Beta Oscillations Research Articles

Anterior piriform cortex dysfunction underlies autism spectrum disorders-related olfactory deficits in Fmr1 conditional deletion mice.

Previous studies indicated that ASD-related olfactory dysfunctions are rooted in the piriform cortex. However, the direct evidence supporting a causal link between the dysfunction of the piriform cortex and olfactory disorders in ASD is limited. In the present study, we explored the role of anterior piriform cortex (aPC) in ASD-related olfactory disorders by specifically ablating Fmr1, a leading known monogenic cause for ASD, in the pyramidal neurons. Our data demonstrated that the targeted deletion of Fmr1 in aPC pyramidal neurons was sufficient to induce deficits in olfactory detection. In vivo and in vitro electrophysiological recordings showed that the deletion of Fmr1 increased the activity of pyramidal neurons, exhibiting an enhanced excitatory response and a reduced inhibitory response upon odor stimulation. Furthermore, specific deletion of Fmr1 enhanced the power of beta oscillations during odor stimuli, meanwhile, disturbed excitatory and inhibitory synaptic transmission. The abnormal morphology of pyramidal neurons induced by the deletion of Fmr1 may be responsible for the impaired aPC neuronal function. These findings suggest that dysfunction of the aPC may play a role in olfactory impairments observed in ASD models related to Fmr1 deficiency.

State dependent motor cortex stimulation reveals distinct mechanisms for corticospinal excitability and cortical responses.

Transcranial magnetic stimulation (TMS) is a non-invasive brain stimulation method that modulates brain activity by inducing electric fields in the brain. Real-time, state-dependent stimulation with TMS has shown that neural oscillation phase modulates corticospinal excitability. However, such motor-evoked potentials (MEPs) only indirectly reflect motor cortex activation and are unavailable at other brain regions of interest. The direct and secondary cortical effects of phase-dependent brain stimulation remain an open question. In this study, we recorded the cortical responses during single-pulse TMS using electroencephalography (EEG) concurrently with the MEP measurements in 20 healthy human volunteers (11 female). TMS was delivered at peak, rising, trough, and falling phases of mu (8-13 Hz) and beta (14-30 Hz) oscillations in the motor cortex. The cortical responses were quantified through TMS-evoked potential components N15, P50, and N100 as peak-to-peak amplitudes (P50-N15 and P50-N100). We further analyzed whether the pre-stimulus frequency band power was predictive of the cortical responses. We demonstrated that phase-specific targeting modulates cortical responses. The phase relationship between cortical responses was different for early and late responses. In addition, pre-TMS mu oscillatory power and phase significantly predicted both early and late cortical EEG responses in mu-specific targeting, indicating the independent causal effects of phase and power. However, only pre-TMS beta power significantly predicted the early and late TEP components during beta-specific targeting. Further analyses indicated distinct roles of mu and beta power on cortical responses. These findings provide insight to mechanistic understanding of neural oscillation states in cortical and corticospinal activation in humans.Significance Statement Understanding the effects of noninvasive neuromodulation on human brain provides valuable insights to its clinical utility. Brain state dependent stimulation helps us understand mechanisms leading to cortical responses and behavioral outcomes. Here we study the effects of the phase of ongoing oscillations in the motor cortex on cortical responses measured by electroencephalography. We also studied the relationship of phase preference between cortical responses and motor evoked potentials. Furthermore, we investigated the effects of the power of ongoing oscillations on cortical responses. These findings are important to understand the changes in biomarkers during state-dependent brain stimulation and their relationship to behavioral outcomes. At large, this helps the researchers to utilize state-dependent brain stimulation to enhance treatment efficacy.

Beta-gamma phase-amplitude coupling of scalp electroencephalography during walking preparation in Parkinson’s disease differs depending on the freezing of gait

IntroductionDespite using beta oscillations within the subthalamic nucleus as a biomarker of akinesia or rigidity in Parkinson’s disease, a specific biomarker for freezing of gait (FOG) remains unclear. Recently, scalp phase-amplitude coupling (PAC) measured through scalp electroencephalography (EEG) has emerged as a promising tool for analyzing brain function. In this study, we examined whether PAC could be a biomarker for FOG.MethodsWe enrolled 11 patients with Parkinson’s disease and recorded scalp EEG in preparation for and during gait while simultaneously assessing motor function, including FOG. We investigated changes in cortical PAC during walking with and without FOG and examined its correlation with the postural instability and gait difficulty (PIGD) score.ResultsPatient characteristics were as follows: mean age 59.1 ± 6.9 years, disease duration 13.9 ± 4.1 years, and seven men. Four trials were excluded from the analysis owing to artifacts. In the trials without FOG (n = 18), beta-gamma PAC in the sensorimotor area decreased during gait preparation (p = 0.011; linear mixed-effects model), which was not the case in trials with FOG (n = 6) (p = 0.64; linear mixed-effects model). Using a support vector machine, machine learning of PAC during preparation for walking predicted the presence of FOG with an accuracy of 71.2%. Conversely, PAC increased during walking in trials with FOG (p = 0.0042; linear mixed-effects model), and PAC 20 s after the start of walking was positively correlated with the PIGD score (correlation coefficient = 0.406, p = 0.032; Pearson’s rank correlation).ConclusionBeta-gamma PAC in the sensorimotor area during preparation for walking differs depending on the emergence of FOG. As gait symptoms worsened, beta-gamma PAC in the sensorimotor area during walking gradually increased. Cortical PAC may be a biomarker for FOG in Parkinson’s disease and may lead to the development of strategies to prevent falls in the future.

The Mindful Brain at Rest: Neural Oscillations and Aperiodic Activity in Experienced Meditators

Abstract Objectives Previous research has demonstrated that mindfulness meditation is associated with a variety of benefits, including improved mental health. Researchers have suggested these benefits may be underpinned by differences in neural oscillations. However, previous studies measuring neural oscillations have not controlled for non-oscillatory neural activity, the power spectrum of which follows a 1/f distribution (whereby the power of neural activity at each frequency is inversely proportional to that frequency (such that as frequency increases, power decreases)) and contributes to power measurements within oscillation frequencies of interest. We applied recently developed methods to determine if past findings related to neural oscillations in meditation are present even after controlling for non-oscillatory 1/f activity. Method Forty-eight experienced meditators and 44 demographically matched non-meditators provided resting electroencephalography (EEG) recordings. Whole-scalp EEG comparisons (topographical ANOVAs) were used to test for differences between meditators and non-meditators in the distribution or global power of activity for theta, alpha, beta, and gamma oscillations, and for the 1/f components slope and intercept using the extended Better OSCillation detection toolbox. Results Results indicated that meditators showed differences in theta, alpha, and gamma oscillatory power compared to non-meditators (all p < 0.05). Post hoc testing suggested that the oscillatory differences were primarily driven by differences in the distribution of neural activity between meditators and non-meditators, rather than differences in the overall power across all scalp electrodes. Conclusions Our results suggest that experience with meditation is associated with higher oscillatory power and altered distributions of theta, alpha, and gamma oscillations, even after controlling for non-oscillatory 1/f activity. Band-specific differences in oscillatory activity may be a mechanism through which meditation leads to neurophysiological benefits. Preregistration This study was not preregistered.

Differential modulations of theta and beta oscillations by audiovisual congruency in letter-speech sound integration.

The integration of visual letters and speech sounds is a crucial part of learning to read. Previous studies investigating this integration have revealed a modulation by audiovisual (AV) congruency, commonly known as the congruency effect. To investigate the cortical oscillations of the congruency effects across different oscillatory frequency bands, we conducted a Japanese priming task in which a visual letter was followed by a speech sound. We analyzed the power and phase properties of oscillatory activities in the theta and beta bands between congruent and incongruent letter-speech sound (L-SS) pairs. Our results revealed stronger theta-band (5-7Hz) power in the congruent condition and cross-modal phase resetting within the auditory cortex, accompanied by enhanced inter-trial phase coherence (ITPC) in the auditory-related areas in response to the congruent condition. The observed congruency effect of theta-band power may reflect increased neural activities in the left auditory region during L-SS integration. Additionally, theta ITPC findings suggest that visual letters amplify neuronal responses to the following corresponding auditory stimulus, which may reflect the differential cross-modal influences in the primary auditory cortex. In contrast, decreased beta-band (20-35 Hz) oscillatory power was observed in the right centroparietal regions for the congruent condition. The reduced beta power seems to be unrelated to the processing of AV integration, but may be interpreted as the brain response to predicting auditory sounds during language processing. Our data provide valuable insights by indicating that oscillations in different frequency bands contribute to the disparate aspects of L-SS integration.

Functional excitation-inhibition ratio indicates near-critical oscillations across frequencies

Abstract The concept of excitation/inhibition (E/I) balance plays an important role in understanding brain function in health and disease. We recently introduced an algorithm to determine a functional E/I ratio based on the critical brain dynamics that emerge in neuronal networks balancing between order and disorder. Little, however, is known about the frequency specificity of E/I regulation and how to measure it. Here, we optimized the algorithm for measuring functional excitation-inhibition ratio (fE/I) in narrow frequency ranges and validated it on a computational model of critical oscillations and EEG data. In the computational model, we confirmed that fE/I discriminated E/I connectivity differences across a wide range of frequencies (1–150 Hz). Twin EEG data revealed significant genetic influences on fE/I across frequencies, whereas contrasting eyes-open and -closed EEG indicated functional changes of fE/I restricted to a subset of alpha and beta oscillations and brain regions. We propose that assessing fE/I with finer frequency resolution will prove useful for understanding the functional role of E/I regulation in a spectrally refined fashion in health and disease.

Electrophysiological signature of interoceptive attention: a spectral and source localization analysis.

The ability to attend to and consciously process interoceptive signals is deemed critical for the development of minimal self, adaptive self-regulation and affective experience, and optimal expression of both instrumental and executive cognitive functions. Yet, notwithstanding the richness of theoretical proposals concerning inferential accounts of interoception, empirical evidence is still scarce. Building on such premises, this study was designed to investigate the electrophysiological signature of cognitive processes leading to aware coding of interoceptive signals via EEG source localization. Thirty-six healthy participants completed an interoceptive accuracy task, i.e., the Heartbeat Counting Task (HCT), while we collected task-related and resting state electrophysiological activity. eLORETA modelling and statistical nonparametric mapping were used to estimate intracortical current density and link such estimates to participants' performance at the task. Source analysis highlighted higher current density estimates for alpha frequencies during HCT with respect to rest, with the primary cortical generator in the right parahippocampal gyrus. Also, a set of medial cortical structures-primarily represented by the cingulate gyrus-showed significant relation between task-related changes in current density estimates for beta oscillations and HCT scores. Findings suggest the informativity of EEG task-related measures of neural activation when used to assess interoceptive skills, as well as of the potential of metrics and analysis based on source localization in the quest to improve our understanding of interoceptive accuracy and neurofunctional correlates of related active inferences.

Modulation of Cerebellar Oscillations with Subthalamic Stimulation in Patients with Parkinson's Disease.

Deep brain stimulation (DBS) targeting the subthalamic nucleus (STN) has emerged as a potent treatment for alleviating motor symptoms in Parkinson's disease (PD). Despite its effectiveness, the impact of high frequency STN-DBS on cerebellar oscillations remains unclear, posing an intriguing challenge for neural modulation. Given the direct and indirect connections between the STN and cerebellum, we investigated whether STN-DBS affects cerebellar oscillations. To observe the effects of STN-DBS on cerebellar oscillations in patients with PD. We recruited 15 PD patients receiving STN-DBS. Electroencephalographic (EEG) signals were recorded from cerebellar regions during resting-state conditions in both the OFF-DBS and STN-DBS conditions. Our analyses centered on spectral features, particularly theta and beta oscillations, guided by prior research and correlation tests to investigate the relationship between oscillatory changes and motor symptom severity. In the mid-cerebellar (Cbz) region, we observed a significant increase in the relative power in all frequency bands, including theta and beta oscillations during STN-DBS, showing the global effect of DBS. Importantly, the correlation results indicated significant associations between mid-cerebellar (Cbz) beta power during the OFF condition and motor severity, which were not evident during STN-DBS. Interestingly, correlations between beta power and motor severity were not observed at the mid-occipital (Oz) and mid-frontal (Cz) regions. Notably, signal similarity analyses demonstrated no evidence of volume conduction effects between the mid-cerebellar (Cbz) and nearby mid-occipital (Oz) regions. While these findings provide valuable insights into the complex interplay between STN-DBS and neural oscillations, further research is essential to decipher their precise functional significance and clinical implications. Understanding these intricacies may contribute to the optimization of DBS therapies for PD.

Functional Roles of Sensorimotor Alpha and Beta Oscillations in Overt Speech Production.

Power decreases, or desynchronization, of sensorimotor alpha and beta oscillations (i.e., alpha and beta ERD) have long been considered as indices of sensorimotor control in overt speech production. However, their specific functional roles are not well understood. Hence, we first conducted a systematic review to investigate how these two oscillations are modulated by speech motor tasks in typically fluent speakers (TFS) and in persons who stutter (PWS). Eleven EEG/MEG papers with source localization were included in our systematic review. The results revealed consistent alpha and beta ERD in the sensorimotor cortex of TFS and PWS. Furthermore, the results suggested that sensorimotor alpha and beta ERD may be functionally dissociable, with alpha related to (somato-)sensory feedback processing during articulation and beta related to motor processes throughout planning and articulation. To (partly) test this hypothesis of a potential functional dissociation between alpha and beta ERD, we then analyzed existing intracranial electroencephalography (iEEG) data from the primary somatosensory cortex (S1) of picture naming. We found moderate evidence for alpha, but not beta, ERD's sensitivity to speech movements in S1, lending supporting evidence for the functional dissociation hypothesis identified by the systematic review.

Changes in high-frequency neural inputs to muscles during movement cancellation

Objective.Cortical beta (13-30 Hz) and gamma (30-60 Hz) oscillations are prominent in the motor cortex and are known to be transmitted to the muscles despite their limited direct impact on force modulation. However, we currently lack fundamental knowledge about the saliency of these oscillations at spinal level. Here, we developed an experimental approach to examine the modulations in high-frequency inputs to motoneurons under different motor states while maintaining a stable force, thus constraining behaviour.Approach.Specifically, we acquired brain and muscle activity during a 'GO'/'NO-GO' task. In this experiment, the effector muscle for the task (tibialis anterior) was kept tonically active during the trials, while participants (N= 12) reacted to sequences of auditory stimuli by either keeping the contraction unaltered ('NO-GO' trials), or by quickly performing a ballistic contraction ('GO' trials). Motor unit (MU) firing activity was extracted from high-density surface and intramuscular electromyographic signals, and the changes in its spectral contents in the 'NO-GO' trials were analysed.Main results.We observed an increase in beta and low-gamma (30-45 Hz) activity after the 'NO-GO' cue in the MU population activity. These results were in line with the brain activity changes measured with electroencephalography. These increases in power occur without relevant alterations in force, as behaviour was restricted to a stable force contraction.Significance.We show that modulations in motor cortical beta and gamma rhythms are also present in muscles when subjects cancel a prepared ballistic action while holding a stable contraction in a 'GO'/'NO-GO' task. This occurs while force levels produced by the task effector muscle remain largely unaltered. Our results suggest that muscle recordings are informative also about motor states that are not force-control signals. This opens up new potential use cases of peripheral neural interfaces.

Excessive propagation of right frontal beta oscillations in patients with a history of major depressive disorder

Excessive propagation of right frontal beta oscillations in patients with a history of major depressive disorder

Beta-frequency sensory stimulation enhances gait rhythmicity through strengthened coupling between striatal networks and stepping movement

Stepping movement is delta (1–4 Hz) rhythmic and depends on sensory inputs. Stepping-related delta-rhythmic neural activity is coupled to beta (10–30 Hz) frequency dynamics that are also prominent in sensorimotor circuits. We explored how beta-frequency sensory stimulation influences stepping and dorsal striatal regulation of stepping. We delivered audiovisual stimulation at 10 or 145 Hz to mice voluntarily locomoting, while recording locomotion, cellular calcium dynamics and local field potentials (LFPs). We found that 10 Hz, but not 145 Hz stimulation prominently entrained striatal LFPs. Even though stimulation at both frequencies promoted locomotion and desynchronized striatal network, only 10 Hz stimulation enhanced the delta rhythmicity of stepping and strengthened the coupling between stepping and striatal LFP delta and beta oscillations. These results demonstrate that higher frequency sensory stimulation can modulate lower frequency striatal neural dynamics and improve stepping rhythmicity, highlighting the translational potential of non-invasive beta-frequency sensory stimulation for improving gait.

Post-Movement Beta Synchrony Inhibits Cortical Excitability.

This study investigates the relationship between movement-related beta synchrony and primary motor cortex (M1) excitability, focusing on the time-dependent inhibition of movement. Voluntary movement induces beta frequency (13-30 Hz) event-related desynchronisation (B-ERD) in M1, followed by post-movement beta rebound (PMBR). Although PMBR is linked to cortical inhibition, its temporal relationship with motor cortical excitability is unclear. This study aims to determine whether PMBR acts as a marker for post-movement inhibition by assessing motor-evoked potentials (MEPs) during distinct phases of the beta synchrony profile. Twenty-five right-handed participants (mean age: 24 years) were recruited. EMG data were recorded from the first dorsal interosseous muscle, and TMS was applied to the M1 motor hotspot to evoke MEPs. A reaction time task was used to elicit beta oscillations, with TMS delivered at participant-specific time points based on EEG-derived beta power envelopes. MEP amplitudes were compared across four phases: B-ERD, early PMBR, peak PMBR, and late PMBR. Our findings demonstrate that MEP amplitude significantly increased during B-ERD compared to rest, indicating heightened cortical excitability. In contrast, MEPs recorded during peak PMBR were significantly reduced, suggesting cortical inhibition. While all three PMBR phases exhibited reduced cortical excitability, a trend toward amplitude-dependent inhibition was observed. This study confirms that PMBR is linked to reduced cortical excitability, validating its role as a marker of motor cortical inhibition. These results enhance the understanding of beta oscillations in motor control and suggest that further research on altered PMBR could be crucial for understanding neurological and psychiatric disorders.

Interaction of motor behaviour, cortical oscillations and deep brain stimulation in Parkinson disease

Abstract Recent progress in the study of Parkinson's disease (PD) has highlighted the pivotal role of beta oscillations within the basal ganglia-thalamo-cortical network in modulating motor symptoms. Predominantly manifesting as transient bursts, these beta oscillations are central to the pathophysiology of PD motor symptoms, especially bradykinesia. Our central hypothesis is that increased bursting duration in cortex, coupled with kinematics of movement, disrupts the typical flow of neural information, leading to observable changes in motor behavior in PD. To explore this hypothesis, we employed an integrative approach, analyzing the interplay between moment-to-moment brain dynamics and movement kinematics, and the modulation of these relationships by therapeutic deep brain stimulation (DBS). Local field potentials were recorded from the hand motor (M1) and premotor cortical (PM) areas, and internal Globus Pallidus (GPi) in 26 PD patients undergoing DBS implantation surgery. Participants executed rapid alternating hand movements in 30-second blocks, both with and without therapeutic pallidal stimulation. Behaviorally, the analysis revealed bradykinesia, with hand movement cycle width increasing linearly over time during DBS-OFF blocks. Crucially, there was a moment-to-moment correlation between M1 low beta burst duration and movement cycle width, a relationship that dissipated with therapeutic DBS. Further analyses suggest that high gamma activity correlates with enhanced motor performance with DBS-ON. Regardless of the nature of coupling, DBS’s modulation of cortical bursting activity appeared to amplify the brain signals’ informational content regarding instantaneous movement changes. Our findings underscore that DBS significantly reshapes the interaction between motor behavior and neural signals in PD, not only modulating specific bands but also expanding the system's capability to process and relay information for motor control. These insights shed light on the possible network mechanisms underlying DBS therapeutic effects, suggesting a profound impact on both neural and motor domains.

Clinico-physiological correlates of Parkinson’s disease from multi-resolution basal ganglia recordings

Parkinson’s disease (PD) has been associated with pathological neural activity within the basal ganglia. Herein, we analyzed resting-state single-neuron and local field potential (LFP) activities from people with PD who underwent awake deep brain stimulation surgery of the subthalamic nucleus (STN; n = 125) or globus pallidus internus (GPi; n = 44), and correlated rate-based and oscillatory features with UPDRSIII off-medication subscores. Rate-based single-neuron features did not correlate with PD symptoms. STN single-neuron and LFP low-beta (12–21 Hz) power and burst dynamics showed modest correlations with bradykinesia and rigidity severity, while STN spiketrain theta (4–8 Hz) power correlated modestly with tremor severity. GPi low- and high-beta (21–30 Hz) power and burst dynamics correlated moderately with bradykinesia and axial symptom severity. These findings suggest that elevated single-neuron and LFP oscillations may be linked to symptoms, though modest correlations imply that the pathophysiology of PD may extend beyond resting-state beta oscillations.

Causal role of frontocentral beta oscillation in comprehending linguistic communicative functions

Linguistic communication is often considered as an action serving the function of conveying the speaker's goal to the addressee. Although neuroimaging studies have suggested a role of the motor system in comprehending communicative functions, the underlying mechanism is yet to be specified. Here, by two EEG experiments and a tACS experiment, we demonstrate that the frontocentral beta oscillation, which represents action states, plays a crucial part in linguistic communication understanding. Participants read scripts involving two interlocutors and rated the interlocutors’ attitudes. Each script included a critical sentence said by the speaker expressing a context-dependent function of either promise, request, or reply to the addressee's query. These functions were behaviorally discriminated, with higher addressee's will rating for the promise than for the reply and higher speaker's will rating for the request than for the reply. EEG multivariate analyses showed that different communicative functions were represented by different patterns of the frontocentral beta activity but not by patterns of alpha activity. Further tACS results showed that, relative to alpha tACS and sham stimulation, beta tACS improved the predictability of communicative functions of request or reply, as measured by the speaker's will rating. These results convergently suggest a causal role of the frontocentral beta activities in comprehending linguistic communications.

Novel cyclic homogeneous oscillation detection method for high accuracy and specific characterization of neural dynamics.

Determining the presence and frequency of neural oscillations is essential to understanding dynamic brain function. Traditional methods that detect peaks over 1/f noise within the power spectrum fail to distinguish between the fundamental frequency and harmonics of often highly non-sinusoidal neural oscillations. To overcome this limitation, we define fundamental criteria that characterize neural oscillations and introduce the cyclic homogeneous oscillation (CHO) detection method. We implemented these criteria based on an autocorrelation approach to determine an oscillation's fundamental frequency. We evaluated CHO by verifying its performance on simulated non-sinusoidal oscillatory bursts and validated its ability to determine the fundamental frequency of neural oscillations in electrocorticographic (ECoG), electroencephalographic (EEG), and stereoelectroencephalographic (SEEG) signals recorded from 27 human subjects. Our results demonstrate that CHO outperforms conventional techniques in accurately detecting oscillations. In summary, CHO demonstrates high precision and specificity in detecting neural oscillations in time and frequency domains. The method's specificity enables the detailed study of non-sinusoidal characteristics of oscillations, such as the degree of asymmetry and waveform of an oscillation. Furthermore, CHO can be applied to identify how neural oscillations govern interactions throughout the brain and to determine oscillatory biomarkers that index abnormal brain function.

Motor practice related changes in the sensorimotor cortices of youth with cerebral palsy.

The altered sensorimotor cortical dynamics seen in youth with cerebral palsy appear to be tightly coupled with their motor performance errors and uncharacteristic mobility. Very few investigations have used these cortical dynamics as potential biomarkers to predict the extent of the motor performance changes that might be seen after physical therapy or in the design of new therapeutic interventions that target a youth's specific neurophysiological deficits. This cohort investigation was directed at evaluating the practice dependent changes in the sensorimotor cortical oscillations exhibited by youth with cerebral palsy as a step towards addressing this gap. We used magnetoencephalography to image the changes in the cortical oscillations before and after youth with cerebral palsy (N = 25; age = 15.2 ± 4.5 years; Gross Motor Function Classification Score Levels I-III) and neurotypical controls (N = 18; age = 14.6 ± 3.1 years) practiced a knee extension isometric target-matching task. Subsequently, structural equation modelling was used to assess the multivariate relationship between changes in beta (16-22 Hz) and gamma (66-82 Hz) oscillations and the motor performance after practice. The structural equation modelling results suggested youth with cerebral palsy who had a faster reaction time after practice tended to also have a stronger peri-movement beta oscillation in the sensorimotor cortices following practicing. The stronger beta oscillations were inferred to reflect greater certainty in the selected motor plan. The models also indicated that youth with cerebral palsy who overshot the targets less and matched the targets sooner tended to have a stronger execution-related gamma response in the sensorimotor cortices after practice. This stronger gamma response may represent improve activation of the sensorimotor neural generators and/or alterations in the GABAergic interneuron inhibitory-excitatory dynamics. These novel neurophysiological results provide a window on the potential neurological changes governing the practice-related outcomes in the context of the physical therapy.

Oscillatory activity in bilateral prefrontal cortices is altered by distractor strength during working memory processing

Working memory (WM) enables the temporary storage of limited information and is a central component of higher order cognitive function. Irrelevant and/or distracting information can have a negative impact on WM processing and suppressing such incoming stimuli is critical to maintaining adequate performance. However, the neural mechanisms and dynamics underlying such distractor inhibition remain poorly understood. In the current study, we enrolled 46 healthy adults (Mage: 27.92, Nfemale: 28) who completed a Sternberg type WM task with high- and low-distractor conditions during magnetoencephalography (MEG). MEG data were transformed into the time-frequency domain and significant task-related oscillatory responses were imaged to identify the underlying anatomical areas. Whole-brain paired t-tests, with cluster-based permutation testing for multiple comparisons correction, were performed to assess differences between the low- and high-distractor conditions for each oscillatory response. Across conditions, we found strong alpha and beta oscillations (i.e., decreases relative to baseline) and increases in theta power throughout the encoding and maintenance periods. Whole-brain contrasts revealed significantly stronger alpha and beta oscillations in bilateral prefrontal regions during maintenance in high- compared to low-distractor trials, with the stronger beta oscillations being centered on the left dorsolateral prefrontal cortex and right inferior frontal gyrus, while those for alpha being within the right anterior prefrontal cortices and the right middle frontal gyrus. These findings suggest that alpha and beta oscillations in the bilateral prefrontal cortices play a major role in the inhibition of distracting information during WM maintenance. Our results also contribute to prior research on cognitive control and functional inhibition, in which prefrontal regions have been widely implicated.

Sedative and hypnotic effects with cortical EEG sleep-wake profiles of Millingtonia hortensis dried flower aqueous in mice

The ethnopharmacological relevance of the Millingtonia hortensis (M. hortensis) flower's aqueous extract lies in its traditional use as a herbal remedy in Southeast Asia. With a rich history in folk medicine, this aqueous has been esteemed for its purported sedative and anxiolytic properties. Our research delves into the scientific basis of these traditional claims, exploring the potential mechanisms underlying the observed effects of M. hortensis flower's aqueous extract on sleep promotion and mood regulation. This study aimed to explore the sleep-promoting effects of M. hortensis dried flower in mice, using an aqueous concentration equivalent to a human concentration of 2.7 mg/mL. Anxiolytic and antidepressant properties were evaluated using behavioural tests, while electroencephalography (EEG) analysis probed the neural mechanisms underlying sleep promotion post-consumption. The aqueous extract of M. hortensis dried flower administered to mice showed a decrease in immobility in the forced swimming test, demonstrating antidepressant-like effects. Moreover, mice treated with M. hortensis aqueous exhibited increased non-rapid eye movement (NREM) sleep duration, corroborating sleep-promoting potential. EEG analysis of mice treated with M. hortensis aqueous revealed heightened beta oscillations in the frontal and parietal cortex, while pre-treatment with M. hortensis aqueous or diazepam enhanced rapid eye movement (REM) sleep after thiopental administration. Interestingly, M. hortensis aqueous pre-treatment augmented delta frequency ranges in the frontal cortex. Overall, these findings indicate that M. hortensis dried flower's aqueous extract, at a human-equivalent dosage, exerts significant behavioural and neural effects specifically, sedative and hypnotic aspects in mice, corroborating its potential as a natural remedy to promote sleep and regulate mood.