Behavioural research over several decades has found that concrete words are processed more quickly and accurately than abstract words (concreteness effect). This advantage is also reflected in their different processing and representation in the human brain. In this electrophysiological study, we explored the interplay of concreteness as a continuous measure and task effects on word processing. Electrophysiological responses of 58 participants were recorded during semantic, affective, and grammatical decision tasks on words parametrically varied in concreteness. Our findings uncovered a fine-grained concreteness effect within four distinct spatiotemporal windows when a coding of semantic information is required. In the semantic decision task, we detected a higher parietal positivity within the P300 time range and an increased left temporo-lateral negative-going amplitude for less concrete concepts. We also identified a concreteness effect characterised by greater negativity in the N400 component. In the affective task, we observed a more pronounced parietal P600-like component for more abstract concepts. Interestingly, we found that the neural representational similarity (starting from 450 ms with a widespread scalp distribution) conformed to the concreteness similarity among concepts (regardless of the task), implying that their semantic representations may be characterised along the concreteness dimension in the brain. Our study transcends the conventional dichotomy of abstract versus concrete words, unearthing not only varied processing dynamics along the concreteness dimension but also distinct fine-grained neural representations. This novel insight positions concreteness as a structural dimension, enriching our comprehension of how the brain organises and processes semantic information.

High frequency heart rate variability (HRV) is a vagally-mediated physiological index reflecting parasympathetic activity that has been linked to emotion regulation capacity. However, very limited research has examined associations of physiological indices of regulation such as HRV with emotional functioning in daily life. The few studies that exist have small samples sizes and typically focus on only a narrow aspect of emotion regulation or emotional functioning. In this study, we examined associations between HRV assessed in the laboratory and emotional/mental health functioning in daily life using a 7-day ecological momentary assessment design in 303 adult community participants. We hypothesized that higher resting HRV would be associated with higher positive affect, lower negative affect, less affective variability, greater wellbeing, fewer depressive and idiographic [person-specific] symptoms, greater use of engagement emotion regulation strategies, and less use of avoidance emotion regulation strategies, as assessed in daily life. Results revealed that higher resting HRV in the laboratory was significantly associated with lower negative affect and less frequent use of avoidance emotion regulation strategies in daily life, although only avoidance strategies remained significant when both were included in the same model. We also observed a trend association, such that idiographic symptoms in daily life were associated with lower resting HRV. Theoretical and clinical implications are discussed, including the association of HRV with negatively-valenced, rather than positively-valenced, daily life experiences.

Research suggests a potential of gamma oscillation entrainment for enhancing memory in Alzheimer’s disease and healthy subjects. Gamma entrainment can be accomplished with oscillatory electrical, but also sensory stimulation. However, comparative studies between sensory stimulation and transcranial alternating current stimulation (tACS) effects on memory processes are lacking. This study examined the effects of rhythmic gamma auditory stimulation (rAS) and temporal gamma-tACS on verbal long-term memory (LTM) and working memory (WM) in 74 healthy individuals. Participants were assigned to two groups according to the stimulation techniques (rAS or tACS). Memory was assessed in three experimental blocks, in which each participant was administered with control, 40 Hz, and 60 Hz stimulation in counterbalanced order. All interventions were well-tolerated, and participants reported mostly comparable side effects between real stimulation (40 Hz and 60 Hz) and the control condition. LTM immediate and delayed recall remained unaffected by stimulations, while immediate recall intrusions decreased during 60 Hz stimulation. Notably, 40 Hz interventions improved WM compared to control stimulations. These results highlight the potential of 60 Hz and 40 Hz temporal cortex stimulation for reducing immediate LTM recall intrusions and improving WM performance, respectively, probably due to the entrainment of specific gamma oscillations in the auditory cortex. The results also shed light on the comparative effects of these neuromodulation tools on memory functions, and their potential applications for cognitive enhancement and in clinical trials.

Integrating auditory and visual inputs plays an important role in language processing and social perception. We presently investigated mechanisms of this audio-visual (A-V) integration by analyzing temporal characteristics of multisensory neurons in the human brain. Specifically, an inter-trial coherence (ITC, neural index for phase resetting) of scalp electroencephalography (EEG) were measured while participants made a temporal-order judgment between a beep (A) and a flash (V). The posterior temporal region showed higher ITC (phase resetting) to bimodal (A+V) than unimodal (A or V) stimuli, showing an involvement of multisensory neurons selectively reacting to the bimodal inputs. They responded more vigorously as a beep-flash SOA (stimulus-onset asynchrony) came closer to 0 ms. Finally, this increase in ITC was most clearly seen in beta band (13-30 Hz). These results indicate that multisensory neurons with a basic rhythm of 13- 30 Hz play a critical role in human A-V integration.

Brain functional modular organization changes with age. Considering the brain as a dynamic system, recent studies have suggested that time-varying connectivity provides more information on brain functions. However, the spontaneous reconfiguration of modular brain structures over time during ageing remains poorly understood. In this study, we investigated the age-related dynamic modular reconfiguration using resting-state functional MRI data (615 participants, aged 18-88 years) from Cam-CAN. We employed a graph-based modularity analysis to investigate modular variability and the transition of nodes from one module to another in modular brain networks across the adult lifespan. Results showed that modular structure exhibits both linear and nonlinear age-related trends. The modular variability is higher in early and late adulthood, with higher modular variability in the association networks and lower modular variability in the primary networks. In addition, the whole brain transition matrix showed that the times of transition from other networks to the dorsal attention network were the largest. Furthermore, the modular structure was closely related to the number of cognitive components and memory-related cognitive performance, suggesting a potential contribution to flexibility cognitive function. Our findings highlighted the notable dynamic characteristics in large-scale brain networks across the adult lifespan, which enhanced our understanding of the neural substrate in various cognition during ageing. These findings also provided further evidence that dedifferentiation and compensation are the outcomes of functional brain interactions.

The current study explores an emerging cardiac metric, heart rate fragmentation (HRF), as a novel biomarker for allostatic load (AL). HRF may better address the limitations of existing cardiac biomarkers (e.g., confounds and interpretation consistency) in applied research settings, with nonclinical samples. The study’s objectives were: 1) can HRF represent response to psychological stress and 2) can resting HRF be used as a measure of predicting subclinical mental health symptoms. One hundred and fifty-six (n = 156; 75% female) undergraduate students were fitted with a chest band to monitor cardiovascular activity, and completed online demographic and psychosocial surveys in which they were grouped as healthy or displaying probable mental health symptoms (pMH; n = 94, 60.25%) based on respective inventory thresholds for depression, anxiety, and posttraumatic stress disorder. Cardiovascular activity was measured capturing the three R’s of cardiac vagal control: a resting baseline, a reactive acute stressor task, and a paced breathing recovery. Results supported the first hypothesis, in that that HRF significantly differentiated between each RRR condition (p < 0.001). While healthy and pMH individuals did not significantly differ within individual conditions, exploratory analyses revealed healthy individuals displayed significantly larger change in HRF reactivity between conditions (p’s < 0.001) in comparison to pMH, which displayed a more blunted pattern. Overall, this study establishes associations between HRF and mental health, and serves as a promising new biomarker that may identify AL in samples that may be otherwise considered “healthy”, while addressing the limitations of prior biomarkers in non-clinical studies.

Despite growing evidence that associations between autonomic nervous system (ANS) responsivity and psychopathic traits vary across stress tasks only a single study has systematically assessed cross-task differences in associations. To advance this limited literature the current study randomized subjects into either a noise blast (countdown) task or a social stressor speech task. Analyses estimated associations between ANS (heart rate, skin conductance) and measures of psychopathic traits (Self-Report Psychopathy Scale-III, Inventory of Callous-Unemotional traits, Levenson Self-Report Psychopathy Scale, Sensation Seeking Scale – Form V). Results indicated that associations between ANS activity and psychopathic traits varied across stress task, ANS measure, and psychopathy measure. Associations that were consistent across analyses included a negative association between heart rate reactivity to the countdown task and SRP total scores, and a negative association between skin conductance reactivity to the social stressor speech task the interpersonal manipulation scale in the SRP. In addition, there was a negative association between resting skin conductance and SSS-V total scores.

Neural correlates of decisions under risk and under ambiguity have been examined for several decades. In the current study, we focus on a neglected aspect that is a potential confounding of the average risk of alternatives in a trial, the average magnitude of the outcomes, and the difference in risk between the two alternatives. We present an experimental approach to solve this problem here and explicitly separate risk and ambiguity. In the present fMRI-study with 20 participants, we created different levels of risk and ambiguity to investigate their effects on behavior and brain activation. In a first experimental block, decisions with mixed-risk options (one high-risk option paired with one low-risk option) were compared to decisions with two high-risk or two low-risk options in terms of the effects on decision-making and neural activity. The second block consisted of the same risk levels crossed with high and low ambiguity by withholding information about the probabilities of the outcomes. During mixed-risk trials participants made cautious decision significantly more often. This effect was strongest during mixed trials with high ambiguity in the second block. In addition, risk behavior of subjects was correlated with the subjective importance of the amount of potential monetary losses or wins and the related probabilities. The fMRI results revealed activation of the dorsal anterior cingulate cortex (dACC), the insula, and the orbitofrontal cortex (OFC) during mixed risk trials without ambiguity. In contrast, activation of the amygdala was specifically present during mixed-risk trials with high ambiguity.

The focus of this research is to investigate the relationship between lactate induced by exercise and inhibition, a key element of executive functions. Lactate is vital for neuronal function as both an energy source and a signalling molecule. The increase in lactate production during exercise is linked to heightened brain uptake, potentially impacting cognitive performance. Through a systematic search, 16 relevant studies were identified. Three, employing cognitive tasks akin to ours, suggested a positive correlation between the changes in cognitive performance and peripheral lactate. However, these studies suffered from methodological limitations such as not having proper non-exercise controls, not manipulating exercise intensity, and having limited analytical robustness. The current study aims to address these gaps by analysing the data from a four-arm randomized crossover trial, incorporating three distinct exercise intensities alongside a control group, focusing on the potential role of lactate in modulating inhibition post-exercise.

Individuals diagnosed with schizophrenia (SZ) demonstrate difficulty distinguishing between internally- and externally-generated stimuli. These aberrations in “source monitoring” have been theorized as contributing to symptoms of the disorder, including hallucinations and delusions. Altered connectivity within the default mode network (DMN) of the brain has been proposed as a mechanism through which discrimination between self-generated and externally-generated events is disrupted. Source monitoring abnormalities in SZ have additionally been linked to impairments in selective attention and inhibitory processing, which are reliably observed via the N100 component of the event-related brain potential elicited during an auditory paired-stimulus paradigm. Given overlapping constructs associated with DMN connectivity and N100 in SZ, the present investigation evaluated relationships between these measures of disorder-related dysfunction and sought to clarify the nature of task-based DMN function in SZ. DMN connectivity and N100 measures were assessed using EEG recorded from SZ after their first episode of illness (N = 52) and demographically-matched healthy comparison participants (N= 25). SZ demonstrated less evoked theta-band connectivity within DMN following presentation of pairs of identical auditory stimuli than HC. Greater DMN connectivity among SZ was associated with better performance on measures of sustained attention (p = 0.03) and working memory (p = 0.09), as well as lower severity of negative symptoms, though it was not predictive of N100 measures. Together, present findings provide EEG evidence of lower task-based connectivity among first-episode SZ, reflecting disruptions of DMN functions that support cognitive processes. Attentional processes captured by N100 appear to be supported by different neural mechanisms.

Dysregulation of the autonomic nervous system (ANS) is commonly observed in different mental disorders, especially when individuals engage in prolonged cognitive-emotional tasks that necessitate an adjustment of the ANS to workload. Although understanding of the temporal dynamics of sympathetic and parasympathetic tones in obsessive compulsive disorder (OCD) is limited, analyzing the ANS reactions on cognitive-emotional workload could provide a valuable insight into the underlying causes of OCD. This study investigated the temporal dynamics of the heart rate (HR) and pupil area (PA) while participants with OCD and healthy volunteers solved antisaccade tasks where affective pictures served as central fixation stimuli. The data of 31 individuals with OCD and 30 healthy volunteers were included in the study. The experiment consisted of three separate blocks, each lasting approximately 8 minutes. The results showed the increase in sympathetic tone in the OCD group. The increase in sympathetic tone of the ANS in OCD at the middle part of the block was most noticeable during presentation of unpleasant stimuli. The healthy volunteers demonstrated adaptive temporal dynamics of the HR and PA from the first block to the last block of tasks, while HR and PA in the OCD group showed less changes in time implying the reduced adaptation of the ANS sympathetic tone to cognitive-emotional workload in OCD.

Adapting to the ever-changing demands of the environment requires a complex interplay between cognitive-affective, neuronal, and autonomic processes. Vagally-mediated heart rate variability (vmHRV) is positively associated with both cognitive-affective functioning and prefrontal cortex (PFC) activity. Accordingly, the Neurovisceral Integration Model has posited a shared role of the PFC in the regulation of cognitive-affective processes and autonomic nervous system (ANS) activity. While there are numerous correlational findings in this regard, no study so far has investigated whether the manipulation of PFC activity induces changes in vmHRV and cognitive-affective processing in an inter-dependent manner. In this study, we examined the effects of continuous (cTBS) and intermittent theta-burst stimulation (iTBS) over the left dorsolateral PFC (dlPFC) on vmHRV and cognitive-affective processing within an emotional stop-signal task (ESST) in 66 participants. Our results revealed that both resting vmHRV and reactivity, at least partly, predicted cognitive-affective processing. Furthermore, we found a dampening effect of cTBS on resting vmHRV, as well as an enhancing effect of iTBS on ESST performance. Our results show no direct association between vmHRV changes and ESST performance alterations following stimulation. We interpret our results in the light of a hierarchical model of neurovisceral integration, suggesting a dynamical situation-dependent recruitment of higher-order cortical areas like the dlPFC in the regulation of the ANS. In conclusion, our results highlight the complex interplay between PFC activity, autonomic regulation, and cognitive-affective processing, emphasizing the need for further research to understand the causal dynamics of the underlying neural mechanisms.

The study examined human performance and related neural mechanisms in a pop-out search with different probabilities of target location and the relation between the target location and feature. In a search array, we introduced the binding relation between two target features and two kinds of location probability. Moreover, in the second half of the experiment, such a probability pattern for location/feature binding was reversed. Behavioral results revealed successful statistical learning of probability for both absolute target location and target’s location-feature binding indicated by faster RTs in the high-probability conditions for both location and location-feature binding. Moreover, the learning benefit for the probability of location-feature binding acquired during 1st (training) phase was still expressed in the 2nd (reversal) phase despite the actual binding probability was reversed. ERP results suggested that both the attentional selection and response selection process were affected by such learning revealed in the difference in N2pc and LRP amplitudes between the two conditions with different binding probability in the reversal phase. An expectation to the high probability for location-feature binding was also suggested from time-frequency analysis and Multi-Variate Pattern Classification (MVPC) indicated by larger alpha ERD magnitude and lower decoding accuracy, respectively, when the target appeared at the high-binding location in the training phase instead of the reversal phase. Overall, we have demonstrated behavioral evidence and 4 EEG markers for the associative learning of the probability of relation between location and feature of target in a pop-out search.

Affective Touch plays a pivotal role in regulating emotions, fostering social bonds and nurturing affiliations with others. The emotional and arousing dimensions associated to Affective Touch are linked to the activation of the CT- fibres system, an afferent pathway attuned to those specific features of tactile stimulations which characterize gentle human caresses, such as touch velocity and the nature of the stroking source. While previous research has examined the physiological responses in relation to these individual features of Affective Touch, no study has explored how they interact to shape autonomic activity. In this study, we investigated whether and how touch velocity (CT-optimal vs. CT-suboptimal) and the nature of the touching effector (Human hand vs. Artificial hand) influenced the participants’ pupil dilation and their subjective experience during tactile stimulation. We observed a higher pupil dilation when touch was delivered simultaneously at CT-optimal speed and by a human hand. This kind of touch invoked a supralinear enhancement of pupil dilation indicating that the combination of these two features induced a significantly stronger autonomic activation than the summed effects of each delivered separately. Moreover, this specific type of touch was perceived as the most pleasant compared to all other tactile stimulations. Therefore, pupil dilation appears to map the positive and pleasant experience of human-to-human tactile interactions. Collectively, our results support the notion that the autonomic nervous system encodes the emotional and hedonic aspects associated with Affective Touch as a complex and holistic social experience, rather than solely responding to its low-level sensory properties.

Visual symmetry activates a network of regions in the extrastriate cortex and generates an event related potential (ERP) called the sustained posterior negativity (SPN). Previous work has found that the SPN is robust to experimental manipulations of task, spatial attention, and memory load. In the current study, we investigated whether the SPN is also robust to alcohol induced changes in mental state. A pilot experiment (N = 13) found that alcohol unexpectedly increased SPN amplitude. We followed this unexpected result with two new experiments on separate groups, using an alcohol challenge paradigm. One group completed an Oddball discrimination task (N = 26). Another group completed a Regularity discrimination task (N =26). In both groups participants consumed a medium dose of alcohol (0.65 g/kg body weight) and placebo drink, in separate sessions. Alcohol reduced SPN amplitude in the Oddball task (contrary to the pilot results) but had no effect on SPN amplitude in the Regularity task. In contrast, the N1 wave was consistently dampened by alcohol in all experiments. Exploratory analysis indicated that the inconsistent effect of alcohol on SPN amplitude may be partly explained by individual differences in alcohol use. Alcohol reduced the SPN in light drinkers and increased it in heavier drinkers. Despite remaining questions, the results highlight the automaticity of symmetry processing. Symmetry still produces a large SPN response, even when participants are intoxicated, and even when symmetry is not task relevant.

The present study combined behavioral measures and EEG to investigate the impact of emotional valence on both auditory and written word processing. Participants were first presented with a series of auditory words with varying emotional valence (positive, neutral and negative) produced in neutral tone, which they rated according to valence level. Subsequently they performed a surprise recognition task with written stimuli (half being foils). Our results revealed a significant valence/arousal effect on word recognition; written words with high-arousal and either positive or negative valence were recognized with higher accuracy compared to low-arousal neutral ones. EEG analyses revealed an effect of valence only for words presented in written format; no effects were found for auditory words. For written words, both positive and negative valence elicited a larger P2 response in comparison to neutral valence, indicating allocation of attentional resources. Critically, a reduced N400 was observed only for negative words, suggesting facilitated processing of unpleasant information perhaps due to better encoding during the auditory presentation. Overall, our study provides valuable insights into the cognitive mechanisms involved in integrating emotional information presented in distinct modalities, shedding light on the influence of valence on word recognition.

Individuals with hoarding disorder (HD) have difficulty parting with personal possessions, which leads to the accumulation of excessive clutter. According to a proposed biphasic neurobiological model, HD is characterized by blunted central and peripheral nervous system activity at rest and during neutral (non-discarding) decisions, and exaggerated activity during decision-making about discarding personal possessions. Here, we compared the error-related negativity (ERN) and psychophysiological responses (skin conductance, heart rate and heart rate variability, and end tidal CO2) during neutral and discarding-related decisions in 26 individuals with HD, 37 control participants with anxiety disorders, and 28 healthy control participants without psychiatric diagnoses. We also compared alpha asymmetry between the HD and control groups during a baseline resting phase. Participants completed a series of Go/No Go decision-making tasks, one involving choosing certain shapes (neutral task) and the other involving choosing images of newspapers to imaginally “discard” (discarding task). Contrary to hypotheses, there were no group differences in the ERN or any psychophysiological measures. Alpha asymmetry at rest did not differ between groups. The findings suggest that the ERN and psychophysiological responses may not differ in individuals with HD during simulated discarding decisions relative to control participants, although the null results may be explained by methodological challenges in using Go/No Go tasks as discarding tasks. Future replication and extension of these results will be needed using ecologically valid discarding tasks.

Regular exercise is known to positively impact neurocognitive health, particularly in aging individuals. However, low adherence, particularly among older adults, hinders the adoption of exercise routines. While neuroplasticity mechanisms largely support the cognitive benefits of exercise, the link between physiological and behavioral factors influencing exercise adherence remains unclear. This study aimed to explore this association in sedentary middle-aged and older adults. Thirty-one participants underwent an evaluation of neuroplasticity using transcranial magnetic stimulation (TMS) to measure changes in motor-evoked potentials following intermittent theta-burst stimulation (iTBS). Health history, cardiorespiratory fitness, and exercise-related behavioral factors were also assessed. The participants engaged in a 2-month supervised aerobic exercise program, attending sessions three times a week for 60 minutes each, totaling 24 sessions at a moderate-to-vigorous intensity. They were divided into Completers (n=19), who attended all sessions, and Dropouts (n=12), who withdrew early. Completers exhibited lower smoking rates, exercise barriers, and resting heart rates compared to Dropouts. For Completers, regression models revealed that post-iTBS changes (β= -7.78, p= .013) and self-efficacy (β= −.51, p= .019) predicted exercise adherence (adjusted-R2= 0.44). Larger post-iTBS increases in motor-evoked potential amplitude indicated greater effectiveness of cortico-motor plasticity and were associated with better exercise adherence. In conclusion, this study highlights the significance of cortico-motor plasticity, self-efficacy, and cardiovascular health in exercise adherence. Given the well-established cognitive benefits of exercise, addressing sedentary behavior and enhancing self-efficacy are crucial for promoting adherence and optimizing brain health. Clinicians and researchers should prioritize assessing these variables to improve the effectiveness of exercise programs.