Eyes-open Conditions Research Articles

Modular brain network in volitional eyes closing: enhanced integration with a marked impact on hubs.

Volitional eyes closing would shift brain's information processing modes from the "exteroceptive" to "interoceptive" state. This transition induced by the eyes closing is underpinned by a large-scale reconfiguration of brain network, which is still not fully comprehended. Here, we investigated the eyes-closing-relevant network reconfiguration by examining the functional integration among intrinsic modules. Our investigation utilized a publicly available dataset with 48 subjects being scanned in both eyes closed and eyes open conditions. It was found that the modular integration was significantly enhanced during the eyes closing, including lower modularity index, higher participation coefficient, less provincial hubs, and more connector hubs. Moreover, the eyes-closing-enhanced integration was particularly noticeable in the hubs of network, mainly located in the default-mode network. Finally, the hub-dominant modular enhancement was positively correlated to the eyes-closing-reduced entropy of BOLD signal, suggesting a close connection to the diminished consciousness of individuals. Collectively, our findings strongly suggested that the enhanced modular integration with substantially reorganized hubs characterized the large-scale cortical underpinning of the volitional eyes closing.

Cognitive analysis based on EEG measurements on children with stunting-indicated in East Nusa Tenggara

Children with stunting have been associated with delayed brain development and poor cognitive performance by a lack of attentional control. The aim of the present study was to determine characteristics of stunting children based on theta (4-8 Hz), alpha (8-12 Hz) and beta (12-30 Hz) oscillation at anterofrontal (AF) and temporoparietal (TP). This research involved two groups: Stunting Group (SG, N=14) and Control Group (C; N=8) from East Nusa Tenggara. EEG was recorded during an eyes-open condition at baseline and puzzle task. Our result revealed alteration of theta oscillation in SG AF8 and TP10 during puzzle task, supporting role of theta oscillation in higher working memory loads although it was not accompanied by proper TP connectivity. Higher alpha and beta AF7 activity in SG compared to control group implying decreasing attentional processing and higher arousal. According to Laterality Index (LI), we revealed alteration in temporoparietal SG during puzzle task. These findings provide new insights about theta, alpha, and beta oscillation in stunting children may reflect that declining attentional functioning during the puzzle task leads to poor cognitive performance.

Poor reactivity of posterior electroencephalographic alpha rhythms during the eyes open condition in patients with dementia due to Parkinson’s disease

Here, we hypothesized that the reactivity of posterior resting-state electroencephalographic (rsEEG) alpha rhythms during the transition from eyes-closed to -open condition might be lower in patients with Parkinson’s disease dementia (PDD) than in patients with Alzheimer’s disease dementia (ADD). A Eurasian database provided clinical-demographic-rsEEG datasets in 73 PDD patients, 35 ADD patients, and 25 matched cognitively unimpaired (Healthy) persons. The eLORETA freeware was used to estimate cortical rsEEG sources. Results showed substantial (greater than −10%) reduction (reactivity) in the posterior alpha source activities from the eyes-closed to the eyes-open condition in 88% of the Healthy seniors, 57% of the ADD patients, and only 35% of the PDD patients. In these alpha-reactive participants, there was lower reactivity in the parietal alpha source activities in the PDD group than in the healthy control seniors and the ADD patients. These results suggest that PDD patients show poor reactivity of mechanisms desynchronizing posterior rsEEG alpha rhythms in response to visual inputs. That neurophysiological biomarker may provide an endpoint for (non) pharmacological interventions for improving vigilance regulation in those patients.

High-beta oscillations at EEG resting state and hyperconnectivity of pain circuitry in fibromyalgia: an exploratory cross-sectional study

BackgroundElectroencephalography (EEG) has identified neural activity in specific brain regions as a potential indicator of the neural signature of chronic pain. This study compared the lagged coherence connectivity between regions of interest (ROIs) associated with the pain connectome in women with fibromyalgia (FM) and healthy women (HC).MethodsWe evaluated 64 participants (49 FM and 15 HC) during resting-state EEG sessions under both eyes open (EO) and eyes closed (EC) conditions. In addition to EEG measurements, we assessed clinical and psychological symptoms and serum levels of brain-derived neurotrophic factor (BDNF). The connectivity between eight ROIs was computed across eight different EEG frequencies.ResultsThe FM group demonstrated increased connectivity between the left dorsolateral prefrontal cortex (DLPFC) and right anterior cingulate cortex (ACC), specifically in the beta-3 frequency band (t = 3.441, p = 0.044). When comparing the EO and EC conditions, FM patients exhibited heightened interhemispheric connectivity between insular areas (t = 3.372, p = 0.024) and between the left insula (INS) and right DLPFC (t = 3.695, p = 0.024) within the beta-3 frequency band. In the EC condition, there was a negative correlation between pain disability and connectivity in the beta-3 frequency band between the left ACC and the left primary somatosensory cortex (SI; r = −0.442, p = 0.043). In the EO condition, there was a negative correlation between central sensitization severity and lagged coherence connectivity in the alpha-2 frequency band between the right ACC and left SI (r = 0.428, p = 0.014). Moreover, in the EO–EC comparison, the lagged coherence connection between the left DLPFC and right INS, indexed by the gamma frequency band, showed a negative correlation with serum BDNF levels (r = −0.506, p = 0.012).ConclusionThese findings indicate that increased connectivity between different pain processing circuits, particularly in the beta-3 frequency band during rest, may serve as neural biomarkers for the chronic pain brain signature associated with neuroplasticity and the severity of FM symptoms.

Neuromodulatory effects of high-definition theta transcranial alternating current stimulation on the parietal cortex: a pilot study of healthy males.

Transcranial alternating current stimulation (tACS) can regulate brain functions by modulating endogenous brain rhythms. Theta-band neural oscillations are associated with memory function. In particular, theta neural oscillatory power evoked in the parietal cortex is closely related to memory retrieval processes. In this study, the immediate effects of high-definition theta transcranial alternating current stimulation (HDθ-tACS) on the human left parietal cortex were investigated using short-latency afferent inhibition (SAI) and electroencephalography (EEG). Ten subjects participated in this study. We used 6-Hz HD tACS to stimulate the left parietal cortex for 15 min. SAI was calculated, and non-linear dynamic analysis of the EEG was performed to analyze neuronal function after HD θ-tACS. The results showed a significant decrease in SAI (p < 0.05), while the left frontoparietal network was reinforced, leading to brain lateralization after HD θ-tACS. During performance of a memory task, F3 signals showed a significant upward trend in approximate entropy following treatment (p < 0.05). There was also a significant decrease in cross-approximate entropy in the C3-C4 and P3-P4 connections following the intervention (p < 0.05) in a resting eyes-open condition and in the memory task condition. In conclusion, HD θ-tACS could alter cholinergic transmission and cortical excitability between the parietal and motor cortices, as well as reinforcing the frontoparietal network and the left-lateralization phenomenon, which may facilitate memory formation, encoding, and consolidation.

Correlation of balance posturographic parameters during quiet standing with the berg balance scale in patients with parkinson’s disease

BackgroundParkinson’s disease (PD) is often clinically associated with posture instability and more easily falling. The Berg balance scale is a clinical indicator commonly used to subjectively evaluate a patient’s balance ability. Meanwhile, computerized force platforms have been used in research on postural control. The various parameters obtained from posturography are interpreted to assess balance ability. The present study aims to explore the correlations between posturographic variables and the BBS, and furthermore to efficiently evaluate postural instability and fall risk of early and moderate PD patients.MethodsA total of 46 PD patients were involved in the experiment. Patients were asked to perform BBS tests and force platform tests under eye open (EO) and eye closed (EC) conditions. The recorded COP signal was analyzed with the time domain statistical method, the frequency domain method of Power Spectral Density (PSD), and structural methods of Stabilogram Diffusion Analysis (SDA), Sway Density Plot (SDP) to retrieve different posturographic variables. The correlation between posturographic variables under EO and EC conditions with BBS was compared statistically. The significantly correlated posturographic parameters were then applied to analyze posturographic differences between different groups: faller vs. non-faller (patients with/without a history of falls in the past 12 months).ResultsAmong the different posturographic parameters, the prediction ellipse area, the slope of the regression line at a high-frequency band of PSD in the medial-lateral (ML) direction, the crossover point of the regression lines of SDA in the anterior-posterior (AP) direction, and the distance between successive peaks of SDP had significant correlations with BBS. These selected BBS-related parameters also showed significant differences between faller and non-faller. The selected posturographic parameters can be used as effective indicators to evaluate the balance ability of Parkinson’s disease patients.

Food-induced brain activity in adult obesity: a quantitative electroencephalographic study

BACKGROUND Obesity may be associated with declined food consumption control through neurological and behavioral processes, as well as heightened responsiveness of the brain’s reward systems. Performing neuroimaging and neurophysiological methods such as electroencephalography (EEG) can examine the connection between brain function and behavior. This study aimed to identify brain regulation of feeding behavior to food cues, which could be a potential neuromodulatory intervention target in adult obesity.&#x0D; METHODS This cross-sectional study was conducted at Cipto Mangunkusumo Hospital, Jakarta, involving 40 adults with obesity. EEG analysis was performed to measure electrophysiological brain activity during eyes-open condition and during exposure to high-calorie food cues. Student’s t-tests were performed to identify any significant differences between the groups (p&lt;0.05).&#x0D; RESULTS Beta waves in the frontal (channel F7) and gamma waves in the central (channels C3 and C4) and parietal (channels P3 and P4) regions were significantly increased during food cues compared to resting state/eyes-open condition without stimulation. Theta waves in the frontal (channels F7 and F8), central (channel C3), and parietal (channels P3 and P4) regions and alpha waves in the central (channels C3 and C4) and parietal (channels P3 and P4) regions were significantly decreased during food cues compared with resting state.&#x0D; CONCLUSIONS In adults with obesity, increased beta activity in the frontal and gamma in the central and parietal regions suggested increased food-cue awareness and heightened attentional focus toward food stimuli. Additionally, decreased alpha and theta activities in frontal regions could underline deficits in executive functions and higher motivation.

The Experience of Meaningful Coincidences Is Associated with Stronger Alpha Power Increases during an Eyes-closed Resting Condition: A Bayesian Replication Approach.

Recognizing and perceiving meaningful patterns in an ever-changing environment is fundamental to (human) beings. Apophenia, patternicity, and the propensity to perceive meaningful coincidences might result from the human brain working as a prediction machine that constantly matches sensory information to prior expectations. The propensity for Type I errors varies between people and, at its extreme, is associated with symptoms of schizophrenia. However, on a nonclinical level seeing meaning in randomness might be benevolent and was found to be associated with creativity and openness. However, hardly any neuroscientific investigation has examined EEG patterns of the propensity to experience meaningful coincidences in this manner. We hypothesized deviations in brain functions as one potential reason why some people experience more meaning in random arrangements than others. The gating by inhibition theory suggests that alpha power increases represent basic control mechanisms of sensory processes during varying task requirements. We found that people perceiving more meaningful coincidences had higher alpha power during an eyes-closed versus eyes-opened condition compared with people experiencing less meaningful coincidences. This indicates deviations in the sensory inhibition mechanism of the brain, which are critically relevant for higher cognitive functions. Applying Bayesian statistics, we replicated this finding in another independent sample.

Influence of age on static postural control in adults with type 2 diabetes mellitus: a cross-sectional study.

It was the aim of this study to assess static postural control characteristics in people with type 2 diabetes mellitus (T2D) of different ages using a force platform. A relationship was also established between static postural control parameters and age in this study. A total of 706 participants with T2D were included in this study. The participants were stratified into three age groups: Group 1 (<60 years old), Group 2 (60-70 years old), and Group 3 (>70 years old). Static postural control assessment during two-leg stance was performed on a force platform by all participants. The center of pressure (CoP)-related parameters were measured under two stance conditions (eyes open and closed). Kruskal-Wallis tests were applied to explore the difference among the different age groups. Multivariate regression analysis was performed to determine the relation between age and static postural control parameters. Group 1 (<60 years old) had significantly less CoP total tracking length (TTL), sway area (SA), and CoP velocity along the Y direction (V-Y) under both eyes-open and eyes-closed conditions compared with Group 2 (60-70 years old) and Group 3 (>70 years old). Group 1 (<60 years old) had significantly less CoP maximum sway length along the X direction (MSL_X) and longer tracking length each area unit (TTL/SA) under the eyes-open condition compared with Group 2 (60-70 years old) and Group 3 (>70 years old). There was a significantly positive correlation between age and the most static postural parameters such as CoP TTL, SA, MSL-X, MSL-Y, and V-Y. There was a significantly negative correlation between age and TTL/SA. This study suggested that older T2D participants had worse static postural control ability than younger ones. Most static postural parameters presented a significant correlation with age; the higher the age, the worse the static postural control.

Resting-state EEG alpha rhythm spectral power in children with specific language impairment: a cross-sectional study.

This study investigated EEG alpha rhythm spectral power in children with Specific Language Impairment (SLI) and compared it to typically developing children to better understand the electrophysiological characteristics of this disorder. Specifically, we explored resting-state EEG, because there are studies that point to it being linked to speech and language development. EEG recordings of 30 children diagnosed with specific language impairment and 30 typically developing children, aged 4.0-6.11 years, were carried out under eyes closed and eyes open conditions. Differences in alpha rhythm spectral power in relation to brain topography and experimental conditions were calculated. In the eyes closed condition, alpha rhythm spectral power was statistically significantly lower in children with specific language impairment in the left temporal (T5) and occipital electrodes (O1, O2) than in typically developing children. In the eyes open condition, children with SLI showed significantly lower alpha rhythm spectral power in the left temporal (T3, T5), parietal (P3, Pz), and occipital electrodes (O1, O2). There were no statistically significant differences between the groups in relation to the relative change (the difference between average alpha rhythm spectral power during eyes closed condition and average alpha rhythm spectral power during eyes open condition divided by average alpha rhythm spectral power during eyes closed condition) in the alpha rhythm spectral power between the conditions. Lower alpha rhythm spectral power in the left temporal, left, midline parietal, and occipital brain regions could be a valuable electrophysiological marker in children with SLI. Further investigation is needed to examine the connection between EEG alpha spectral power and general processing and memory deficits in patients with SLI.

Short-Term Cast Immobilization of a Unilateral Lower Extremity and Physical Inactivity Induce Postural Instability during Standing in Healthy Young Men.

Previous studies have reported an increased postural sway after short-term unilateral lower limb movement restriction, even in healthy subjects. However, the associations of motion limitation have not been fully established. The question of whether short-term lower limb physical inactivity and movement restriction affect postural control in the upright position remains. One lower limb of each participant was fixed with a soft bandage and medical splint for 10 h while the participant sat on a manual wheelchair. The participants were instructed to stand still for 60 s under eyes-open (EO) and eyes-closed (EC) conditions. Using a single force plate signal, we measured the center of pressure (COP) signal in the horizontal plane and calculated the total, anterior-posterior (A-P), and medial-lateral (M-L) path lengths, sway area, and mean COP displacements in A-P and M-L directions. The COP sway increased and the COP position during the upright stance shifted from the fixed to the non-fixed side after cast removal, compared to before the cast application, under both EO and EC conditions. These findings indicated that 10 h of unilateral lower limb movement restriction induced postural instability and postural control asymmetry, suggesting the acute adverse effects of cast immobilization.

Prefrontal activation in response to a plantar contact task under open and closed eye conditions in patients with cerebral infarction.

This study investigates the effect of a bilateral (paralyzed side, healthy side) plantar contact task on dorsolateral prefrontal activation in patients recovering from cerebral infarction under open and closed eye conditions. We selected 10 patients with cerebral infarction, admitted to the neurorehabilitation center of Beijing Rehabilitation Hospital, affiliated with Capital Medical University, from January 2019 to July 2020, who met our established criteria. Under open-eye and closed-eye conditions, the paralyzed and healthy sides performed the plantar contact tasks separately. The dorsolateral prefrontal region was monitored simultaneously with functional near-infrared spectroscopy (fNIRS), and activation was analyzed according to the curve-type changes of oxyhemoglobin and deoxyhemoglobin changes in the dorsolateral prefrontal cortex with 560 near-infrared monitoring channels. After stratifying the data based on the eyes-open and eyes-closed conditions, some degree of heterogeneity was observed between the layers. Under the eyes-closed condition, the Pearson χ2 was 0.142, with a p value of 0.706, indicating no significant impact of the eyes-closed condition on the activation of the dorsolateral prefrontal cortex during the plantar task, whether performed on the paralyzed or the healthy side.In contrast, the Pearson χ2 value was 15.15 for the eyes-open condition, with a p value of 0.002. This suggests that carrying out the plantar task, either on the paralyzed or the healthy side, with eyes open significantly influenced the activation of the dorsolateral prefrontal cortex. Furthermore, activation of the dorsolateral prefrontal cortex was 1.55 times higher when the task was executed with the paralyzed side compared to the healthy side. This implies that the paralyzed side was more likely to activate the dorsolateral prefrontal lobe when performing the plantar contact task under eyes-open conditions. Observations via fNIRS revealed that the plantar contact task elicited dorsolateral prefrontal cortex activation. Moreover, the activation effect was intensified when performed on the paralyzed side under eyes-open conditions. Therapeutic methods that leverage these findings-namely cognitive-motor therapies that promote the recovery of motor functions by activating cognitive control brain regions via perception (information construction)-may hold promise.

Impact of five floor coverings on the orthostatic balance of healthy subjects.

Plantar skin sensitivity contributes to the regulation of postural control and, therefore, changing the characteristics of the plantar support surface can modify this control. This study aimed at assessing the impact of five different floor coverings on the orthostatic balance in 48 healthy subjects. Static posturography was performed with eyes open or closed on a platform in a control condition (no covering) and with five different covering surfaces: foam, silicone, ethyl vinyl acetate, and two textured mats with small (height 2mm) or large pimples (7mm). The average velocity of center of pressure (CoP) displacement was the primary endpoint measure and ten other posturographic variables were assessed. Comfort and pain produced by the covering were also scored. In eyes open condition, the average velocity of CoP displacement was increased when subjects stood on the foam mat, the silicone mat, and especially the textured mat with large pimples. Several other posturographic variables showed significant changes with different types of floor coverings with eyes open. These changes were not correlated to the comfort or pain scores associated with the different surfaces. In contrast, no difference was observed compared to the control condition (no covering) with eyes closed. This study shows that adding smooth or textured floor covering can alter balance in eyes open condition. In eyes closed condition, although more disturbing for balance, healthy subjects achieved better postural adaptation, probably by mobilizing more of their proprioceptive resources. This posturographic examination procedure could, therefore, be used to assess "proprioceptive reserve" capacities in clinical practice.

Introducing a New Mobile Electroencephalography System and Evaluating Its Quality in Comparison to Clinical Electroencephalography.

Electroencephalography (EEG) is a crucial tool in cognitive neuroscience, enabling the study of neurophysiological function by measuring the brain's electrical activity. Its applications include perception, learning, memory, language, decision making and neural network mapping. Recently, interest has surged in extending EEG measurements to domestic environments. However, the high costs associated with traditional laboratory EEG systems have hindered accessibility for many individuals and researchers in education, research, and medicine. To tackle this, a mobile-EEG device named "DreamMachine" was developed. A more affordable alternative to both lab-based EEG systems and existing mobile-EEG devices. This system boasts 24 channels, 24-bit resolution, up to 6 h of battery life, portability, and a low price. Our open-source and open-hardware approach empowers cognitive neuroscience, especially in education, learning, and research, opening doors to more accessibility. This paper introduces the DreamMachine's design and compares it with the lab-based EEG system "asalabTM" in an eyes-open and eyes-closed experiment. The Alpha band exhibited higher power in the power spectrum during eyes-closed conditions, whereas the eyes-open condition showed increased power specifically within the Delta frequency range. Our analysis confirms that the DreamMachine accurately records brain activity, meeting the necessary standards when compared to the asalabTM system.

The effect of visual deprivation on basic taste modalities

AbstractIn this pilot study, the effects of temporary visual deprivation on sensitivity to the basic tastes in normal sighted subjects were assessed. The sip‐and‐spit method to assess taste recognition thresholds was applied. The recognition thresholds of five basic tastes were assessed in two conditions: when the participants were blindfolded and when their blindfolds were removed and their eyes were open. In the blindfolded condition, the recognition threshold for sweet taste (saccharose) was lower than in the eyes open condition (means: 2.49 g/L vs. 3.80 g/L, p = .046). For bitter taste, a similar tendency was observed, but the difference did not reach statistical significance (means: 0.11 g/L vs. 0.13 g/L, p = .078). No difference in taste recognition thresholds between these two conditions were noted for salty, sour, and umami. Thus, the impact of temporary visual deprivation on taste experience seems stronger for sweet than for other taste modalities.Practical ApplicationsOur pilot study suggests potential applications, for example, re‐evaluating sugar content in foods served in dim/dark environments, like cinemas or blind cafés where food is consumed in total darkness. The sweet taste recognition threshold for saccharose being lower by 1.3 g/L in dark surroundings than in lit environments may become an incentive for beverages/snacks/desserts producers to lower sugar content. Coco‐Cola Original Taste has 10.6 g of sugar/100 mL, and a 1‐L Coca‐Cola serving (one of the cinema‐sized beverages) contains 106 g of sugar (22 teaspoons). An appropriate reduction of sugar in such beverages should not change their taste/palatability, and may benefit consumers and producers (Valicente et al., 2023, Journal of Sensory Studies, 38(1), e12803). For instance, Coca‐Cola/Coke is produced by mixing a relevant syrup with water and adding CO2 (Coca‐Cola Original Taste/Zero Sugar/Cherry, etc.); producing an additional syrup with lower than original sugar content seems feasible for a company regularly introducing new products to the market.

Do visual and step height factors cause imbalance during bipedal and unipedal stances? A plantar pressure perspective.

Objective: The plantar pressure analysis technique was used to explore the static balance ability and stability of healthy adult males under the influence of visual and step height factors during bipedal and unipedal stances. Methods: Thirty healthy adult males volunteered for the study. Experiments used the F-scan plantar pressure analysis insoles to carry out with eyes open (EO) and eyes closed (EC) at four different step heights. The plantar pressure data were recorded for 10s and pre-processed to derive kinematic and dynamic parameters. Results: For unipedal stance, most of kinematic parameters of the subjects' right and left feet were significantly greater when the eyes were closed compared to the EO condition and increased with step height. The differences in toe load between right and left feet, open and closed eyes were extremely statistically significant (p < 0.001). The differences in midfoot load between the EO and EC conditions were statistically significant (p = 0.024) and extremely statistically significant between the right and left feet (p < 0.001). The difference in rearfoot load between EO and EC conditions was extremely statistically significant (p < 0.001) and statistically significant (p = 0.002) between the right and left feet. For bipedal stance, most of kinematic parameters of the subjects' EO and EC conditions were statistically significant between the right and left feet and increased with step height. The overall load's difference between EO and EC states was statistically significant (p = 0.003) for both feet. The overall load's difference between the right and left feet was extremely statistically significant (p < 0.001) in the EC state. The differences between the right and left feet of the forefoot and rearfoot load with EO and EC suggested that the right foot had a smaller forefoot load, but a larger rearfoot load than the left foot (p < 0.001). The differences between the forefoot and rearfoot load of the subjects' both feet with EO and EC were extremely statistically significant (p < 0.001). Conclusion: Both visual input and step height factors, even the dominant foot, act on kinematic and dynamic parameters that affect the maintenance of static balance ability.

Association of the Brain-Derived Neurotrophic Factor Gene (BDNF) Val66Met Polymorphism with Individual Alpha Peak Frequency and Alpha Power in Adults

—A single nucleotide polymorphism in the brain-derived neurotrophic factor (BDNF) gene (Val66Met) functions to regulate activity-dependent secretion of (BDNF), which plays an important role in neuroprotection and synaptic plasticity. In several studies, the Met allele was associated with lower electroencephalogram (EEG) α-power values, calculated in the standard frequency range, in young subjects. In addition to α-power, one of the inherited EEG correlates of brain functioning is individual alpha peak frequency (IAPF). Although IAPF has a separate functional role, its association with BDNF Val66Met polymorphism has not been studied. IAPF is also used to determine the boundaries of individual frequency ranges, which, unlike the standard ones, are more consistent with functional rhythm characteristics. Using a sample of 192 subjects aged 18–78 years, the association between parietal-occipital IAPF and BDNF polymorphism, as well as the genotype differences in α-power calculated in standard (8–12 Hz) and individual frequency ranges (from (IAPF –2) to (IAPF +2) Hz) were examined. A decrease of IAPF in Val/Met compared to Val/Val was observed. For power calculated in the individual frequency range, genetic differences in both eyes-closed (Val/Met > homozygous genotypes) and eyes-open (Val-carriers > Met/Met) conditions were revealed. Analysis within the standard frequency range showed differences only in the eyes-open condition, which could be due to a shift of power indicators calculated in the α-rhythm functional range to the low frequency region among Val/Met carriers, which showed a decrease in IAPF. The results suggest that the inclusion of Val/Met in the pooled group of Met carriers in the analysis of genetic differences in brain activity may level out the differences between the Val/Val and Val/Met genotypes and show the advantage of using individual frequency bands in the analysis of BDNF Val66Met-associated EEG features.

Brain and cognitive reserve mitigate balance dysfunction in multiple sclerosis.

Approximately two-thirds of patients with multiple sclerosis (MS) complain different degrees of balance dysfunction, but some of them are able to withstand considerable disease burden without an overt balance impairment. Here, we tested the hypothesis that brain and cognitive reserve lessen the effect of MS-related tissue damage on balance control. We measured the postural sway of 148 patients and 74 sex- and age-matched healthy controls by force platform under different conditions reflecting diverse neuro-pathological substrates of balance dysfunction: eyes opened (EO), eyes closed (EC), and while performing the Stroop test, i.e., dual-task (DT). Lesion volumes on T2-hyperintense and T1-hypointense sequences, and normalized brain volume provided estimations of MS-related tissue damage in patients with MS. Hierarchical linear regressions explored the protective effect against the MS-related tissue damage of intracranial volume and educational attainment (proxies for brain and cognitive reserve, respectively) on balance. Larger intracranial volume and high educational attainment mitigated the detrimental effect of MS-related tissue damage on postural sway under EO (adjusted-R2=0.20 and 0.27, respectively, p<0.01) and DT (adjusted-R2=0.22 and 0.30, respectively, p<0.06) conditions. Neither educational level nor brain size was associated with postural sway under EC condition. Our findings suggest a protective role of brain and cognitive reserve even on balance, an outcome that relies on both motor control and higher order processing resources. The lack of a protective effect on postural sway under EC condition confirms that this latter outcome is closer associated with spinal cord rather than brain damage.

Val66Met Polymorphism of Brain-Derived Neurotrophic Factor (BDNF) is Associated with Individual Alpha Peak Frequency and Alpha Power in Adults

Single-nucleotide polymorphism within the BDNF gene (Val66Met) influences activity-dependent secretion of the brain-derived neurotrophic factor (BDNF), which affects neuroprotection and synaptic plasticity. Several studies found associations between Met allele and lower power of the EEG α-rhythm determined in the standard frequency range in young adults. Along with the power, one of the highly heritable EEG correlates of brain functions is the individual α-peak frequency (IAPF). Although IAPF has independent functional significance, its association with the Val66Met BDNF polymorphism has not been studied. IAPF is also used to determine the boundaries of individual frequency ranges; in contrast to the standard ones, they reflect functional characteristics of rhythms to a greater extent. We explored in 192 subjects aged 18–78 years whether parieto-occipital IAPF is associated with BDNF polymorphism and tested genotypic differences in α-power calculated in standard (8−12 Hz) and individual (from (IAPF –2) to (IAPF +2) Hz) frequency ranges. IAPF was decreased in Val/Met in comparison to Val/Val. For individual frequency range, genetic differences were found in both eyes closed (Val/Met homozygous genotypes) and eyes open (Val-carriers Met/Met) condition. For standard frequency range – only in eyes open condition, which may be due to a shift of the α-functional range towards a region of low frequencies among Val/Met-carriers that showed a decrease in IAPF. The results indicate that the inclusion of Val/Met in the combined group of Met-carriers in the analysis of genetic differences in brain activity can eliminate the differences between Val/Val and Val/Met genotypes, as well as the advantage of using individual frequency bands in the analysis of BDNF-associated features of EEG.

Self-Mobilization Exercise Program Improved Postural Stability in the Anterior-Posterior Direction with Eyes Closed

Maintenance of equilibrium is influenced by postural symmetry and deviations such as a forward head. An exercise program involving an effect such as self-joint mobilization was developed to address spinal curvature; however, its effect on postural stability is still unclear. The purpose of this study was to address to what extent the self-mobilization exercise program would influence postural sway while standing still. The Exercise group (n = 16) performed the self-mobilization while lying supine on a cylinder-shaped tube (98 cm length, 15 cm diameter), consisting of three warm-up positionings followed by seven motions. The Control group (n = 16) laid supine on a flat surface with their legs flexed. Before and immediately after respective interventions, the plantar center of pressure was quantified while subjects were standing with eyes open and closed. The results show the exercise group reduced the postural sway in the antero-posterior direction only during the eyes-closed condition. Neither exercise nor control groups showed a significant change in postural sway during the eyes-open condition. Our findings indicate the self-mobilization exercise program improved the participant’s stability when visual feedback was not reliable for postural control. The improved postural control in the antero-posterior direction may be accounted for by facilitated activation of planterflexors and dorsiflexors which are primary muscles in ankle strategy for postural control. Effects of this exercise program on postural stability appear to be direction dependent, which provide insight when healthcare professionals incorporate exercise programs for postural symmetry.