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Reducing state anxiety with alpha-frequency transcranial alternating current stimulation.

BACKGROUND: Anxiety reactivity to acute stress is a transdiagnostic vulnerability factor. We tested whether a single session of alpha-frequency transcranial alternating current stimulation (tACS) targeting the frontoparietal control network reduces stress-evoked state anxiety in healthy adults. METHODS: In a randomized, blinded, sham-controlled study, 42 participants (mean age 58.9 years) completed an acute stress task before and after stimulation. The task was an adapted moving-circles paradigm in which circle collisions triggered a brief aversive event (mild electric shock plus unpleasant noise and a white flash). Active stimulation consisted of 20 min of 10-Hz tACS (2.0 mA/channel; 30-s ramp up/down) delivered via electrodes at F3, P3, Cz, and T7 (0° phase at F3/P3; 180° at Cz/T7). Sham stimulation used the same montage and ramp periods but no sustained current. RESULTS: State anxiety showed a significant Time × Protocol interaction (F(1,35) = 4.22, p = .047): STAI-S decreased after active tACS (Δ = -3.16) but increased slightly after sham (Δ = +1.17). Perceived stress appraisal (SAAS) did not change. Resting-state alpha power at F3/P3 showed no reliable pre-post effects. During the task, left-frontal relative alpha differed by protocol and showed a trend toward larger increases following active tACS. Electrodermal and pupil indices changed across sessions in both groups, with no differential stimulation effects. CONCLUSIONS: A single alpha-tACS session produced a modest, selective reduction in stress-evoked state anxiety, supporting oscillatory neuromodulation as a scalable approach to dampen anxiety reactivity.

Humans

Disentangling oscillatory and aperiodic neural activity in autism: A spectral parameterization analysis of neurofeedback intervention.

BACKGROUND: Autism Spectrum Disorder (ASD) is characterized by atypical neural oscillations and heterogeneous alterations in excitation/inhibition (E/I) balance, the directionality of which varies across individuals, neural circuits, and developmental stages. While Alpha-band neurofeedback (NFB) is a promising intervention, its underlying neurophysiological mechanisms remain unclear, partly due to the conflation of periodic and aperiodic signals in traditional EEG analysis. METHODS: This randomized controlled trial recruited 40 children with ASD, assigned to either an experimental group (Alpha-training NFB) or a no-feedback group. Resting-state EEG and behavioral assessments (SRS, ABC) were collected pre- and post-intervention. We employed spectral parameterization to decompose neural activity into aperiodic (1/f slope, offset) and periodic (periodic alpha power, center frequency) components. RESULTS: NFB training yielded significant behavioral improvements in social cognition and relating skills. Physiologically, the experimental group exhibited a significant steepening of the aperiodic slope (increased exponent), reflecting a reduction in neural noise and potential optimization of inhibitory modulation. Furthermore, we observed enhanced periodic alpha power and an acceleration of the alpha center frequency (ACF), indicative of improved neural efficiency and maturation. These physiological shifts in frontal and occipital regions were significantly correlated with improvements in behavioral scores. CONCLUSION: Alpha-training NFB was associated with improvements in caregiver-rated behavioral scores and modulated spectral features of resting-state EEG in children with ASD. These findings validate the utility of spectral parameterization markers in evaluating neuromodulatory interventions.

Humans

Dissociating behavioral, neural and experiential effects of prefrontal HD-tDCS during conflict resolution.

Inconsistent evidence regarding the cognitive effects of transcranial direct current stimulation (tDCS) highlights the need for more comprehensive approaches to assess its impact. This study aimed to investigate the effects of high-definition tDCS (HD-tDCS) on conflict resolution by combining behavioral, neural, and subjective experience measures. Sixty participants were randomly assigned to anodal, cathodal, or sham HD-tDCS groups and completed a 30-min flanker task. EEG was recorded during the first and last blocks (without stimulation), while stimulation was applied during the intermediate blocks of the task. Using a multidimensional methodological approach including Drift-Diffusion Modeling (DDM), EEG spectral analysis, Lempel-Ziv complexity, and Temporal Experience Tracing (TET), we assessed the cognitive, neural, and phenomenological effects of stimulation. Behavioral results indicated no significant improvements in reaction times or accuracy across the stimulation groups. Similarly, DDM parameters showed no effect of HD-tDCS on latent cognitive processes. However, EEG data revealed a significant reduction in neural complexity in the anodal group during resting-state, suggesting a stabilization or reorganization of neural dynamics. Subjective experience analysis identified two distinct clusters of task-related feelings, though time spent in these experiential states did not differ between groups. Interestingly, sensation of stimulation was significantly higher for anodal stimulation than sham when analyzed as a single dimension. Despite null behavioral effects, this study provides important insights into the neural and subjective responses to HD-tDCS and highlights the value of integrating complementary multidimensional approaches to better characterize brain stimulation effects. These findings contribute to the ongoing debate about the efficacy of tDCS in cognitive enhancement.

Humans

Predicting training outcomes for developmental dyslexia from EEG data.

Developmental dyslexia (DD) is characterised by lower-than-average reading abilities and is diagnosed in approximately 10% of individuals. The societal barriers may limit professional fulfilment and psychological wellbeing of individuals with DD, calling for the development of effective interventions to counteract them. As DD is associated with challenges in both phonological and visuo-attentional domains, different longitudinal training approaches were developed to strengthen them. However, they require a considerable amount of personal, social and economic resources and the outcomes may vary depending on individual differences in behavioural and neurophysiological functionality. Hence, predicting training outcomes might help in developing personalised treatment protocols and optimising the use of resources. In the present work we applied machine learning to resting-state EEG to predict longitudinal training outcomes in adults with DD enrolled in a randomized clinical trial. In particular, one group received a visuo-attentional training combined with transcranial alternating current stimulation (tACS), another group received visuo-attentional training with sham/placebo stimulation, and the third group received a phonological training with sham/placebo stimulation. The improvement in text reading speed was associated with spectral power in low-beta and individual frequencies in the alpha (IAF) and beta (IBF) bands, while the improvement in pseudoword reading was associated with IBF. The findings highlight the potential of capturing neural markers of treatment responsiveness in DD. Future studies should focus on the generalisability of predictive models to real-world settings, while investigating whether specific EEG markers predict responsiveness to distinct remediation protocols, thus supporting the development of personalised interventions.

Humans

Cerebellar iTBS enhances gait adaptation by modulating cortical sensorimotor network dynamics: a randomized controlled trial.

Gait adaptation enables individuals to maintain locomotor stability under persistent perturbations. Although the cerebellum is critical for sensory prediction error-based (SPE) adaptation, how cerebellar neuromodulation reshapes cortical sensorimotor networks to enhance gait adaptation remains unclear. This study investigated the behavioral effects and underlying cortical neurodynamic mechanisms of cerebellar intermittent theta-burst stimulation (iTBS) on gait adaptation. Thirty-two healthy adults received either active or sham cerebellar iTBS. Participants performed a split-belt treadmill adaptation task before and after intervention. Cortical responsiveness was evaluated using TMS-evoked EEG over primary motor cortex (M1), while resting-state EEG was analyzed to assess spectral power and directional functional connectivity. Compared to sham, cerebellar iTBS significantly enhanced gait adaptation, evidenced by a faster adaptation rate (p = 0.035) and enhanced Early Adaptation SLS (p = 0.011), without altering initial perturbation responses or post-adaptation outcomes. The iTBS increased TMS-evoked α (p = 0.031) and γ (p = 0.022) power in M1, while the α power was correlated with faster adaptation (r = 0.526, p = 0.002). Furthermore, iTBS strengthened PPC-to-M1 directed connectivity in the β (p = 0.025) and γ (p = 0.013) bands. Enhanced parieto-motor directionality were positively associated with adaptation rate (β: r = 0.515, p = 0.003; γ: r = 0.463, p = 0.009). These findings suggest that cerebellar iTBS facilitates gait adaptation by modulating cortical responsiveness and directional sensorimotor network connectivity, providing multi-level neurodynamic evidence for the cerebello-cortical modulation during gait adaptation and offering a strong physiological rationale for targeted neuromodulation in gait rehabilitation strategies.

Humans

Comparison of the clinical efficacy, safety and EEG functional connectivity changes between 18-Hz rTMS and iTBS of accelerated dTMS treatment for major depressive disorder: a randomized controlled trial.

Although the antidepressant efficacy of 18-Hz deep transcranial magnetic stimulation (dTMS) has been validated, its prolonged treatment duration has considerable limitations for treatment capacity and patient adherence. Therefore, novel short-course protocols such as accelerated dTMS and intermittent theta burst stimulation (iTBS) present promising alternative options. Here we addressed the question of whether iTBS of accelerated dTMS achieves comparable therapeutic and electrophysiological effects to accelerated dTMS with the conventional 18-Hz rTMS protocol in patients with major depressive disorder (MDD). In a randomized controlled trial (n&#x2009;=&#x2009;73), participants received either 18-Hz rTMS of accelerated dTMS (rTMS-dTMS group), iTBS of accelerated dTMS (iTBS-dTMS group), or pharmacotherapy alone (drug group). Both dTMS protocols were administered twice daily for 10 days targeting the left lateral prefrontal cortex including the dorsolateral region. Results showed that Hamilton Depression Rating Scale (HAMD) score of the iTBS-dTMS group decreased significantly from 22.5&#x2009;&#xb1;&#x2009;3.7 before treatment to 8.2&#x2009;&#xb1;&#x2009;4.1 after treatment (t&#x2009;=&#x2009;15.900, p&#x2009;<&#x2009;0.001). HAMD score of the rTMS-dTMS group decreased significantly from 21.3&#x2009;&#xb1;&#x2009;2.9 before treatment to 8.0&#x2009;&#xb1;&#x2009;3.8 after treatment (t&#x2009;=&#x2009;17.232, p&#x2009;<&#x2009;0.001). The drug group also exhibited significantly improved patients' mood symptoms, and the HAMD score decreased from 24.7&#x2009;&#xb1;&#x2009;6.8 to 14.0&#x2009;&#xb1;&#x2009;5.0 (t&#x2009;=&#x2009;6.363, p&#x2009;<&#x2009;0.001). The treatment response rate was 85.7% in the iTBS-dTMS group and 76.9% in the rTMS-dTMS group, which was much higher than that of the drug group (42.1%). The remission rate was 50.0% in the iTBS-dTMS group and 42.3% in the rTMS-dTMS group, which was significantly higher than 10.5% of the drug group. We demonstrate here that both accelerated dTMS protocols significantly reduced HAMD scores, improved the response rates, and remission rates, outperforming pharmacotherapy alone. Resting-state EEG analysis further revealed unique frequency-specific functional connectivity (FC) modulation effects: the rTMS-dTMS group primarily exhibited weakened alpha-band functional connectivity within the fronto-occipital, fronto-temporal and fronto-central networks after treatment, whereas the iTBS-dTMS group predominantly demonstrated reduced theta-band functional connectivity within the fronto-parietal, fronto-occipital and fronto-temporal pathways after treatment. These findings indicate that iTBS of accelerated dTMS demonstrates comparable efficacy and tolerability to 18-Hz rTMS of accelerated dTMS, whilst inducing treatment-specific network-level neurophysiological alterations. In the rTMS-dTMS group, relative changes in FC between the frontal and temporal/precentral regions showed significant negative correlation with HAMD score reduction rates, while relative changes in FC between the frontal lobe and parietal lobe showed a significant positive correlation with the rate of HAMD score reduction for the iTBS-dTMS group. This study revealed novel mechanisms by which accelerated dTMS protocols modulate brain networks, providing evidence for the clinical application of accelerated iTBS-dTMS as an efficient, evidence-based treatment for MDD.

Humans

Brain network alterations underlying cue reactivity and craving in abstinent methamphetamine users: a systematic review of functional MRI findings.

BACKGROUND: Methamphetamine use disorder (MUD) is marked by intense craving and high relapse risk, often triggered by drug-related cues. Functional magnetic resonance imaging (fMRI) provides key insight into the neural basis of this cue reactivity, implicating large-scale brain networks for reward, motivation, and control. Yet, findings remain inconsistent across studies due to differences in task design, abstinence duration, and participant characteristics. OBJECTIVE: This systematic review synthesises evidence on how abstinence influences brain network alterations underlying cue reactivity and craving in methamphetamine users, integrating task-based and resting-state fMRI findings within leading neurobiological models of addiction. METHODS: A systematic search of PubMed, Scopus, Web of Science, and Ovid was conducted up to August 10, 2025, following PRISMA 2020 guidelines. Eligible fMRI studies examined cue reactivity or craving in abstinent methamphetamine users. Data were extracted on activation, connectivity, and brain-behaviour associations, and synthesised narratively. RESULTS: Task-based studies revealed heightened activation across reward, salience, and control networks during cue exposure, which diminished as parietal and executive control systems re-engaged with longer abstinence. Resting-state findings showed disrupted intrinsic connectivity among default mode, salience, and frontoparietal networks, reflecting persistent imbalances linked to craving and use severity. CONCLUSION: fMRI evidence shows that MUD is marked by network-level disruption linking reward, salience, and control systems. Task-based findings reveal strong cue reactivity in reward circuits, while resting-state data show persistent imbalance among default mode and control networks. With abstinence, partial restoration of network integrity emerges, highlighting both vulnerability and opportunities for targeted, recovery-based interventions.

Humans

Functional neuroimaging subtypes of obsessive-compulsive disorder: A systematic review and meta-analysis.

Obsessive-compulsive disorder (OCD) exhibits substantial clinical heterogeneity that may reflect underlying neurobiological diversity. Neuroimaging-based subtyping may advance precision psychiatry by identifying biologically distinct subgroups with differential treatment responses. This study systematically synthesized evidence from functional neuroimaging subtyping studies in OCD to identify reproducible neurobiological subtypes, characterize their clinical profiles, and establish a consensus-based classification framework. We reviewed 40 original studies employing machine learning, clustering, normative modeling, or classification approaches, encompassing approximately 8,150 patients. Consensus clustering identified three reproducible neurobiological subtypes. The Limbic-Hyperactive subtype, comprising approximately 40% of patients, exhibited amygdala and insula hyperconnectivity, elevated anxiety levels, predominant contamination and washing symptoms, and favorable response to cognitive-behavioral therapy. The Fronto-Striatal-Hypoconnected subtype, comprising approximately 35% of patients, demonstrated reduced orbitofrontal-striatal connectivity, cognitive inflexibility, predominant checking and ordering symptoms, and a favorable response to selective serotonin reuptake inhibitors. The Global-Disrupted subtype, comprising approximately 25% of patients, exhibited widespread connectivity disruption, greater symptom severity, and poor treatment response. Support vector machine classification achieved 81.5% accuracy for subtype assignment, though classification of OCD versus healthy controls showed limited generalizability in multisite settings (AUC 0.567-0.673). These findings support a neuroimaging-based framework for personalized treatment selection but require prospective validation.

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High-frequency contralesional dorsal premotor cortex and low-frequency contralesional primary motor cortex rTMS in subacute stroke with severe upper limb impairment: comparable motor outcomes and differential regional degree centrality changes.

BACKGROUND: The contralesional dorsal premotor cortex has been proposed as a potential neuromodulatory target for patients with severe upper limb impairment due to subacute ischemic stroke. This proof-of-concept study aimed to compare behavioral outcomes and resting-state neuroimaging findings between high-frequency repetitive transcranial magnetic stimulation (rTMS) over the contralesional dorsal premotor cortex and guideline-supported low-frequency stimulation over the contralesional primary motor cortex. METHODS: In this randomized trial, 46 patients with severe upper limb impairment in the subacute stage after ischemic stroke were randomly assigned to receive either high-frequency rTMS over the contralesional dorsal premotor cortex or low-frequency rTMS over the contralesional primary motor cortex. Low-frequency stimulation over the contralesional primary motor cortex served as an evidence-supported active comparator for poststroke upper limb motor recovery. Stimulation was administered five times per week for two weeks using magnetic resonance imaging-guided neuronavigation. All participants received concurrent standard rehabilitation therapy. The primary outcome was the Fugl-Meyer Assessment for Upper Extremity. Secondary outcomes included the Arm Subscore of the Motricity Index, the Hong Kong version of the Functional Test for the Hemiplegic Upper Extremity, the Modified Barthel Index, and resting-state functional magnetic resonance imaging-derived degree centrality. RESULTS: Both groups showed significant improvements in the primary and secondary behavioral measures (p&#x202f;<&#x202f;0.01), with no significant between-group differences in the magnitude of change (p&#x202f;>&#x202f;0.05). In neuroimaging analyses, patients receiving high-frequency rTMS over the contralesional dorsal premotor cortex showed significantly greater degree centrality changes in the ipsilesional middle occipital gyrus, contralesional medial superior frontal gyrus, and contralesional middle frontal gyrus than those receiving low-frequency rTMS over the contralesional primary motor cortex (p&#x202f;<&#x202f;0.05). Within the high-frequency stimulation group, degree centrality changes in the ipsilesional middle occipital gyrus were positively correlated with improvements in the Fugl-Meyer Assessment for Upper Extremity (r&#x202f;=&#x202f;0.619, false discovery rate-corrected p&#x202f;=&#x202f;0.018). CONCLUSIONS: High-frequency rTMS over the contralesional dorsal premotor cortex produced behavioral improvements comparable to guideline-supported low-frequency rTMS over the contralesional primary motor cortex, without establishing superiority or formal non-inferiority. Exploratory neuroimaging analyses showed greater degree centrality changes in the ipsilesional middle occipital gyrus after high-frequency premotor stimulation, and these changes correlated with upper-limb motor improvement. These findings support further investigation of contralesional dorsal premotor cortex-targeted high-frequency rTMS for severe subacute post-stroke upper limb impairment. REGISTRATION: URL: http://www.chictr.org.cn; Unique identifier: ChiCTR2000038049.

Humans

Ictal electroencephalography and heart rate as treatment criteria in electroconvulsive therapy: a systematic review of the literature.

BACKGROUND: Decades before the emergence of precision medicine, psychiatrists raised the question of whether specific seizure characteristics could help optimize electroconvulsive therapy (ECT), as relationships between some of these characteristics and better outcomes were found. From 1990 onward, researchers focused on electroencephalography (EEG) and cardiovascular markers, which were broadly adopted by guidelines worldwide. However, the prognostic value of these markers is still controversial. Here, we provide a systematic summary of the studies on this topic. METHODS: We conducted a literature review on the use of ictal EEG and heart rate as outcome predictors in ECT using the PubMed, EMBASE, Cochrane and PsycINFO databases. RESULTS: Thirty-seven studies addressing more than 100 quality markers fulfilled our inclusion criteria. Single EEG markers were assigned to five categories (postictal inhibition, amplitude, coherence, regularity, and seizure duration). Heart rate and composite markers were considered separately. In contrast to single EEG markers, heart rate and composite markers could be consistently linked to better outcomes in patients with depression. Only a few studies on schizophrenia could be retrieved. CONCLUSION: Multiparametric markers outperformed single markers. Furthermore, changes in heart rate during seizures were related to better outcomes. Although clinical assessment remains the cornerstone of treatment guidance decisions, EEG and cardiac monitoring could help prevent insufficient seizures during the period preceding clinical improvement. Evidence on schizophrenia remains limited. More randomized trials are needed to analyze the role of composite markers as prognostic tools.

Humans

Sleep stage-dependent distribution of interictal epileptiform discharges in epilepsy: A systematic review.

BACKGROUND: Sleep and epilepsy interact through complex bidirectional mechanisms. Although NREM sleep facilitates interictal epileptiform discharges (IED), the diagnostic contribution of individual sleep stages remains uncertain. In particular, it is unclear whether deeper sleep stages such as N3 provide an advantage over N2 for spike detection or localization in clinical (electroencephalography) EEG practice. METHODS: This systematic review followed PRISMA 2020 guidelines. PubMed and Web of Science were searched for studies reporting quantitative IED measures across sleep stages in patients with epilepsy. Eligible studies included scalp EEG, video-EEG, polysomnography, or intracranial recordings. Mean IED rates per minute were derived when possible. Comparisons between NREM and REM sleep and between N2 and N3 stages were performed using study level non-parametric tests. Risk of bias was assessed with the ROBINS-I tool. RESULTS: Ten observational studies including 266 patients (mean age 30.1&#xa0;years) were analyzed. IED rates were significantly higher during NREM than REM sleep (Wilcoxon signed-rank test, W&#xa0;=&#xa0;0, p&#xa0;=&#xa0;0.0019, r&#xa0;=&#xa0;0.87). No significant difference was observed between N2 and N3 sleep, although median spike rates were slightly higher during N3 than N2 (0.99 vs 0.86 IED/min). REM showed the lowest activity. CONCLUSIONS: NREM sleep consistently exhibited higher IED rates than REM sleep, reinforcing the neurophysiological association between sleep stage and epileptiform activity without establishing diagnostic superiority.

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Early infantile developmental and epileptic encephalopathy: clinical spectrum, diagnosis, outcomes, and evolving treatment strategies.

Early infantile developmental and epileptic encephalopathy (EIDEE) is among the most severe epilepsy syndromes, with onset before three months of age and an estimated incidence of approximately 10 per 100,000 live births. The 2022 International League Against Epilepsy classification unified the historically distinct Ohtahara syndrome and early myoclonic encephalopathy under a single diagnostic framework defined by frequent drug-resistant tonic and/or myoclonic seizures, an abnormal neurological examination, and an abnormal interictal electroencephalogram-most characteristically a burst-suppression pattern. This narrative review synthesizes the clinical, electrophysiological, neuroimaging, genetic, and therapeutic literature within the EIDEE framework. The clinical phenotype is characterized by central hypotonia, postnatal microcephaly, cortical visual impairment, and age-dependent syndromic evolution toward infantile epileptic spasms syndrome or Lennox-Gastaut syndrome in the majority of patients. Electroencephalography remains essential for syndromic classification, while systematic metabolic screening and early trio whole-exome or whole-genome sequencing are central to the etiologic workup, achieving diagnostic yields of 60-65%. The most commonly identified genetic causes include STXBP1, KCNQ2, and SCN2A variants. Outcomes are poor overall and strongly etiology-dependent: vitamin-responsive disorders carry a substantially more favorable prognosis, whereas mortality reaches 25% in genetic cohorts. Genotype-guided pharmacotherapy is now applicable to a clinically meaningful subset of patients, with sodium channel blockers, potassium channel openers, and emerging antisense oligonucleotide therapies representing important therapeutic advances. Gene therapy trials are underway but have encountered early safety signals, underscoring the vulnerability of this population. Critical unmet needs include earlier molecular diagnosis, precision therapies targeting developmental outcomes beyond seizure control, and prospective international registries to characterize the long-term natural history of EIDEE.

Humans

Short-term effects of foot reflexology on pain, anxiety, and physiological responses in women with shoulder and neck pain: A randomized controlled trial.

OBJECTIVES: Shoulder and neck pain (SNP) is a common musculoskeletal complaint among women and is often accompanied by heightened anxiety. Foot reflexology (FR) is a complementary therapy proposed to promote relaxation and short-term psychophysiological regulation. This study examined the short-term effects of a single session of FR on pain, anxiety, and physiological responses in women with SNP. METHODS: A single-blind randomized controlled trial was conducted with 80 women aged 20-64&#xa0;years in southern Taiwan. Participants were randomly allocated to one of three groups: FR, exercise, or passive rest control. Each group received a single 50-min session. Pain intensity and anxiety were assessed using the Numeric Rating Scale (NRS) and the State-Trait Anxiety Inventory (STAI), respectively. Heart rate and blood pressure were recorded as physiological indicators. Outcomes were measured at baseline, immediately post-intervention, and at 24-h follow-up. RESULTS: Baseline pain, anxiety, and physiological measures did not significantly differ among groups. Immediately after the intervention, both the FR and exercise groups demonstrated greater reductions in pain intensity compared with the passive rest control (P&#xa0;<&#xa0;0.001 and P&#xa0;=&#xa0;0.018, respectively). The FR group additionally showed greater reductions in anxiety and heart rate compared with the passive rest group (P&#xa0;=&#xa0;0.005 and P&#xa0;=&#xa0;0.001, respectively). Pain reduction in the FR group remained significant at the 24-h follow-up (P&#xa0;=&#xa0;0.013), whereas anxiety reductions were not sustained. No significant between-group differences were observed for systolic blood pressure. CONCLUSION: A single session of FR was associated with immediate and short-term reductions in pain, anxiety, and heart rate among women with SNP. Foot reflexology may serve as a supportive, non-pharmacological approach for short-term modulation, although sustained effects require further investigation.

Humans

Theta-range SEEG stimulation for intracranial mapping: extending conventional 1-Hz and 50-Hz protocols.

OBJECTIVE: Electrical brain stimulations (EBS) are central to epileptic network identification and functional mapping during stereo-electroencephalography, yet stimulation frequencies remain empirical, and standardized across patients and brain regions, producing false negatives and false positives, and potentially compromising surgical outcome. We prospectively investigated theta-range EBS (7&#xa0;Hz) in the temporal lobe, a prominent physiological frequency band in this region, and compared it with conventional 1-Hz and 50-Hz protocols. METHODS: We analyzed 1,408 temporal EBS in 25 drug-resistant epileptic patients. Epileptic responses (afterdischarges, seizures) and clinical signs were assessed across the epileptic network and temporal structures (amygdala, hippocampus, neocortex, parahippocampal gyrus, white matter), and confronted to stimulation parameters (frequency, intensity, duration, total charge). RESULTS: At matched intensity and duration, 7-Hz EBS were associated with a higher occurrence of afterdischarges and clinical signs than 1-Hz EBS in several temporal structures. Effects on usual seizure induction were less consistent. Comparisons with 50&#xa0;Hz showed no systematic significant differences, with responses observed at one or both frequencies depending on structure and outcome. When controlling for total charge, frequency-related differences were attenuated. Some effects were sporadically observed at both intermediate frequency and charge quantity. CONCLUSIONS: EBS responses emerge from the interaction between all electrical parameters and anatomical location and local excitability, and can hardly be disentangled. However, 7-Hz EBS can provide complementary clinical information during temporal-lobe mapping, with a targeted approach. SIGNIFICANCE: These findings support targeted evaluation of broader stimulation parameter spaces, including intermediate frequencies, rather than routine reliance on fixed low- and high-frequency protocols alone.

Humans

Assessing the effects of non-invasive transcranial electrical stimulation (tACS and tDCS) on electrophysiological sleep parameters - a systematic review.

Transcranial electrical stimulation (tES), including transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS), is considered a safe method to modulate cortical activity and endogenous brain oscillations. Given the therapeutic potential of tES across various clinical conditions and the central role of sleep in restoration and memory consolidation, numerous studies have investigated its effects on sleep and sleep-related parameters, yielding inconsistent results. This systematic review provides an up-to-date synthesis of 51 studies assessing the impact of tES on objectively measured electrophysiological sleep outcomes in both healthy individuals and clinical populations. The reviewed studies demonstrate heterogeneous effects, reflecting substantial variability in study designs. Nonetheless, consistent trends emerge, including reduced NREM1 and increases in total sleep time, NREM2, and NREM3 following tES. Moreover, slow-oscillatory tES increased slow-wave power during sleep. Here we show that tES, particularly slow-oscillatory tES, may positively influence sleep architecture and continuity by modulating endogenous brain oscillations. However, due to heterogeneous stimulation protocols, inconsistent findings, the limited number of significant effects and substantial risk of bias the current evidence remains inconclusive. Well-designed, large-scale trials targeting specific sleep outcomes are needed to clarify the therapeutic potential of tES.

Humans

Electroencephalographic evidence of cortical network disruption preceding overt cardioinhibition during tilt-induced reflex syncope.

OBJECTIVE: Reflex syncope is a common cause of transient loss of consciousness. However, the early cerebral mechanisms underlying cardiovascular changes remain poorly understood. Our objective was to investigate early cerebral changes by quantitatively analyzing EEG activity preceding overt cardioinhibition during tilt-induced reflex syncope. METHODS: EEG recordings from patients undergoing tilt testing were retrospectively analyzed. Patients who experienced reflex syncope were compared to those who did not. Spectral and functional connectivity analyses were performed across baseline, pre-cardioinhibition, and syncopal phases. RESULTS: Prior to the onset of cardioinhibitory pathological reflex, a significant increase in theta-band spectral power was observed in the right temporal region, accompanied by a widespread increase in functional connectivity within the same frequency band. These findings suggest the involvement of brain networks before cardioinhibition. CONCLUSIONS: EEG changes in the theta band (power and functional connectivity) were observed before overt cardioinhibition during tilt-induced reflex syncope. SIGNIFICANCE: Our findings support the hypothesis of cortical processing preceding cardioinhibition in reflex syncope. EEG may represent a valuable complementary tool for improving the understanding and diagnosis of these events.

Humans

Reliability of resting heart rate measurements in atrial fibrillation.

BACKGROUND: Heart rate (HR) control in atrial fibrillation (AF) is commonly guided by resting HR measurements, usually with 12&#x2011;lead ECG or in-office pulse palpation. OBJECTIVES: We aimed to assess the reliability of resting HR measurements in AF patients with long-term ambulatory ECG and activity monitoring. METHODS: We included patients who had recorded a full-disclosure ambulatory ECG with a mobile cardiac telemetry device equipped with an accelerometer (PocketECG, MEDICALgorithmics, Poland), with at least 95% AF. Resting HR samples (&#x2264;20 per individual/day) were collected as 10-s daytime (8&#xa0;am to 8&#xa0;pm) measurements after &#x2265;10&#xa0;min of rest. These samples were compared to each individual's mean daytime resting HR. RESULTS: In 832 patients (median age 77 (interquartile range (IQR) 69-83) years, 42% women) with a median registration duration of 13&#xa0;days (IQR 7-22), the population mean daytime resting HR was 85 (&#xb1;15) beats per minute (bpm). A single resting HR differed from the mean daytime resting HR by a mean of &#xb1;10.4% (IQR 3.6-14.4%). When the mean daytime resting HR was &#x2265;110&#xa0;bpm, 29% of resting HR samples were&#xa0;<&#xa0;110&#xa0;bpm, and when the mean daytime resting HR was 80-109&#xa0;bpm,11% of samples were&#xa0;&#x2265;&#xa0;110&#xa0;bpm. Resting HR measurement variability decreased to 5.3% (IQR 1.9-7.5%) when four resting HR samples were averaged. CONCLUSION: In patients with AF, a single resting HR measurement often differs substantially from the mean daytime resting HR. When a precise measurement is clinically relevant, repeated resting HR sampling or ambulatory monitoring can address this measurement imprecision.

Humans

Infra-low-frequency neurofeedback alters EEG network efficiency: exploratory evidence from healthy volunteers.

Infra-Low-Frequency Neurofeedback (ILF-NFB) combines classic frequency-band (FB) and infra-low-frequency (ILF) EEG components in implicit training protocols and is increasingly applied in clinical contexts. Yet, the neurophysiological mechanisms underlying ILF-NFB remain to be further elucidated. In this randomized, sham-controlled and double-blind study, we explored the online impact of a one-session ILF-NFB application on EEG correlates in healthy participants (39 analyzed datasets). Continuous 31-channel EEG was recorded during verum and sham feedback in a double-blind, randomized crossover design. In this exploratory analysis approach, functional connectivity was estimated using the debiased weighted phase-lag index (dwPLI) and analyzed with graph-theoretical measures. The results revealed higher global efficiency during verum compared to sham in the Beta1 band (12-15 Hz), reaching significance in the primary comparison but not surviving Bonferroni correction across the five tested bands; block-wise follow-ups showed a significant verum-sham difference in the first half of the neurofeedback session and a directionally consistent pattern in the second half. The Condition&#x202f;&#xd7;&#x202f;Block interaction was not significant. No consistent differences were observed in other frequency bands, nor for betweenness centrality. While preliminary, these exploratory results point to possible network-level effects during ILF-NFB and motivate further confirmatory work in extended training protocols and clinical populations.

Humans