Frontiers in Human Neuroscience

Many pathological conditions, including chronic pain (CP), can impair cognitive functions. These functions are essential for adapting and evolving in concordance with the environment, which are key processes for coping with CP. However, in CP centers, cognitive assessment is rarely included in CP patient follow-up due to a lack of time, appropriate tools, or trained health professionals. To fill this gap, our team developed EasyCog, a digital tool that enables rapid self-assessment of cognitive functions. It enables cognitive evaluation without an experimenter's help, thanks to speech recognition powered by an artificial neural network. In the initial validation steps, we established normative values for 7 cognitive functions on a cohort of 76 healthy subjects. Because EasyCog includes tests comparable to the Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Examination (MMSE), we assessed its reliability against available normative values. To assess its specificity, we compared data from healthy subjects with 15 subjects with mild cognitive impairment (MCI) and 15 age-matched CP patients selected from a medical center. Finally, we tested EasyCog's test-retest reliability by repeating sessions at different time intervals. EasyCog showed excellent sensitivity to age-related decline, similar to MoCA normative values. Several cognitive functions were significantly and differentially impaired in MCI subjects and CP patients compared to normative values in healthy subjects, confirming good specificity. Finally, test-retest analysis showed no effect at a 4-month interval. In conclusion, EasyCog appears to be a convenient and reliable numeric tool for rapidly assessing and monitoring cognitive functions in patients.

Neuromarketing mainly seeks to enhance the prediction of marketing stimuli success, such as commercials and movie trailers, by integrating neurophysiological measures with traditional behavioral measures. In the current study, the authors tested whether neural activity could predict consumer valuation and how preferences change after watching commercials, both immediately and over time. Participants (n=161) watched images of products followed by commercials advertising those products while their neural activity was recorded using electroencephalograph (EEG). They watched the product images again a week later without EEG recordings. Immediately after each stimulus exposure, participants stated their willingness to pay (WTP) for the product and how much they liked the commercial. Standard EEG measures showed weak and inconsistent relationships with behavior and yielded near-chance predictions. In contrast, deep learning models applied to the raw neural data achieved substantially higher predictive accuracy, successfully predicting both immediate and delayed WTP and ad liking. Importantly, the authors were able to successfully predict preferences for new participants and/or new products the models were not trained on. However, accuracy declined as generalization demands increased. Moreover, prediction performance declined as value differences narrow. Together, these findings show that neural responses carry reliable and temporally persistent information about consumer valuation and its evolution over time.

Communication is inherently interactive, yet most neuroimaging studies examine individuals in isolation. Here, we used functional near-infrared spectroscopy (fNIRS) hyperscanning to investigate interbrain synchrony (IBS) during naturalistic communication. In Study 1, 13 healthy familiar dyads completed Joint Singing, Joint Reading, and Picture Guessing tasks. IBS was quantified using wavelet transform coherence across bilateral frontal and temporoparietal regions. Joint Singing produced higher IBS than the other tasks in several regions, including the dorsolateral prefrontal cortex and temporoparietal junction, and selected effects were greater in true than pseudo-dyads. In Study 2, we applied the same paradigm to five individuals with chronic post-stroke aphasia interacting with trained speech-language pathologists. IBS could be estimated in all dyads after lesion-informed channel exclusion, although regional coverage varied with lesion location. These findings demonstrate that fNIRS hyperscanning can capture task-dependent interpersonal neural coupling during spoken interaction and can be extended to communication involving individuals with aphasia. This approach provides a foundation for studying how neural coordination between communication partners relates to functional communication and partner-supported interaction.

Purpose: Electrical stimulation of the occipital cortex evokes visual percepts known as phosphenes. To date, most human studies have examined phosphenes elicited by large surface or depth electrodes. These differ considerably from the small penetrating intracortical microelectrodes capable of stimulating highly localized cortical populations that are the basis of current next-generation devices. Here, we provide a detailed characterization of phosphenes evoked by such intracortical microelectrodes. Methods: As part of the CORTIVIS clinical trial, a Utah Electrode Array with 100 penetrating electrodes was implanted in the early visual cortex of four blind volunteers. Participants completed drawing and description tasks in response to single-electrode stimulation. Two participants also performed forced-choice tasks to determine whether phosphenes elicited by different electrodes could be reliably discriminated. Results: Single-electrode stimulation reliably evoked phosphenes in all participants. Most percepts appeared in the contralateral visual field, although two participants reported near-midline ipsilateral percepts. Phosphenes ranged from simple dots to elongated, textured, circular, or otherwise idiosyncratic forms. One participant reported distinguishable phosphene colors, which depended on electrode and amplitude structure and varied across sessions. The two participants tested on forced-choice discrimination could successfully identify electrode-specific phosphenes across multiple sessions. Conclusions: Intracortical microstimulation of the human visual cortex produces phosphenes with diverse, electrode-specific appearances that are recognizable across repeated trials. These findings indicate that penetrating microelectrodes often evoke more structured percepts than simple points or blobs, providing foundational evidence that electrode-specific encoding strategies will be necessary in future visual prosthetic devices.

Background Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and post-COVID condition are complex, debilitating illnesses characterized by persistent fatigue and post-exertional malaise. Recovery is uncommon without targeted intervention; however, emerging clinical reports suggest that a subset of patients experience full resolution of symptoms after engaging in mind-body approaches. Patient perspectives on these interventions are divided, and qualitative evidence exploring successful recovery pathways is rare. This protocol outlines a study to investigate the contextual factors and patient-constructed explanations surrounding full recovery from ME/CFS or post-COVID condition using mind-body approaches. Methods and analysis We will employ a qualitative descriptive design rooted in a constructivist paradigm. Purposive and snowball sampling will be used to recruit approximately 20 adults from established infection-associated fatigue networks who self-report full recovery (lasting three months or more) from ME/CFS or post-COVID condition following a mind-body approach. Data will be collected through semi-structured interviews conducted via Zoom, and investigator reflexivity will be reported. Demographic information, including comorbidities, will be documented to contextualize the sample. Data will be analyzed inductively using reflexive thematic analysis. To ensure research rigor and reporting transparency, the study will adhere to the 15-point checklist of criteria for good thematic analysis proposed by Braun and Clarke. Dissemination We will publish our findings in a peer-reviewed, open-access journal and present at relevant academic conferences. A lay summary of the results will also be shared directly with participating patient recovery networks.

The validation of objective neurophysiological monitoring of concussion from diagnosis to return to play has the potential to improve the clinical care of athletes. Extracted from event-related potentials (ERP), brain vital signs offer a non-invasive objective neurophysiological measure of three well established ERP responses that complement existing clinical assessments: 1) the N100 response related to auditory sensation; 2) the P300 response related to basic attention; and 3) the N400 response related to cognitive processing. The N400, in particular, has increasingly been demonstrated to be sensitive to head impact related cognitive impairment. Accordingly, brain vital sign measures were collected in n =165 rugby league players from two Australian professional National Rugby League clubs (NRL), with concussed players (n =26) being subsequently assessed over a total of five separate time points (Baseline, Day 2, Day 5, Day 10, and Day 42). This timeline aligned with acute (Day 2), NRL mandatory minimum return-to-play (RTP) guidelines (Day 10), and an extended post RTP period. Relative to baseline, the results revealed significant N400 cognitive processing latency delays at Day 2 post-concussion (p =0.002). The N400 latency delays persisted past day 5, significantly returning to baseline values at Day 10, consistent with the RTP mandatory minimum requirement. The findings indicated that neurophysiological recovery occurred in this cohort within an approximate 10-day time frame. Future studies monitoring brain vital sign changes across the trajectory of injury to recovery are needed in sports related concussion management.

Flow is a subjective state where tasks feel effortless and rewarding. It has been linked to distinct neural signatures, yet dynamics of these signals remain poorly understood. Here, we investigated spectral dynamics of brain activity in flow. We recorded electroencephalogram (EEG) data at positions AF7, AF8, TP9, and TP10 using a lightweight wearable device worn by ten adult participants while they completed a go-signal task and two stop-signal tasks. Task difficulty was continuously adjusted to induce either a sense of flow or frustration. Time-resolved spectral power and interregional coherence were extracted with continuous wavelet and wavelet coherence transforms; subjective flow was assessed after each block with the short-form Flow-State Scale. Subjective ratings confirmed that the flow and frustration conditions diverged in perception of flow. In the flow block, errors on stop trials coincided with pre-stimulus reductions in right temporoparietal gamma power and frontal beta and gamma power, alongside diminished frontotemporal gamma coherence. Comparison of flow and frustration revealed higher temporal beta power during frustration, consistent with greater cognitive load. Flow may involve finely balanced beta and gamma dynamics, and brief collapses of these rhythms may predict task errors. Spectral dynamics are actionable features for closed-loop engagement monitoring applications.

Mobile EEG can link neuroimaging to natural behavior, but effects recorded during movement, and sport in particular, are difficult to interpret because neural activity overlaps with signals from movement, muscle activity, and cable movement artifacts. We analyzed the OpenNeuro Real World Table Tennis dataset to test whether peri-hit spectral activity could be analyzed and how it differed between human-opponent and ball-machine play. Data from 25 participants comprising EEG, noise-layers, EMG and motion recordings was analyzed with pre-hit, impact, and post-hit windows. EEG power bands were residualized using trial-level root mean square from noise-layer, EMG, and motion/miscellaneous channels. Spectral parameterization modeled spectra as an aperiodic component plus periodic peaks. The principal short-window model was resolution-aware; sensitivity analyses reduced model complexity, used a 2.0-s peri-hit subwindow (-1.0 to +1.0 s), or disabled periodic fitting. Results showed residualized alpha and beta power was lower during ball-machine play, including pre-hit posterior alpha power. The clearest context difference was a higher ball-machine aperiodic exponent over posterior and parietal sensors, corresponding to a steeper broadband spectral slope. Posterior post-hit means were 0.451 and 0.606 for human-opponent and ball-machine play, respectively. A focal parietal effect persisted across specifications. The results support artifact-informed, resolution-aware spectral analysis as an effective approach for detecting robust spectral differences between naturalistic visuomotor contexts and suggest that EEG may provide useful information about the processes engaged by different practice environments, without establishing a single cognitive or physiological mechanism or demonstrating a training outcome.

Chronic spatial neglect after right-hemisphere stroke reflects network dysfunction, with recovery influenced by structural connectivity. Music recruits coordinated bi-hemispheric activity and may promote interhemispheric communication after stroke. Following our pilot study in post-stroke aphasia, we asked whether classical music modulates connectivity and behavior in chronic neglect. Three patients completed a crossover protocol comparing two weeks of daily audiovisual classical music with an audiobook control, with neglect, mood, quality-of-life, diffusion MRI, and resting-state high-density EEG measures. All showed right superior longitudinal fasciculus II disconnection with preserved callosal pathways. In N2, line bisection shifted leftward across all five lines after music, together with increased posterior interhemispheric theta-band weighted symbolic mutual information (wSMI), then deteriorated into the pathological range after the audiobook, without mood improvement. N1 showed mixed behavioral effects, with mood and quality of life improving after music. N3 showed no significant spatial improvement and worsened mood after music. These heterogeneous responses motivate larger studies of connectional predictors. The findings support the feasibility of classical music as an adjunct to neglect rehabilitation and suggest that cognitive changes may occur independently of mood, while the audiobook cannot be considered an inert control.

Navigating the world requires our brains to constantly process a massive influx of information from the environment. One of the most remarkable yet complex feats the human brain performs daily is speech perception. It is a multifaceted, hierarchical process that relies heavily on the integration of auditory and visual cues, particularly in noisy environments. Neural integration of these streams is hypothesized to depend on temporal mechanisms governed by individual alpha frequency (IAF, 8-12 Hz), which serves as a key neural correlate of the temporal binding window (TBW). While IAF has been linked to multisensory integration, its role in shaping multisensory illusions remains largely unexplored. Here, we tested this directly using transcranial alternating current stimulation (tACS) to modulate occipital activity during multisensory conflict. In a two-day protocol involving 27 healthy participants, resting-state EEG was recorded to determine IAF. On Day 2, participants then performed a multisensory speech task involving congruent (pa/, /ta/, /ka/) and incongruent McGurk stimuli (auditory /pa/, visual /ka/), both at baseline and during tACS applied at IAF and offset frequencies (IAF +/- 2 Hz) over occipital electrodes. While accuracy for congruent syllables remained high across conditions, results revealed that tACS significantly reduced the perception of illusory /ta/ percepts during McGurk trials. Finally, using a phenomenological model based on Kuramoto oscillators, we provided a mechanistic explanation for the percentage of illusory responses observed across participants under the influence of tACS at IAF and offsets. This study highlights the potential for targeted neuromodulatory interventions to influence multisensory processing in clinical or professional settings.

Neurofeedback shows promise as a clinical intervention, but its effectiveness is hindered by variability of response across individuals. One factor influencing neurofeedback success may be endogenous brain states, particularly the baseline power within target frequency bands. Transcranial alternating current stimulation (tACS) provides a potential mechanism to modulate these baseline frequency bands. This study explored whether tACS could effectively enhance participants' ability to gain neurofeedback control by increasing lateralised posterior alpha activity prior to engagement in a covert spatial attention-based neurofeedback task. Participants completed three counterbalanced sessions: 1) alpha tACS and active neurofeedback, 2) alpha tACS and sham neurofeedback, 3) gamma (40Hz) tACS and active neurofeedback. Neurofeedback performance was assessed via lateralised posterior alpha power shifts and Posner task reaction times. We identified no difference in reaction times or lateralised alpha power shifts across conditions. While participants reliably demonstrated lateralised posterior alpha patterns, consistent with the covert spatial attention neurofeedback protocol, no advantage of active neurofeedback over sham was observed. The lack of significant effects underscores the need for further rigorous tACS studies to identify the parameters essential for successful neural entrainment, and to evaluate its potential in enhancing neurofeedback efficacy.

Bodily sensations shape the emotional experience of music, yet the neural underpinnings of embodied musical emotions remain poorly understood. Here we investigated the correspondence between neural activity patterns and self-reported bodily sensations induced by emotional music. Participants (n=74) listened to emotionally engaging (aggressive, happy, sad, scary) music while their hemodynamic brain activity was measured with functional magnetic resonance imaging (fMRI). Music-induced bodily sensations were measured after imaging. Representational similarity analysis (RSA) was used to identify brain regions where the representational geometries of neural responses to music align with the topographical patterns of the corresponding bodily sensations, emotions, and musical features. Bodily sensations maps (BSMs) showed emotion-specific topographies. Univariate general linear model (GLM) analysis revealed increased neural activity within motor, somatosensory, interoceptive, limbic, and auditory brain regions during music listening, with little difference between the emotion categories. In contrast, RSA revealed significant correspondence between the representational geometries of neural activity patterns and emotion category-specific bodily sensations in motor, somatosensory, emotion-related and auditory brain regions. Multivariate pattern (MVP) classification analysis showed that activity in the auditory cortex accurately predicted the emotion categories. Our results indicate neural correspondence to bodily sensations in somatomotor and somatosensory brain regions, providing novel evidence for the neural basis of embodied music-induced emotions.

Motor effort has been shown to bias perceptual decisions toward less effortful choices, but it remains unknown whether this bias already takes effect during the early stages of decision formation through preparatory attentional allocation or sensory processing, or during later-stage evidence accumulation preceding response execution. This study investigated when motor effort becomes integrated into decision formation by focusing on the temporal evolution of neural processing during perceptual decision-making. While 64-channel EEG was recorded, twenty-four healthy adults performed an orientation discrimination task in which two Gabor patches appeared simultaneously in the left and right visual hemifield and decisions were reported using two pressure-sensitive response buttons requiring different levels of force. We found that motor effort modulated EEG activity at both the preparatory and later decision stages: pre-stimulus alpha power was reduced over the occipito-parietal cortex contralateral to the low-effort option, and mean centro-parietal positivity (CPP) amplitude preceding response execution was greater over centro-parietal cortex for low-effort choices, while leaving early sensory representations intact as indicated by no differences in P1 or N1 amplitude following stimulus onset. Trial-by-trial CPP amplitude preceding response execution increased with the likelihood of selecting the low-effort option, whereas the pre-stimulus alpha modulation was not associated with behavioral decision bias. These findings suggest that motor effort biases perceptual decisions primarily during later-stage evidence accumulation, thereby providing insight into the neural basis of embodied perceptual decision making.

Background and Objectives: Code-modulated visual evoked potentials (c-VEPs) provide fast and reliable control signals for reactive brain-computer interfaces (rBCIs). However, deployment beyond laboratories remains limited by visually intrusive stimulation, reliance on wet electroencephalography (EEG), and false activations during non-control periods. We introduce a usability-oriented c-VEP rBCI combining low-salience textured stimulation, slow flashing codes, asynchronous evidence accumulation, and semi-dry EEG acquisition. Methods: Thirty participants evaluated the system on a standard screen using an 11-class keypad typing task. Two identical online typing sessions were separated by a 2-min video-viewing period serving as an explicit idle condition. Feasibility was then assessed in virtual reality (VR) through a proof-of-concept shell-game task involving head movements and immersive rendering constraints. Visual comfort, peripheral distraction, and fatigue were assessed subjectively in both conditions. Results: In the keypad task, the system achieved 99.8% accuracy with 33 s of calibration data and a mean decoding time of 4.3 s. No spurious commands occurred during the tested 2-min idle condition. In VR, online accuracy reached 100%, with a mean decoding time of 5.6 s. Participants reported high visual comfort and minimal peripheral distraction in both conditions, although fatigue was higher in VR. Conclusion: The proposed c-VEP rBCI combines short calibration, high accuracy, comfortable stimulation, semi-dry EEG, and asynchronous decision-making. Performance during the explicit idle condition and VR implementation support the feasibility of wearable and practical c-VEP systems for self-paced interaction beyond laboratory environments. These findings encourage evaluation in longer idle periods and real-world tasks.

Motor imagery and overt action are proposed to share common planning mechanisms while relying on distinct processes during movement performance. To investigate how repetition affects physical and imagined movements, participants physically or mentally drew paths while avoiding barriers. The barrier orientations were either repeated or different across consecutive trials, and the modality (execution or imagery) of the trials either changed or remained the same for two consecutive trials. Reaction time and movement time were analysed as measures of movement planning and task performance, respectively. Imagined movements produced longer reaction times and movement times than physical movements. Repetition of orientation reduced reaction times in both physical and imagined trials, indicating that trajectory repetition facilitated movement preparation. In contrast, previous trial type influenced reaction times only for physical movements, which were only initiated faster when preceded by another physical trial. Different effects emerged for movement time. Physical movements were faster when the same trajectory was repeated no matter the previous trial type, whereas imagined movements were unaffected by orientation and instead showed shorter durations when preceded by another imagined trial. The findings indicate that physical and imagined movements rely on more similar trajectory representations during the planning stage, but diverge during task performance. While physical movements appear to benefit from the persistence of previously generated movement trajectories, imagined trials seems more influenced by modality-specific cognitive processes. These results provide behavioural support for the Motor-Cognitive model and contribute to understanding how movement repetition influences overt and imagined actions.

Understanding how native speakers and second language (L2) learners process language differently is fundamental to theories of language acquisition, comprehension, and use. A central debate in this literature concerns the inconsistent findings in emotional prosody processing between native speakers and L2 learners, partly attributable to stimulus lexicality: some studies use real words, whereas others use pseudowords. To resolve this discrepancy, we measured fMRI responses in 15 native speakers and 15 L2 learners while they listened to Mandarin real-word and pseudoword stimuli. Both groups engaged in overlapping auditory, cognitive, and affective regions, including the auditory cortex, inferior frontal cortex, superior temporal cortex, and the temporoparietal junction. However, the two groups showed distinct responses depending on lexicality: native speakers showed stronger recruitment of temporal regions for pseudowords, whereas L2 learners showed greater frontoparietal activation for real words. These patterns were consistent across positive and negative prosody conditions. Furthermore, among L2 learners, higher proficiency was associated with greater frontal activation for real words, but not pseudowords. Together, these findings demonstrate that the differences between native speakers and L2 learners depend critically on stimulus lexicality, highlighting the role of lexicality in bilingual emotion processing.

Making choices about whether and when to engage cognitive effort is a common feature of human everyday experience with important consequences for academic, career, and health outcomes. Yet, despite its importance, little is understood about the neurochemical mechanisms that underlie individual differences in the willingness to engage in cognitively effortful activities. To examine this question, we employed a multi-modal neuroimaging approach in which participants performed the Cognitive Effort Discounting paradigm (Cog-ED) while simultaneous PET-fMRI was acquired. We assessed both individual differences in dopamine-D2 receptor availability and brain activity during decision-making. In addition, the same participants performed a parametric working memory task (N-Back) and reported the cognitive effort associated with their daily life activities through a seven-day Ecological Momentary Assessment (EMA) protocol. The findings suggest a central role for caudate dopamine-D2 receptors in modulating cognitive effort-related motivation. People with higher caudate dopamine-D2 receptor availability had better working memory function, heightened sensitivity to effort costs, and greater modulation of brain activity during effort valuation. These laboratory findings also translated directly to daily life: higher levels of caudate dopamine-D2 receptors were associated with greater engagement in cognitively effortful activities. Together, the results suggest that how individuals determine the motivational value of cognitively effortful activities strongly depends on the dopamine system.

BackgroundThe balance between excitatory and inhibitory neuronal signalling (E/I balance), proposed as a key mechanism controlling neuronal activity, is disrupted in many neurodevelopmental conditions. One such condition is Neurofibromatosis Type 1, a monogenic neurodevelopmental disorder characterised by increased inhibitory tone. While previous research suggests that E/I balance may be altered in infancy, it is unknown whether E/I balance remains altered during adolescence in NF1. Here we investigated this question using the aperiodic exponent of the resting electroencephalogram (EEG) power spectrum, a proposed electrophysiological index of E/I balance. MethodThe aperiodic exponent of the EEG power spectrum ( 1/f) was estimated for 16 adolescents with NF1 diagnosis aged 11-16, and 16 age- and sex-matched neurotypical controls. General linear models (GLM) were fit to estimate effects of NF1 diagnosis, age and their interaction on aperiodic exponent. We also estimated the peak dominant frequency and power in oscillatory activity of the EEG signal and fitted the same structure of GLM models. Cognitive assessments across domains of memory, executive function and attention were also analysed with GLM to examine brain-cognition associations. ResultsThe NF1 group had higher aperiodic exponent compared to neurotypical controls, but the aperiodic exponent was not associated with cognitive performance. After accounting for aperiodic activity, the NF1 group also had lower dominant oscillatory frequency than the control group. There was no significant interaction between NF1 diagnosis and age on PAF. There were no group differences in peak alpha power. ConclusionsWe demonstrate for the first time that the alterations to aperiodic activity in NF1 are consistent with the proposed mechanism of increased inhibitory tone. These findings show the potential of this paradigm for future pharmacological and brain stimulation trials investigating treatment-related changes in cortical function.

Developmental dyslexia is associated with impaired cortical tracking of continuous speech and difficulties in perceiving within-word prosodic structure in children and adults. For adults and continuous speech, both low-frequency delta- and theta-band impairments and high-frequency gamma- and beta-band differences are found. To date, perceptual difficulties with intra-word prosody have not been studied in direct relation to neural speech encoding. Here neurotypical adults and adults with dyslexia listened to multisyllabic words. EEG was recorded, and cortical encoding was quantified using temporal response function (TRF) modelling. Four speech representations were explored: lexical stress pattern (intra-word prosodic prominence), the low-frequency speech envelope, word onsets and syllable onsets. Adults with dyslexia showed significantly reduced encoding of intra-word prosodic prominence (delta band) and of the speech envelope (delta and theta bands). In contrast, encoding of word and syllable onsets was preserved. Pinpointing delta-band cortical tracking as central to encoding intra-word prosodic prominence opens new avenues for research.

Rhythmic visual stimulation offers a non-invasive means of modulating oscillatory brain activity, but conventional flicker may induce considerable visual discomfort. We developed an individualized Gabor flicker stimulation designed to balance neural entrainment and tolerability. In Experiment 1, thirty-four participants passively viewed Plain and Gabor flickers presented at their individual alpha frequency (IAF), IAF - 2 Hz, or IAF + 2 Hz, and at threshold-adjusted or full intensity. Steady-state visual evoked potential signal-to-noise ratio (SNR) was highest at IAF and increased with intensity. Plain and Gabor flickers produced comparable overall SNR, but Gabor flicker was rated as substantially more comfortable and less mentally fatiguing, with stimulation at IAF providing the most favorable balance between neural entrainment and tolerability. In Experiment 2, the optimized stimulation parameters were applied during a retro-cue working memory task using individualized theta and alpha frequency flickers. Stimulation increased SNR and inter-trial phase coherence relative to a non rhythmic Natural condition. No behavioral benefit was observed in the full sample. However, an exploratory subgroup analysis indicated higher accuracy with theta stimulation of cued representations and alpha stimulation of uncued representations than in the Natural condition among participants who showed limited baseline retro-cue benefits. These findings show that individualized Gabor flicker can provide robust and well-tolerated neural entrainment during passive viewing and working memory retention, although its behavioral effects may vary across individuals according to their cognitive performance.