Brain Topography最新文献

Parkinson's Disease (PD) is a neurological disorder characterized by impaired postural control (PC) and balance issues. To date, few studies have explored the relationship between brain activity and responses during specific tasks designed to challenge balance in individuals with PD. Our exploratory research employs an innovative paradigm to assess PC by integrating virtual reality (VR) and electroencephalography (EEG). In the study, 20 individuals diagnosed with PD who self-reported postural instability participated in the BioVRSea paradigm. This paradigm tested their PC using visuomotor stimuli and collected EEG signals to assess brain responses throughout the experiment. The results of the Parkinson's group were compared with those of 22 age-matched healthy controls (CTR). From the functional connectivity between brain regions, we extracted brain network states (BNSs) using the k-means++ clustering algorithm. These BNSs capture the dynamic organization of brain activity and were compared with canonical resting-state networks (RSNs) to investigate neural alterations in individuals with PD. Six distinct BNSs were identified, with the dorsal attention network (DAN) dominant in five states. A significant reduction in the coverage of BNS2 was observed in PD patients during both the PRE (adjusted p-value = 0.019) and MOV (adjusted p-value = 0.036) phases compared to CTR. This reduced BNS2 coverage suggests impaired visuomotor integration in PD patients during PC tasks. DAN dominance highlights its crucial role in maintaining attentional control during the task. The findings of this study highlight the potential of using brain dynamics as a biomarker of neural dysfunction in PD, especially during specific PC tasks. Altered BNSs, particularly in networks associated with attention and sensorimotor integration, reveal key neural deficits related to PD.

Cigarette smoking is known to be associated with altered static functional connectivity in the brain. However, investigating its dynamics may offer novel and insightful perspectives for elucidating the neural mechanisms underlying smoking addiction. The aim of this study was to explore the characteristics of dynamic functional network connectivity in heavy smokers. This study is a secondary analysis of a previously acquired dataset, leveraging novel dynamic functional network connectivity methodologies to investigate distinct research questions. Resting-state functional magnetic resonance imaging data were collected from 34 heavy smokers and 36 non-smokers. Forty-two meaningful independent components were selected after the group independent component analysis. Four distinct brain states were identified based on a sliding window approach and k-means clustering analysis. The temporal properties of these states were compared between the two groups, and correlations between these differences and smoking-related factors were examined in heavy smokers. Compared with non-smokers, heavy smokers exhibited a lower occurrence rate and mean dwell time in state 2 characterized by synchrony within the default mode network and anticorrelation with other domains, and a reduced mean dwell time in state 3 marked by high connectivity within the sensory domains. Network-based statistics revealed that cognitive control and cerebellar domains played important roles in the altered subnetworks. In heavy smokers, the occurrence rate showed negative relationships with the duration of smoking in state 2. These findings advance our understanding of the temporal and network-level dysfunctions associated with smoking addiction, offering a new framework for future studies aimed at developing targeted treatments and preventive strategies.

α-band-mediated brain network communication underlies visual processing and is disrupted in visual deficits. We aimed to develop and evaluate an EEG-based neurofeedback targeting α-band connectivity of source-reconstructed visual areas with the rest of the brain, to determine whether modulating this network enhances detection of low-contrast visual stimuli. In this randomized, active-controlled study, 28 participants received real-time auditory neurofeedback designed to increase global α-band connectivity between target regions and the rest of the brain. Feedback targeted interactions with the visual cortex (V1-V3) in the active group and with the frontal cortex in the control group. Each participant completed two neurofeedback sessions on separate days. Resting-state connectivity, visual, and attentional performance were assessed on the days preceding and following training. 50% of participants in the active group successfully increased α-band connectivity of the targeted visual cortex, whereas connectivity decreased in the control and non-responder groups. Improvements in stimulus detection were observed primarily in male participants and appeared to be influenced by additional factors, including baseline performance levels. Even brief network-based neurofeedback interventions can enhance α-band connectivity of visual areas.

Exercise dependence is a behavioral disorder characterized by an obsessive and uncontrolled compulsion to exercise, which ultimately leads to detrimental outcomes for both physical health (e.g., injury, exhaustion) and mental state (e.g., anxiety, impaired social functioning). To investigate whether exercise-dependent individuals show altered brain network properties and if these properties relate to specific addictive behavioral tendencies. Resting-state EEG signals were collected from two groups of adult participants: individuals with a high risk of exercise dependence and those with a low risk, as classified using the Chinese version of the Exercise Dependence Scale (EDS). Source analysis and brain network graph-theory analysis were applied to examine key global and local network measures. The results show that group differences were observed in local graph measures (nodal degree of the right ventral prefrontal cortex and left temporal pole), which survived FDR correction, as well as in global graph measures (global clustering coefficient and small-worldness), which did not reach FDR-corrected significance but showed moderate effect sizes. Furthermore, the nodal degree of the left temporal pole, global clustering coefficient, and small-worldness were independently associated with the total score of the Chinese version of the EDS and correlated significantly with scores on specific sub-scales. The findings suggest that high EDS individuals demonstrate altered brain functional networks that are significantly associated with their specific addictive behavioral tendencies.

This randomized controlled trial investigated the effects of motor imagery training (MIT) monitored by functional near-infrared spectroscopy (fNIRS) on upper limb motor function and cortical activation in stroke patients. Seventy participants were allocated to either an MI group, which received conventional rehabilitation therapy (CRT) supplemented with visual and kinesthetic-based MIT, or a control group (CON group), which received CRT alone. The CRT intervention consisted of 30-min sessions administered four times per day over a 4-week period. The MI group underwent an additional daily 25-min session of MIT, whereas the CON group watched neutral nature documentaries (landscapes and animals) for an equivalent duration. Functional outcomes were assessed using the Fugl-Meyer Assessment for Upper Extremity (FMA-UE) and the modified Barthel Index (MBI). Additionally, fNIRS was used to monitor changes in oxyhemoglobin (HbO₂) levels in the motor cortex before and after the intervention in the MI group. Sixty-three participants completed the study (MI group: n = 32, CON group: n = 31). Both groups showed significant improvements in FMA-UE and MBI scores after the intervention (P < 0.05). The MI group demonstrated significantly greater improvement in MBI compared with the CON group (P < 0.05), although between-group differences in FMA-UE were not significant (P > 0.05). fNIRS revealed increased cortical activation in the MI group, specifically showing enhanced activation intensity in the supplementary motor area (channel 3) and sensorimotor cortex (channels 18, 19, 21) (P < 0.05). These findings suggest that functional improvements may be mediated through neural plasticity changes. The combined application of MIT and CRT appears to enhance motor cortex activation and promote functional recovery in stroke rehabilitation.

This study examined how different types of semantic relationships modulate cortical activity during spatial judgments in an augmented reality (AR) setting. Participants viewed triads of everyday objects that were either thematically (co-occurring) or functionally (sharing a purpose) related and made spatial judgments varying in reference frame, egocentric (object closest to you?) vs. allocentric (object closest to another? ), and relation type, coordinate (distance-based) vs.categorical (left-right). Cortical activity was measured using functional near-infrared spectroscopy (fNIRS). Results showed that semantic modulation was most evident during allocentric-coordinate judgments, with increased activation in temporal regions for thematic triads compared to functional ones. In general, functionally related triads engaged parietal regions more broadly across conditions, while egocentric judgments elicited widespread parietal activity with reduced semantic modulation. Finally, categorical judgments showed minimal differences between semantic conditions. By combining AR with fNIRS, this study provides evidence that semantic knowledge influences cortical recruitment during spatial processing, offering a novel window into how meaning and spatial representation interact.

Infrared neural stimulation (INS) represents an invasive technique for modulating brain activity in animals, particularly primates, which serve as effective models for human brain research. Noninvasive approaches, such as transcranial laser stimulation, are safer but have lower spatial and temporal resolution, primarily altering metabolic processes rather than directly stimulating specific neurons. Invasive techniques provide better resolution by targeting neurons with focused laser beams but require intricate surgeries that damage the meninges, limiting studies to short-term experiments conducted mostly on anesthetized animals. We present a minimally invasive approach for long-term, high-resolution laser INS that does not disrupt brain tissue integrity and minimizes the risk of inflammation. Laser radiation is delivered through contact between a flexible optical fiber and the outer surface of the dura mater, allowing for chronic experiments on non-anesthetized primates who maintain their cognitive functions and physical activities. This method has enabled us to conduct a multi-day INS experiment and collect statistically reliable data on neurophysiological responses in a cognitively intact primate subjected to targeted high-resolution INS. We analyzed electrocorticogram and evoked potentials in various cortical areas while applying infrared laser stimulation directed at a selected point on the primary visual cortex of a rhesus macaque. Results indicated that even low-intensity laser stimulation (below conscious perception thresholds) caused synchronous biopotential changes not only at the stimulation site but also in certain distant cortical regions, suggesting a more complex brain response mechanism to INS than merely the activation of stimulated neurons. We believe the presented method will significantly facilitate chronic INS studies, further contributing to fundamental and clinical outcomes.

This study investigated the neuromodulatory effects of 40 Hz rhythmic light (RL) versus a rhythmic light control condition (RLCC) on microstate dynamics in individuals classified with mild cognitive impairment (MCI) and healthy controls. This study employed a two-session, within-subjects design in which each participant completed both 40 Hz and RLCC sessions. EEG was recorded immediately before (pre) and during each RL session, while cognitive assessments were conducted pre and post each session. Twenty-four participants classified with MCI and 27 healthy controls were exposed to both light conditions and underwent electroencephalography recordings, cognitive performance testing (2-back task), and subjective sleepiness questionnaires (Karolinska Sleepiness Scale). We used microstate analysis to examine alterations in microstate dynamics in responses to each light condition. Microstate analysis revealed a reduction in the duration of microstate B and the occurrence rate of microstate C following 40 Hz RL stimulation, suggesting enhanced neural processing efficiency. Both MCI and control participants exhibited stable microstate configurations (A-D) across light conditions, with balanced coverage (~ 20-30%) and subtle shifts-particularly between microstates A and B-indicating dynamic brain state reorganization under 40 Hz stimulation, especially in the MCI group. 40 Hz RL may support compensatory neural mechanisms in individuals with MCI while enhancing sensory and cognitive processing in healthy aging individuals. These findings highlight the potential use of 40 Hz RL as a non-invasive intervention to modulate brain networks and promote cognitive function. Future longitudinal studies are needed to explore the sustained effects of 40 Hz RL on cognitive function and neural integrity in aging populations.

Inhibitory control is crucial for humans to select useful information from the complex environment. The bilateral DLPFC, which is implicated in inhibitory control, was activated under psychological stress. The present study investigated the influence of acute psychological stress on inhibitory control process using the color-word Stroop task. The stress was induced by the Trier Social Stress Task (TSST). After TSST (stress group) or placebo TSST (control group), the male participants performed a color-word Stroop task, and their brain activity was measured using functional near-infrared spectroscopy (fNIRS). The results showed that elevated subjective stress, heart rate, and salivary cortisol were found in the stress than control groups, indicating that the stress had been induced successfully. Reduced RT Stroop effect (RT_incongruent - RT_congruent) was found for the stress group compared to the control group. The fNIRS results revealed greater activation in bilateral dorsolateral prefrontal cortex (DLPFC) in the stress than control groups. In addition, the activation in left DLPFC was increased for the stress than control groups in incongruent trials, but not in the congruent trials, resulting in a larger magnitude of the activation Stroop effect (activation_incongruent - activation_congruent) in the stress group. These results demonstrate that acute psychological stress may potentially improve inhibitory control in healthy men.