Multisensory mechanisms of gait and balance in Parkinson's disease: an integrative review

Understanding the neural underpinning of human gait and balance is one of the most pertinent challenges for 21st-century translational neuroscience due to the profound impact that falls and mobility disturbances have on our aging population. Posture and gait control does not happen automatically, as previously believed, but rather requires continuous involvement of central nervous mechanisms. To effectively exert control over the body, the brain must integrate multiple streams of sensory information, including visual, vestibular, and somatosensory signals. The mechanisms which underpin the integration of these multisensory signals are the principal topic of the present work. Existing multisensory integration theories focus on how failure of cognitive processes thought to be involved in multisensory integration leads to falls in older adults. Insufficient emphasis, however, has been placed on specific contributions of individual sensory modalities to multisensory integration processes and cross-modal interactions that occur between the sensory modalities in relation to gait and balance. In the present work, we review the contributions of somatosensory, visual, and vestibular modalities, along with their multisensory intersections to gait and balance in older adults and patients with Parkinson's disease. We also review evidence of vestibular contributions to multisensory temporal binding windows, previously shown to be highly pertinent to fall risk in older adults. Lastly, we relate multisensory vestibular mechanisms to potential neural substrates, both at the level of neurobiology (concerning positron emission tomography imaging) and at the level of electrophysiology (concerning electroencephalography). We hope that this integrative review, drawing influence across multiple subdisciplines of neuroscience, paves the way for novel research directions and therapeutic neuromodulatory approaches, to improve the lives of older adults and patients with neurodegenerative diseases.

The "plant neurobiology" revolution

The 21st-century "plant neurobiology" movement is an amalgam of scholars interested in how "neural processes", broadly defined, lead to changes in plant behavior. Integral to the movement (now called plant behavioral biology) is a triad of historically marginalized subdisciplines, namely plant ethology, whole plant electrophysiology and plant comparative psychology, that set plant neurobiology apart from the mainstream. A central tenet held by these "triad disciplines" is that plants are exquisitely sensitive to environmental perturbations and that destructive experimental manipulations rapidly and profoundly affect plant function. Since destructive measurements have been the norm in plant physiology, much of our "textbook knowledge" concerning plant physiology is unrelated to normal plant function. As such, scientists in the triad disciplines favor a more natural and holistic approach toward understanding plant function. By examining the history, philosophy, sociology and psychology of the triad disciplines, this paper refutes in eight ways the criticism that plant neurobiology presents nothing new, and that the topics of plant neurobiology fall squarely under the purview of mainstream plant physiology. It is argued that although the triad disciplines and mainstream plant physiology share the common goal of understanding plant function, they are distinct in having their own intellectual histories and epistemologies.

Common bean under different water availability reveals classifiable stimuli-specific signatures in plant electrome

Plant electrophysiology has unveiled the involvement of electrical signals in the physiology and behavior of plants. Spontaneously generated bioelectric activity can be altered in response to changes in environmental conditions, suggesting that a plant's electrome may possess a distinct signature associated with various stimuli. Analyzing electrical signals, particularly the electrome, in conjunction with Machine Learning (ML) techniques has emerged as a promising approach to classify characteristic electrical signals corresponding to each stimulus. This study aimed to characterize the electrome of common bean (Phaseolus vulgaris L.) cv. BRS-Expedito, subjected to different water availabilities, seeking patterns linked to these stimuli. For this purpose, bean plants in the vegetative stage were subjected to the following treatments: (I) distilled water; (II) half-strength Hoagland's nutrient solution; (III) -2 MPa PEG solution; and (IV) -2 MPa NaCl solution. Electrical signals were recorded within a Faraday's cage using the MP36 electronic system for data acquisition. Concurrently, plant water status was assessed by monitoring leaf turgor variation. Leaf temperature was additionally measured. Various analyses were conducted on the electrical time series data, including arithmetic average of voltage variation, skewness, kurtosis, Probability Density Function (PDF), autocorrelation, Power Spectral Density (PSD), Approximate Entropy (ApEn), Fast Fourier Transform (FFT), and Multiscale Approximate Entropy (ApEn(s)). Statistical analyses were performed on leaf temperature, voltage variation, skewness, kurtosis, PDF µ exponent, autocorrelation, PSD β exponent, and approximate entropy data. Machine Learning analyses were applied to identify classifiable patterns in the electrical time series. Characterization of the electrome of BRS-Expedito beans revealed stimulus-dependent profiles, even when alterations in water availability stimuli were similar in terms of quality and intensity. Additionally, it was observed that the bean electrome exhibits high levels of complexity, which are altered by different stimuli, with more intense and aversive stimuli leading to drastic reductions in complexity levels. Notably, one of the significant findings was the 100% accuracy of Small Vector Machine in detecting salt stress using electrome data. Furthermore, the study highlighted alterations in the plant electrome under low water potential before observable leaf turgor changes. This work demonstrates the potential use of the electrome as a physiological indicator of the water status in bean plants.

Games to support teaching clinical reasoning in health professions education: a scoping review

INTRODUCTION

Given the complexity of teaching clinical reasoning to (future) healthcare professionals, the utilization of serious games has become popular for supporting clinical reasoning education. This scoping review outlines games designed to support teaching clinical reasoning in health professions education, with a specific emphasis on their alignment with the 8-step clinical reasoning cycle and the reflective practice framework, fundamental for effective learning.

METHODS

A scoping review using systematic searches across seven databases (PubMed, CINAHL, ERIC, PsycINFO, Scopus, Web of Science, and Embase) was conducted. Game characteristics, technical requirements, and incorporation of clinical reasoning cycle steps were analyzed. Additional game information was obtained from the authors.

RESULTS

Nineteen unique games emerged, primarily simulation and escape room genres. Most games incorporated the following clinical reasoning steps: patient consideration (step 1), cue collection (step 2), intervention (step 6), and outcome evaluation (step 7). Processing information (step 3) and understanding the patient's problem (step 4) were less prevalent, while goal setting (step 5) and reflection (step 8) were least integrated.

CONCLUSION

All serious games reviewed show potential for improving clinical reasoning skills, but thoughtful alignment with learning objectives and contextual factors is vital. While this study aids health professions educators in understanding how games may support teaching of clinical reasoning, further research is needed to optimize their effective use in education. Notably, most games lack explicit incorporation of all clinical reasoning cycle steps, especially reflection, limiting its role in reflective practice. Hence, we recommend prioritizing a systematic clinical reasoning model with explicit reflective steps when using serious games for teaching clinical reasoning.

Sex differences in the prospective association of excessively long reaction times and hazardous cannabis use at six months

Objective

The neurocognitive risk mechanisms predicting divergent outcomes likely differ between men and women who use cannabis recreationally. Increasingly, the use of descriptive distributions including the ex-Gaussian has been applied to draw stronger inferences about neurocognitive health in clinical populations. The current project examines whether the long tail of reaction times (RTs) in a distribution, as characterized by the ex-Gaussian parameter tau which may represent difficulty with the regulation of arousal, predicts problematic cannabis use 6 months later in those who use cannabis recreationally, and whether sex moderates these prospective associations.

Method

Young adults (ages 18-30, mean age 20.5 years, N =159, 57.2% women, 69.2% Caucasian) who recreationally used cannabis either occasionally (at least once per month) or frequently (three times or more per week) completed the Stroop Color-Word Task at baseline. Ex-Gaussian parameter tau was estimated for each participant. Self-report of hazardous cannabis use (CUDIT-R) and dysregulation of negative (DERS) and positive emotions (DERS-Positive) were obtained at baseline and 6-month follow-up.

Results

For those with larger tau at baseline, being a man (but not a woman) was associated with increased difficulty regulating positive emotions concurrently (b = -0.01, F (1,159) = 5.48, p = 0.02), and with hazardous cannabis use six months later (b = -0.007, F (1,159) = 4.42, p = 0.037) after controlling for baseline hazardous cannabis use.

Conclusions

Excessively long RTs during cognitive performance may help characterize men at risk for increased hazardous use, which contributes to understanding between-sex heterogeneity in pathways towards cannabis use disorders.

Associations between PTSD and temporal discounting: The role of future thinking

BACKGROUND AND OBJECTIVES

Despite documented alterations in future thinking in posttraumatic stress disorder (PTSD), our understanding of how individuals with PTSD make future-oriented decisions is limited. We tested the hypothesis that increased discounting in association with PTSD reflects failure to spontaneously envision future rewarding situations.

METHODS

Thirty-seven trauma exposed war-zone veterans completed a standard temporal discounting task as well as a temporal discounting task accompanied by episodic future thinking cues.

RESULTS

Severity of PTSD symptoms was associated with preference for sooner, smaller rewards in the standard task. Consistent with our hypothesis, when participants engaged in future thinking, greater PTSD symptom severity was no longer associated with steeper discounting. Moreover, difficulty anticipating future events, as measured contemporaneously in a separate task (Verfaellie et al., 2024), mediated the relationship between PTSD symptom severity and degree of discounting in the standard task. Among PTSD symptom clusters, the severity of avoidance and negative alterations in cognition and mood was related to steeper discounting. Measures of depression and alcohol use were not associated with discounting.

LIMITATIONS

The sample included mostly male, predominantly White veterans who experienced primarily combat-related trauma.

CONCLUSIONS

PTSD-associated alterations in temporal discounting reflect failure to spontaneously imagine future positive events. Two common correlates of PTSD, depression and alcohol use, could not account for the observed associations between PTSD and future-oriented decisions.

Towards an evidence-based integrative lighting score: a proposed multi-level approach

Background: Human circadian clocks are synchronized daily with the external light-dark cycle and entrained to the 24-hour day. There is increasing evidence that a lack of synchronization and circadian entrainment can lead to adverse health effects. Beyond vision, light plays a critical role in modulating many so-called non-visual functions, including sleep-wake cycles, alertness, mood and endocrine functions. To assess (and potentially optimize) the impact of light on non-visual functions, it is necessary to know the exact 'dose' (i.e. spectral irradiance and exposure duration at eye level) of 24-hour light exposures, but also to include metadata about the lighting environment, individual needs and resources.

Problem statement: To address this problem, a new assessment tool is needed that uses existing metrics to provide metadata and information about light quality and quantity from all sources. In this commentary, we discuss the need to develop an evidence-based integrative lighting score that is tailored to specific audiences and lighting environments. We will summarize the most compelling evidence from the literature and outline a future plan for developing such a lighting score using internationally accepted metrics, stakeholder and user feedback.

Conclusion: We propose a weighting system that combines light qualities with physiological and behavioral effects, and the use of mathematical modelling for an output score. Such a scoring system will facilitate a holistic assessment of a lighting environment, integrating all available light sources.

The antipsychotic potential of Salix Mucronata on ketamine-induced rats

Salix mucronata is one of the herbal plants offered by the traditional health practitioners in KwaZulu-Natal, South Africa for the treatment of schizophrenia. This study aimed to investigate the effects of repeated administration of ketamine on social interaction, novelty and motivation in adult, male Sprague Dawley rats. It also aimed to investigate the potential of risperidone and the herbal extract of S. mucronata to reverse impairments that are induced by ketamine. Experimental rats (n=45) received a dose of ketamine at 30 mg/kg via intraperitoneal injection for 5 consecutive days. They were then allocated into their respective treatment groups and given risperidone (APD) and the herbal extract of S. mucronata (TM) at doses of 6 mg/kg and 5 mg/kg, respectively, for 7 consecutive days. Social behaviour was tested using the 3-chambered sociability test, and anhedonia was tested using the sucrose preference test. Ketamine induction elicited social withdrawal and reduced social novelty which were later successfully reversed by risperidone and S. mucronata. The rats showed reduced preference to sucrose post-induction and post-treatment. Ketamine and mild stress caused by scruff restraint elicited reduced weight gain for the animals. No differences were noted on brain mass between controls and experimental groups and also between risperidone and S. mucronata groups. However, reduced brain volume was noted in experimental groups. Dopamine and acetylcholine concentration levels were high in groups which received risperidone and S. mucronata. These findings highlight that the antipsychotic potential of S. mucronata is similar to risperidone.

Enhanced performance of EEG-based brain-computer interfaces by joint sample and feature importance assessment

Electroencephalograph (EEG) has been a reliable data source for building brain-computer interface (BCI) systems; however, it is not reasonable to use the feature vector extracted from multiple EEG channels and frequency bands to perform recognition directly due to the two deficiencies. One is that EEG data is weak and non-stationary, which easily causes different EEG samples to have different quality. The other is that different feature dimensions corresponding to different brain regions and frequency bands have different correlations to a certain mental task, which is not sufficiently investigated. To this end, a Joint Sample and Feature importance Assessment (JSFA) model was proposed to simultaneously explore the different impacts of EEG samples and features in mental state recognition, in which the former is based on the self-paced learning technique while the latter is completed by the feature self-weighting technique. The efficacy of JSFA is extensively evaluated on two EEG data sets, i.e., SEED-IV and SEED-VIG. One is a classification task for emotion recognition and the other is a regression task for driving fatigue detection. Experimental results demonstrate that JSFA can effectively identify the importance of different EEG samples and features, leading to enhanced recognition performance of corresponding BCI systems.

Citation bias, diversity, and ethics

How often a researcher is cited usually plays a decisive role in that person's career advancement, because academic institutions often use citation metrics, either explicitly or implicitly, to estimate research impact and productivity. Research has shown, however, that citation patterns and practices are affected by various biases, including the prestige of the authors being cited and their gender, race, and nationality, whether self-attested or perceived. Some commentators have proposed that researchers can address biases related to social identity or position by including a Citation Diversity Statement in a manuscript submitted for publication. A Citation Diversity Statement is a paragraph placed before the reference section of a manuscript in which the authors address the diversity and equitability of their references in terms of gender, race, ethnicity, or other factors and affirm a commitment to promoting equity and diversity in sources and references. The present commentary considers arguments in favor of Citation Diversity Statements, and some practical and ethical issues that these statements raise.

Self-control problems in Intermittent Explosive Disorder: Presentation of an explanatory approach

BACKGROUND AND OBJECTIVES

Intermittent Explosive Disorder (IED) is an impulsive aggression disorder with self-control problems. However, the mechanisms underpinning the self-control problems in IED have not been clearly investigated. Therefore, this study examined the nature of self-control problems and their types, including cognitive inhibition, behavioral inhibition, and emotional interference in IED.

METHODS

Participants included three groups: IED (n = 54), psychiatric control (n = 59), and healthy control (n = 62). They were first screened with SCL-90-R, and then they were clinically interviewed. They all did computerized neurocognitive tasks, including Color-Word Stroop Task, Emotional Stroop Task, Go-NoGo Task, and Stop-Signal Task.

RESULTS

MANOVA analyses showed that the IED group had poorer performance in cognitive inhibition, response inhibition, and increased emotional interference than the two psychiatric and healthy control groups. They performed much worse than the other two groups, particularly in action cancellation (Stop-Signal Task), and showed increasingly emotional interference.

LIMITATIONS

The brain reaction of individuals while doing the tasks was not examined, and some variables were not measured. Also, it is unclear how the emotional eruption interferes with cognitive content and behavioral inhibition.

CONCLUSIONS

These findings indicate that self-control problems in IED can be due to deficient cognitive, emotional, and behavioral inhibitions, each appearing sequentially during a step-by-step process and facilitating the onset of IED signs and symptoms. Such a distinguished understanding of the role of neurocognitive mechanisms can lead to the development of accurate explanatory approaches and increase the effectiveness of treatment.

Neuroimaging biomarkers for the diagnosis and prognosis of patients with disorders of consciousness

The progress in neuroimaging and electrophysiological techniques has shown substantial promise in improving the clinical assessment of disorders of consciousness (DOC). Through the examination of both stimulus-induced and spontaneous brain activity, numerous comprehensive investigations have explored variations in brain activity patterns among patients with DOC, yielding valuable insights for clinical diagnosis and prognostic purposes. Nonetheless, reaching a consensus on precise neuroimaging biomarkers for patients with DOC remains a challenge. Therefore, in this review, we begin by summarizing the empirical evidence related to neuroimaging biomarkers for DOC using various paradigms, including active, passive, and resting-state approaches, by employing task-based fMRI, resting-state fMRI (rs-fMRI), electroencephalography (EEG), and positron emission tomography (PET) techniques. Subsequently, we conducted a review of studies examining the neural correlates of consciousness in patients with DOC, with the findings holding potential value for the clinical application of DOC. Notably, previous research indicates that neuroimaging techniques have the potential to unveil covert awareness that conventional behavioral assessments might overlook. Furthermore, when integrated with various task paradigms or analytical approaches, this combination has the potential to significantly enhance the accuracy of both diagnosis and prognosis in DOC patients. Nonetheless, the stability of these neural biomarkers still needs additional validation, and future directions may entail integrating diagnostic and prognostic methods with big data and deep learning approaches.

A behavioural exploration of language aptitude and experience, cognition and more using Graph Analysis

Language aptitude has recently regained interest in cognitive neuroscience. Traditional language aptitude testing included phonemic coding ability, associative memory, grammatical sensitivity and inductive language learning. Moreover, domain-general cognitive abilities are associated with individual differences in language aptitude, together with factors that have yet to be elucidated. Beyond domain-general cognition, it is also likely that aptitude and experience in domain-specific but non-linguistic fields (e.g. music or numerical processing) influence and are influenced by language aptitude. We investigated some of these relationships in a sample of 152 participants, using exploratory graph analysis, across different levels of regularisation, i.e. sensitivity. We carried out a meta cluster analysis in a second step to identify variables that are robustly grouped together. We discuss the data, as well as their meta-network groupings, at a baseline network sensitivity level, and in two analyses, one including and the other excluding dyslexic readers. Our results show a stable association between language and cognition, and the isolation of multilingual language experience, musicality and literacy. We highlight the necessity of a more comprehensive view of language and of cognition as multivariate systems.

Increasing inter-word spacing reduces migration errors and improves reading comprehension in students with dyslexia

We report a small study in which we explored the effects of manipulating narrative text on levels of comprehension for students with and without dyslexia. Using two pieces of standardised narrative text deemed to be of similar difficulty and length, we manipulated the texts such that we could present two texts to each participant, one in each condition. The first condition was text using standard inter-word spacing; the second condition used increased inter-word spacing. Scores on standardised comprehension questions were significantly improved for participants with dyslexia. Additionally, given that there is evidence of delayed visual attention disengagement in individuals with specific forms of dyslexia, we hypothesised that the phenomena of migration of letters and words for some readers might be mitigated by increasing inter-word spacing. We did indeed find that incidence of migration was significantly reduced in this condition for all participants.

Influence of odor environments on cognitive efficiency: A comprehensive review

Cognitive efficiency, characterized by the rapid and accurate processing of information, significantly enhances work and learning outcomes. This efficiency manifests in improved time management, decision-making, learning capabilities, and creativity. While the influence of thermal, acoustic, and lighting conditions on cognitive performance has been extensively studied, the role of olfactory stimuli remains underexplored. Olfactory perception, distinguished by its intensity, speed of perception, and the breadth of stimuli, plays a pivotal role in cognitive efficiency. This review investigates the mechanisms through which odor environments influence cognitive performance. We analyze how odor environments can affect cognitive efficiency through two different scenarios (work and sleep) and pathways (direct and indirect effects). Current research, which mainly focuses on the interplay between odors, emotional responses, and cognitive efficiency through both subjective and objective measures, is thoroughly analyzed. We highlight existing research gaps and suggest future directions for investigating the influence of odor environments on cognitive efficiency. This review aims to establish a theoretical basis for managing and leveraging odor environments in workplace settings.

The perceptual span in dyslexic reading and visual search

Many studies have attempted to identify the root cause of dyslexia. Different theories of dyslexia have proposed either a phonological, attentional, or visual deficit. While research has used eye-tracking to study dyslexia, only two previous studies have used the moving-window paradigm to explore the perceptual span in dyslexic reading, and none have done so in visual search. The present study analysed the perceptual span using both reading and visual search tasks to identify language-independent attentional impairments in dyslexics. We found equivocal evidence that the perceptual span was impaired in dyslexic reading and no evidence of impairment in visual search. However, dyslexic participants did show deficits in the visual search task, with lower search accuracy and shorter saccades compared with controls. These results lend support for a visual, rather than attentional or phonological, account of dyslexia.

A quantitative comparison of atlas parcellations on the human superior temporal sulcus

The superior temporal sulcus (STS) has a functional topography that has been difficult to characterize through traditional approaches. Automated atlas parcellations may be one solution while also being beneficial for both dimensional reduction and standardizing regions of interest, but they yield very different boundary definitions along the STS. Here we evaluate how well machine learning classifiers can correctly identify six social cognitive tasks from STS activation patterns dimensionally reduced using four popular atlases (Glasser et al., 2016; Gordon et al., 2016; Power et al., 2011 as projected onto the surface by Arslan et al., 2018; Schaefer et al., 2018). Functional data was summarized within each STS parcel in one of four ways, then subjected to leave-one-subject-out cross-validation SVM classification. We found that the classifiers could readily label conditions when data was parcellated using any of the four atlases, evidence that dimensional reduction to parcels did not compromise functional fingerprints. Mean activation for the social conditions was the most effective metric for classification in the right STS, whereas all the metrics classified equally well in the left STS. Interestingly, even atlases constructed from random parcellation schemes (null atlases) classified the conditions with high accuracy. We therefore conclude that the complex activation maps on the STS are readily differentiated at a coarse granular level, despite a strict topography having not yet been identified. Further work is required to identify what features have greatest potential to improve the utility of atlases in replacing functional localizers.

Empathic pain: Exploring the multidimensional impacts of biological and social aspects in pain

Empathic pain refers to an individual's perception, judgment, and emotional response to others' pain. This complex social cognitive ability is crucial for healthy interactions in human society. In recent years, with the development of multidisciplinary research in neuroscience, psychology and sociology, empathic pain has become a focal point of widespread attention in these fields. However, the neural mechanism underlying empathic pain remain a controversial and unresolved area. This review aims to comprehensively summarize the history, influencing factors, neural mechanisms and pharmacological interventions of empathic pain. We hope to provide a comprehensive scientific perspective on how humans perceive and respond to others' pain experiences and to provide guidance for future research directions and clinical applications. This article is part of the Special Issue on "Empathic Pain".

Adolescent oral oxycodone self-administration disrupts neurobehavioral and neurocognitive development

Nonmedical use of prescription opioids peaks during late adolescence, a developmental period associated with the maturation of higher-order cognitive processes. To date, however, how chronic adolescent oxycodone (OXY) self-administration alters neurobehavioral (i.e., locomotion, startle reactivity) and/or neurocognitive (i.e., preattentive processes, intrasession habituation, stimulus-reinforcement learning, sustained attention) function has not yet been systematically evaluated. Hence, the rationale was built for establishing the dose-dependency of adolescent OXY self-administration on the trajectory of neurobehavioral and neurocognitive development. From postnatal day (PD) 35 to PD 105, an age in rats that corresponds to the adolescent and young adult period in humans, male and female F344/N rats received access to either oral OXY (0, 2, 5, or 10 mg/kg) or water under a two-bottle choice experimental paradigm. Independent of biological sex or dose, rodents voluntarily escalated their OXY intake across ten weeks. A longitudinal experimental design revealed prominent OXY-induced impairments in neurobehavioral development, characterized by dose-dependent increases in locomotion and sex-dependent increases in startle reactivity. Systematic manipulation of the interstimulus interval in prepulse inhibition supports an OXY-induced impairment in preattentive processes. Despite the long-term cessation of OXY intake, rodents with a history of chronic adolescent oral OXY self-administration exhibited deficits in sustained attention; albeit no alterations in stimulus-reinforcement learning were observed. Taken together, adolescent oral OXY self-administration induces selective long-term alterations in neurobehavioral and neurocognitive development enjoining the implementation of safer prescribing guidelines for this population.

Abnormalities in static and dynamic intrinsic neural activity and neurotransmitters in first-episode OCD

BACKGROUND

Obsessive-compulsive disorder (OCD) is a disabling disorder in which the temporal variability of regional brain connectivity is not well understood. The aim of this study was to investigate alterations in static and dynamic intrinsic neural activity (INA) in first-episode OCD and whether these changes have the potential to reflect neurotransmitters.

METHODS

A total of 95 first-episode OCD patients and 106 matched healthy controls (HCs) were included in this study. Based on resting-state functional magnetic resonance imaging (rs-fMRI), the static and dynamic local connectivity coherence (calculated by static and dynamic regional homogeneity, sReHo and dReHo) were compared between the two groups. Furthermore, correlations between abnormal INA and PET- and SPECT-derived maps were performed to examine specific neurotransmitter system changes underlying INA abnormalities in OCD.

RESULTS

Compared with HCs, OCD showed decreased sReHo and dReHo values in left superior, middle temporal gyrus (STG/MTG), left Heschl gyrus (HES), left putamen, left insula, bilateral paracentral lobular (PCL), right postcentral gyrus (PoCG), right precentral gyrus (PreCG), left precuneus and right supplementary motor area (SMA). Decreased dReHo values were also found in left PoCG, left PreCG, left SMA and left middle cingulate cortex (MCC). Meanwhile, alterations in INA present in brain regions were correlated with dopamine system (D2, FDOPA), norepinephrine transporter (NAT) and the vesicular acetylcholine transporter (VAChT) maps.

CONCLUSION

Static and dynamic INA abnormalities exist in first-episode OCD, having the potential to reveal the molecular characteristics. The results help to further understand the pathophysiological mechanism and provide alternative therapeutic targets of OCD.

Different structural connectivity patterns in the subregions of the thalamus, hippocampus, and cingulate cortex between schizophrenia and psychotic bipolar disorder

OBJECTIVE

Schizophrenia (SCZ) and psychotic bipolar disorder (PBD) are two major psychotic disorders with similar symptoms and tight associations on the psychopathological level, posing a clinical challenge for their differentiation. This study aimed to investigate and compare the structural connectivity patterns of the limbic system between SCZ and PBD, and to identify specific regional disruptions associated with psychiatric symptoms.

METHODS

Using sMRI data from 146 SCZ, 160 PBD, and 145 healthy control (HC) participants, we employed a data-driven approach to segment the hippocampus, thalamus, hypothalamus, amygdala, and cingulate cortex into subregions. We then investigated the structural connectivity patterns between these subregions at the global and nodal levels. Additionally, we assessed psychotic symptoms by utilizing the subscales of the Brief Psychiatric Rating Scale (BPRS) to examine correlations between symptom severity and network metrics between groups.

RESULTS

Patients with SCZ and PBD had decreased global efficiency (Eglob) (SCZ: adjusted P<0.001; PBD: adjusted P = 0.003), local efficiency (Eloc) (SCZ and PBD: adjusted P<0.001), and clustering coefficient (Cp) (SCZ and PBD: adjusted P<0.001), and increased path length (Lp) (SCZ: adjusted P<0.001; PBD: adjusted P = 0.004) compared to HC. Patients with SCZ showed more pronounced decreases in Eglob (adjusted P<0.001), Eloc (adjusted P<0.001), and Cp (adjusted P = 0.029), and increased Lp (adjusted P = 0.024) compared to patients with PBD. The most notable structural disruptions were observed in the hippocampus and thalamus, which correlated with different psychotic symptoms, respectively.

CONCLUSION

This study provides evidence of distinct structural connectivity disruptions in the limbic system of patients with SCZ and PBD. These findings might contribute to our understanding of the neuropathological basis for distinguishing SCZ and PBD.

Toward a neurocircuit-based sequential transcranial magnetic stimulation treatment of pediatric bipolar II disorder

BACKGROUND

Abnormalities in large-scale neuronal networks-the frontoparietal central executive network (CEN)-are consistent findings in bipolar disorder and potential therapeutic targets for transcranial magnetic stimulation (TMS).

OBJECTIVE

The present study aimed to assess the effects of CEN neurocircuit-based sequential TMS on the clinical symptoms and cognitive functions of adolescents with bipolar II disorder.

METHODS

The study was a single-blinded, randomized, placebo-control trial. Participants with DSM-5-defined bipolar disorder II were recruited and randomized to receive either a sham treatment (n = 20) or an active TMS treatment (n = 22). The active group patients were taking medication, with intermittent theta burst stimulation (iTBS) treatment provided as adjunctive treatment targeting the left DLPFC, the left ITG, and the left PPC nodes consecutively. Patients completed the measurements of HAMD and the Das-Naglieri Cognition Assessment System at baseline and 3 weeks after the intervention.

RESULTS

A significant group-by-time interaction was observed in the HAMD, total cognition, and planning. Post-hoc analysis revealed that patients in the active group significantly improved HAMD scores following neurostimulation. Moreover, within-subject analysis indicated that the active group significantly improved in scores of total cognition and planning, while the sham group did not. No significant differences were seen in the other cognitive measures.

CONCLUSION

The neurocircuit-based sequential TMS protocol targeting three CEN nodes, in conjunction with medication, safely and effectively improved depressive symptoms and cognitive function in adolescents with bipolar II disorder.

Early-life risk factors for depression among young adults in the United States general population: Attributable risks and gender differences

BACKGROUND

This study adopts individual and societal-level approaches to examine the contribution of childhood risk factors to major depressive episodes (MDE) in 2526 American young adults.

METHODS

Nationally representative data from the 2017 U.S. Panel Study of Income Dynamics - Transition into Adulthood Supplement (PSID-TAS) were analyzed using multivariate methods to assess the impact of parental mental illness, childhood adversities, childhood mental disorders, and childhood physical conditions. Adjusted odds ratios and population attributable risk proportions (PARPs) are calculated to estimate the proportion of MDE cases related to risk factors.

RESULTS

The 12-month prevalence of positive screens for MDE was 25.4 %. Approximately 34 % of these were attributable to childhood mental disorders, 24 % to childhood physical conditions, 21 % to childhood adversities, and 16 % to parental mental illness. Childhood and parental depression were critical risk factors, both at the individual (odds ratio exceeding 2) and societal (PARP approximately 24 %) levels. Gender-specific risk factors were identified, with childhood physical abuse and childhood anxiety disorders constituting risk factors for females, and childhood externalizing disorders and childhood headaches as risk factors for males. Approximately 60 % of U.S. young adult MDE cases are attributable to risk factors before age 18.

LIMITATIONS

Possible over reporting of MDE may have biased the associations between predictors and depression.

CONCLUSIONS

Exposure to depression at a young age-one's own or parental depression-is a robust risk factor for both genders. Policies and interventions focused at alleviating the societal burden of depression should value its generational transmission.

The interaction between physical activity and ambient particulate matters on cognitive function among Chinese community-dwelling older adults

BACKGROUND

The interaction between physical activity (PA) and ambient particulate matters (PMs) on cognition is rarely investigated. Our study aimed to assess the interactions of PA and PMs on cognitive function in older adults.

METHODS

Our study comprised 3937 Chinese community-dwelling older adults. Cognition was evaluated using the Mini-Mental State Examination. PA information was gathered using the International Physical Activity Questionnaire. The data of PMs were obtained from China High Air Pollutants (CHAP). Linear regressions model and interaction plots were applied to assess and visualize the interaction of PA and PMs on cognition, respectively. Bayesian kernel machine regression (BKMR) method was employed to visualize discernible thresholds for the interaction.

RESULTS

PMs were negatively associated with MMSE scores (PM1: β = -0.40, 95 % CI: -0.58, -0.28; PM2.5: β = -0.46, 95 % CI: -0.64, -0.29; PM10: β = -0.44, 95 % CI: -0.61, -0.26), and PA was positively affiliated with MMSE scores (β = 0.18, 95 % CI: -0.01, 0.38). Interaction plots and BKMR demonstrated that adverse connotations of PMs with MMSE increased with the elevated PA levels, and the positive associations of PA with MMSE scores were attenuated by increased PMs (all Pinteraction < 0.20). Discernible thresholds for the interaction between PMs and PA on MMSE were found.

CONCLUSIONS

Our findings suggest that PA should not be taken at higher PMs concentrations, and that low level of PA could be performed in PMs polluted environment to improve cognitive function. Further experimental and cohort researches are required to reproduce our discovery.

Epigenetic molecular underpinnings of brain structural-functional connectivity decoupling in patients with major depressive disorder

BACKGROUND

Major depressive disorder (MDD) is progressively recognized as a stress-related disorder characterized by aberrant brain network dynamics, encompassing both structural and functional domains. Yet, the intricate interplay between these dynamic networks and their molecular underpinnings remains predominantly unexplored.

METHODS

Both structural and functional networks were constructed using multimodal neuroimaging data from 183 MDD patients and 300 age- and gender-matched healthy controls (HC). structural-functional connectivity (SC-FC) coupling was evaluated at both the connectome- and nodal-levels. Methylation data of five HPA axis key genes, including NR3C1, FKBP5, CRHBP, CRHR1, and CRHR2, were analyzed using Illumina Infinium Methylation EPIC BeadChip.

RESULTS

We observed a significant reduction in SC-FC coupling at the connectome-level in patients with MDD compared to HC. At the nodal level, we found an imbalance in SC-FC coupling, with reduced coupling in cortical regions and increased coupling in subcortical regions. Furthermore, we identified 23 differentially methylated CpG sites on the HPA axis, following adjustment for multiple comparisons and control of age, gender, and medication status. Notably, three CpG sites on NR3C1 (cg01294526, cg19457823, and cg23430507), one CpG site on FKBP5 (cg25563198), one CpG site on CRHR1 (cg26656751), and one CpG site on CRHR2 (cg18351440) exhibited significant associations with SC-FC coupling in MDD patients.

CONCLUSIONS

These findings provide valuable insights into the connection between micro-scale epigenetic changes in the HPA axis and SC-FC coupling at macro-scale connectomes. They unveil the mechanisms underlying increased susceptibility to MDD resulting from chronic stress and may suggest potential pharmacological targets within the HPA-axis for MDD treatment.

Association between sleep duration, suicidal ideation, suicidal attempt and suicidal behavior among Chinese adolescents

BACKGROUND

A relatively small number of studies have researched the relationship between sleep duration and suicidal ideation, attempts, and behavior. This research aims to investigate the link between sleep duration and suicide in Chinese adolescents, and to examine the role of depression as a mediating factor.

METHOD

Data were collected from 3315 students using a multi-stage random cluster sampling method and self-administered questionnaires. The study applied logistic regression to investigate the relationship between sleep duration and various forms of suicidal behavior, and mediation analysis to understand how depression might influence this relationship.

RESULTS

The average sleep duration among the adolescents was 7.25 h (±0.20), with 59.67 % reporting insufficient sleep. The logistic regression analysis showed that longer sleep duration is linked with lower risks of suicidal ideation (OR: 0.753, 95%CI: 0.696 to 0.814), suicidal attempts (OR: 0.830, 95%CI: 0.748 to 0.922), and suicidal behavior (OR: 0.841, 95%CI: 0.713 to 0.992). Analysis using restricted cubic spline plots indicated the connection between sleep duration and these suicidal factors was not linear. The study found that depression plays a partial mediating role between sleep duration and suicidal ideation, with an effect of 52.29 %.

LIMITATIONS

The cross-sectional study design could not prove causation.

CONCLUSIONS

There is a clear non-linear association between sleep duration and suicidal tendencies in adolescents, with depression acting as a mediator. This suggests that future research could focus on sleep and mood management as ways to address suicide risk in this age group.

Intrauterine chromium exposure and cognitive developmental delay: The modifying effect of genetic predisposition

There is limited evidence on the effects of intrauterine chromium (Cr) exposure on children's cognitive developmental delay (CDD). Further, little is known about the genetic factors in modifying the association between intrauterine Cr exposure and CDD. The present study involved 2361 mother-child pairs, in which maternal plasma Cr concentrations were assessed, a polygenic risk score for the child was constructed, and the child's cognitive development was evaluated using the Bayley Scales of Infant Development. The risks of CDD conferred by intrauterine Cr exposure in children with different genetic backgrounds were evaluated by logistic regression. The additive interaction between intrauterine Cr exposure and genetic factors was evaluated by calculating the relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP), and synergy index (SI). According to present study, higher intrauterine Cr exposure was significantly associated with increased CDD risk [each unit increase in ln-transformed maternal plasma Cr concentration (ln-Cr): adjusted OR (95 % CI), 1.18 (1.04-1.35); highest vs lowest quartile: adjusted OR (95 % CI), 1.57 (1.10-2.23)]. The dose-response relationship of intrauterine Cr exposure and CDD for children with high genetic risk was more prominent [each unit increased ln-Cr: adjusted OR (95 % CI), 1.36 (1.09-1.70)]. Joint effects between intrauterine Cr exposure and genetic factors were found. Specifically, for high genetic risk carriers, the association between intrauterine Cr exposure and CDD was more evident [highest vs lowest quartile: adjusted OR (95 % CI), 2.33 (1.43-3.80)]. For those children with high intrauterine Cr exposure and high genetic risk, the adjusted AP was 0.39 (95 % CI, 0.07-0.72). Conclusively, intrauterine Cr exposure was a high-risk factor for CDD in children, particularly for those with high genetic risk. Intrauterine Cr exposure and one's adverse genetic background jointly contribute to an increased risk of CDD in children.

Shaping dynamical neural computations using spatiotemporal constraints

Dynamics play a critical role in computation. The principled evolution of states over time enables both biological and artificial networks to represent and integrate information to make decisions. In the past few decades, significant multidisciplinary progress has been made in bridging the gap between how we understand biological versus artificial computation, including how insights gained from one can translate to the other. Research has revealed that neurobiology is a key determinant of brain network architecture, which gives rise to spatiotemporally constrained patterns of activity that underlie computation. Here, we discuss how neural systems use dynamics for computation, and claim that the biological constraints that shape brain networks may be leveraged to improve the implementation of artificial neural networks. To formalize this discussion, we consider a natural artificial analog of the brain that has been used extensively to model neural computation: the recurrent neural network (RNN). In both the brain and the RNN, we emphasize the common computational substrate atop which dynamics occur-the connectivity between neurons-and we explore the unique computational advantages offered by biophysical constraints such as resource efficiency, spatial embedding, and neurodevelopment.

How bipedalism shapes humans' actions with hand tools

The task for an embodied cognitive understanding of humans' actions with tools is to elucidate how the human body, as a whole, supports the perception of affordances and dexterous action with objects in relation to other objects. Here, we focus on the relationship between humans' actions with handheld tools and bipedal posture. Posture plays a pivotal role in shaping animals' perception and action dynamics. While humans stand and locomote bipedally, other primates predominantly employ quadrupedal postures and locomotion, relying on both hands and feet to support the body. Drawing upon evidence from evolutionary biology, developmental psychology and performance studies, we elucidate the influence of bipedalism on our actions with objects and on our proficiency in using tools. We use the metaphor of cascades to capture the dynamic, nonlinear transformations in morphology and behaviour associated with posture and the use of tools across evolutionary and developmental timescales. Recent work illustrates the promise of multifractal cascade analysis to reveal nonlinear, cross-scale interactions across the entire body in real-time, supporting the perception of affordances for actions with tools. Cascade analysis enriches our comprehension of real-time performance and facilitates exploration of the relationships among whole-body coordination, individual development, and evolutionary processes.This article is part of the theme issue 'Minds in movement: embodied cognition in the age of artificial intelligence'.

The role of action concepts in physical reasoning: insights from late childhood

A fundamental component of human cognition is the ability to intuitively reason about behaviours of objects and systems in the physical world without resorting to explicit scientific knowledge. This skill was traditionally considered a symbolic process. However, in the last decades, there has been a shift towards ideas of embodiment, suggesting that accessing physical knowledge and predicting physical outcomes is grounded in bodily interactions with the environment. Infants and children, who learn mainly through their embodied experiences, serve as a model to probe the link between reasoning and physical concepts. Here, we tested school-aged children (5- to 15-year-olds) in online reasoning games that involve different physical action concepts such as supporting, launching and clearing. We assessed changes in children's performance and strategies over development and their relationships with the different action concepts. Children reasoned more accurately in problems that involved supporting actions compared to launching or clearing actions. Moreover, when children failed, they were more strategic in subsequent attempts when problems involved support rather than launching or clearing. Children improved with age, but improvements differed across action concepts. Our findings suggest that accessing physical knowledge and predicting physical events are affected by action concepts, and those effects change over development. This article is part of the theme issue 'Minds in movement: embodied cognition in the age of artificial intelligence'.

Active inference goes to school: the importance of active learning in the age of large language models

Human learning essentially involves embodied interactions with the material world. But our worlds now include increasing numbers of powerful and (apparently) disembodied generative artificial intelligence (AI). In what follows we ask how best to understand these new (somewhat 'alien', because of their disembodied nature) resources and how to incorporate them in our educational practices. We focus on methodologies that encourage exploration and embodied interactions with 'prepared' material environments, such as the carefully organized settings of Montessori education. Using the active inference framework, we approach our questions by thinking about human learning as epistemic foraging and prediction error minimization. We end by arguing that generative AI should figure naturally as new elements in prepared learning environments by facilitating sequences of precise prediction error enabling trajectories of self-correction. In these ways, we anticipate new synergies between (apparently) disembodied and (essentially) embodied forms of intelligence. This article is part of the theme issue 'Minds in movement: embodied cognition in the age of artificial intelligence'.

Ethnokinesiology: towards a neuromechanical understanding of cultural differences in movement

Each individual's movements are sculpted by constant interactions between sensorimotor and sociocultural factors. A theoretical framework grounded in motor control mechanisms articulating how sociocultural and biological signals converge to shape movement is currently missing. Here, we propose a framework for the emerging field of ethnokinesiology aiming to provide a conceptual space and vocabulary to help bring together researchers at this intersection. We offer a first-level schema for generating and testing hypotheses about cultural differences in movement to bridge gaps between the rich observations of cross-cultural movement variations and neurophysiological and biomechanical accounts of movement. We explicitly dissociate two interacting feedback loops that determine culturally relevant movement: one governing sensorimotor tasks regulated by neural signals internal to the body, the other governing ecological tasks generated through actions in the environment producing ecological consequences. A key idea is the emergence of individual-specific and culturally influenced motor concepts in the nervous system, low-dimensional functional mappings between sensorimotor and ecological task spaces. Motor accents arise from perceived differences in motor concept topologies across cultural contexts. We apply the framework to three examples: speech, gait and grasp. Finally, we discuss how ethnokinesiological studies may inform personalized motor skill training and rehabilitation, and challenges moving forward.This article is part of the theme issue 'Minds in movement: embodied cognition in the age of artificial intelligence'.

Embodiment in the enfacement illusion is mediated by self-other overlap

The enfacement illusion is a facial version of the rubber hand illusion, in which participants experience tactile stimulation of their own faces synchronously with the observation of the same stimulation applied to another's face. In previous studies, participants have reported experiencing an illusory embodiment of the other's face following synchronous compared to asynchronous stimulation. In a series of three experiments, we addressed the following three questions: (i) how does similarity between the self and the other, operationalized here as being of the same or different gender to the other, impact the experience of embodiment in the enfacement illusion; (ii) does the experience of embodiment result from alterations to the self-concept; and (iii) is susceptibility to the experience of embodiment associated with interoceptive processing, i.e. perception of the internal state of the body? Results indicate that embodiment is facilitated by the similarity between the self and the other and is mediated by the incorporation of the other into the self-concept, but sensitivity to one's own internal states does not impact upon embodiment within the enfacement illusion. This article is part of the theme issue 'Minds in movement: embodied cognition in the age of artificial intelligence'.

Minds in movement: embodied cognition in the age of artificial intelligence

This theme issue brings together researchers from diverse fields to assess the current status and future prospects of embodied cognition in the age of generative artificial intelligence. In this introduction, we first clarify our view of embodiment as a potentially unifying concept in the study of cognition, characterizing this as a perspective that questions mind-body dualism and recognizes a profound continuity between sensorimotor action in the world and more abstract forms of cognition. We then consider how this unifying concept is developed and elaborated by the other contributions to this issue, identifying the following two key themes: (i) the role of language in cognition and its entanglement with the body and (ii) bodily mechanisms of interpersonal perception and alignment across the domains of social affiliation, teaching and learning. On balance, we consider that embodied approaches to the study of cognition, culture and evolution remain promising, but will require greater integration across disciplines to fully realize their potential. We conclude by suggesting that researchers will need to be ready and able to meet the various methodological, theoretical and practical challenges this will entail and remain open to encountering markedly different viewpoints about how and why embodiment matters. This article is the part of this theme issue 'Minds in movement: embodied cognition in the age of artificial intelligence'.

Peripersonal space: why so last-second?

A vast range of neurophysiological, neuropsychological and behavioural results in monkeys and humans have shown that the immediate surroundings of the body, also known as peripersonal space (PPS), are processed in a unique way. Three roles have been ascribed to PPS mechanisms: to react to threats, to avoid obstacles and to act on objects. However, in many circumstances, one does not wait for objects or agents to enter PPS to plan these behaviours. Typically, one has more chances to survive if one starts running away from the lion when one sees it in the distance than if it is a few steps away. PPS makes sense in shortsighted creatures but we are not such creatures. The crucial question is thus twofold: (i) why are these adaptive processes triggered only at the last second or even milliseconds? And (ii) what is their exact contribution, especially for defensive and navigational behaviours? Here, we propose that PPS mechanisms correspond to a plan B, useful in unpredictable situations or when other anticipatory mechanisms have failed. Furthermore, we argue that there are energetic, cognitive and behavioural costs to PPS mechanisms, which explain why this plan B is triggered only at the last second. This article is part of the theme issue 'Minds in movement: embodied cognition in the age of artificial intelligence'.

Spontaneous movement synchrony as an exogenous source for interbrain synchronization in cooperative learning

Learning through cooperation with conspecifics-'cooperative learning'-is critical to cultural evolution and survival. Recent progress has established that interbrain synchronization (IBS) between individuals predicts success in cooperative learning. However, the likely sources of IBS during learning interactions remain poorly understood. To address this dearth of knowledge, we tested whether movement synchrony serves as an exogenous factor that drives IBS, taking an embodiment perspective. We formed dyads of individuals with varying levels of prior knowledge (high-high (HH), high-low (HL), low-low (LL) dyads) and instructed them to collaboratively analyse an ancient Chinese poem. During the task, we simultaneously recorded their brain activity using functional near-infrared spectroscopy and filmed the entire experiment to parse interpersonal movement synchrony using the computer-vision motion energy analysis. Interestingly, the homogeneous groups (HH and/or LL) exhibited stronger movement synchrony and IBS compared with the heterogeneous group. Importantly, mediation analysis revealed that spontaneous and synchronized body movements between individuals contribute to IBS, hence facilitating learning. This study therefore fills a critical gap in our understanding of how interpersonal transmission of information between individual brains, associated with behavioural entrainment, shapes social learning. This article is part of the theme issue 'Minds in movement: embodied cognition in the age of artificial intelligence'.

Symbol ungrounding: what the successes (and failures) of large language models reveal about human cognition

Large language models can handle sophisticated natural language processing tasks. This raises the question of how their understanding of semantic meaning compares to that of human beings. Supporters of embodied cognition often point out that because these models are trained solely on text, their representations of semantic content are not grounded in sensorimotor experience. This paper contends that human cognition exhibits capabilities that fit with both the embodied and artificial intelligence approaches. Evidence suggests that semantic memory is partially grounded in sensorimotor systems and dependent on language-specific learning. From this perspective, large language models demonstrate the richness of language as a source of semantic information. They show how our experience with language might scaffold and extend our capacity to make sense of the world. In the context of an embodied mind, language provides access to a valuable form of ungrounded cognition.This article is part of the theme issue 'Minds in movement: embodied cognition in the age of artificial intelligence'.

Efficacy of exercise rehabilitation for managing patients with Alzheimer's disease

Alzheimer's disease (AD) is a progressive and degenerative neurological disease characterized by the deterioration of cognitive functions. While a definitive cure and optimal medication to impede disease progression are currently unavailable, a plethora of studies have highlighted the potential advantages of exercise rehabilitation for managing this condition. Those studies show that exercise rehabilitation can enhance cognitive function and improve the quality of life for individuals affected by AD. Therefore, exercise rehabilitation has been regarded as one of the most important strategies for managing patients with AD. Herein, we provide a comprehensive analysis of the currently available findings on exercise rehabilitation in patients with AD, with a focus on the exercise types which have shown efficacy when implemented alone or combined with other treatment methods, as well as the potential mechanisms underlying these positive effects. Specifically, we explain how exercise may improve the brain microenvironment and neuronal plasticity. In conclusion, exercise is a cost-effective intervention to enhance cognitive performance and improve quality of life in patients with mild to moderate cognitive dysfunction. Therefore, it can potentially become both a physical activity and a tailored intervention. This review may aid the development of more effective and individualized treatment strategies to address the challenges imposed by this debilitating disease, especially in low- and middle-income countries.

A cross-cultural comparison of finger-based and symbolic number representations

The current study examined predictions from embodied cognition for effects of finger counting on number processing. Although finger counting is spontaneous and nearly universal, counting habits reflect learning and culture. European cultures use a sub-base-five system, requiring a full hand plus additional fingers to express numbers exceeding 5. Chinese culture requires only one hand to express such numbers. We investigated the differential impact of early-acquired finger-based number representations on adult symbolic number processing. In total, 53 European and 56 Chinese adults performed two versions of the magnitude classification task, where numbers were presented either as Arabic symbols or as finger configurations consistent with respective cultural finger-counting habits. Participants classified numbers as smaller/larger than 5 with horizontally aligned buttons. Finger-based size and distance effects were larger in Chinese compared with Europeans. These differences did not, however, induce reliably different symbol processing signatures. This dissociation challenges the idea that sensory and motor habits shape our conceptual representations and implies notation-specific processing patterns.

Effortful retrieval of semantic memories induces forgetting of related negative and neutral episodic memories

Retrieval-induced forgetting (RIF) experiments show that the act of retrieving some recently encoded items from a given conceptual category leads to greater forgetting of competing items from that same category. However, RIF studies using emotional stimuli have produced mixed results, perhaps due to the reinstatement of arousal or negative affect during retrieval practice. To induce forgetting of negative episodic memories more indirectly, we examined if retrieving neutral semantic memories leads to RIF of related negative memories. In two experiments, participants studied eight categorized lists comprised of an equal number of negative and neutral words (Experiment 1) or neutral words preceded by neutral or negative images (Experiment 2). To avoid re-exposing individuals to negative material during retrieval practice, participants then performed a semantic memory retrieval task in which they generated (i.e., completed word-stems for) new neutral words from half of the studied categories. We found that semantic retrieval, or word generation, induced forgetting of recently studied words irrespective of their emotional valence or original emotional context. Additionally, across both experiments, less successful word generation was associated with stronger RIF effects. In Experiment 2, the magnitude of RIF was also correlated with higher subjective ratings of retrieval effort during word generation. Together, these results suggest that even when retrieving neutral semantic memories, effortful retrieval may enhance inhibitory processes that lead to forgetting of both neutral and negative episodic memories.

Mind the instructions: Reward cues are liked first, wanted later

Current theories propose that mental effort is invested only when the anticipated benefits, such as rewards, outweigh the associated costs, like task difficulty. Yet, it remains unclear whether this motivational and mitigating aspect of reward processing is reflected in the evaluation of reward/difficulty cues as such, and to what extent it depends on task experience. In a pre-registered experiment (N = 84), we used the affect misattribution procedure (AMP) to gauge affective evaluations of nonword cues predicting reward and task difficulty levels. Contrary to previous studies, the AMP was administered at the outset, after cue instructions, and after the cues were used in a random dot motion (RDM) task. Compared to baseline, cues predicting a larger reward were evaluated more positively after RDM task experience, and most importantly, already after cue instructions, with no difference between the two phases. This evaluative effect manifested in increased performance after larger reward cues in the RDM task. Our results suggest that AMP effects may generally capture performance expectations which are independent of task experience. Importantly, these instructed expectations of reward and difficulty play a crucial role in the evaluation and subsequent investment of mental effort.

Brain Insulin Signaling is Associated with Late-Life Cognitive Decline

Type-2 diabetes is associated with an increased risk of dementia, and the underlying mechanism might involve abnormal insulin signaling in the brain. The objective of this study was to examine the association of postmortem brain insulin signaling with late-life cognitive decline. Among participants of Religious Orders Study, a community-based clinical-pathological cohort, 150 deceased and autopsied older individuals (75 with diabetes matched to 75 without by age at death, sex, and education) had postmortem brain insulin signaling measurements collected in the prefrontal cortex using ELISA and immunohistochemistry. By using adjusted linear mixed-effects models, we examined the association of postmortem brain insulin signaling with late-life cognitive function assessed longitudinally (mean follow-up duration = 9.4 years) using a battery of neuropsychological tests. We found that a higher level of serine/threonine-protein kinase (AKT) phosphorylation (pT308AKT1/total AKT1) was associated with a faster decline in global cognition (estimate = -0.023, p = 0.030), and three domains: episodic memory (estimate = -0.024, p = 0.032), working memory (estimate = -0.018, p = 0.012), and visuospatial abilities (estimate = -0.013, p = 0.027). The level of insulin receptor substrate-1 (IRS1) phosphorylation (pS307IRS1/total IRS1) was not associated with decline in global cognition or most cognitive domains, except for perceptual speed (estimate = 0.020, p = 0.020). The density of pS616IRS1-stained cells was not associated with decline in global cognition or any of the domains. In conclusion, these findings provide novel evidence for an association between brain insulin signaling and late-life cognitive decline. AKT phosphorylation is associated with a decline in global cognition and memory in particular, whereas IRS1 phosphorylation is associated with a decline in perceptual speed.

Tools and methods to study and replicate experiments addressing human social cognition in interactive scenarios

In the last decade, scientists investigating human social cognition have started bringing traditional laboratory paradigms more "into the wild" to examine how socio-cognitive mechanisms of the human brain work in real-life settings. As this implies transferring 2D observational paradigms to 3D interactive environments, there is a risk of compromising experimental control. In this context, we propose a methodological approach which uses humanoid robots as proxies of social interaction partners and embeds them in experimental protocols that adapt classical paradigms of cognitive psychology to interactive scenarios. This allows for a relatively high degree of "naturalness" of interaction and excellent experimental control at the same time. Here, we present two case studies where our methods and tools were applied and replicated across two different laboratories, namely the Italian Institute of Technology in Genova (Italy) and the Agency for Science, Technology and Research in Singapore. In the first case study, we present a replication of an interactive version of a gaze-cueing paradigm reported in Kompatsiari et al. (J Exp Psychol Gen 151(1):121-136, 2022). The second case study presents a replication of a "shared experience" paradigm reported in Marchesi et al. (Technol Mind Behav 3(3):11, 2022). As both studies replicate results across labs and different cultures, we argue that our methods allow for reliable and replicable setups, even though the protocols are complex and involve social interaction. We conclude that our approach can be of benefit to the research field of social cognition and grant higher replicability, for example, in cross-cultural comparisons of social cognition mechanisms.

Estimating the Reliability and Stability of Cognitive Processes Contributing to Responses on the Implicit Association Test

Implicit measures were initially assumed to assess stable individual differences, but other perspectives posit that they reflect context-dependent processes. This pre-registered research investigates whether the processes contributing to responses on the race Implicit Association Test are temporally stable and reliably measured using multinomial processing tree modeling. We applied two models-the Quad model and the Process Dissociation Procedure-to six datasets (N = 2,036), each collected over two occasions, examined the within-measurement reliability and between-measurement stability of model parameters, and meta-analyzed the results. Parameters reflecting accuracy-oriented processes demonstrate adequate stability and reliability, which suggests these processes are relatively stable within individuals. Parameters reflecting evaluative associations demonstrate poor stability but modest reliability, which suggests that associations are either context-dependent or stable but noisily measured. These findings suggest that processes contributing to racial bias on implicit measures differ in temporal stability, which has practical implications for predicting behavior using the Implicit Association Test.

The effect of transcranial direct current and magnetic stimulation on fear extinction and return of fear: A meta-analysis and systematic review

BACKGROUND

We conducted a meta-analysis and qualitative review on the randomized controlled trials investigating the effects of transcranial direct current stimulation and transcranial magnetic stimulation on fear extinction and the return of fear in non-primate animals and humans.

METHODS

The meta-analysis was conducted by searching PubMed, Web of science, PsycINFO, and Cochrane Library and extracting fear response in the active and sham groups in the randomized controlled trials. The pooled effect size was quantified by Hedges' g using a three-level meta-analytic model in R.

RESULTS

We identified 18 articles on the tDCS effect and 5 articles on the TMS effect, with 466 animal subjects and 621 human subjects. Our findings show that tDCS of the prefrontal cortex significantly inhibit fear retrieval in animal models (Hedges' g = -0.50). In human studies, TMS targeting the dorsolateral/ventromedial prefrontal cortex has an inhibiting effect on the return of fear (Hedges' g = -0.24).

LIMITATIONS

The limited number of studies and the heterogeneous designs of the selected studies made cross-study and cross-species comparison difficult.

CONCLUSIONS

Our findings shed light on the optimal non-invasive brain stimulation protocols for targeting the neural circuitry of threat extinction in humans.

When social hierarchy matters grammatically: Investigation of the processing of honorifics in Korean

Korean grammar encodes relative social hierarchies among interlocutors in various ways. This study utilized honorific subject-verb agreement in Korean to investigate how social hierarchies are processed during sentence comprehension. The experimental results showed that honorific violations elicited processing difficulties. The use of an honorific verb with an unhonorifiable subject resulted in lower naturalness ratings, longer reading times, and elicited a P600, similar to effects observed with number, person, and gender agreement in Spanish or English. These findings suggest that social hierarchies have become integrated into grammar, constraining how native Korean speakers process sentences. However, the agreement between honorific subjects and verbs seems asymmetrical; the mismatch effect was smaller or absent when an honorifiable subject was not accompanied by an honorific verb, suggesting that while an honorific verb requires an honorifiable subject, the reverse is not necessarily true. The results indicate that the -si agreement in Korean is a form of morpho-syntactic agreement, despite its asymmetrical nature.

The lifestyle for brain health index, the cluster of differentiation 33 (CD33) gene, and cognitive function among rural Chinese older adults: A population-based study

BACKGROUND

We sought to examine the associations of the Lifestyle for Brain Health (LIBRA) index with cognitive function among rural Chinese older adults and to explore the potential role of cluster of differentiation 33 gene (CD33) in the associations.

METHODS

This population-based cross-sectional study included 4914 dementia-free participants (age ≥60 years; 56.43 % women) in the 2018 baseline examination of MIND-China. The LIBRA index was generated from 11 factors. We used a neuropsychological test battery to assess episodic memory, verbal fluency, attention, executive function, and global cognition. The CD33(rs3865444) polymorphism was detected using multiple-polymerase chain reaction amplification. Data were analyzed using the general linear regression models.

RESULTS

A higher LIBRA index was associated with multivariable-adjusted β-coefficient (95 %CI) of -0.011(-0.020- -0.001) for global cognitive z-score, -0.020(-0.033- -0.006) for episodic memory, and -0.016(-0.029- -0.004) for verbal fluency. The CD33(rs3865444) was associated with a lower global cognitive z-score in the additive (CA vs. CC: β-coefficient=0.042; 95 %CI=0.008-0.077), the dominant (CA+AA vs. CC: 0.040; 0.007-0.073), and the over-dominant (CA vs. CC+AA: 0.043; 0.009-0.077) models. Similar results were obtained for verbal fluency and attention. The CD33 gene showed statistical interactions with LIBRA index on cognitive function (Pinteraction<0.05) such that a higher LIBRA index was significantly associated with lower z-scores of global cognition and attention only among CD33 CC carriers (P < 0.05).

CONCLUSIONS

This population-based study reveals for the first time that a higher LIBRA index is associated with worse cognitive performance in rural Chinese older adults and that CD33 gene could modify the association.

Temporal dynamics and neural variabilities underlying the interplay between emotion and inhibition in Chinese autistic children

This study investigated the neural dynamics underlying the interplay between emotion and inhibition in Chinese autistic children. Electroencephalography (EEG) signals were recorded from 50 autistic and 46 non-autistic children during an emotional Go/Nogo task. Based on single-trial ERP analyses, autistic children, compared to their non-autistic peers, showed a larger Nogo-N170 for angry faces and an increased Nogo-N170 amplitude variation for happy faces during early visual perception. They also displayed a smaller N200 for all faces and a diminished Nogo-N200 amplitude variation for happy and neutral faces during inhibition monitoring and preparation. During the late stage, autistic children showed a larger posterior-Go-P300 for angry faces and an augmented posterior-Nogo-P300 for happy and neutral faces. These findings clarify the differences in neural processing of emotional stimuli and inhibition between Chinese autistic and non-autistic children, highlighting the importance of considering these dynamics when designing intervention to improve emotion regulation in autistic children.

Malleability of the sense of bodily self in early childhood: 5- and 6-year-old children show the enfacement illusion

The mechanisms underlying the developing sense of bodily self are debated. Whereas some scholars stress the role of sensory factors, others propose the importance of contextual factors. By manipulating multisensory stimulation and social familiarity with the other person, we explored two factors that are proposed to relate to young children's developing sense of bodily self. Including an adult sample allowed us to investigate age-related differences of the malleability of the bodily self. To this end, the study implemented an enfacement illusion with children (N = 64) and adults (N = 33). Participants were exposed to one trial with synchronous interpersonal multisensory stimulation and one trial with asynchronous interpersonal multisensory stimulation-either with a stranger or with the mother as the other person. A self-recognition task using morph videos of self and other and an enfacement questionnaire were implemented as dependent measures. Results revealed evidence for the presence of the enfacement effect in children in both measures. The identity of the other person had a significant effect on the self-recognition task. Contrary to our hypothesis, the effect was significantly smaller in the caregiver condition. No significant differences between children and adults emerged. Our results demonstrate the role of both multisensory stimulation and contextual-here social familiarity-factors for the construction and development of a bodily self. The study provides developmental science with a novel approach to the bodily self by showing the validity of the self-recognition task in a child sample. Overall, the study supports proposals that the sense of bodily self is malleable early in development.

Association of physical function with connectivity in the sensorimotor and dorsal attention networks: why examining specific components of physical function matters

Declining physical function with aging is associated with structural and functional brain network organization. Gaining a greater understanding of network associations may be useful for targeting interventions that are designed to slow or prevent such decline. Our previous work demonstrated that the Short Physical Performance Battery (eSPPB) score and body mass index (BMI) exhibited a statistical interaction in their associations with connectivity in the sensorimotor cortex (SMN) and the dorsal attention network (DAN). The current study examined if components of the eSPPB have unique associations with these brain networks. Functional magnetic resonance imaging was performed on 192 participants in the BNET study, a longitudinal and observational trial of community-dwelling adults aged 70 or older. Functional brain networks were generated for resting state and during a motor imagery task. Regression analyses were performed between eSPPB component scores (gait speed, complex gait speed, static balance, and lower extremity strength) and BMI with SMN and DAN connectivity. Gait speed, complex gait speed, and lower extremity strength significantly interacted with BMI in their association with SMN at rest. Gait speed and complex gait speed were interacted with BMI in the DAN at rest while complex gait speed, static balance, and lower extremity strength interacted with BMI in the DAN during motor imagery. Results demonstrate that different components of physical function, such as balance or gait speed and BMI, are associated with unique aspects of brain network organization. Gaining a greater mechanistic understanding of the associations between low physical function, body mass, and brain physiology may lead to the development of treatments that not only target specific physical function limitations but also specific brain networks.