Influence Brain Activity Research Articles

The Impact of Long-Term Tai Chi Practice on the Trust Behavior of Middle-Aged People.

Trust behavior is of fundamental importance for social stability and development. Middle-aged people, owing to their abundant social resources and extensive experience, have a significant impact through their trust behavior. However, research on enhancing their trust behavior is relatively scarce. Tai Chi, as an activity that combines physical and mental exercise characteristics, may potentially influence the trust behavior of middle-aged people, yet direct research in this regard is lacking. The objective of this study is to explore the impact of Tai Chi on the trust behavior of middle-aged people and its underlying neural mechanisms. This study recruited two groups of middle-aged individuals as research participants. Specifically, the Tai Chi group consisted of 37 middle-aged people with long-term Tai Chi practice experience, while the control group comprised 29 middle-aged individuals without any Tai Chi practice background. The behavioral performance and EEG data of the participants in both groups were recorded during their participation in the trust game. At the behavioral level, the trust rate of the Tai Chi group was higher than the random level (50%), and they made decisions more quickly. The event-related potential (ERP) data revealed that there were interaction effects between the Tai Chi group and the control group in the P2 and N2 components, which are ERP indicators during the decision-making stage. Moreover, in the feedback stage, the feedback-related negativity (FRN) amplitude evoked in the Tai Chi group was smaller than that in the control group. Long-term practice of Tai Chi can enhance decision-making speed and influence brain activity. It provides important reference for understanding the relationship between Tai Chi and the trust behavior of middle-aged people. Although there are limitations in this study, it lays a foundation for future research.

The Influence of Realism on the Sense of Presence in Virtual Reality: Neurophysiological Insights Using EEG

One of the most crucial aspects of the user experience in virtual reality (VR) is the sense of presence. To evaluate this, both subjective and objective methods can be employed. While subjective methods are easy to implement and interpret, they may not fully capture user feedback, and the results can sometimes lack consistency. In contrast, using objective methods, such as electroencephalography (EEG), can provide more reliable insights. To investigate the influence of realism on the sense of presence, we conducted an EEG study with 21 participants who experienced two VR environments—one realistic and one non-realistic. During the study, we continuously measured their brain activity using an EEG device. Our findings showed that alteration in the level of realism in an environment can be detected through changes in brain activity. Notably, we observed that users take longer to adapt to a non-realistic environment when transitioning from a realistic scene, compared to the reverse. Although our study has limitations, such as the total number of participants, we gained valuable initial insights into how realism may influence brain activity. These findings suggest that higher realism may lead to reduced cognitive load, increased attention, improved decision-making, and suppression of irrelevant information.

Transcranial low-level laser stimulation in the near-infrared-II region (1064 nm) for brain safety in healthy humans

BackgroundThe use of near-infrared lasers for transcranial photobiomodulation (tPBM) offers a non-invasive method for influencing brain activity and is beneficial for various neurological conditions. However, comprehensive quantitative studies on its safety are lacking. ObjectiveThis study aims to investigate the safety of 1064-nm laser-based tPBM across brain structure, brain function, neural damage, cognitive ability and tolerance. MethodsWe employed a multimodal approach, using magnetic resonance imaging (MRI), electroencephalogram (EEG), biochemical analyses, and cognitive testing to quantitatively assess the potential adverse effects of tPBM on brain structure or function, neurons, glial cells, and executive function (EF). Additionally, a detailed questionnaire was used to evaluate subjective tolerance. ResultsAt the whole-brain structural level, no significant variations in gray matter, white matter, or cerebrospinal fluid volume or density were observed as a result of tPBM. There was no increase in neuron-specific enolase (NSE) or S100β levels suggesting no neuronal damage, but an unexpected significant reduction in NSE was detected which requires further study to assess its implications. EEG, analyzed through power spectra and expert evaluation, revealed no potential disease-inducing effects. A series of cognitive tests demonstrated no impairment in any of the EF components. Furthermore, the questionnaire data revealed minimal discomfort across fatigue, itching, pain, burning, warmth, dizziness, and drowsiness. ConclusionsOur data indicate that 1064 nm laser tPBM does not induce adverse effects on brain structure or function, nor does it impair cognitive abilities. tPBM is safe for specific parameters, highlighting its good tolerability.

Understanding novel neuromodulation pathways in tDCS: brain stem recordings in rats during trigeminal nerve direct current stimulation

tDCS is widely assumed to cause neuromodulation via the electric field in the cortex acting directly on cortical neurons. However, recent evidence suggests that tDCS may indirectly influence brain activity through cranial nerve pathways, notably the trigeminal nerve, but these neuromodulatory pathways remain unexplored. To investigate the first stages in this potential pathway we developed an animal model to study the effect of trigeminal nerve direct current stimulation (TN-DCS) on neuronal activity in the principal sensory nucleus (NVsnpr) and the mesencephalic nucleus of the trigeminal nerve (MeV). We conducted experiments on twenty-four male Sprague Dawley rats (n = 10 NVsnpr, n = 10 MeV during anodic stimulation, and n = 4 MeV during cathodic stimulation). DC stimulation, ranging from 0.5 to 3 mA, targeted the trigeminal nerve’s marginal branch. Concurrently, single-unit electrophysiological recordings were obtained using a 32-channel silicon probe, encompassing three 1-min intervals: pre, during, and post-stimulation. Xylocaine trigeminal nerve blockage served as a control. TN-DCS increased neuronal spiking activity in both NVsnpr and MeV, returning to baseline during the post-stimulation phase. The 3 mA DC stimulation of the blocked trigeminal nerve failed to induce increased spiking activity in the trigeminal nuclei. These findings provide empirical support for trigeminal nuclei modulation via TN-DCS, suggesting the cranial nerve pathways could play a role in mediating the tDCS effects in humans.

A new perspective on binaural beats: Investigating the effects of spatially moving sounds on human mental states.

When individuals are exposed to two pure tones with close frequencies presented separately in each ear, they perceive a third sound known as binaural beats (BB), characterized by a frequency equal to the difference between the two tones. Previous research has suggested that BB may influence brain activity, potentially benefiting attention and relaxation. In this study, we hypothesized that the impact of BB on cognition and EEG is linked to the spatial characteristics of the sound. Participants listened to various types of spatially moving sounds (BB, panning and alternate beeps) at 6Hz and 40Hz frequencies. EEG measurements were conducted throughout the auditory stimulation, and participants completed questionnaires on relaxation, affect, and a sustained attention task. The results indicated that binaural, panning sounds and alternate beeps had a more pronounced effect on electrical brain activity than the control condition. Additionally, an improvement in relaxation was observed with these sounds at both 6Hz and 40Hz. Overall, these findings support our hypothesis that the impact of auditory stimulation lies in the spatial attributes rather than the sensation of beating itself.

The Effects of Osteopathic Manipulative Treatment on Brain Activity: A Scoping Review of MRI and EEG Studies.

Osteopathic manipulative treatment (OMT) is a hands-on therapy aiming to achieve the global homeostasis of the patient. OMT focuses on treating the somatic dysfunctions characterized by tissue modifications, body asymmetry, and range-of-motion restrictions. The benefits related to OMT are thought to be associated with the interconnectedness of the body's systems and the inherent capacity for self-healing. However, whether OMT can influence brain activity, and, consequently, neurophysiological responses is an open research question. Our research investigates the literature to identify the effects of OMT on brain activity. The main purpose of the research question is: can OMT influence brain activity and consequently neurophysiological responses? A scoping review was conducted, searching the following databases: PubMed, Google Scholar, and OSTEOMED.DR (Osteopathic Medical Digital Repository), Scopus, Web of Science (WoS), and Science Direct. The initial search returned 114 articles, and after removing duplicates, 69 were considered eligible to be included in the final sample. In the end, eight studies (six randomized controlled trials, one pilot study, and one cross-over study) were finally included and analyzed in this review. In conclusion, OMT seems to have a role in influencing functional changes in brain activity in healthy individuals and even more in patients with chronic musculoskeletal pain. However, further RCT studies are needed to confirm these findings. Registration protocol: CRD42024525390.

(016) ENHANCING SEXUAL AND MENTAL HEALTH THROUGH TANTRA MINDFULNESS THERAPY (TMT®): NEUROPHYSIOLOGICAL INSIGHTS FROM QEEG MEASUREMENTS

Abstract Introduction Emerging psychotherapeutic treatments have increasingly recognized the importance of mindfulness practices in mental and sexual health. Tantra Mindfulness Therapy (TMT®), a synthesis of ancient meditative techniques with modern psychological practices, promises significant health benefits by influencing brain activity. Prior research indicates that mindfulness can profoundly affect emotional well-being and interpersonal dynamics through modifications in neural oscillations. Objective The purpose of this study is to explore the impact of TMT® on specific brain wave frequencies-including Gamma waves, associated with cognitive functions like altruism and love-and to examine its effects on psychological states among participants. In addition to how it would affect their sex lives. Methods Participants enrolled in a series of TMT® sessions were monitored using quantitative electroencephalogram (QEEG) tools, including the Muse and Mind Monitor systems, which tracked changes in Alpha, Theta, Delta, Beta, and Gamma wave activity. Psychological health was assessed before and after the therapy sessions using a Likert scale (0-10) to evaluate levels of anxiety, depression, and stress. Results Post-TMT®, there was a significant elevation in Gamma wave activity, correlating with improved emotional processing and empathy. Concurrently, Beta waves showed dual behavior with initial decreases followed by increases, suggesting enhanced focus and concentration. Alpha waves, typically associated with relaxation, and Theta waves, linked to deep meditation, also saw increases. These changes were accompanied by statistically significant reductions in anxiety and stress (p < 0.05), with notable decreases in depression symptoms reported by participants. Additionally, enhanced feelings of relaxation and euphoria were consistently documented, highlighting the therapy’s positive psychological impact. In addition participants experience less sexual anxiety and erectile dysfunction. Conclusions Tantra Mindfulness Therapy (TMT®) effectively induces neurophysiological changes that align with better emotional and mental health outcomes. The complex modulation of Beta, Alpha, and Theta wave activities underlines the therapy’s capacity to enhance focus, relaxation, and meditative depth, thereby making it a valuable psychotherapeutic tool for enhancing sexual and mental wellness. These findings support the integration of TMT® into broader psychotherapeutic practices, offering a new avenue for treating sexual and psychological health issues. Disclosure No.

Elevating understanding: Linking high-altitude hypoxia to brain aging through EEG functional connectivity and spectral analyses.

High-altitude hypoxia triggers brain function changes reminiscent of those in healthy aging and Alzheimer's disease, compromising cognition and executive functions. Our study sought to validate high-altitude hypoxia as a model for assessing brain activity disruptions akin to aging. We collected EEG data from 16 healthy volunteers during acute high-altitude hypoxia (at 4,000 masl) and at sea level, focusing on relative changes in power and aperiodic slope of the EEG spectrum due to hypoxia. Additionally, we examined functional connectivity using wPLI, and functional segregation and integration using graph theory tools. High altitude led to slower brain oscillations, that is, increased δ and reduced α power, and flattened the 1/f aperiodic slope, indicating higher electrophysiological noise, akin to healthy aging. Notably, functional integration strengthened in the θ band, exhibiting unique topographical patterns at the subnetwork level, including increased frontocentral and reduced occipitoparietal integration. Moreover, we discovered significant correlations between subjects' age, 1/f slope, θ band integration, and observed robust effects of hypoxia after adjusting for age. Our findings shed light on how reduced oxygen levels at high altitudes influence brain activity patterns resembling those in neurodegenerative disorders and aging, making high-altitude hypoxia a promising model for comprehending the brain in health and disease.

ANALYSIS OF THE VARIATIONS IN BRAIN ACTIVITY IN RESPONSE TO VARIOUS COMPUTER GAMES

The influence of video games on the human brain has been a topic of extensive research and discussion. Video games, characterized by their dynamic and immersive qualities, have demonstrated the capacity to impact diverse cognitive processes. In this study, we conducted a detailed analysis of brain response variations to different genres of computer games, specifically focusing on boring, calm, horror, and funny games. To achieve this, we computed the sample entropy and approximate entropy of electroencephalograms (EEG) signals recorded from participants while they engaged with each type of game. Our findings revealed that EEG signals exhibited the highest complexity during the funny game and the lowest complexity during the calm game. This suggests that the brain is most active when playing the funny game and least active during the calm game. These results provide valuable insights into how different types of video game content can influence brain activity. The methodology employed in this study can be extended to explore brain activity under various conditions, potentially offering a broader understanding of how different stimuli impact cognitive processes. This approach can be useful in examining the effects of various interactive media on brain function and could inform the design of video games and other digital experiences to optimize cognitive engagement and mental well-being.

EEG microstates are associated with music training experience.

Music training facilitates the development of individual cognitive functions and influences brain plasticity. A comprehensive understanding of the pathways and processes through which music affects the human brain, as well as the neurobiological mechanisms underlying human brain perception of music, is necessary to fully harness the plasticity that music offers for brain development. To investigate the resting-state electroencephalogram (EEG) activity of individuals with and without music training experience, and explore the microstate patterns of EEG signals. In this study, an analysis of electroencephalogram (EEG) microstates from 57 participants yielded temporal parameters(mean duration, time coverage, occurrence, and transition probability)of four classic microstate categories (Categories A, B, C, and D) for two groups: those with music training experience and those without. Statistical analysis was conducted on these parameters between groups. The results indicate that compared to individuals without music training experience, participants with music training experience exhibit significantly longer mean durations of microstate A, which is associated with speech processing. Additionally, they show a greater time coverage of microstate B, which is associated with visual processing. Transition probabilities from microstate A to microstate B were greater in participants with music training experience compared to those without. Conversely, transition probabilities from microstate A to microstate C and from microstate C to microstate D were greater in participants without music training experience. Our study found differences in characteristic parameters of certain microstates between individuals with and without music training experience. This suggests distinct brain activity patterns during tasks related to speech, vision, and attention regulation among individuals with varying levels of music training experience. These findings support an association between music training experience and specific neural activities. Furthermore, they endorse the hypothesis of music training experience influencing brain activity during resting states. Additionally, they imply a facilitative role of music training in tasks related to speech, vision, and attention regulation, providing initial evidence for further empirical investigation into the cognitive processes influenced by music training.

Phase-locked breathing does not affect episodic visual recognition memory but does shape its corresponding ERPs.

Recent studies have indicated that breathing shapes the underlying oscillatory brain activity critical for episodic memory, potentially impacting memory performance. However, the literature has presented conflicting results, with some studies suggesting that nasal inhalation enhances visual memory performance, while others have failed to observe any significant effects. Furthermore, the specific influence of breathing route (nasal vs. mouth) and the precise phase of the respiratory cycle during which stimuli are presented have remained elusive. To address this, we employed a visual recognition memory (VRM) and electroencephalography paradigm in which stimuli presentation was phase-locked to either inhalation or exhalation onset, using a within-subject design where participants performed the memory task while engaging in separate sessions of nose and mouth breathing. We show that neither breathing route nor breathing phase has a significant impact on VRM performance as measured by d-prime, with the data supporting the null hypothesis. However, we did find an effect of breathing phase on response bias, with participants adopting a more conservative decision criterion during exhalation. Moreover, we found that breathing phase during memory encoding shaped the late parietal effect (LPE) amplitude, while the Frontal Negative Component (FN400) and LPE during recognition were less impacted. While our study demonstrates that breathing does not shape VRM performance, it shows that it influences brain activity, reinforcing the importance of further research to elucidate the extent of respiratory influence on perception, cognition, and behavior.

Altered patterns of brain activity during a fMRI memory task in cognitively normal adults carrying the APOE ε4 allele

AbstractBackgroundThe ε4 allele of the Apolipoprotein E gene (APOE) is a well‐established risk factor for Alzheimer’s disease (AD), ε4 carriers showing earlier onset and more severe memory impairment than non‐carriers. Neuroimaging evidence suggests that APOEε4 may modulate neural activity in AD since early stages. The purpose of this study was to determine whether APOEε4 influences brain activity in the memory circuit in older cognitively unimpaired individuals.MethodThirty cognitively unimpaired participants (n = 10 APOEε4 heterozygous carriers, age = 65± 5 years, 50% females, MMSE score = 29±1; n = 20 APOEε4 non‐carriers, age = 68±5 years, 35% females, MMSE score = 30±1) were recruited and underwent multidomain (i.e., memory, visuospatial abilities, language, attention) neuropsychological exams and functional MRI scan during an associative memory task, which consisted of two phases: (i) encoding of face‐name associations; (ii) recognition of the name associated to each face. Image preprocessing and voxel‐wise comparisons were conducted using the Statistical Parametric Mapping (SPM, v12). Clusters were considered significant at an uncorrected threshold of p<0.001.ResultParticipants were comparable for demographic and cognitive features (p>0.10) and performed similarly on the in‐scanner face‐name association memory task (p>0.10). Compared to ε4 non‐carriers, carriers showed (i) greater activation during the encoding task in the left temporo‐occipital cortex/fusiform gyrus, (ii) greater activation during the recognition task in the middle temporal gyrus/temporo‐occipital cortex bilaterally and in the right cerebellum, and (iii) lower activation during the recognition task in the medial supplementary motor area.ConclusionThese preliminary results confirm that the APOE ε4 allele is associated with a different pattern of brain functional activity during an associative memory task in cognitively unimpaired older. Given the similar cognitive performance between groups, higher activation in temporo‐occipital regions might reflect a compensatory process in regions vulnerable to AD pathology.

Altered patterns of brain activity during a fMRI memory task in cognitively normal adults carrying the APOE ε4 allele

AbstractBackgroundThe e4 allele of the Apolipoprotein E gene (APOE) is a well‐established risk factor for Alzheimer’s disease (AD), e4 carriers showing earlier onset and more severe memory impairment than non‐carriers. Neuroimaging evidence suggests that APOEe4 may modulate neural activity in AD since early stages. The purpose of this study was to determine whether APOEe4 influences brain activity in the memory circuit in older cognitively unimpaired individuals.MethodThirty cognitively unimpaired participants (n = 10 APOEe4 heterozygous carriers, age = 65± 5 years, 50% females, MMSE score = 29±1; n = 20 APOEe4 non‐carriers, age = 68±5 years, 35% females, MMSE score = 30±1) were recruited and underwent multidomain (i.e., memory, visuospatial abilities, language, attention) neuropsychological exams and functional MRI scan during an associative memory task, which consisted of two phases: (i) encoding of face‐name associations; (ii) recognition of the name associated to each face. Image preprocessing and voxel‐wise comparisons were conducted using the Statistical Parametric Mapping (SPM, v12). Clusters were considered significant at an uncorrected threshold of p<0.001.ResultParticipants were comparable for demographic and cognitive features (p>0.10) and performed similarly on the in‐scanner face‐name association memory task (p>0.10). Compared to e4 non‐carriers, carriers showed (i) greater activation during the encoding task in the left temporo‐occipital cortex/fusiform gyrus, (ii) greater activation during the recognition task in the middle temporal gyrus/temporo‐occipital cortex bilaterally and in the right cerebellum, and (iii) lower activation during the recognition task in the medial supplementary motor area.ConclusionThese preliminary results confirm that the APOE e4 allele is associated with a different pattern of brain functional activity during an associative memory task in cognitively unimpaired older. Given the similar cognitive performance between groups, higher activation in temporo‐occipital regions might reflect a compensatory process in regions vulnerable to AD pathology.

Astrocytic calcium waves: unveiling their roles in sleep and arousal modulation.

Neuron-astrocyte interactions are vital for the brain's connectome. Understanding astrocyte activities is crucial for comprehending the complex neural network, particularly the population-level functions of neurons in different cortical states and associated behaviors in mammals. Studies on animal sleep and wakefulness have revealed distinct cortical synchrony patterns between neurons. Astrocytes, outnumbering neurons by nearly fivefold, support and regulate neuronal and synaptic function. Recent research on astrocyte activation during cortical state transitions has emphasized the influence of norepinephrine as a neurotransmitter and calcium waves as key components of ion channel signaling. This summary focuses on a few recent studies investigating astrocyte-neuron interactions in mouse models during sleep, wakefulness, and arousal levels, exploring the involvement of noradrenaline signaling, ion channels, and glutamatergic signaling in different cortical states. These findings highlight the significant impact of astrocytes on large-scale neuronal networks, influencing brain activity and responsiveness. Targeting astrocytic signaling pathways shows promise for treating sleep disorders and arousal dysregulation. More research is needed to understand astrocytic calcium signaling in different brain regions and its implications for dysregulated brain states, requiring future human studies to comprehensively investigate neuron-astrocyte interactions and pave the way for therapeutic interventions in sleep- and arousal-related disorders.

Brain and antennal transcriptomes of host ants reveal potential links between behaviour and the functioning of socially parasitic colonies.

Insect social parasites are characterized by exploiting the hosts' social behaviour. Why exactly hosts direct their caring behaviour towards these parasites and their offspring remains largely unstudied. One hypothesis is that hosts do not perceive their social environment as altered and accept the parasitic colony as their own. We used the ant Leptothorax acervorum, host of the dulotic, obligate social parasite Harpagoxenus sublaevis, to shed light on molecular mechanisms underlying behavioural exploitation by contrasting tissue-specific transcriptomes in young host workers. Host pupae were experimentally (re-)introduced into fragments of their original, another conspecific, heterospecific or parasitic colony. Brain and antennal mRNA was extracted and sequenced from adult ants after they had lived in the experimental colony for at least 50 days after eclosion. The resulting transcriptomes of L. acervorum revealed that ants were indeed affected by their social environment. Host brain transcriptomes were altered by the presence of social parasites, suggesting that the parasitic environment influences brain activity, which may be linked to behavioural changes. Transcriptional activity in the antennae changed most with the presence of unrelated individuals, regardless of whether they were conspecifics or parasites. This suggests early priming of odour perception, which was further supported by sensory perception of odour as an enriched function of differentially expressed genes. Furthermore, gene expression in the antennae, but not in the brain corresponded to ant worker behaviour before sampling. Our study demonstrated that the exploitation of social behaviours by brood parasites correlates with transcriptomic alterations in the central and peripheral nervous systems.

Neural mechanisms underlying uninstructed orofacial movements during reward-based learning behaviors

During reward-based learning tasks, animals make orofacial movements that globally influence brain activity at the timings of reward expectation and acquisition. These orofacial movements are not explicitly instructed and typically appear along with goal-directed behaviors. Here, we show that reinforcing optogenetic stimulation of dopamine neurons in the ventral tegmental area (oDAS) in mice is sufficient to induce orofacial movements in the whiskers and nose without accompanying goal-directed behaviors. Pavlovian conditioning with a sensory cue and oDAS elicited cue-locked and oDAS-aligned orofacial movements, which were distinguishable by a machine-learning model. Inhibition or knockout of dopamine D1 receptors in the nucleus accumbens inhibited oDAS-induced motion but spared cue-locked motion, suggesting differential regulation of these two types of orofacial motions. In contrast, inactivation of the whisker primary motor cortex (wM1) abolished both types of orofacial movements. We found specific neuronal populations in wM1 representing either oDAS-aligned or cue-locked whisker movements. Notably, optogenetic stimulation of wM1 neurons successfully replicated these two types of movements. Our results thus suggest that accumbal D1-receptor-dependent and -independent neuronal signals converge in the wM1 for facilitating distinct uninstructed orofacial movements during a reward-based learning task.

Group identity modulates bidding behavior in repeated lottery contest: neural signatures from event-related potentials and electroencephalography oscillations.

A contest usually involves expenditures, termed "overbidding," exceeding the theoretical Nash equilibrium. A considerable number of studies have shown that group identity can affect decision-making and competitive behavior, thus providing a new perspective on alleviating the overbidding problem. How group identity influences brain activity when competitors bid in different groups is not yet clear, however. In this study, we implemented group identity manipulation into the lottery contest game and we recorded behavioral and electroencephalography (EEG) data at the same time. Two experimental treatments were conducted to study the effect of group identity on bidding behavior. The event-related potentials (ERP) and event-related oscillations (ERO) techniques were utilized to explore brain activity differences caused by participants' different bidding behaviors under in-group and out-group conditions. Behavioral results showed that individual expenditure was significantly lower when bidding with in-group opponents than with out-group opponents. Analyses of EEG results revealed that compared to in-group conditions, greater N2 amplitudes and theta power were found under out-group conditions. To extend previous studies, we performed supplementary analysis to explore whether enhancement of group identity had effects on conflict alleviation. Behavioral results indicated that individual expenditure was significantly lower after enhancing group identity when bidding with in-group, and EEG results showed more negative N2 amplitudes, smaller P3 amplitudes and larger theta power after enhancing group identity. Collectively, these findings indicate that group identity modulated bidding behavior, and they provide insight into a mechanism to de-escalate group conflict by enhancing group identity.

Active search signatures in a free-viewing task exploiting concurrent EEG and eye movements recordings.

Tasks we often perform in our everyday lives, such as reading or looking for a friend in the crowd, are seemingly straightforward but they actually require the orchestrated activity of several cognitive processes. Free-viewing visual search requires a plan to move our gaze on the different items, identifying them, and deciding on whether to continue with the search. Little is known about the electrophysiological signatures of these processes in free-viewing because there are technical challenges associated with eye movement artefacts. Here, we aimed to study how category information, as well as ecologically relevant variables such as the task performed, influence brain activity in a free-viewing paradigm. Participants were asked to observe/search from an array of faces and objects embedded in random noise. We concurrently recorded electroencephalogram and eye movements and applied a deconvolution analysis approach to estimate the contribution of the different elements embedded in the task. Consistent with classical fixed-gaze experiments and a handful of free-viewing studies, we found a robust categorical effect around 150 ms in occipital and occipitotemporal electrodes. We also report a task effect, more negative in posterior central electrodes in visual search compared with exploration, starting at around 80 ms. We also found significant effects of trial progression and an interaction with the task effect. Overall, these results generalise the characterisation of early visual face processing to a wider range of experiments and show how a suitable analysis approach allows to discern among multiple neural contributions to the signal, preserving key attributes of real-world tasks.

Effects of handedness on brain oscillatory activity during imagery and execution of upper limb movements.

Brain activation during left- and right-hand motor imagery is a popular feature used for brain-computer interfaces. However, most studies so far have only considered right-handed participants in their experiments. This study aimed to investigate how handedness influences brain activation during the processes of imagining and executing simple hand movements. EEG signals were recorded using 32 channels while participants repeatedly squeezed or imagined squeezing a ball using their left, right, or both hands. The data of 14 left-handed and 14 right-handed persons were analyzed with a focus on event-related desynchronization/synchronization patterns (ERD/S). Both handedness groups showed activation over sensorimotor areas; however, the right-handed group tended to display more bilateral patterns than the left-handed group, which is in contrast to earlier research results. Furthermore, a stronger activation during motor imagery than during motor execution could be found in both groups.

Effect of LSD and music on the time-varying brain dynamics

RationalePsychedelics are getting closer to being widely used in clinical treatment. Music is known as a key element of psychedelic-assisted therapy due to its psychological effects, specifically on the emotion, meaning-making, and sensory processing. However, there is still a lack of understanding in how psychedelics influence brain activity in experimental settings involving music listening.ObjectivesThe main goal of our research was to investigate the effect of music, as a part of “setting,” on the brain states dynamics after lysergic acid diethylamide (LSD) intake.MethodsWe used an open dataset, where a group of 15 participants underwent two functional MRI scanning sessions under LSD and placebo influence. Every scanning session contained three runs: two resting-state runs separated by one run with music listening. We applied K-Means clustering to identify the repetitive patterns of brain activity, so-called brain states. For further analysis, we calculated states’ dwell time, fractional occupancy and transition probability.ResultsThe interaction effect of music and psychedelics led to change in the time-varying brain activity of the task-positive state. LSD, regardless of the music, affected the dynamics of the state of combined activity of DMN, SOM, and VIS networks. Crucially, we observed that the music itself could potentially have a long-term influence on the resting-state, in particular on states involving task-positive networks.ConclusionsThis study indicates that music, as a crucial element of “setting,” can potentially have an influence on the subject’s resting-state during psychedelic experience. Further studies should replicate these results on a larger sample size.