Cardiac sympathetic-vagal activity initiates a functional brain-body response to emotional arousal.

A century-long debate on bodily states and emotions persists. While the involvement of bodily activity in emotion physiology is widely recognized, the specificity and causal role of such activity related to brain dynamics has not yet been demonstrated. We hypothesize that the peripheral neural control on cardiovascular activity prompts and sustains brain dynamics during an emotional experience, so these afferent inputs are processed by the brain by triggering a concurrent efferent information transfer to the body. To this end, we investigated the functional brain­heart interplay under emotion elicitation in publicly available data from 62 healthy subjects using a computational model based on synthetic data generation of electroencephalography and electrocardiography signals. Our findings show that sympathovagal activity plays a leading and causal role in initiating the emotional response, in which ascending modulations from vagal activity precede neural dynamics and correlate to the reported level of arousal. The subsequent dynamic interplay observed between the central and autonomic nervous systems sustains the processing of emotional arousal. These findings should be particularly revealing for the psychophysiology and neuroscience of emotions.

The Influence of Emotion Regulation on the Association Between Depression and Heart Rate Variability in Cardiac Patients.

OBJECTIVE: Poor vagally mediated heart rate variability (vmHRV) is a mechanism linking depression to coronary heart disease (CHD). Reduced vmHRV is also considered an index of emotion dysregulation-the frequent use of maladaptive emotion regulation strategies, one of the most important being expressive suppression-which is a key component of depression. Therefore, this study aimed to investigate the moderating role of expressive suppression in the relation between depression and vmHRV in patients with CHD. METHODS: The sample included 235 patients with CHD (mean [standard deviation] age = 61.6 [9.8] years; 12% women) admitted to cardiac rehabilitation after a cardiac intervention. The Beck Depression Inventory-II was administered to assess depressive symptoms. Emotion regulation strategies based on either expressive suppression or cognitive reappraisal were assessed through the Emotion Regulation Questionnaire. Resting electrocardiographic recordings were collected for 5 minutes to compute HRV indices. RESULTS: Expressive suppression moderated the relation between depressive symptoms and vmHRV ( b = -0.03, p = .012). Patients with lower expressive suppression scores showed no association between depressive symptoms and vmHRV ( b = -0.00, p = .94), whereas those with higher expressive suppression scores showed a significant negative association between depressive symptoms and vmHRV ( b = -0.05, p = .015). CONCLUSIONS: The use of expressive suppression is likely to potentiate the relation between depressive symptoms and poor vmHRV, which could increase the cardiac risk in these patients. Targeting emotion regulation skills in cardiac rehabilitation programs may be useful for reducing the impact of depression in cardiac patients.

The case for preregistering all region of interest (ROI) analyses in neuroimaging research.

In neuroimaging studies, small sample sizes and the resultant reduced statistical power to detect effects that are not large, combined with inadequate analytic choices, concur to produce inflated or false-positive findings. To mitigate these issues, researchers often restrict analyses to specific brain areas, using the region of interest (ROI) approach. Crucially, ROI analysis assumes the a priori justified definition of the target region. Nonetheless, reports often lack details about where in the timeline, ranging from study conception to the data analysis and interpretation of findings, were ROIs selected. Frequently, the rationale for ROI selection is vague or inadequately founded on the existing literature. These shortcomings have important implications for ROI-based studies, augmenting the risk that observed effects are inflated or even false positives. Tools like preregistration and registered reports could address this problem, ensuring the validity of ROI-based studies. The benefits could be enhanced by additional practices such as selection of ROIs using quantitative methods (i.e., meta-analysis) and the sharing of whole-brain unthresholded maps of effect size, as well as of binary ROIs, in publicly accessible repositories.

Brain activity during facial processing in autism spectrum disorder: an activation likelihood estimation (ALE) meta-analysis of neuroimaging studies.

BACKGROUND: Though aberrant face processing is a hallmark of autistic spectrum disorder (ASD), findings on accompanying brain activity are divergent. Therefore, we conducted an activation likelihood estimation (ALE) meta-analysis of studies examining brain activity during face processing. METHODS: We searched PubMed and PsycINFO using combinations of terms as 'fMRI', 'Autism Spectrum Disorder', 'Face Perception'. Eligible studies reported on DSM-diagnosed ASD individuals, compared to controls (HC), using face stimuli presented in fMRI and reporting whole-brain analysis coordinates. We compared two approaches: 'convergence of differences' (primary analysis) using study-level coordinates from ASD vs. HC contrasts, and 'differences in convergence' (secondary) pooling coordinates within each group separately, and contrasting the resultant ALE maps. RESULTS: Thirty-five studies (655 ASD and 668 HC) were included. Primary analysis identified a cluster in amygdala/parahippocampus where HC showed greater convergence of activation. Secondary analysis yielded no significant results. CONCLUSIONS: Results suggest that ASD dysfunction in face processing relies on structures involved in emotional processing rather than perception. We also demonstrate that the two ALE methodologies lead to divergent results.

Increased emotional eating during COVID-19 associated with lockdown, psychological and social distress.

Due to the spread of COVID 2019, the Italian government imposed a lockdown on the national territory. Initially, citizens were required to stay at home and not to mix with others outside of their household (Phase 1); eventually, some of these restrictions were lifted (Phase 2). To investigate the impact of lockdown on emotional and binge eating, an online survey was conducted to compare measures of self-reported physical (BMI), psychological (Alexithymia), affective (anxiety, stress, and depression) and social (income, workload) state during Phase 1 and Phase 2. Data from 365 Italian residents showed that increased emotional eating was predicted by higher depression, anxiety, quality of personal relationships, and quality of life, while the increase of bingeing was predicted by higher stress. Moreover, we showed that higher alexithymia scores were associated by increased emotional eating and higher BMI scores were associated with both increased emotional eating and binge eating. Finally, we found that from Phase 1 to Phase 2 binge and emotional eating decreased. These data provide evidence of the negative effects of isolation and lockdown on emotional wellbeing, and, relatedly, on eating behaviour.

Human Chemosignals and Brain Activity: A Preliminary Meta-analysis of the Processing of Human Body Odors.

Across phyla, chemosignals are a widely used form of social communication and increasing evidence suggests that chemosensory communication is present also in humans. Chemosignals can transfer, via body odors, socially relevant information, such as specific information about identity or emotional states. However, findings on neural correlates of processing of body odors are divergent. The aims of this meta-analysis were to assess the brain areas involved in the perception of body odors (both neutral and emotional) and the specific activation patterns for the perception of neutral body odor (NBO) and emotional body odor (EBO). We conducted an activation likelihood estimation (ALE) meta-analysis on 16 experiments (13 studies) examining brain activity during body odors processing. We found that the contrast EBO versus NBO resulted in significant convergence in the right middle frontal gyrus and the left cerebellum, whereas the pooled meta-analysis combining all the studies of human odors showed significant convergence in the right inferior frontal gyrus. No significant cluster was found for NBOs. However, our findings also highlight methodological heterogeneity across the existing literature. Further neuroimaging studies are needed to clarify and support the existing findings on neural correlates of processing of body odors.

A protocol for a multicentre, parallel-group, pragmatic randomised controlled trial to evaluate the NEVERMIND system in preventing and treating depression in patients with severe somatic conditions.

BACKGROUND: Depressive symptoms are common in individuals suffering from severe somatic conditions. There is a lack of interventions and evidence-based interventions aiming to reduce depressive symptoms in patients with severe somatic conditions. The aim of the NEVERMIND project is to address these issues and provide evidence by testing the NEVERMIND system, designed to reduce and prevent depressive symptoms in comparison to treatment as usual. METHODS: The NEVERMIND study is a parallel-groups, pragmatic randomised controlled trial to assess the effectiveness of the NEVERMIND system in reducing depressive symptoms among individuals with severe somatic conditions. The NEVERMIND system comprises a smart shirt and a user interface, in the form of a mobile application. The system is a real-time decision support system, aiming to predict the severity and onset of depressive symptoms by modelling the well-being condition of patients based on physiological data, body movement, and the recurrence of social interactions. The study includes 330 patients who have a diagnosis of myocardial infarction, breast cancer, prostate cancer, kidney failure, or lower limb amputation. Participants are randomised in blocks of ten to either the NEVERMIND intervention or treatment as usual as the control group. Clinical interviews and structured questionnaires are administered at baseline, at 12 weeks, and 24 weeks to assess whether the NEVERMIND system is superior to treatment as usual. The endpoint of primary interest is Beck Depression Inventory II (BDI-II) at 12 weeks defined as (i) the severity of depressive symptoms as measured by the BDI-II. Secondary outcomes include prevention of the onset of depressive symptoms, changes in quality of life, perceived stigma, and self-efficacy. DISCUSSION: There is a lack of evidence-based interventions aiming to reduce and prevent depressive symptoms in patients with severe somatic conditions. If the NEVERMIND system is effective, it will provide healthcare systems with a novel and innovative method to attend to depressive symptoms in patients with severe somatic conditions. TRIAL REGISTRATION: DRKS00013391. Registered 23 November 2017.

ROI and phobias: The effect of ROI approach on an ALE meta-analysis of specific phobias.

About 90% of fMRI findings on specific phobias (SP) include analysis of region of interest (ROI). This approach characterized by higher sensitivity may produce inflated results, particularly when findings are aggregated in meta-analytic maps. Here, we conducted a systematic review and activation likelihood estimation (ALE) meta-analysis on SP, testing the impact of the inclusion of ROI-based studies. ALE meta-analyses were carried out either including ROI-based results or focusing on whole-brain voxelwise studies exclusively. To assess the risk of bias in the neuroimaging field, we modified the Newcastle-Ottawa Scale (NOS) and measured the reliability of fMRI findings. Of the 31 selected investigations (564 patients and 485 controls) one-third did not motivate ROI selection: five studies did not report an explicit rationale, whereas four did not cite any specific reference in this regard. Analyses including ROI-based studies revealed differences between phobics and healthy subjects in several regions of the limbic circuit. However, when focusing on whole-brain analysis, only the anterior midcingulate cortex differentiated SP from controls. Notably, 13 studies were labeled with low risk of bias according to the adapted NOS. The inclusion of ROI-based results artificially inflates group differences in fMRI meta-analyses. Moreover, a priori, well-motivated selection of ROIs is desirable to improve quality and reproducibility in SP neuroimaging studies. Lastly, the use of modified NOS may represent a valuable way to assess and evaluate biases in fMRI studies: "low risk" of bias was reported for less than half of the included studies, indicating the need for better practices in fMRI.

Sponsorship bias in the comparative efficacy of psychotherapy and pharmacotherapy for adult depression: meta-analysis.

BACKGROUND: Sponsorship bias has never been investigated for non-pharmacological treatments like psychotherapy. AIMS: We examined industry funding and author financial conflict of interest (COI) in randomised controlled trials directly comparing psychotherapy and pharmacotherapy in depression. METHOD: We conducted a meta-analysis with subgroup comparisons for industry v. non-industry-funded trials, and respectively for trial reports with author financial COI v. those without. RESULTS: In total, 45 studies were included. In most analyses, pharmacotherapy consistently showed significant effectiveness over psychotherapy, g = -0.11 (95% CI -0.21 to -0.02) in industry-funded trials. Differences between industry and non-industry-funded trials were significant, a result only partly confirmed in sensitivity analyses. We identified five instances where authors of the original article had not reported financial COI. CONCLUSIONS: Industry-funded trials for depression appear to subtly favour pharmacotherapy over psychotherapy. Disclosure of all financial ties with the pharmaceutical industry should be encouraged.

Smartphone Application for the Analysis of Prosodic Features in Running Speech with a Focus on Bipolar Disorders: System Performance Evaluation and Case Study.

Bipolar disorder is one of the most common mood disorders characterized by large and invalidating mood swings. Several projects focus on the development of decision support systems that monitor and advise patients, as well as clinicians. Voice monitoring and speech signal analysis can be exploited to reach this goal. In this study, an Android application was designed for analyzing running speech using a smartphone device. The application can record audio samples and estimate speech fundamental frequency, F0, and its changes. F0-related features are estimated locally on the smartphone, with some advantages with respect to remote processing approaches in terms of privacy protection and reduced upload costs. The raw features can be sent to a central server and further processed. The quality of the audio recordings, algorithm reliability and performance of the overall system were evaluated in terms of voiced segment detection and features estimation. The results demonstrate that mean F0 from each voiced segment can be reliably estimated, thus describing prosodic features across the speech sample. Instead, features related to F0 variability within each voiced segment performed poorly. A case study performed on a bipolar patient is presented.

Moderating effects of empathic concern and personal distress on the emotional reactions of disaster volunteers.

This study examines stress and mood outcomes in community volunteers who undertook one week's worth of post-disaster relief work in L'Aquila, Italy, which had been hit by an earthquake four months earlier. The study team obtained pre- and post-relief work data from 130 volunteers involved in activities such as preparing food for the displaced, cleaning the camps and distributing clean linen. The Perceived Stress Scale, the State-Trait Anxiety Inventory and the Profile of Mood States were administered at the start and at the end of the aid activities. Psychopathological symptoms and empathy were assessed in the beginning, using the Symptom Checklist 90 Revised and the Interpersonal Reactivity Index, respectively. The results show that, following the assistance work, volunteers displayed decreases in perceived stress, general distress, anxiety and anger, as well as increases in positive emotions. The empathy facets empathic concern and personal distress showed different patterns in modulating the post-disaster relief work adaptation for some of the mood outcomes.

Assessment of suicidality in trials of psychological interventions for depression: a meta-analysis.

BACKGROUND: Psychological interventions that are efficacious as treatments for depression could indirectly affect suicide-related outcomes. We examined suicidal thoughts and behaviours as eligibility criteria, outcomes, and adverse events across trials of psychotherapy for depression. METHODS: We used a publicly available meta-analytic database developed through systematic searches (updated as of May 1, 2023) to identify randomised controlled trials in which a psychological intervention for depression was compared with an inactive or non-specific control condition in adults with depression and in which any suicide-related outcomes were reported. We also identified studies in which suicide risk was an exclusion criterion. We excluded inpatient studies and trials of unguided digital interventions or collaborative care that included a psychological component. Pairs of reviewers worked independently to select studies and extract data. In a random-effects meta-analysis with robust variance estimation, we assessed the effect of the psychological intervention on suicide outcomes in trials in which suicide was explicitly assessed as an outcome with clinical scales with established psychometric properties. Risk of bias was assessed with the Cochrane risk-of-bias tool (version 2). FINDINGS: Of the 469 randomised trials we identified in which a psychological intervention was compared with an inactive control in people with depression, 251 excluded people judged at risk of suicide. Any assessment of suicide was included in only 45 trials, 12 of which assessed suicidal ideation or risk as an outcome. These 12 trials included 3930 participants, 2795 (71%) of whom were female and 1135 (29%) of whom were male; data for age and ethnicity were not consistently reported. Psychological interventions for depression were associated with a small reduction in suicidal ideation and risk in 11 trials (one trial reported only follow-up data) after the intervention (standardised mean difference -0·31 [95% CI -0·60 to -0·03]) but not at follow-up (-0·49 [-1·31 to 0·32]). Suicide-related adverse events were reported in 25 trials, and suicide-related serious adverse events (eg, suicide attempts, deaths by suicide) were reported in 13 trials. Heterogeneity was substantial across all analyses, and prediction intervals crossed zero. INTERPRETATION: Trials of psychological interventions for depression rarely report assessments of suicide. Psychological interventions might reduce suicidal ideation in patients with depression, but more randomised controlled trials are required to clarify this effect. Monitoring and reporting of suicide-related adverse events should be improved in trials of psychological interventions for depression, and future trials should incorporate outcomes related to suicidal thoughts or behaviours. FUNDING: None. TRANSLATION: For the Spanish translation of the abstract see Supplementary Materials section.

Low odor awareness predicts reduced olfactory abilities in women with depressive symptoms, but not with anxiety symptoms.

BACKGROUND: Olfactory disorders and affective symptoms are tightly related. However, the factors underlying this association are not yet understood. One candidate factor is "odor awareness": the degree of attention individuals pays to the odors. However, the association between odor awareness and olfactory abilities in individuals with affective symptoms has not been clarified yet. METHOD: The present study examined whether odor awareness may moderate (a) the relation between olfactory dysfunctions and depressive and anxiety symptoms; (b) the relation between the perceptual ratings of the odors and depressive and anxiety symptoms in a sample of healthy women (n = 214). Self-report measures of depression and anxiety were collected, whereas the Sniffin' Stick test was employed to measure olfactory abilities. RESULTS: Linear regression analysis revealed that individuals with higher depressive symptoms presented lower olfactory abilities and that odor awareness was a significant moderator of the association between depressive symptoms and olfactory abilities. Anxiety symptoms were not related to any of the olfactory abilities considered, and this relationship did not change according to odor awareness. The familiarity rating of the odor was significantly predicted by odor awareness. These results were confirmed by Bayesian statistics. LIMITATIONS: The sample was composed only of women. CONCLUSIONS: In a healthy population of women, only the presence of depressive symptoms is related to reduced olfactory performance. Odor awareness may be implicated in the development and maintenance of olfactory dysfunction; hence it could be used as a useful target for specific treatments in clinical settings.

A New Validation of Montreal Cognitive Assessment on a Large Sample of Elderly Patients Undergoing Elective Orthopedic Surgery.

Objective: The hip and knee arthroplasties are reliable and suitable surgical procedures aimed at restoring the patients' functioning. The most representative age range for these replacement surgeries is between 65 and 84 years for females. With aging, the likelihood of developing cognitive deficits increases, and there is evidence that elderly patients undergoing surgery orthopedic are at higher risk of developing cognitive problems in the postoperative phase. The Montreal Cognitive Assessment (MoCA) is often used for cognitive evaluation, but different cut-offs and validations are available in the literature. Given the importance of the problem, in this work we studied a hospitalized population candidate for orthopedic surgery to determine a new specific validation of the MoCA to assess the risk of MCI. Method: We applied MoCA and Mini-Mental State Examination (MMSE) to a sample of 492 (333 women) hospitalized patients for knee (74%) or hip surgery. A non-parametric receiver operating characteristic (ROC) curve analysis was conducted to investigate the predictive accuracy of the MoCA to assess cognitive impairment, using MMSE as the gold standard. Results: A score of 22.52 gives a sensitivity of 70% and a specificity of 78%. This value is providing a more coherent diagnosis with the MMSE as compared to the other cut-offs presented in the other available validations. No differences were found between patients in terms of age and gender, suggesting a general uniformity of the selected sample. Conclusions: Deepening the coherence in MCI diagnosis between MMSE and the other MoCA's scoring considered, our new cut-off seems reasonably better than previous Italian validation on an elderly population in matching MMSE classification.

The moderating role of depressive symptoms in the association between heart rate variability and cognitive performance in cardiac patients.

INTRODUCTION: Coronary heart disease (CHD) is strongly associated with cognitive impairment, which is a core feature of depression, highly prevalent in patients with CHD. Interestingly, patients with CHD and individuals with depression display reduced heart rate variability (HRV), which proxies a complex network integrating autonomic and attentional systems. This study investigated the moderating role of depressive symptoms in the relation between reduced HRV and cognitive performance in patients with CHD. METHOD: The sample included 274 patients with CHD (mean [standard deviation] age = 62 [9.5] years; 13 % women) admitted to cardiac rehabilitation units. Visual attention and task switching were assessed through the Trail Making Test (TMT). Depressive symptoms were assessed with the Beck Depression Inventory-II (BDI-II). Resting electrocardiographic recordings were collected to compute HRV indices. RESULTS: Patients with more severe depressive symptoms displayed an inverse association between HRV and cognitive performance (TMT-A: b = -0.08, p = .022; TMTB: b = -0.07, p = .042), whereas patients with milder depressive symptoms showed no significant association (TMT-A: b = -0.00, p = .90; TMTB: b = -0.02, p = .44). CONCLUSIONS: Depressive symptoms may strengthen the relation between reduced HRV and poorer cognitive performance in cardiac patients. The presence of depressive symptoms may signal the dysfunction of a network subserving autonomic and cognitive function.

Emotion regulation difficulties in the relation between stress-related insomnia symptoms and brain response to emotional faces: An fMRI study.

The aim of the current study was to investigate whether the experience of insomnia symptoms per se and symptoms of insomnia due to stress are associated with an increased brain response to the presentation of emotional faces. In addition, we also examined whether the effect of these sleep difficulties on emotional reactivity at the brain level depends on the experience of emotion regulation (ER) difficulties. The current sample consisted of 37 individuals (20 females, 17 males) selected from a larger group of 120 respondents who completed a survey about sleep problems and ER difficulties. Our results indicate that the tendency to experience stress-related insomnia symptoms but not insomnia symptoms per se modulates brain responses to emotional facial expressions, especially in areas of the parietal cortex, insula, and surrounding opercular voxels. Furthermore, difficulties in ER might play an important role, as the effect of stress-related insomnia symptoms on most of these brain regions disappears when controlling for difficulties in ER. However, an effect in the insula was maintained during the presentation of angry faces, suggesting that stress-related insomnia symptoms may increase the brain response to anger in the insula relatively independent from difficulties in ER. These findings suggest that individuals affected by stress-related insomnia symptoms show an enhanced brain response when presented with emotional stimuli (either positive or negative) in brain areas associated with hyperarousal, which could represent a possible ER deficit in these individuals. Thus, interventions that focus on targeting ER difficulties might be effective in reducing the hyperarousal state in individuals affected by stress-related insomnia symptoms.

Physiologically-Informed Gaussian Processes for Interpretable Modelling of Psycho-Physiological States.

The widespread popularity of Machine Learning (ML) models in healthcare solutions has increased the demand for their interpretability and accountability. In this paper, we propose the Physiologically-Informed Gaussian Process (PhGP) classification model, an interpretable machine learning model founded on the Bayesian nature of Gaussian Processes (GPs). Specifically, we inject problem-specific domain knowledge of inherent physiological mechanisms underlying the psycho-physiological states as a prior distribution over the GP latent space. Thus, to estimate the hyper-parameters in PhGP, we rely on the information from raw physiological signals as well as the designed prior function encoding the physiologically-inspired modelling assumptions. Alongside this new model, we present novel interpretability metrics that highlight the most informative input regions that contribute to the GP prediction. We evaluate the ability of PhGP to provide an accurate and interpretable classification on three different datasets, including electrodermal activity (EDA) signals collected during emotional, painful, and stressful tasks. Our results demonstrate that, for all three tasks, recognition performance is improved by using the PhGP model compared to competitive methods. Moreover, PhGP is able to provide physiological sound interpretations over its predictions.

Alexithymia modulates the attitudes towards odors but not the olfactory abilities or the affective reactions to odors.

Although emotion and olfaction are closely linked, only a few studies have investigated olfactory processing in alexithymia, a condition characterized by altered emotional processing. These results do not allow comprehensive conclusions on whether individuals with alexithymia present lower olfactory abilities or only altered affective reactions and awareness of odors. Three pre-registered experiments were conducted to clarify this relation. We assessed olfactory functions, the affective qualities of odors, the awareness of odors, the attitudes towards them, and the ability to form olfactory images in the mind. Bayesian statistics were used to assess differences between low, medium and high alexithymia groups, and Linear Mixed Models (LMMs) were applied to investigate the modulation of the affective and cognitive components of alexithymia. We observed that individuals with a high level of alexithymia presented the same olfactory abilities, and did not show differences in their rating of odors compared to individuals with low alexithymia levels, while they reported lower levels of social and common odor awareness and a more indifferent attitude towards odors. Olfactory imagery was not affected by alexithymia level, and the affective and cognitive components of alexithymia, when considered separately, modulated olfactory perception differently. Learning more about olfactory perception in individuals with alexithymia leads to a better understanding of how alexithymia impacts the perception of hedonic stimuli coming from different sensory modalities. Our results imply that treatment goals for alexithymia should be the enhancement of the conscious perception of odors, supporting the use of mindfulness-based protocols in the alexithymia treatment.

Complexity Modulation in functional Brain-Heart Interplay series driven by Emotional Stimuli: an early study using Fuzzy Entropy.

Increasing attention has recently been devoted to the multidisciplinary investigation of functional brain-heart interplay (BHI), which has provided meaningful insights in neuroscience and clinical domains including cardiology, neurology, clinical psychology, and psychiatry. While neural (brain) and heartbeat series show high nonlinear and complex dynamics, a complexity analysis on BHI series has not been performed yet. To this end, in this preliminary study, we investigate BHI complexity modulation in 17 healthy subjects undergoing a 3-minute resting state and emotional elicitation through standardized image slideshow. Electroencephalographic and heart rate variability series were the inputs of an adhoc BHI model, which provides directional (from-heart-to-brain and from-brain-to-heart) estimates at different frequency bands. A Fuzzy entropy analysis was performed channel-wise on the model output for the two experimental conditions. Results suggest that BHI complexity increases in the emotional elicitation phase with respect to a resting state, especially in the functional direction from the heart to the brain. We conclude that BHI complexity may be a viable computational tool to characterize neurophysiological and pathological states under different experimental conditions.