Delving into the relationship between regular physical exercise and cardiac interoception in two cross-sectional studies.

Cardiac interoception, the ability to sense and process cardiac afferent signals, has been shown to improve after a single session of acute physical exercise. However, it remains unclear whether repetitive engagement in physical exercise over time leads to long-term changes in cardiac interoceptive accuracy. It is also unknown whether those changes affect the neural activity associated with the processing of afferent cardiac signals, assessed by the heart-evoked potential (HEP). In this study, we aimed to investigate this hypothesis through two cross-sectional studies, categorizing participants as active or inactive based on physical fitness (Study I; N = 45) or self-reported physical activity levels (Study II; N = 60). Interoception was assessed at rest using the HEP (Studies I and II), the Heartbeat Counting task (Study II), and the Rubber Hand Illusion (RHI) (Study II). Study I showed strong evidence of better cardiovascular fitness in the active group than in the inactive group as well as robust between-group differences in electrocardiogram (ECG) recordings. Study 2 replicated the clear differences in ECG as a function of regular physical activity. Those results were expected due to clear differences in physical activity habits. In contrast, our analysis revealed no robust differences between groups across cardiac interoception tasks and the RHI, although the direct relevance of these measures to interoception remains under investigation. In sum, our results do not provide convincing evidence to support a strong version of the notion that regular physical exercise is associated with an enhanced in cardiac interoception.

Replacing academic journals.

Replacing traditional journals with a more modern solution is not a new idea. Here, we propose ways to overcome the social dilemma underlying the decades of inaction. Any solution needs to not only resolve the current problems but also be capable of preventing takeover by corporations: it needs to replace traditional journals with a decentralized, resilient, evolvable network that is interconnected by open standards and open-source norms under the governance of the scholarly community. It needs to replace the monopolies connected to journals with a genuine, functioning and well-regulated market. In this new market, substitutable service providers compete and innovate according to the conditions of the scholarly community, avoiding sustained vendor lock-in. Therefore, a standards body needs to form under the governance of the scholarly community to allow the development of open scholarly infrastructures servicing the entire research workflow. We propose a redirection of money from legacy publishers to the new network by funding bodies broadening their minimal infrastructure requirements at recipient institutions to include modern infrastructure components replacing and complementing journal functionalities. Such updated eligibility criteria by funding agencies would help realign the financial incentives for recipient institutions with public and scholarly interest.

An umbrella review of randomized control trials on the effects of physical exercise on cognition.

Extensive research links regular physical exercise to an overall enhancement of cognitive function across the lifespan. Here we assess the causal evidence supporting this relationship in the healthy population, using an umbrella review of meta-analyses limited to randomized controlled trials (RCTs). Despite most of the 24 reviewed meta-analyses reporting a positive overall effect, our assessment reveals evidence of low statistical power in the primary RCTs, selective inclusion of studies, publication bias and large variation in combinations of pre-processing and analytic decisions. In addition, our meta-analysis of all the primary RCTs included in the revised meta-analyses shows small exercise-related benefits (d = 0.22, 95% confidence interval 0.16 to 0.28) that became substantially smaller after accounting for key moderators (that is, active control and baseline differences; d = 0.13, 95% confidence interval 0.07 to 0.20), and negligible after correcting for publication bias (d = 0.05, 95% confidence interval -0.09 to 0.14). These findings suggest caution in claims and recommendations linking regular physical exercise to cognitive benefits in the healthy human population until more reliable causal evidence accumulates.

The heartbeat evoked potential is a questionable biomarker in nightmare disorder: A replication study.

Frequent nightmares are highly prevalent and constitute a risk factor for a wide range of psychopathological conditions. Despite its prevalence and clinical relevance however, the pathophysiological mechanisms of nightmares are poorly understood. A recent study (Perogamvros et, al 2019) examined the heart beat evoked potential (HEP) in a small group of nightmare sufferers (N = 11) and matched healthy controls (N = 11) and observed markedly different (Hedges' g = 1.42 [0.62-2.22]) HEP response across the groups during Rapid Eye Movement (REM) sleep. Moreover, the HEP correlated with depression scores in the nightmare group only. The authors concluded that the HEP in REM sleep could be used as a trait-like biomarker reflecting pathological emotional-and sleep regulation in nightmare disorder. To replicate the above study, we performed the same analyses of HEPs in two separate, and larger databases comprising the polysomnographic recordings of nightmare sufferers and matched controls (NStudy 1 = 39 ; NStudy 2 = 41). In contrast to the original findings, we did not observe significant differences in HEP across the two groups in either of the two databases. Moreover, we found no associations between depression scores and HEP amplitudes in the relevant spatiotemporal cluster. Our data cast doubts on the utility of HEP as a biomarker in the diagnostic and treatment procedures of nightmare disorder and suggests that the interpretation of HEP as a marker of impaired arousal and emotional processing during REM sleep is premature and requires further validation.

Physical activity and interoceptive processing: Theoretical considerations for future research.

Interoception, defined as the sense of the internal bodily state, plays a critical role in physical, cognitive, emotional and social well-being. Regarding physical well-being, contemporary models of exercise regulation incorporate interoceptive processes in the regulation of physical exertion. Top-down processes continuously monitor the physiological condition of the body to ensure allostasis is maintained, however, flagged perturbations also appear to influence these higher order processes in return. More specifically, enhancing one's physiological arousal by means of physical activity is a viable way of manipulating the afferent input entering the interoceptive system, appearing to optimise the integration of early sensory stimulation with later affective responses. Despite this, the relationship between physical activity and top-down regulation is underrepresented in interoceptive research. We here address this gap by integrating findings from different disciplines to support the overlapping mechanisms, with the hope of stimulating further research in this field. Developing our understanding of how interoceptive processes are shaped by physical activity could hold significant clinical implications considering the impact of interoceptive deficits to mental health and well-being.

Cortical monitoring of cardiac activity during rapid eye movement sleep: the heartbeat evoked potential in phasic and tonic rapid-eye-movement microstates.

Sleep is a fundamental physiological state that facilitates neural recovery during periods of attenuated sensory processing. On the other hand, mammalian sleep is also characterized by the interplay between periods of increased sleep depth and environmental alertness. Whereas the heterogeneity of microstates during non-rapid-eye-movement (NREM) sleep was extensively studied in the last decades, transient microstates during rapid-eye-movement (REM) sleep received less attention. REM sleep features two distinct microstates: phasic and tonic. Previous studies indicate that sensory processing is largely diminished during phasic REM periods, whereas environmental alertness is partially reinstated when the brain switches into tonic REM sleep. Here, we investigated interoceptive processing as quantified by the heartbeat evoked potential (HEP) during REM microstates. We contrasted the HEPs of phasic and tonic REM periods using two separate databases that included the nighttime polysomnographic recordings of healthy young individuals (N = 20 and N = 19). We find a differential HEP modulation of a late HEP component (after 500 ms post-R-peak) between tonic and phasic REM. Moreover, the late tonic HEP component resembled the HEP found in resting wakefulness. Our results indicate that interoception with respect to cardiac signals is not uniform across REM microstates, and suggest that interoceptive processing is partially reinstated during tonic REM periods. The analyses of the HEP during REM sleep may shed new light on the organization and putative function of REM microstates.

CoVidAffect, real-time monitoring of mood variations following the COVID-19 outbreak in Spain.

The COVID-19 outbreak and the ensuing confinement measures are expected to bear a significant psychological impact on the affected populations. To date, all available studies designed to investigate the psychological effects of this unprecedented global crisis are based on cross-sectional surveys that do not capture emotional variations over time. Here, we present the data from CoVidAffect, a nationwide citizen science project aimed to provide longitudinal data of mood changes following the COVID-19 outbreak in the spanish territory. Spain is among the most affected countries by the pandemic, with one of the most restrictive and prolonged lockdowns worldwide. The project also collected a baseline of demographic and socioeconomic data. These data can be further analyzed to quantify emotional responses to specific measures and policies, and to understand the effect of context variables on psychological resilience. Importantly, to our knowledge this is the first dataset that offers the opportunity to study the behavior of emotion dynamics in a prolonged lockdown situation.

Exercise practice associates with different brain rhythmic patterns during vigilance.

Cardiovascular fitness has repeatedly been associated to enhanced cognitive and brain functioning, generally in the form of differences in reaction time and response accuracy, as well as in event-related potentials (ERPs) and blood-oxygen-level-dependent imaging while participants performed executive demanding tasks. However, the evidence regarding potential differences in oscillatory neural activity, an inherent characteristic of brain functioning, is scarce. To fill this gap, here, we extracted and analysed (using a data-driven exploratory approach) brain oscillatory activity, both tonic (overall electroencephalographic - EEG - oscillatory activity) and transient (event related spectral perturbation [ERSP] and inter-trial coherence [ITC]), from a previous published dataset (Luque-Casado et al. 2016), where we showed different behavioural and ERP patterns during a vigilance/sustained attention task as a function of cardiovascular fitness in young adults. The ERSP results of the current study revealed increased theta (4-8 Hz) and upper beta (20-40 Hz) power and reduced lower beta (14-20 Hz) suppression after the target stimulus presentation in the higher-fit group compared to their lower-fit peers, but these differences disappeared in the second part of the task. ITC results mimicked the ERSP pattern within theta (4-8 Hz), while no differences were observed for the remaining frequency bands. Interestingly, the overall time-dependent effect in transient oscillatory activity followed the reaction time pattern of results. The analysis of the overall EEG oscillatory (tonic) dynamics did not show significant differences between groups. In sum, cardiorespiratory fitness was related to a brain oscillatory differential response pattern over a wide range of the frequency spectrum and spatio-temporal distribution, which seems to underlie the positive relationship between aerobic fitness and behavioural performance in a sustained attention task. Future studies are warranted to study the causal nature (beyond mere association) of these findings.

Smartphone-Based Platform for Affect Monitoring through Flexibly Managed Experience Sampling Methods.

The identification of daily life events that trigger significant changes on our affective state has become a fundamental task in emotional research. To achieve it, the affective states must be assessed in real-time, along with situational information that could contextualize the affective data acquired. However, the objective monitoring of the affective states and the context is still in an early stage. Mobile technologies can help to achieve this task providing immediate and objective data of the users' context and facilitating the assessment of their affective states. Previous works have developed mobile apps for monitoring affective states and context, but they use a fixed methodology which does not allow for making changes based on the progress of the study. This work presents a multimodal platform which leverages the potential of the smartphone sensors and the Experience Sampling Methods (ESM) to provide a continuous monitoring of the affective states and the context in an ubiquitous way. The platform integrates several elements aimed to expedite the real-time management of the ESM questionnaires. In order to show the potential of the platform, and evaluate its usability and its suitability for real-time assessment of affective states, a pilot study has been conducted. The results demonstrate an excellent usability level and a good acceptance from the users and the specialists that conducted the study, and lead to some suggestions for improving the data quality of mobile context-aware ESM-based systems.

The relationship between vigilance capacity and physical exercise: a mixed-effects multistudy analysis.

A substantial body of work has depicted a positive association between physical exercise and cognition, although the key factors driving that link are still a matter of scientific debate. Here, we aimed to contribute further to that topic by pooling the data from seven studies (N = 361) conducted by our research group to examine whether cardiovascular fitness (VO2), sport type participation (externally-paced (e.g., football or basketball) and self-paced (e.g., triathlon or track and field athletes) vs. sedentary), or both, are crucial factors to explain the association between the regular practice of exercise and vigilance capacity. We controlled for relevant variables such as age and the method of VO2 estimation. The Psychomotor Vigilance Task was used to measure vigilance performance by means of reaction time (RT). The results showed that externally-paced sport practice (e.g., football) resulted in significantly shorter RT compared to self-paced sport (e.g., triathlon) and sedentary condition, depicting larger effects in children and adolescents than in adults. Further analyses revealed no significant effect of cardiovascular fitness and self-paced sport practice, in comparison to the sedentary condition, on RT. Our data point to the relevance of considering the type of sport practice over and above the level of cardiovascular fitness as crucial factor to explain the positive association between the regular practice of exercise and vigilance capacity.

Oscillatory brain activity during acute exercise: Tonic and transient neural response to an oddball task.

Intense physical exercise exerts measurable changes at various physiological levels that are well documented in the literature. However, despite the key role of the brain in processing inputs from internal organ systems and the external environment to coordinate and optimize behavior, little is known about brain dynamics during exercise. The present study investigates tonic and transient oscillatory brain activity in a group of participants performing an oddball task during a single bout of aerobic exercise. Twenty young males (19-32 years) were recruited for two experimental sessions on separate days. EEG activity was recorded during a session of cycling at 80% (moderate-to-high intensity) of VO2max (maximum rate of oxygen consumption) while participants responded to infrequent targets (red square and big blue circle) presented among frequent nontargets (small blue circle). This was compared to a (baseline) light intensity session (30% VO2max ) to control any potential effect of dual tasking (i.e., pedaling and performing the oddball task). A cluster-based nonparametric permutations test revealed an increase in power across the entire frequency spectrum during the moderate-to-high intensity exercise compared to light intensity. Furthermore, the more salient target (red square) elicited a lower increase in (stimulus-evoked) theta power in the 80% VO2max than in the light intensity condition. Alpha and lower beta power decreased less in the standard trials (small blue circle) during the moderate-to-high exercise condition than in the light exercise condition. The present study unveils, for the first time, a complex brain activity pattern during vigorous exercise while attending to task-relevant stimuli.

Physical exercise increases overall brain oscillatory activity but does not influence inhibitory control in young adults.

Extant evidence suggests that acute exercise triggers a tonic power increase in the alpha frequency band at frontal locations, which has been linked to benefits in cognitive function. However, recent literature has questioned such a selective effect on a particular frequency band, indicating a rather overall power increase across the entire frequency spectrum. Moreover, the nature of task-evoked oscillatory brain activity associated to inhibitory control after exercising, and the duration of the exercise effect, are not yet clear. Here, we investigate for the first time steady state oscillatory brain activity during and following an acute bout of aerobic exercise at two different exercise intensities (moderate-to-high and light), by means of a data-driven cluster-based approach to describe the spatio-temporal distribution of exercise-induced effects on brain function without prior assumptions on any frequency range or site of interest. We also assess the transient oscillatory brain activity elicited by stimulus presentation, as well as behavioural performance, in two inhibitory control (flanker) tasks, one performed after a short delay following the physical exercise and another completed after a rest period of 15' post-exercise to explore the time course of exercise-induced changes on brain function and cognitive performance. The results show that oscillatory brain activity increases during exercise compared to the resting state, and that this increase is higher during the moderate-to-high intensity exercise with respect to the light intensity exercise. In addition, our results show that the global pattern of increased oscillatory brain activity is not specific to any concrete surface localization in slow frequencies, while in faster frequencies this effect is located in parieto-occipital sites. Notably, the exercise-induced increase in oscillatory brain activity disappears immediately after the end of the exercise bout. Neither transient (event-related) oscillatory activity, nor behavioural performance during the flanker tasks following exercise showed significant between-intensity differences. The present findings help elucidate the effect of physical exercise on oscillatory brain activity and challenge previous research suggesting improved inhibitory control following moderate-to-high acute exercise.

Tramadol effects on physical performance and sustained attention during a 20-min indoor cycling time-trial: A randomised controlled trial.

OBJECTIVES: To investigate the effect of tramadol on performance during a 20-min cycling time-trial (Experiment 1), and to test whether sustained attention would be impaired during cycling after tramadol intake (Experiment 2). DESIGN: Randomized, double-blind, placebo controlled trial. METHODS: In Experiment 1, participants completed a cycling time-trial, 120-min after they ingested either tramadol or placebo. In Experiment 2, participants performed a visual oddball task during the time-trial. Electroencephalography measures (EEG) were recorded throughout the session. RESULTS: In Experiment 1, average time-trial power output was higher in the tramadol vs. placebo condition (tramadol: 220W vs. placebo: 209W; p<0.01). In Experiment 2, no differences between conditions were observed in the average power output (tramadol: 234W vs. placebo: 230W; p>0.05). No behavioural differences were found between conditions in the oddball task. Crucially, the time frequency analysis in Experiment 2 revealed an overall lower target-locked power in the beta-band (p<0.01), and higher alpha suppression (p<0.01) in the tramadol vs. placebo condition. At baseline, EEG power spectrum was higher under tramadol than under placebo in Experiment 1 while the reverse was true for Experiment 2. CONCLUSIONS: Tramadol improved cycling power output in Experiment 1, but not in Experiment 2, which may be due to the simultaneous performance of a cognitive task. Interestingly enough, the EEG data in Experiment 2 pointed to an impact of tramadol on stimulus processing related to sustained attention. TRIAL REGISTRATION: EudraCT number: 2015-005056-96.

The relationship between sustained attention and aerobic fitness in a group of young adults.

BACKGROUND: A growing set of studies has shown a positive relationship between aerobic fitness and a broad array of cognitive functions. However, few studies have focused on sustained attention, which has been considered a fundamental cognitive process that underlies most everyday activities. The purpose of this study was to investigate the role of aerobic fitness as a key factor in sustained attention capacities in young adults. METHODS: Forty-four young adults (18-23 years) were divided into two groups as a function of the level of aerobic fitness (high-fit and low-fit). Participants completed the Psychomotor Vigilance Task (PVT) and an oddball task where they had to detect infrequent targets presented among frequent non-targets. RESULTS: The analysis of variance (ANOVA) showed faster responses for the high-fit group than for the low-fit group in the PVT, replicating previous accounts. In the oddball task, the high-fit group maintained their accuracy (ACC) rate of target detection over time, while the low-fit group suffered a significant decline of response ACC throughout the task. DISCUSSION: Importantly, the results show that the greater sustained attention capacity of high-fit young adults is not specific to a reaction time (RT) sustained attention task like the PVT, but it is also evident in an ACC oddball task. In sum, the present findings point to the important role of aerobic fitness on sustained attention capacities in young adults.

Mathematical detection of aortic valve opening (B point) in impedance cardiography: A comparison of three popular algorithms.

The preejection period (PEP) is an index of left ventricle contractility widely used in psychophysiological research. Its computation requires detecting the moment when the aortic valve opens, which coincides with the B point in the first derivative of impedance cardiogram (ICG). Although this operation has been traditionally made via visual inspection, several algorithms based on derivative calculations have been developed to enable an automatic performance of the task. However, despite their popularity, data about their empirical validation are not always available. The present study analyzes the performance in the estimation of the aortic valve opening of three popular algorithms, by comparing their performance with the visual detection of the B point made by two independent scorers. Algorithm 1 is based on the first derivative of the ICG, Algorithm 2 on the second derivative, and Algorithm 3 on the third derivative. Algorithm 3 showed the highest accuracy rate (78.77%), followed by Algorithm 1 (24.57%) and Algorithm 2 (13.82%). In the automatic computation of PEP, Algorithm 2 resulted in significantly more missed cycles (48.57%) than Algorithm 1 (6.3%) and Algorithm 3 (3.5%). Algorithm 2 also estimated a significantly lower average PEP (70 ms), compared with the values obtained by Algorithm 1 (119 ms) and Algorithm 3 (113 ms). Our findings indicate that the algorithm based on the third derivative of the ICG performs significantly better. Nevertheless, a visual inspection of the signal proves indispensable, and this article provides a novel visual guide to facilitate the manual detection of the B point.

Take the Money and Run: Psychopathic Behavior in the Trust Game.

We study the association among different sources of individual differences such as personality, cognitive ability and risk attitudes with trust and reciprocate behavior in an incentivized experimental binary trust game in a sample of 220 (138 females) undergraduate students. The game involves two players, player 1 (P1) and player 2 (P2). In the first stage, P1 decides whether to trust and let P2 decide, or to secure an egalitarian payoff for both players. If P1 trusts P2, the latter can choose between a symmetric payoff that is double than the secure alternative discarded by P1, and an asymmetric payoff in which P2 earns more than in any other case but makes P1 worse off. Before the main experiment, we obtained participants' scores for Abstract Reasoning (AR), risk attitudes, basic personality characteristics, and specific traits such as psychopathy and impulsivity. During the main experiment, we measured Heart Rate (HR) and ElectroDermal Activity (EDA) variation to account for emotional arousal caused by the decision and feedback processes. Our main findings indicate that, on one hand, P1 trust behavior associates to positive emotionality and, specifically, to the extraversion's warmth facet. In addition, the impulsivity facet of positive urgency also favors trust behavior. No relation to trusting behavior was found for either other major personality aspects or risk attitudes. The physiological results show that participants scoring high in psychopathy exhibit increased EDA and reduced evoked HR deceleration at the moment in which they are asked to decide whether or not to trust. Regarding P2, we find that AR ability and mainly low disagreeable disinhibition favor reciprocal behavior. Specifically, lack of reciprocity significantly relates with a psychopathic, highly disinhibited and impulsive personality. Thus, the present study suggests that personality characteristics would play a significant role in different behaviors underlying cooperation, with extraversion/positive emotionality being more relevant for initiating cooperation, and low disagreeable disinhibition for maintaining it.

Transient autonomic responses during sustained attention in high and low fit young adults.

Maintaining vigilance over long periods of time is especially critical in performing fundamental everyday activities and highly responsible professional tasks (e.g., driving, performing surgery or piloting). Here, we investigated the role of aerobic fitness as a crucial factor related to the vigilance capacity. To this end, two groups of young adult participants (high-fit and low-fit) were compared in terms of reaction time (RT) performance and event-related heart rate responses in a 60' version of the psychomotor vigilance task. The results showed shorter RTs in high-fit participants, but only during the first 24' of the task. Crucially, this period of improved performance was accompanied by a decelerative cardiac response pattern present only in the high-fit group that also disappeared after the first 24'. In conclusion, high aerobic fitness was related to a pattern of transient autonomic responses suggestive of an attentive preparatory state that coincided with improved behavioural performance, and that was sustained for 24'. Our findings highlight the importance of considering the role of the autonomic nervous system reactivity in the relationship between fitness and cognition in general, and sustained attention in particular.

Differences in Sustained Attention Capacity as a Function of Aerobic Fitness.

PURPOSE: We investigated the relationship between aerobic fitness and sustained attention capacity by comparing task performance and brain function, by means of event-related potentials (ERP), in high- and low-fit young adults. METHODS: Two groups of participants (22 higher-fit and 20 lower-fit) completed a 60-min version of the Psychomotor Vigilance Task (PVT). Behavioral (i.e., reaction time) and electrophysiological (ERP) (i.e., contingent negative variation and P3) were obtained and analyzed as a function of time-on-task. A submaximal cardiorespiratory fitness test confirmed the between-groups difference in terms of aerobic fitness. RESULTS: The results revealed shorter reaction time in higher-fit than in lower-fit participants in the first 36 min of the task. This was accompanied by larger contingent negative variation amplitude in the same period of the task in higher-fit than in lower-fit group. Crucially, higher-fit participants maintained larger P3 amplitude throughout the task compared to lower-fit, who showed a reduction in the P3 magnitude over time. CONCLUSIONS: Higher fitness was related to neuroelectric activity suggestive of better overall sustained attention demonstrating a better ability to allocate attentional resources over time. Moreover, higher fitness was related to enhanced response preparation in the first part of the task. Taken together, the current data set demonstrated a positive association between aerobic fitness, sustained attention, and response preparation.