Attentional state-synchronous peripheral electrical stimulation during action observation induced distinct modulation of corticospinal plasticity after stroke.

Introduction: Brain computer interface-based action observation (BCI-AO) is a promising technique in detecting the user's cortical state of visual attention and providing feedback to assist rehabilitation. Peripheral nerve electrical stimulation (PES) is a conventional method used to enhance outcomes in upper extremity function by increasing activation in the motor cortex. In this study, we examined the effects of different pairings of peripheral nerve electrical stimulation (PES) during BCI-AO tasks and their impact on corticospinal plasticity. Materials and methods: Our innovative BCI-AO interventions decoded user's attentive watching during task completion. This process involved providing rewarding visual cues while simultaneously activating afferent pathways through PES. Fifteen stroke patients were included in the analysis. All patients underwent a 15 min BCI-AO program under four different experimental conditions: BCI-AO without PES, BCI-AO with continuous PES, BCI-AO with triggered PES, and BCI-AO with reverse PES application. PES was applied at the ulnar nerve of the wrist at an intensity equivalent to 120% of the sensory threshold and a frequency of 50 Hz. The experiment was conducted randomly at least 3 days apart. To assess corticospinal and peripheral nerve excitability, we compared pre and post-task (post 0, post 20 min) parameters of motor evoked potential and F waves under the four conditions in the muscle of the affected hand. Results: The findings indicated that corticospinal excitability in the affected hemisphere was higher when PES was synchronously applied with AO training, using BCI during a state of attentive watching. In contrast, there was no effect on corticospinal activation when PES was applied continuously or in the reverse manner. This paradigm promoted corticospinal plasticity for up to 20 min after task completion. Importantly, the effect was more evident in patients over 65 years of age. Conclusion: The results showed that task-driven corticospinal plasticity was higher when PES was applied synchronously with a highly attentive brain state during the action observation task, compared to continuous or asynchronous application. This study provides insight into how optimized BCI technologies dependent on brain state used in conjunction with other rehabilitation training could enhance treatment-induced neural plasticity.

Alterations in cortical thickness of frontoparietal regions in patients with social anxiety disorder.

Although functional changes of the frontal and (para)limbic area for emotional hyper-reactivity and emotional dysregulation are well documented in social anxiety disorder (SAD), prior studies on structural changes have shown mixed results. This study aimed to identify differences in cortical thickness between SAD and healthy controls (CON). Thirty-five patients with SAD and forty-two matched CON underwent structural magnetic resonance imaging. A vertex-based whole brain and regional analyses were conducted for between-group comparison. The whole-brain analysis revealed increased cortical thickness in the left insula, left superior parietal lobule, left superior temporal gyrus, and left frontopolar cortex in patients with SAD compared to CON, as well as decreased thickness in the left superior/middle frontal gyrus and left fusiform gyrus in patients (after multiple-correction). The results from the ROI analysis did not align with these findings at the statistically significant level after multiple corrections. Changes in cortical thickness were not correlated with social anxiety symptoms. While consistent results were not obtained from different analysis methods, the results from the whole-brain analysis suggest that patients with SAD exhibit distinct neural deficits in areas involved in salience, attention, and socioemotional processing.

Effect of immersive virtual mirror visual feedback on Mu suppression and coherence in motor and parietal cortex in stroke.

We investigated the activation pattern of the motor cortex (M1) and parietal cortex during immersive virtual reality (VR)-based mirror visual feedback (MVF) of the upper limb in 14 patients with chronic stroke and severe upper limb hemiparesis and in 21 healthy controls. Participants performed wrist extension with unaffected wrists (dominant side in controls). In the MVF condition, movement of the affected hand was synchronized with that of the unaffected hand. In the no-MVF condition, only the movement of unaffected hand was shown. Mu suppression in bilateral M1 and parietal cortex and mu coherence were analyzed. In patients with stroke, MVF induced significant mu suppression in both the ipsilesional M1 and parietal lobes (p = 0.006 and p = 0.009, respectively), while mu suppression was observed in the bilateral M1 (p = 0.003 for ipsilesional and p = 0.041 for contralesional M1, respectively) and contralesional parietal lobes in the controls (p = 0.036). The ipsilesional mu coherence between the M1 and parietal cortex in patients with stroke was stronger than controls, regardless of MVF condition (p < 0.001), while mu coherence between interhemispheric M1 cortices was significantly weaker in patients with stroke (p = 0.032). Our findings provide evidence of the neural mechanism of MVF using immersive VR in patients with stroke.

Attentional State-Dependent Peripheral Electrical Stimulation During Action Observation Enhances Cortical Activations in Stroke Patients.

Brain-computer interface (BCI) is a promising technique that enables patients' interaction with computers or machines by analyzing specific brain signal patterns and provides patients with brain state-dependent feedback to assist in their rehabilitation. Action observation (AO) and peripheral electrical stimulation (PES) are conventional methods used to enhance rehabilitation outcomes by promoting neural plasticity. In this study, we assessed the effects of attentional state-dependent feedback in the combined application of BCI-AO with PES on sensorimotor cortical activation in patients after stroke. Our approach involved showing the participants a video with repetitive grasping actions under four different tasks. A mu band suppression (8-13 Hz) corresponding to each task was computed. A topographical representation showed that mu suppression of the dominant (healthy) and affected hemispheres (stroke) gradually became prominent during the tasks. There were significant differences in mu suppression in the affected motor and frontal cortices of the stroke patients. The involvement of both frontal and motor cortices became prominent in the BCI-AO+triggered PES task, in which feedback was given to the patients according to their attentive watching. Our findings suggest that synchronous stimulation according to patient attention is important for neurorehabilitation of stroke patients, which can be achieved with the combination of BCI-AO feedback with PES. BCI-AO feedback combined with PES could be effective in facilitating sensorimotor cortical activation in the affected hemispheres of stroke patients.

Brain-computer interface-based action observation combined with peripheral electrical stimulation enhances corticospinal excitability in healthy subjects and stroke patients.

Objective.Action observation (AO) combined with brain-computer interface (BCI) technology enhances cortical activation. Peripheral electrical stimulation (PES) increases corticospinal excitability, thereby activating brain plasticity. To maximize motor recovery, we assessed the effects of BCI-AO combined with PES on corticospinal plasticity.Approach.Seventeen patients with chronic hemiplegic stroke and 17 healthy subjects were recruited. The participants watched a video of repetitive grasping actions with four different tasks for 15 min: (A) AO alone; (B) AO + PES; (C) BCI-AO + continuous PES; and (D) BCI-AO + triggered PES. PES was applied at the ulnar nerve of the wrist. The tasks were performed in a random order at least three days apart. We assessed the latency and amplitude of motor evoked potentials (MEPs). We examined changes in MEP parameters pre-and post-exercise across the four tasks in the first dorsal interosseous muscle of the dominant hand (healthy subjects) and affected hand (stroke patients).Main results.The decrease in MEP latency and increase in MEP amplitude after the four tasks were significant in both groups. The increase in MEP amplitude was sustained for 20 min after tasks B, C, and D in both groups. The increase in MEP amplitude was significant between tasks A vs. B, B vs. C, and C vs. D. The estimated mean difference in MEP amplitude post-exercise was the highest for A and D in both groups.Significance.The results indicate that BCI-AO combined with PES is superior to AO alone or AO + PES for facilitating corticospinal plasticity in both healthy subjects and patients with stroke. Furthermore, this study supports the idea that synchronized activation of cortical and peripheral networks can enhance neuroplasticity after stroke. We suggest that the BCI-AO paradigm and PES could provide a novel neurorehabilitation strategy for patients with stroke.

Distraction Classification During Target Tracking Tasks Involving Target and Cursor Flickering Using EEGNet.

Keeping patients from being distracted while performing motor rehabilitation is important. An EEG-based biofeedback strategy has been introduced to help encourage participants to focus their attention on rehabilitation tasks. Here, we suggest a BCI-based monitoring method using a flickering cursor and target that can evoke a steady-state visually evoked potential (SSVEP) using the fact that the SSVEP is modulated by a patient's attention. Fifteen healthy individuals performed a tracking task where the target and cursor flickered. There were two tracking sessions, one with and one without flickering stimuli, and each session had four conditions in which each had no distractor (non-D), a visual (vis-D) or cognitive distractor (cog-D), and both distractors (both-D). An EEGNet was trained as a classifier using only non-D and both-D conditions to classify whether it was distracted and validated with a leave-one-subject-out scheme. The results reveal that the proposed classifier demonstrates superior performance when using data from the task with the flickering stimuli compared to the case without the flickering stimuli. Furthermore, the observed classification likelihood was between those corresponding to the non-D and both-D when using the trained EEGNet. This suggests that the classifier trained for the two conditions could also be used to measure the level of distraction by windowing and averaging the outcomes. Therefore, the proposed method is advantageous because it can reveal a robust and continuous level of patient distraction. This facilitates its successful application to the rehabilitation systems that use computerized technology, such as virtual reality to encourage patient engagement.

Usefulness of electronic stimulation in restless legs syndrome: a pilot study.

PURPOSE: This study aims to investigate the effect of electronic stimulation (ES) as a non-pharmacological treatment in restless legs syndrome (RLS). METHODS: This is a randomized, single-blind study. A total of 46 patients were included, consisting of an active group and a sham group with 22 and 24 members, respectively. The stimulation was administered to bilateral lower legs using the tapping mode (3 Hz) on a handheld ES device, and symptom changes were measured in both groups. The effects of the stimuli were analyzed with repeated measures ANOVA. RESULTS: The symptom severity was significantly reduced in the active group, and showed significant interaction effects in the time * group (F = 4.441, p = 0.031). Although both the active and sham groups reported improved symptoms upon receiving longer periods of treatment, the effect of the ES was greater in the active group. CONCLUSIONS: ES treatment resulted in symptom improvement when using ideal levels of stimulation intensity. ES can be considered as a non-pharmacological treatment option for RLS.

Superior Facilitation of an Action Observation Network by Congruent Character Movements in Brain-Computer Interface Action-Observation Games.

Action observation (AO) is a promising strategy for promoting motor function in neural rehabilitation. Recently, brain-computer interface (BCI)-AO game rehabilitation, which combines AO therapy with BCI technology, has been introduced to improve the effectiveness of rehabilitation. This approach can improve motor learning by providing feedback, which can be interactive in an observation task, and the game contents of the BCI-AO game paradigm can affect rehabilitation. In this study, the effects of congruent rather than incongruent feedback in a BCI-AO game on mirror neurons were investigated. Specifically, the mu suppression with congruent and incongruent BCI-AO games was measured in 17 healthy adults. The mu suppression in the central motor cortex was significantly higher with the congruent BCI-AO game than with the incongruent one. In addition, the satisfaction evaluation results were excellent for the congruent case. These results support the fact that providing feedback congruent with the motion of an action video facilitates mirror neuron activity and can offer useful guidelines for the design of BCI-AO games for rehabilitation.

Clinical Application of Virtual Reality for Upper Limb Motor Rehabilitation in Stroke: Review of Technologies and Clinical Evidence.

Neurorehabilitation for stroke is important for upper limb motor recovery. Conventional rehabilitation such as occupational therapy has been used, but novel technologies are expected to open new opportunities for better recovery. Virtual reality (VR) is a technology with a set of informatics that provides interactive environments to patients. VR can enhance neuroplasticity and recovery after a stroke by providing more intensive, repetitive, and engaging training due to several advantages, including: (1) tasks with various difficulty levels for rehabilitation, (2) augmented real-time feedback, (3) more immersive and engaging experiences, (4) more standardized rehabilitation, and (5) safe simulation of real-world activities of daily living. In this comprehensive narrative review of the application of VR in motor rehabilitation after stroke, mainly for the upper limbs, we cover: (1) the technologies used in VR rehabilitation, including sensors; (2) the clinical application of and evidence for VR in stroke rehabilitation; and (3) considerations for VR application in stroke rehabilitation. Meta-analyses for upper limb VR rehabilitation after stroke were identified by an online search of Ovid-MEDLINE, Ovid-EMBASE, the Cochrane Library, and KoreaMed. We expect that this review will provide insights into successful clinical applications or trials of VR for motor rehabilitation after stroke.

Deactivation of anterior cingulate cortex during virtual social interaction in obsessive-compulsive disorder.

Studies about social functioning in obsessive-compulsive disorder (OCD) are lacking, even though neuroimaging studies and metacognition evaluation results suggest abnormal neural responses during social interactions. This study examined neural responses of OCD patients during handshakes with a virtual avatar. Because of the nature of the handshaking task, we expected that OCD patients with predominantly contamination/washing symptoms (CON) would show different neural responses compared to healthy controls (HCs) and to disease-controlled (NCON) patients. Thirteen CON, 13 NCON, and 18 HC participants performed handshake tasks with clean or dirty virtual avatars while undergoing functional magnetic resonance imaging. During handshakes with a clean avatar, deactivation in the left anterior cingulate cortex was found in CON patients compared to NCON and HC subjects. This cortical deactivation also occurred with dirty-avatar handshakes, but the difference was significant only between the two OCD groups and HC patients. Deactivation in the left anterior cingulate cortex was correlated with both OCD symptom severity and social anxiety traits. This cortical deactivation in OCD, especially in CON patients, suggests that social dysfunction in OCD may be due to interactions between OCD symptoms and impairment in social cognition, including emotional processing.

Transcranial Direct Current Stimulation Effect on Virtual Hand Illusion.

Virtual reality (VR) is effectively used to evoke the mirror illusion, and transcranial direct current stimulation (tDCS) synergistically facilitates this illusion. This study investigated whether a mirror virtual hand illusion (MVHI) induced by an immersive, first-person-perspective, virtual mirror system could be modulated by tDCS of the primary motor cortex. Fourteen healthy adults (average age 21.86 years ±0.47, seven men and seven women) participated in this study, and they experienced VR with and without tDCS-the tDCS and sham conditions, each of which takes ∼30 minutes-on separate days to allow the washout of the tDCS effect. While experiencing VR, the movements of the virtual left hand reflected the flexion and extension of the real right hand. Subsequently, electroencephalogram was recorded, the magnitude of the proprioceptive shift was measured, and the participants provided responses to a questionnaire regarding hand ownership. A significant difference in the proprioceptive shift was observed between the tDCS and sham conditions. In addition, there was significant suppression of the mu power in Pz, and augmentation of the beta power in the Pz, P4, O1, and O2 channels. The difference in proprioceptive deviation between the two conditions showed significant negative correlation with mu suppression over the left frontal lobe in the tDCS condition. Finally, the question "I felt that the virtual hand was my own hand" received a significantly higher score under the tDCS condition. In short, applying tDCS over the motor cortex facilitates the MVHI by activating the attentional network over the parietal and frontal lobes such that the MVHI induces more proprioceptive drift, which suggests that the combination of VR and tDCS can enhance the immersive effect in VR. This result provides better support for the use of the MVHI paradigm in combination with tDCS for recovery from illnesses such as stroke.

Development of a flickering action video based steady state visual evoked potential triggered brain computer interface-functional electrical stimulation for a rehabilitative action observation game.

BACKGROUND: This study focused on developing an upper limb rehabilitation program. In this regard, a steady state visual evoked potential (SSVEP) triggered brain computer interface (BCI)-functional electrical stimulation (FES) based action observation game featuring a flickering action video was designed. OBJECTIVE: In particular, the synergetic effect of the game was investigated by combining the action observation paradigm with BCI based FES. METHODS: The BCI-FES system was contrasted under two conditions: with flickering action video and flickering noise video. In this regard, 11 right-handed subjects aged between 22-27 years were recruited. The differences in brain activation in response to the two conditions were examined. RESULTS: The results indicate that T3 and P3 channels exhibited greater Mu suppression in 8-13 Hz for the action video than the noise video. Furthermore, T4, C4, and P4 channels indicated augmented high beta (21-30 Hz) for the action in contrast to the noise video. Finally, T4 indicated suppressed low beta (14-20 Hz) for the action video in contrast to the noise video. CONCLUSION: The flickering action video based BCI-FES system induced a more synergetic effect on cortical activation than the flickering noise based system.

Alterations in Salience Network Functional Connectivity in Individuals with Restless Legs Syndrome.

BACKGROUND AND PURPOSE: Restless legs syndrome (RLS) is a neurological disorder which is most commonly identified by an urge to move the legs. It often shows alterations in sensory processing which implies the salience network (SN) is experiencing changes. This study investigates the functional connectivity (FC) between the SN and other areas of the brain in RLS patients during the resting state period. METHODS: Thirty patients with drug naïve idiopathic RLS and 30 healthy age and gender matched controls were included in this study. Resting state fMRIs were performed in the morning during the asymptomatic period. The SN comparisons were conducted between the two groups. RESULTS: The RLS group showed a reduction in SN FC in the right pyramis, and an increase in SN FC in the bilateral orbitofrontal gyri and right postcentral gyrus. CONCLUSIONS: The results of this study give reason to believe that SN FC in RLS patients is altered during asymptomatic periods. This could have an influence on the processing of the saliency of information, particularly sensory information processing and inhibition mechanisms.

Resting-state connectivity and the effects of treatment in restless legs syndrome.

OBJECTIVES: Resting-state brain connectivity has been shown to differ for Restless Legs Syndrome (RLS) compared to healthy control (CON) groups. This study evaluates the degree these RLS-CON differences are changed by concurrent treatment. METHODS: Resting-state functional MRIs were obtained from 32 idiopathic RLS patients during the morning asymptomatic period and 16 age and gender-matched CON subjects. Of the 32 RLS patients, 16 were drug-naïve (DN-RLS), and 16 were regularly drug-treated using a dopamine agonist (DT-RLS). Various assessments of disease characteristics were also performed. The primary purpose was to assess the replicability of prior results and the effects of treatment on these differences between controls and untreated RLS patients. Resting-state connectivity was analyzed by a seed-based method using the bilateral ventral-posterolateral nuclei (VPLN) in the thalamus. RESULTS: In the DN-RLS group, compared to the CON group, three areas (the bilateral lingual gyri and right middle temporal gyrus) were replicated. The three replicated areas did not significantly differ for DT-RLS compared to DN-RLS. DT-RLS compared to DN-RLS had significantly higher thalamic connectivity for the left uvula, right tuber, left anterior insula, and right declive. CONCLUSIONS: Thalamic connectivity to the bilateral lingual gyri and right middle temporal gyrus is a replicable finding in DN-RLS that was not affected by dopamine agonist treatments. Other changes in thalamic connectivity were altered by dopamine agonist treatment. These treatment effects may be pertinent to the known treatment benefits of a dopamine agonist on RLS symptoms.

Multiple-command single-frequency SSVEP-based BCI system using flickering action video.

BACKGROUND: The number of commands in a brain-computer interface (BCI) system is important. This study proposes a new BCI technique to increase the number of commands in a single BCI system without loss of accuracy. NEW METHOD: We expected that a flickering action video with left and right elbow movements could simultaneously activate the different pattern of event-related desynchronization (ERD) according to the video contents (e.g., left or right) and steady-state visually evoked potential (SSVEP). The classification accuracy to discriminate left, right, and rest states was compared under the three following feature combinations: SSVEP power (19-21 Hz), Mu power (8-13 Hz), and simultaneous SSVEP and Mu power. RESULTS: The SSVEP feature could discriminate the stimulus condition, regardless of left or right, from the rest condition, while the Mu feature discriminated left or right, but was relatively poor in discriminating stimulus from rest. However, combining the SSVEP and Mu features, which were evoked by the stimulus with a single frequency, showed superior performance for discriminating all the stimuli among rest, left, or right. COMPARISON WITH THE EXISTING METHOD: The video contents could activate the ERD differently, and the flickering component increased its accuracy, such that it revealed a better performance to discriminate when considering together. CONCLUSIONS: This paradigm showed possibility of increasing performance in terms of accuracy and number of commands with a single frequency by applying flickering action video paradigm and applicability to rehabilitation systems used by patients to facilitate their mirror neuron systems while training.

Three-Dimensional Augmented Reality System for Balance and Mobility Rehabilitation in the Elderly: A Randomized Controlled Trial.

We attempted to evaluate the clinical efficiency of a novel three-dimensional interactive augmented reality system (3D-ARS) for balance and mobility rehabilitation. This system enables participant training with a realistic 3D interactive balance exercise and assessing movement parameters and joint angles by using a kinetic sensor system. We performed a randomized controlled trial in a general hospital. Thirty-six participants (age, 56-76 years) who could independently walk and stand on one leg were recruited. The participants were randomly assigned to either group. The control group (n = 18) underwent a conventional physical fitness program such as lower-extremity strengthening and balance training thrice per week for 1 month. The experimental group (n = 18) experienced 3D-ARS training thrice per week (1 session = 30 minutes) for 4 weeks. Training comprised a balloon game for hip exercise, cave game for knee exercise, and rhythm game for one-leg balance exercise. Lower-extremity clinical scale scores, fall index, and automatic balance score were measured by using Tetrax® posturography before, during, and after training. Significant group (3D-ARS vs. control) × time (before and after exercise) interaction effect was observed for Berg balance scale (BBS) scores (p = 0.04) and timed-up-and-go (TUG; p < 0.001). Overall improvements occurred in stability index, weight distribution index, fall risk index, and Fourier transformations index of posturography for both groups. However, score changes were significantly greater in the 3D-ARS group. Significant group × time interaction effect was observed for the fall risk index. This demonstrates that the 3D-ARS system can improve balance in the elderly more effectively.

A Brain-Computer Interface-Based Action Observation Game That Enhances Mu Suppression.

Action observation training based on the theory of activation of the mirror-neuron system has been used for the rehabilitation of patients with stroke. In this paper, we sought to assess whether a brain-computer interface (BCI)-based action observation rehabilitation game, using a flickering action video, could preferentially activate the mirror-neuron system. Feedback of stimulus observation, evoked by the flickering action video, was provided using steady state visually evoked potential and event-related desynchronization. Fifteen healthy subjects have experienced the game with BCI interaction (game and interaction), without BCI interaction (game without interaction), observed non-flickering stimuli, and flickering stimuli without the game background (stimuli only) in a counter-balanced order. The game and interface condition was resulted in significantly stronger activation of the mirror-neuron system than did the other three conditions. In addition, the amount of mirror-neuron system activation is gradually decreased in the game without interface, non-flickering stimuli, and stimuli only conditions in a time-dependent manner; however, in the game and interface condition, the amount of mirror-neuron system activation was maintained until the end of the training. Taken together, these data suggest that the proposed game paradigm, which integrates the action observation paradigm with BCI technology, could provide interactive responses for whether watching video clips can engage patients and enhance rehabilitation.

Mobile Game Induces Active Engagement on Neuromuscular Electrical Stimulation Training in Patients with Stroke.

This study aimed to investigate the effectiveness of the mobile game-based neuromuscular electrical stimulation (MG-NMES) with assessing usability issues, such as attention and curiosity, and intrinsically interesting issues, which is necessary for successful poststroke rehabilitation. With the conventional NMES (C-NMES) system, the subjects underwent active repetitive cyclic NMES training. For assessment of usability issues, 20 hemiplegic stroke subjects were randomly divided into two groups. The subjects in the MG-NMES group (n = 9) and C-NMES group (n = 11) underwent 20 minutes of training each day for 5 days. We assessed the subjects' attention, curiosity, and intrinsically interesting issues; and using questionnaires they answered questions regarding their expectations of the training outcome after each training session. We found that the subjects in the MG-NMES group maintained their attention and interest for the 5 days, and their curiosity and expectation of a positive training outcome gradually increased as the training proceeded. In contrast, the C-NMES group reported no change in their attention or curiosity, but it was lower than the subjects in the MG-NMES group. In addition, their interest gradually decreased, which may have reduced their expectations of a positive outcome as the sessions progressed. There were no side effects during the training sessions in either group. The MG-NMES training paradigm developed is a new, readily available, and highly motivating MG-NMES training system. Based on the usability test, the reported advantages of the system were improved attention and flow experience during NMES training.

Diurnal variation of default mode network in patients with restless legs syndrome.

OBJECTIVE: Restless legs syndrome (RLS) patients compared to controls have been found to have abnormal patterns in the default mode network (DMN) in the morning when symptom threshold is the highest and symptoms are least likely to occur. If these morning abnormalities in DMN are pertinent to disease expression, then similar or further detectable differences may be expected on a nighttime assessment when RLS symptom threshold is at its lowest. The purpose of this study was to elucidate the potential neural mechanisms underlying the circadian aspect of RLS symptom expression by assessing diurnal changes in DMN. METHODS: Fifteen drug-naïve subjects with idiopathic RLS and 15 age- and gender-matched healthy subjects had fMRI scans in the morning and evening. The DMN patterns were compared both for differences between morning and evening and between RLS and controls. RESULTS: RLS patients compared to the healthy controls showed significant differences in morning and evening DMN. In particular, RLS patients showed consistent increased connectivity in the parietal lobule in both the morning and evening. In contrast, connectivity in the thalamus was increased in the morning and reduced in the evening. In addition, there were negative correlations between thalamic connectivity and the Korean versions of the international RLS scale and the quality-of-life subscore. CONCLUSIONS: The results indicated diurnal disturbances of the DMN in RLS subjects are consistent with both the circadian rhythm and severity of RLS. The circadian expression of RLS may relate to changes in arousal cortical-activation thresholds occurring with diurnal changes in the thalamic circuits of the DMN.

The left middle temporal gyrus in the middle of an impaired social-affective communication network in social anxiety disorder.

BACKGROUND: Previous studies on patients diagnosed with social anxiety disorder (SAD) reported changed patterns of the resting-state functional connectivity network (rs-FCN) between the prefrontal cortices and other prefrontal, amygdalar or striatal regions. Using a graph theory approach, this study explored the modularity-based community profile and patterns of inter-/intra-modular communication for the rs-FCN in SAD. METHODS: In total, for 28 SAD patients and 27 healthy controls (HC), functional magnetic resonance imaging (fMRI) data were acquired in resting-state and subjected to a graph theory analysis. RESULTS: The within-module degree z-score for a hub region [out of a total of 10 hub regions ranked using the participation coefficient] named left middle temporal gyrus was impaired in SAD compared to HC, proportional to the severity of clinician-scored and patient-reported functional impairment in SAD. LIMITATIONS: Most of participants included in this study were undergraduate students in their early-to-mid 20's. CONCLUSIONS: This study showed the importance of functional communication from the left middle temporal gyrus with other opercular-insular-subcortical regions for better objective functioning and lesser subjective disability in SAD.