Theta Spectral Power Research Articles

Frontal Theta Asymmetry may be a new target for reducing the severity of depression and improving cognitive function in depressed patients

BackgroundThe prevalence of depressive disorder is increasing due to a variety of factors, which brings a huge strain on individuals, families and society. This study aims to investigate whether there is Frontal Theta Asymmetry (FTA) in depressed patients, and whether FTAs are related to depression severity and cognitive function changes in depressed patients. MethodsParticipants who met the inclusion criteria were enrolled in this study. Socio-demographic data of each participant were recorded. Zung's self-rating Depression Scale was used to assess the depression status of participants. P300 was used to evaluate the cognitive function of participants. EEG data from participants were collected by the NeuroScan SynAmps RT EEG system. t-test, Wilcoxon rank-sum test and Chi-square test were used to detect the differences of different variables between the two groups. Multiple linear regression analysis and multiple logistic regression analysis were used to analyze relationships between FTAs in different regions and participants' depression status and cognitive function. ResultsA total of 66 depressed participants and 47 healthy control participants were included in this study. The theta spectral power of the left frontal lobe was slightly stronger than that of the right frontal lobe in the depression group, while the opposite was true in the healthy control group. The FTA in F3/F4 had certain effects on the emergence of depression in participants, the emergence of depression in participants and Changes in cognitive function. ConclusionsFTAs are helpful to assess the severity of depression and early identify cognitive impairment in patients with depression.

Quantitative sleep electroencephalogram and cognitive performance in Parkinson's disease with and without rapid eye movement sleep behavior disorder.

Parkinson's disease (PD) patients with REM sleep behavior disorder (RBD) are at greater risk for cognitive decline and RBD has been associated with alterations in sleep-related EEG oscillations. This study evaluates differences in sleep quantitative EEG (qEEG) and cognition in PD participants with (PD-RBD) and without RBD (PD-no-RBD). In this cross-sectional study, polysomnography (PSG)-derived qEEG and a comprehensive level II neuropsychological assessment were compared between PD-RBD (n = 21) and PD-no-RBD (n = 31). Following artifact rejection, qEEG analysis was performed in the frontal and central leads. Measures included Scalp-slow wave (SW) density, spindle density, morphological properties of SW and sleep spindles, SW-spindle phase-amplitude coupling, and spectral power analysis in NREM and REM. The neurocognitive battery had at least two tests per domain, covering five cognitive domains as recommended by the Movement Disorders Society Task Force for PD-MCI diagnosis. Differences in qEEG features and cognitive performance were compared between the two groups. Stepwise linear regression was performed to evaluate predictors of cognitive performance. Multiple comparisons were corrected using the Benjamini-Hochberg method. Spindle density and SW-spindle co-occurrence percent were lower in participants with PD-RBD compared to PD-no-RBD. The PD-RBD group also demonstrated higher theta spectral power during REM. Sleep spindles and years of education, but not RBD, were predictors of cognitive performance. PD participants with RBD have alterations in sleep-related qEEG compared to PD participants without RBD. Although PD-RBD participants had worse cognitive performance compared to PD-no-RBD, regression models suggest that lower sleep spindle density, rather than presence of RBD, predicts worse comprehensive cognitive score. Future studies should include longitudinal evaluation to determine whether sleep-related qEEG alterations are associated with more rapid cognitive decline in PD-RBD.

Long-term practice of intuitive inquiry meditation modulates EEG dynamics during self-schema processing

ObjectiveIntuitive inquiry meditation is a unique form of Buddhist Zen/Chan practice in which individuals actively and intuitively utilize the cognitive functions to cultivate doubt and explore the concept of the self. This event-related potential (ERP) study aimed to investigate the neural correlates by which long-term practice of intuitive inquiry meditation induces flexibility in self-schema processing, highlighting the role of doubt and belief processes in this exploration. MethodsTwenty experienced and eighteen beginner meditators in intuitive inquiry meditation were recruited for this ERP study. The interactions of doubt and belief processes with concepts of the self and Buddha were investigated. A 128-channel electroencephalography (EEG) system was used to collect EEG data. The ERP data were processed and analyzed using EEGLAB. ResultsThe data showed a double dissociation between beginners and experienced meditators (monks) in the concepts of the self and Buddha: intuitive inquiry meditation reduced the brain activity of beginners when viewing Buddha image but not when viewing a picture of themselves. However, in experienced meditators, intuitive inquiry meditation reduced brain activity when they viewed images of themselves but not when they viewed Buddha image. Further event-related spectral perturbation (ERSP) analysis revealed that experienced meditators had a greater theta spectral power and higher intertrial coherence (ITC), indicating that they could more flexibly modulate ongoing cognitive processes than beginner meditators. ConclusionIntuitive inquiry meditation could help beginner meditators detach from the concept of Buddha but not from that of the self. However, in experienced meditators, the opposite was true. ERSP analysis showed that only experienced meditators exhibited significant alterations in brain activity dynamics during intuitive inquiry meditation, which might enable these practitioners to become spontaneously detached from the concept of the self. These findings revealed the neural mechanism by which long-term practice of intuitive inquiry meditation can influence the doubting process and its effect on self-schema processing.

Cortical dopamine D5 receptors regulate neuronal circuit oscillatory activity and memory in rats.

The dopamine D5 receptor (D5R) shows high expression in cortical regions, yet the role of the receptor in learning and memory remains poorly understood. This study evaluated the impact of prefrontal cortical (PFC) D5R knockdown in rats on learning and memory and assessed the role of the D5R in the regulation of neuronal oscillatory activity and glycogen synthase kinase-3 (GSK-3β), processes integral to cognitive function. Using an adeno-associated viral (AAV) vector, male rats were infused with shRNA to the D5R bilaterally into the PFC. Local field potential recordings were taken from freely moving animals and spectral power and coherence were evaluated in, and between, the PFC, orbitofrontal cortex (OFC), hippocampus (HIP), and thalamus. Animals were then assessed in object recognition, object location, and object in place tasks. The activity of PFC GSK-3β, a downstream effector of the D5R, was evaluated. AAV-mediated knockdown of the D5R in the PFC induced learning and memory deficits. These changes were accompanied by elevations in PFC, OFC, and HIP theta spectral power and PFC-OFC coherence, reduced PFC-thalamus gamma coherence, and increased PFC GSK-3β activity. This work demonstrates a role for PFC D5Rs in the regulation of neuronal oscillatory activity and learning and memory. As elevated GSK-3β activity has been implicated in numerous disorders of cognitive dysfunction, this work also highlights the potential of the D5R as a novel therapeutic target via suppression of GSK-3β.

Modulation of EEG theta by naturalistic social content is not altered in infants with family history of autism

Theta oscillations (spectral power and connectivity) are sensitive to the social content of an experience in typically developing infants, providing a possible marker of early social brain development. Autism is a neurodevelopmental condition affecting early social behaviour, but links to underlying social brain function remain unclear. We explored whether modulations of theta spectral power and connectivity by naturalistic social content in infancy are related to family history for autism. Fourteen-month-old infants with (family history; FH; N = 75) and without (no family history; NFH; N = 26) a first-degree relative with autism watched social and non-social videos during EEG recording. We calculated theta (4–5 Hz) spectral power and connectivity modulations (social–non-social) and associated them with outcomes at 36 months. We replicated previous findings of increased theta power and connectivity during social compared to non-social videos. Theta modulations with social content were similar between groups, for both power and connectivity. Together, these findings suggest that neural responses to naturalistic social stimuli may not be strongly altered in 14-month-old infants with family history of autism.

3.43 More Severe Executive Function Impairments Are Associated With Increases in Frontal Theta and Decreases in Beta and Gamma EEG Power in Young Children With ASD

3.43 More Severe Executive Function Impairments Are Associated With Increases in Frontal Theta and Decreases in Beta and Gamma EEG Power in Young Children With ASD

Brain Activity During Paired and Individual Mindfulness Meditation: A Controlled EEG Study

Objective: In this study, we evaluated brain electroencephalographic (EEG) activity in healthy participants during the performance of paired and individual mindfulness meditation (MM). We hypothesized that EEG activity is differentially affected by meditation in pairs compared to individual meditation. Methods: A total of 20 healthy female university students (mean age 19.54 years, SD =1.53) with no prior experience in MM participated in this study. All participants had to perform a 5-minute MM task together and individually while the other participant was in rest or performing a concentration task (control condition). To exclude social interaction as main factor, participants were separated from their research partner by an opaque screen while instructions were given through headphones. Brain electroencephalographic (EEG) activity from each individual student was measured during all conditions. Results: The main findings indicate that left-frontal alpha and theta spectral EEG power was significantly higher during the paired MM condition compared to individual MM and control condition. Conclusions: This controlled MM study demonstrates differences in brain activity between practicing mindfulness in pairs compared to practicing it individually. We conclude that the increased alpha and theta EEG power during paired MM may be associated with social facilitation or the activation of "theory of mind." The results invite further reflection on interpersonal communication and mindfulness.

Vibro-motor Reprocessing Therapy towards Managing Motion Sickness Reduction: Evidence from EEG.

This study examines the neural activities of participants undergoing vibro-motor reprocessing therapy (VRT) while experiencing motion sickness. We evaluated the efficacy of vibro-motor reprocessing therapy, a novel therapeutic technique based on eye movement desensitization and reprocessing (EMDR), in reducing motion sickness. Based on visually induced motion sickness in two sets of performed sessions, eight participants were exposed to VRT stimulation in a VRT/non-VRT setting. Simultaneously, brain activity changes were recorded using electroencephalography (EEG) at baseline and during stimulus exposure, and comparisons made across the VRT/non-VRT conditions. A significant reduction in the alpha (8-12 Hz) spectral power was observed in the frontal and occipital locations, consistent across all participants. Furthermore, significant reductions were also found in the frontal and occipital delta (0.5-4 Hz) and theta (4-8 Hz) spectral power frequency bands between non-VRT and VRT conditions (p < 0.05). Our results offer novel insights for a potential nonpharmacological treatment and attenuation of motion sickness. Furthermore, symptoms can be observed, and alleviated, in real-time using the reported techniques. Clinical relevance - Instead of using drugs to treat motion sickness, patients could safely use this VRT technique.

Comatose Patients After Cardiopulmonary Resuscitation: An Analysis Based on Quantitative Methods of EEG Reactivity.

ObjectiveEvery year, approximately 50–110/1,00,000 people worldwide suffer from cardiac arrest, followed by hypoxic-ischemic encephalopathy after cardiopulmonary resuscitation (CPR), and approximately 40–66% of patients do not recover. The purpose of this study was to identify the brain network parameters and key brain regions associated with awakening by comparing the reactivity characteristics of the brain networks between the awakening and unawakening groups of CPR patients after coma, thereby providing a basis for further awakening interventions.MethodThis study involved a prospective cohort study. Using a 64-electrode electroencephalography (EEG) wireless 64A system, EEG signals were recorded from 16 comatose patients after CPR in the acute phase (<1 month) from 2019 to 2020. MATLAB (2017b) was used to quantitatively analyze the reactivity (power spectrum and entropy) and brain network characteristics (coherence and phase lag index) after pain stimulation. The patients were divided into an awakening group and an unawakening group based on their ability to execute commands or engage in repeated and continuous purposeful behavior after 3 months. The above parameters were compared to determine whether there were differences between the two groups.Results(1) Power spectrum: the awakening group had higher gamma, beta and alpha spectral power after pain stimulation in the frontal and parietal lobes, and lower delta and theta spectral power in the bilateral temporal and occipital lobes than the unawakening group. (2) Entropy: after pain stimulation, the awakening group had higher entropy in the frontal and parietal lobes and lower entropy in the temporal occipital lobes than the unawakening group. (3) Connectivity: after pain stimulation, the awakening group had stronger gamma and beta connectivity in nearly the whole brain, but weaker theta and delta connectivity in some brain regions (e.g., the frontal-occipital lobe and parietal-occipital lobe) than the unawakening group.ConclusionAfter CPR, comatose patients were more likely to awaken if there was a higher stimulation of fast-frequency band spectral power, higher entropy, stronger whole-brain connectivity and better retention of frontal-parietal lobe function after pain stimulation.

0298 Kynurenic Acid Synthesis Inhibitor Promotes Enhanced Sleep Recovery Following Acute Sleep Deprivation in Adult Wistar Rats

Abstract Introduction Sleep disorders and cognitive dysfunction often afflict the general population and are common amongst patients with neuropsychiatric disorders like schizophrenia. Sleep deprivation (SD) disrupts cognitive function, yet little is known about underlying mechanisms. The tryptophan metabolite kynurenic acid (KYNA), an endogenous a7nACh and NMDA receptor antagonist, is synthesized by kynurenine aminotransferase II (KAT II). KYNA is increased in the brain of patients with schizophrenia and our translational studies demonstrate that elevated KYNA disrupts hippocampal learning and sleep architecture in rodents (Pocivavsek et al. 2017 Sleep). We hypothesize a mechanistic link between KYNA, sleep, and cognitive dysfunction. Methods In vivo microdialysis in the dorsal hippocampus and simultaneous EEG/EMG telemetry was conducted in adult male Wistar rats (N=3-5 per group). Using a within-subjects experimental design, rats underwent a control and SD day. Animals received either vehicle or KAT II inhibitor PF-04859989 (PF), 30mg/kg s.c., on both days at zeitgeber time (ZT) 0 or ZT6. SD occurred from ZT0-6 by gentle handling. KYNA levels were evaluated in the microdialysate. Results SD effectively eliminated REM sleep (100%) and significantly reduced NREM (94%) during ZT0-6. Extracellular KYNA levels in the hippocampus significantly increased with SD (2-way ANOVA, time x SD: **P&amp;lt;0.0001) and PF readily prevented this accumulation. Initial sleep recovery (ZT6-12) did not significantly differ between treatment groups. During the dark phase (ZT12-24), PF treatment of SD animals promoted REM sleep parameters, including total REM duration (2-way ANOVA, SD x treatment ZT: P&amp;lt;0.05). PF treatment enhanced theta spectral power determined by Discrete Fourier transform during REM sleep recovery (ZT12-24). PF alone during the control day enhanced NREM delta power (P&amp;lt;0.05) during the late light phase (ZT6-12). Conclusion Importantly, the KAT II inhibitor PF promoted sleep recovery following acute SD, supporting our hypothesis that the accumulation of KYNA may exacerbate sleep disruptions. Changes in sleep parameters elicited by PF, a potential therapeutic avenue, may be indicative of mild somnolence. The present and future complementary experiments with cognitive behavioral tasks in rodents support our understanding of the role of KYNA in modulating sleep and cognition. Support (If Any) National Institutes of Health Grant No. NIH R01 NS102209

Sesamin: Insights into its protective effects against lead-induced learning and memory deficits in rats

BackgroundLead (Pb) is one of the most hazardous pollutants that induce a wide spectrum of neurological changes such as learning and memory deficits. Sesamin, a phytonutrient of the lignan class, exhibits anti-inflammatory, anti-apoptotic, and neuroprotective properties. The present study was designed to investigate the effects of sesamin against Pb-induced learning and memory deficits, disruption of hippocampal theta and gamma rhythms, inflammatory response, inhibition of blood δ-aminolevulinic acid dehydratase (δ-ALA-D) activity, Pb accumulation, and neuronal loss in rats. MethodsSesamin treatment (30 mg/kg/day; P.O.) was started simultaneously with Pb acetate exposure (500 ppm in standard drinking water) in rats, and they continued for eight consecutive weeks. ResultsThe results showed that chronic exposure to Pb disrupted the learning and memory functions in both passive-avoidance and water-maze tests, which was accompanied by increase in spectral theta power and theta/gamma ratio, and a decrease in spectral gamma power in the hippocampus. Additionally, Pb exposure resulted in an enhanced tumor necrosis factor-alpha (TNF-α) content, decreased interleukin-10 (IL-10) production, inhibited blood δ-ALA-D activity, increased Pb accumulation, and neuronal loss of rats. In contrast, sesamin treatment improved all the above-mentioned Pb-induced pathological changes. ConclusionThis data suggests that sesamin could improve Pb-induced learning and memory deficits, possibly through amelioration of hippocampal theta and gamma rhythms, modulation of inflammatory status, restoration of the blood δ-ALA-D activity, reduction of Pb accumulation in the blood and the brain tissues, and prevention of neuronal loss.

Use of quantitative electroencephalography as a marker of severity of patients with autism spectrum disorder

Autism spectrum disorder is a neurodevelopmental disorder with increasing prevalence over the past years. Its grading depends on a time-consuming Scales like CARS, ADOS and GARS scales. Our aim is to study if quantitative EEG can be used as a marker of ASD severity. This is a cross sectional study conducted in the period from September 2021 till March 2022. It included 53 patients (41 males and12 females, with age ranging between 3 and 12 years) diagnosed by an experienced psychiatrist according to DSM5 criteria. Patients were recruited from 4 autism centers in Al-Hillah city. All patients were assessed by history, physical examination and Gilliam autism rating scale (GARS 3). Then they undergo quantitative electroencephalographic recording in awake state. The study results showed that spectral power of delta wave both total and regional were significantly increased as the severity of ASD symptoms increased, while alpha spectral power was decreased with increasing severity of ASD. Beta and theta spectral power was unchanged. Also, at cut off value of power spectrum of delta of =27 Mv, give 75% sensitivity and 100 specificity for grading severe ASD.

EEG-explained cortical correlates of transfemoral amputees during balancing with vibrotactile feedback: A pilot study

Improving postural stability of lower limb amputees by integrating vibrotactile sensory feedback (VF) with balancing exercises has been proved advantageous. However, the cortical processes engaged in human balance control which process the VF and help to improve postural stability remain elusive. To this end, Electroencephalography in synchronization with the center of pressure (CoP) signals was collected from six transfemoral amputees during a balance control task in two sessions: with and without VF. The improved limit of stability (LOS) during the balance task with VF was in response to elicited strong theta and gamma oscillations. The secondary somatosensory cortex-S2 (contralateral to amputated side) processes the sensory information from VF by significantly reducing the theta spectral power. Additionally, the fronto-central (FC) region executed the motor response to improve the LOS by significantly increasing the gamma power. The intra-regional functional-connectivity at the S2 and FC region was significantly stronger with VF, in comparison to no feedback condition, and the two regions (S2 and FC) were strongly connected while perceiving the VF during forward voluntary sway in comparison to no feedback sessions. These findings provide fundamental insights into the cortical activity associated with the VF and helps in understanding the cortical mechanism of balance improvement in transfemoral amputees.

N-Pep-12 supplementation after ischemic stroke positively impacts frequency domain QEEG.

N-Pep-12 is a dietary supplement with neuroprotective and pro-cognitive effects, as shown in experimental models and clinical studies on patients after ischemic stroke. We tested the hypothesis that N-Pep-12 influences quantitative electroencephalography (QEEG) parameters in patients with subacute to chronic supratentorial ischemic lesions. We performed secondary data analysis on an exploratory clinical trial (ISRCTN10702895), assessing the efficacy and safety of 90 days of once-daily treatment with 90 mg N-Pep-12 on neurocognitive function and neurorecovery outcome in patients with post-stroke cognitive impairment against a control group. All participants performed two 32-channel QEEG in resting and active states at baseline (30-120 days after stroke) and 90 days later. Power spectral density on the alpha, beta, theta, delta frequency bands, delta/alpha power ratio (DAR), and (delta+theta)/(alpha+beta) ratio (DTABR) were computed and compared across study groups using means comparison and descriptive methods. Secondarily, associations between QEEG parameters and available neuropsychological tests were explored. Our analysis showed a statistically significant main effect of EEG segments (p<0.001) in alpha, beta, delta, theta, DA, and DTAB power spectral density. An interaction effect between EEG segments and time was noticed in the alpha power. There was a significant difference in theta spectral power between patients with N-Pep-12 supplementation versus placebo at 0.05 alpha level (p=0.023), independent of time points. A 90-day, 90 mg daily administration of N-Pep-12 had significant impact on some QEEG indicators in patients after supratentorial ischemic stroke, confirming possible enhancement of post-stroke neurorecovery. Further research is needed to consolidate our findings.

Intermittent Theta Burst Stimulation (iTBS) as an Optimal Treatment for Schizophrenia Risk Decision: an ERSP Study.

Objective: People with schizophrenia have serious impairments in social function, especially in decision-making ability. Transcranial magnetic stimulation modified intermittent theta burst transcranial magnetic stimulation (iTBS) has been shown to regulate the functional connection of brain networks. Our study explored the therapeutic effect of iTBS on decision-making disorders in schizophrenia.Methods: Participants were pseudorandomized and assigned to iTBS (n = 16) or sham (n = 16) group. iTBS group was administered 1,800 pulses on the target of the left dorsol lateral prefrontal cortex (L-DLPFC) per day for 14 consecutive days. We compared Iowa gambling task performance and associated event-related spectral perturbation results (ERSP) among two groups.Results: The results show that participants' performance in the high-lose in the iTBS group had stronger stimulation of theta spectral power than those in the sham group. Specifically, we found that under high-risk conditions, compared with the control group, the iTBS group showed significant activation of the theta spectrum power in the FPZ, FZ, FCZ, and CZ regions after treatment.Conclusions: Our results provide evidence that long-term iTBS stimulation effectively improves the decision-making ability of schizophrenia. After receiving negative feedback, patients can turn to safety options. These findings support that iTBS may be a potential treatment for clinical decision-making disorders.

Delta and theta eeg activity during resting state is altered in patients affected by major depression

IntroductionMajor depression (MD) is associated with cognitive and behavioral alterations in many domains. It is not well clear what cortical structures and functional alterations characterize MD patients during resting state, a condition during which mind wandering process is prevailing.ObjectivesIn MD patients with severe levels of depression we expected, during resting state, an altered asymmetry of cortical activity in the EEG bands that generally mark neurological impairment, i.e. Delta and Theta EEG bands.Methods30 MD patients under pharmacological treatment and 32 matched controls underwent an EEG recording (38 scalp sites) during 5 min resting state with open eyes. Eye movements were corrected by ICA modeling and the 5 min recording was divided in 2 sec epochs from which Delta and Theta spectral powers were extracted.ResultsSpectral analysis of the 5 min resting state revealed a significant difference between the two groups at the level of left temporal lobe. MD patients showed larger Delta and Theta spectral power in the left superior temporal gyrus at the level of Brodmann’s Areas 22 and 42.ConclusionsResults evidenced a cortical inhibition (greater EEG Delta and Theta activity) in left temporal linguistic areas in severe depression, a result pointing to a different mind wandering process and thought architecture in MD patients during resting state.

Inverse effects of time-on-task in task-related and task-unrelated theta activity.

The phenomenon of mental fatigue has recently been investigated extensively by means of the EEG. Studies deploying spectral analysis consistently reported an increase of spectral power in the lower frequencies with increasing time-on-task, whereas event-related studies observed decreases in various measures related to task engagement and attentional resources. The results from these two lines of research cannot be aligned easily. (Frontal) theta power has been linked to cognitive control and was found to increase with time-on-task. In contrast, theoretical frameworks on mental fatigue suggest a decline in task-engagement as causal for the performance decline observed in mental fatigue. The goal of the present study was to investigate mental fatigue in time-frequency space using linear regression on single-trial data in order to obtain a better understanding about how time-on-task affects theta oscillatory activity. A data-driven analysis approach indicated an increase of alpha and theta power during the intertrial interval. In contrast, task-related theta activity declined. This reduction of stimulus-locked theta power may be interpreted as a reduction of task engagement with increasing mental fatigue. The increase of theta spectral power in the intertrial interval, moreover, could possibly be explained by an increased idling of cognitive control networks. Alternatively, it might be the case that the increase of theta power with time-on-task is a by-product an alpha power increase. As alpha peak frequency systematically decreases with time-on-task, the theta band might be affected as well.

Aging-related changes in cortical mechanisms supporting postural control during base of support and optic flow manipulations.

Behavioral findings suggest that aging alters the involvement of cortical sensorimotor mechanisms in postural control. However, corresponding accounts of the underlying neural mechanisms remain sparse, especially the extent to which these mechanisms are affected during more demanding tasks. Here, we set out to elucidate cortical correlates of altered postural stability in younger and older adults. 3D body motion tracking and high-density electroencephalography (EEG) were measured while 14 young adults (mean age=24years, 43% women) and 14 older adults (mean age=77years, 50% women) performed a continuous balance task under four different conditions. Manipulations were applied to the base of support (either regular or tandem (heel-to-toe) stance) and visual input (either static visual field or dynamic optic flow). Standing in tandem, the more challenging position, resulted in increased sway for both age groups, but for the older adults, only this effect was exacerbated when combined with optic flow compared to the static visual display. These changes in stability were accompanied by neuro-oscillatory modulations localized to midfrontal and parietal regions. A cluster of electro-cortical sources localized to the supplementary motor area showed a large increase in theta spectral power (4-7Hz) during tandem stance, and this modulation was much more pronounced for the younger group. Additionally, the older group displayed widespread mu (8-12Hz) and beta (13-30Hz) suppression as balance tasks placed more demands on postural control, especially during tandem stance. These findings may have substantial utility in identifying early cortical correlates of balance impairments in otherwise healthy older adults.

Modulation of functional network properties in major depressive disorder following electroconvulsive therapy (ECT): a resting-state EEG analysis

Electroconvulsive therapy (ECT) is a highly effective neuromodulatory intervention for treatment-resistant major depressive disorder (MDD). Presently, however, understanding of its neurophysiological effects remains incomplete. In the present study, we utilised resting-state electroencephalography (RS-EEG) to explore changes in functional connectivity, network topology, and spectral power elicited by an acute open-label course of ECT in a cohort of 23 patients with treatment-resistant MDD. RS-EEG was recorded prior to commencement of ECT and again within 48 h following each patient’s final treatment session. Our results show that ECT was able to enhance connectivity within lower (delta and theta) frequency bands across subnetworks largely confined to fronto-central channels, while, conversely, more widespread subnetworks of reduced connectivity emerged within faster (alpha and beta) bands following treatment. Graph-based topological analyses revealed changes in measures of functional segregation (clustering coefficient), integration (characteristic path length), and small-world architecture following ECT. Finally, post-treatment enhancement of delta and theta spectral power was observed, which showed a positive association with the number of ECT sessions received. Overall, our findings indicate that RS-EEG can provide a sensitive measure of dynamic neural activity following ECT and highlight network-based analyses as a promising avenue for furthering mechanistic understanding of the effects of convulsive therapies.

An electrophysiological investigation on the emotion regulatory mechanisms of brief open monitoring meditation in novice non-meditators

Despite a growing literature supporting the salutary effects of mindfulness meditation on emotion regulation, the underlying mechanisms linking neural and subjective changes occurring during the actual practice of meditation with emotion regulatory effects observed after meditation remains virtually unexplored. The current study sought to address this gap in knowledge by testing the hypothesis that adoption of internally-directed focused attention, indexed by increased alpha and theta spectral power, during brief open monitoring (OM) mindfulness meditation predicts reduced emotional reactivity, as measured by the late positive potential (LPP). Results revealed that the OM meditation did not produce demonstrable differences in alpha and theta power but did increase self-reported sleepiness relative to controls. Follow-up analyses showed that sleepiness uniquely moderated the effect of meditation on the LPP, such that less sleepiness during meditation, but not the control audio, corresponded to smaller LPPs to negative images. Change in theta, but not alpha power, between meditation and rest was positively correlated with the LPP even after controlling for sleepiness. Although the primary hypothesis was unsupported, the findings demonstrate that phenomenological and neural changes occurring during OM meditation may modulate its subsequent “off-the-cushion” effects on emotional reactivity.