follow-up, the group of ex-users was the one that achieved scores closer to those of healthy controls.

CONCLUSION

FEP patients, both cannabis users and non-users, showed attention deficits. However, the patients who had never used cannabis fared better than cannabis users.

Altered Neural Network Connectivity Predicts Depression in de novo Parkinson’s Disease

Background

Depression, one of the most frequent non-motor symptoms in Parkinson’s disease (PD), was proposed to be related to neural network dysfunction in advanced PD patients. However, the underlying mechanisms in the early stage remain unclear. The study was aimed to explore the alterations of large-scale neural networks in de novo PD patients with depression.

Methods

We performed independent component analysis (ICA) on the data of resting-state functional magnetic resonance imaging from 21 de novo PD patients with depression (dPD), 34 de novo PD patients without depression (ndPD), and 43 healthy controls (HCs) to extract functional networks. Intranetwork and internetwork connectivity was calculated for comparison between groups, correlation analysis, and predicting the occurrence of depression in PD.

Results

We observed an ordered decrease of connectivity among groups within the ventral attention network (VAN) (dPD < ndPD < HCs), mainly located in the left middle temporal cortex. Besides, dPD patients exhibited hypoconnectivity between the auditory network (AUD) and default mode network (DMN) or VAN compared to ndPD patients or healthy controls. Correlation analysis revealed that depression severity was negatively correlated with connectivity value within VAN and positively correlated with the connectivity value of AUD-VAN in dPD patients, respectively. Further analysis showed that the area under the curve (AUC) for dPD prediction was 0.863 when combining the intranetwork connectivity in VAN and internetwork connectivity in AUD-DMN and AUD-VAN.

Conclusion

Our results demonstrated that early dPD may be associated with abnormality of attention bias and especially auditory attention processing. Altered neural network connectivity is expected to be a potential neuroimaging biomarker to predict depression in PD.

Investigating cognitive flexibility deficit in schizophrenia using task-based whole-brain functional connectivity

BACKGROUND

Cognitive flexibility is a core cognitive control function supported by the brain networks of the whole-brain. Schizophrenic patients show deficits in cognitive flexibility in conditions such as task-switching. A large number of neuroimaging studies have revealed abnormalities in local brain activations associated with deficits in cognitive flexibility in schizophrenia, but the relationship between impaired cognitive flexibility and the whole-brain functional connectivity (FC) pattern is unclear.

METHOD

We investigated the task-based functional connectivity of the whole-brain in patients with schizophrenia and healthy controls during task-switching. Multivariate pattern analysis (MVPA) was utilized to investigate whether the FC pattern can be used as a feature to discriminate schizophrenia patients from healthy controls. Graph theory analysis was further used to quantify the degrees of integration and segregation in the whole-brain networks to interpret the different reconfiguration patterns of brain networks in schizophrenia patients and healthy controls.

RESULTS

The results showed that the FC pattern classified schizophrenia patients and healthy controls with significant accuracy. Moreover, the altered whole-brain functional connectivity pattern was driven by a lower degree of network integration and segregation in schizophrenia, indicating that both global and local information transfers at the entire-network level were less efficient in schizophrenia patients than in healthy controls during task-switching processing.

CONCLUSION

These results investigated the group differences in FC profiles during task-switching and not only elucidated that FC patterns are changed in schizophrenic patients, suggesting that task-based FC could be used as a potential neuromarker to discriminate schizophrenia patients from healthy controls in cognitive flexibility but also provide increased insight into the brain network organization that may contribute to impaired cognitive flexibility.

Large-scale reconfiguration of connectivity patterns among attentional networks during context-dependent adjustment of cognitive control

The ability to adjust our behavior flexibly depending on situational demands and changes in the environment is an important characteristic of cognitive control. Previous studies have proved that this type of adaptive control plays a crucial role in selective attention, but have barely explored whether and how attentional networks support adaptive control. In the present study, a Stroop task with a different proportion of incongruent trials was used to investigate the brain activity and connectivity of six typical attentional control networks (i.e., the fronto-parietal network (FPN), cingulo-opercular network (CON), default mode network (DMN), dorsal attention network (DAN), and ventral attention network/salience network (VAN/SN)) in the environment with changing control demand. The behavioral analysis indicated a decreased Stroop interference (incongruent vs. congruent trial response time [RT]) with the increase in the proportion of incongruent trials within a block, indicating that cognitive control was improved there. The fMRI data revealed that the attenuate Stroop interference was accompanied by the activation of frontal and parietal regions, such as bilateral dorsolateral prefrontal cortex and anterior cingulate cortex. Crucially, the improved cognitive control induced by the increased proportion of incongruent trials was associated with the enhanced functional connectivity within the five networks, and a greater connection between CON with the DAN/SN, and between DMN with the CON/DAN/SN. Meanwhile, however, the functional coupling between the FPN and VAN was decreased. These results suggest that flexible regulations of cognitive control are implemented by the large-scale reconfiguration of connectivity patterns among the attentional networks.