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A body of research implicates dopamine in the average speed of simple movements. However, naturalistic movements span a range of different shaped trajectories and rarely proceed at a single constant speed. Instead, speed is reduced when drawing "corners" compared to "straights" (i.e., speed modulation), and the extent of this slowing down is dependent upon the global shape of the movement trajectory (i.e., speed meta-modulation) - for example whether the shape is an ellipse or a rounded square. At present, it is not known how (or whether) dopaminergic function controls continuous changes in speed during movement execution. The current paper reports effects on these kinematic features of movement following two forms of dopamine manipulation: Study One highlights movement differences in individuals with PD both ON and OFF their dopaminergic medication (N = 32); Study Two highlights movement differences in individuals from the general population on haloperidol (a dopamine receptor blocker, or "antagonist") and placebo (N = 43). Evidence is presented implicating dopamine in speed, speed modulation and speed meta-modulation, whereby low dopamine conditions are associated with reductions in these variables. These findings move beyond vigour models implicating dopamine in average movement speed, and towards a conceptualisation that involves the modulation of speed as a function of contextual information.
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Difficulties in reasoning about others' mental states (i.e., mentalising/Theory of Mind) are highly prevalent among disorders featuring dopamine dysfunctions (e.g., Parkinson's disease) and significantly affect individuals' quality of life. However, due to multiple confounding factors inherent to existing patient studies, currently little is known about whether these sociocognitive symptoms originate from aberrant dopamine signalling or from psychosocial changes unrelated to dopamine. The present study, therefore, investigated the role of dopamine in modulating mentalising in a sample of healthy volunteers. We used a double-blind, placebo-controlled procedure to test the effect of the D2/D3 antagonist haloperidol on mental state attribution, using an adaptation of the Heider and Simmel (1944) animations task. On 2 separate days, once after receiving 2.5 mg haloperidol and once after receiving placebo, 33 healthy adult participants viewed and labelled short videos of 2 triangles depicting mental state (involving mentalistic interaction wherein 1 triangle intends to cause or act upon a particular mental state in the other, e.g., surprising) and non-mental state (involving reciprocal interaction without the intention to cause/act upon the other triangle's mental state, e.g., following) interactions. Using Bayesian mixed effects models, we observed that haloperidol decreased accuracy in labelling both mental and non-mental state animations. Our secondary analyses suggest that dopamine modulates inference from mental and non-mental state animations via independent mechanisms, pointing towards 2 putative pathways underlying the dopaminergic modulation of mental state attribution: action representation and a shared mechanism supporting mentalising and emotion recognition. We conclude that dopaminergic pathways impact Theory of Mind, at least indirectly. Our results have implications for the neurochemical basis of sociocognitive difficulties in patients with dopamine dysfunctions and generate new hypotheses about the specific dopamine-mediated mechanisms underlying social cognition.
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Haloperidol , Receptores de Dopamina D2 , Receptores de Dopamina D3 , Humanos , Receptores de Dopamina D2/metabolismo , Masculino , Adulto , Haloperidol/farmacologia , Feminino , Receptores de Dopamina D3/metabolismo , Método Duplo-Cego , Adulto Jovem , Teoria da Mente , Dopamina/metabolismo , Antagonistas de Dopamina/farmacologia , MentalizaçãoRESUMO
Recent findings suggest that stigma and camouflaging contribute to mental health difficulties for autistic individuals, however, this evidence is largely based on UK samples. While studies have shown cross-cultural differences in levels of autism-related stigma, it is unclear whether camouflaging and mental health difficulties vary across cultures. Hence, the current study had two aims: (1) to determine whether significant relationships between autism acceptance, camouflaging, and mental health difficulties replicate in a cross-cultural sample of autistic adults, and (2) to compare these variables across cultures. To fulfil these aims, 306 autistic adults from eight countries (Australia, Belgium, Canada, Japan, New Zealand, South Africa, the United Kingdom, and the United States) completed a series of online questionnaires. We found that external acceptance and personal acceptance were associated with lower levels of depression but not camouflaging or stress. Higher camouflaging was associated with elevated levels of depression, anxiety, and stress. Significant differences were found across countries in external acceptance, personal acceptance, depression, anxiety, and stress, even after controlling for relevant covariates. Levels of camouflaging also differed across countries however this effect became non-significant after controlling for the covariates. These findings have significant implications, identifying priority regions for anti-stigma interventions, and highlighting countries where greater support for mental health difficulties is needed.
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Transtorno do Espectro Autista , Transtorno Autístico , Adulto , Humanos , Transtorno Autístico/psicologia , Saúde Mental , Publicação Pré-Registro , Comparação Transcultural , Inquéritos e Questionários , Transtorno do Espectro Autista/psicologiaRESUMO
Background: In recent years, there have been increasing discussions surrounding the appropriate terminology to talk about autism. Initially, this debate revolved around the use of person-first language (e.g., person with autism) versus identity-first language (IFL; e.g., autistic person) but has recently expanded to other autism-related terms (e.g., deficits). However, to date, studies investigating autism-related language preferences have been limited to English-speaking countries, and little is known about preferences in other languages. This study addresses this gap by investigating the language preferences of French-speaking autistic adults. Methods: Five hundred and forty-one French-speaking autistic adults (formal diagnosis and self-identified) completed an online survey where they selected terms they preferred to use to talk about: (1) the nomenclature of autism; (2) an autistic person; (3) someone's autistic identity; (4) autism more broadly; (5) the abilities of autistic people; and (6) people without a diagnosis of autism. Participants also revealed more about their language preferences via an open-text response. Results: The most preferred terms were "Autisme," "Personne autiste," "Autiste," "Est Autiste," "Différence neurologique/cérébrale," "Différences," "Difficultés," "Personne neurotypique," "Neurotypique," and "Personne non-autiste." To better understand these preferences, participants' open comments were analyzed, revealing further support for IFL and the social model of disability, and a preference for simple, precise, and validated terms. Conclusions: These results are consistent with autism terminology preferences in English-speaking countries and provide additional insight into the reasons underlying these preferences. Such work has implications for informing the language of researchers, clinicians, and other professionals in the field, as well as the general public.
Community brief: Why is this an important issue?: More and more research is investigating which words should be used to talk about autism. Initially, this discussion revolved around the use of person-first language (e.g., person with autism) versus identity-first language (e.g., autistic person) but has recently expanded to other autism-related terms (e.g., disorder, deficits, high-functioning autism). To date, all the studies on this topic have focused on language preferences in English-speaking countries, and little is known about preferences in other languages.What was the purpose of this study?: We wanted to know whether French-speaking autistic adults would show similar or different autism-related language preferences than English-speaking autistic individuals. We also wanted to know the reasons for these language preferences.What did the researchers do?: In an online survey, we asked 541 French-speaking autistic adults around the world what terms they prefer to use to talk about (1) the nomenclature of autism, (2) an autistic person, (3) someone's autistic identity, (4) autism more broadly, (5) the abilities of autistic people, and (6) someone without an autism diagnosis. Participants also had the opportunity to tell us more about their language preferences in an open comment.What were the results of this study?: The most preferred terms were "Autisme," "Personne autiste," "Autiste," "Est Autiste," "Différence/neurologique," "Différences," "Difficultés," "Personne neurotypique," "Neurotypique," and "Personne non autiste." To better understand the reasons underlying these preferences, participants' open comments were analyzed, revealing further support for identity-first language and the social model of disability, and a preference for simple, precise, and validated terms. What do these findings add to what was already known?: We previously knew about language preferences of English-speaking autistic people. This study extends these findings by showing that French-speaking autistic adults also prefer terms that reflect the ideas of identity-first language (e.g., "Est Autiste," "Personne autiste") and the social model of disability (e.g., "Différence," "Handicap"). We also show that these are not the only reasons behind language preferences: Term simplicity, precision, and validity are also important when talking about autism.What are the potential weaknesses in the study?: The reported preferences are not representative of all autistic individuals, as our sample did not include children and adolescents. In addition, we did not make specific adaptations to our questionnaire for non-speaking people or people with intellectual difficulties, so we do not know to what extent their opinions are represented in our data. Further, recruitment was done almost exclusively online, resulting in a self-selecting recruitment method for our sample (i.e., participants who have access to Internet and a computer). Finally, participants who responded to the advertisements and completed the questionnaire are probably interested in the debate regarding language to talk about autism. Therefore, our sample may be more representative of the online autistic, pro-neurodiversity community.How will these findings help autistic adults now or in the future?: This study is the first to look at the language preferences of French-speaking autistic adults. Further, our results have substantial implications for informing the language of researchers, clinicians, and other professionals in the field, as well as the general public.
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Over the past two decades, there have been increasing discussions around which terms should be used to talk about autism. Whilst these discussions have largely revolved around the suitability of identity-first language and person-first language, more recently this debate has broadened to encompass other autism-related terminology (e.g., 'high-functioning'). To date, academic studies have not investigated the language preferences of autistic individuals outside of the United Kingdom or Australia, nor have they compared levels of endorsement across countries. Hence, the current study adopted a mixed-methods approach, employing both quantitative and qualitative techniques, to explore the linguistic preferences of 654 English-speaking autistic adults across the globe. Despite variation in levels of endorsement between countries, we found that the most popular terms were similar-the terms 'Autism', 'Autistic person', 'Is autistic', 'Neurological/Brain Difference', 'Differences', 'Challenges', 'Difficulties', 'Neurotypical people', and 'Neurotypicals' were consistently favored across countries. Despite relative consensus across groups, both our quantitative and qualitative data demonstrate that there is no universally accepted way to talk about autism. Our thematic analysis revealed the reasons underlying participants' preferences, generating six core themes, and illuminated an important guiding principle-to respect personal preferences. These findings have significant implications for informing practice, research and language policy worldwide.
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Transtorno do Espectro Autista , Transtorno Autístico , Adulto , Humanos , Austrália , Pesquisa Qualitativa , IdiomaRESUMO
INTRODUCTION: Hand dexterity is the ability to execute the skilful movements using the hand and fingers. It is commonly impaired poststroke resulting in a profound deterioration in the quality of life for patients with stroke. Transcranial direct current stimulation (tDCS) is a form of non-invasive brain stimulation, which has gained a popularity as an adjunct therapy in recovering motor dysfunction poststroke. Promising results have been gained from applying tDCS in combination with motor rehabilitation, however, the outcome of tDCS on the upper limb motor function poststroke has been varied. Different results are potentially related to the discrepancy of the area of brain stimulation. Therefore, we aim to enhance the application of tDCS to improve its effectiveness in recovering hand dexterity through testing our hypothesis that stimulating the primary motor cortex could improve fine dexterity more than gross dexterity. METHODS AND ANALYSIS: This protocol has been reported according to Preferred Reporting Items for Systematic Review and Meta-Analyses Protocols guidelines. CENTRAL, MEDLINE, EMBASE, SCOPUS, Web of Science and CINAHL databases will be searched with no restriction in language and publication date. The selected studies will be randomised controlled trial investigating the effect of tDCS alone or in combination with motor rehabilitation in improving hand dexterity of patients with stroke with upper limb hemiparesis. The outcomes of interest are fine and gross hand dexterity measures. Two independent reviewers will assess the eligibility of the study, extract data and appraise the methodological quality. The data will be pooled in a meta-analysis if applicable or interpreted narratively. Grading of Recommendations, Assessment, Development and Evaluation approach will be used to assess the overall quality of evidence for the fine and gross dexterity measures. ETHICS AND DISSEMINATION: Ethical approval is not required for this study. The dissemination plan is to publish the results in a peer-review journal and presenting results in a conference. PROSPERO REGISTRATION NUMBER: CRD42021262186.
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Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral , Estimulação Transcraniana por Corrente Contínua , Humanos , Metanálise como Assunto , Qualidade de Vida , Acidente Vascular Cerebral/complicações , Reabilitação do Acidente Vascular Cerebral/métodos , Revisões Sistemáticas como Assunto , Estimulação Transcraniana por Corrente Contínua/métodos , Extremidade Superior/fisiologiaRESUMO
Alexithymia concerns a difficulty identifying and communicating one's own emotions, and a tendency towards externally-oriented thinking. Recent work argues that such alexithymic traits are due to altered arousal response and poor subjective awareness of "objective" arousal responses. Although there are individual differences within the general population in identifying and describing emotions, extant research has focused on highly alexithymic individuals. Here we investigated whether mean arousal and concordance between subjective and objective arousal underpin individual differences in alexithymic traits in a general population sample. Participants rated subjective arousal responses to 60 images from the International Affective Picture System whilst their skin conductance was recorded. The Autism Quotient was employed to control for autistic traits in the general population. Analysis using linear models demonstrated that mean arousal significantly predicted Toronto Alexithymia Scale scores above and beyond autistic traits, but concordance scores did not. This indicates that, whilst objective arousal is a useful predictor in populations that are both above and below the cut-off values for alexithymia, concordance scores between objective and subjective arousal do not predict variation in alexithymic traits in the general population.
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Sintomas Afetivos , Emoções , Sintomas Afetivos/diagnóstico , Sintomas Afetivos/psicologia , Nível de Alerta/fisiologia , Humanos , Individualidade , Modelos LinearesAssuntos
Transtorno do Espectro Autista/psicologia , Transtorno do Espectro Autista/terapia , Serviços de Saúde Mental , Adolescente , Adulto , Transtorno do Espectro Autista/diagnóstico , Comportamento , Criança , Comportamento Infantil , Características Culturais , Feminino , Saúde Global , Humanos , Masculino , Análise de Regressão , Projetos de Pesquisa , Inquéritos e Questionários , Adulto JovemRESUMO
According to dual-process signal-detection (DPSD) theories, short- and long-term recognition memory draws upon both familiarity and recollection. It remains unclear how primate prefrontal cortex (PFC) contributes to these processes, but frequency-specific neuronal activities are considered to play a key role. In Experiment 1, nonhuman primate (NHP) local field potential (LFP) electrophysiological recordings in macaque left dorsolateral PFC (dlPFC) revealed performance-related differences in a low-beta frequency range during the sample presentation phase of a visual object recognition memory task. Experiment 2 employed a similar task in humans and targeted left dlPFC (and vertex as a control) with repetitive transcranial magnetic stimulation (rTMS) at 12.5 Hz during occasional sample presentations. This low-beta frequency rTMS to dlPFC decreased DPSD derived indices of recollection, but not familiarity, in subsequent memory tests of the targeted samples after short delays. The same number of rTMS pulses over the same total duration albeit at a random frequency had no effect on either recollection or familiarity. Neither stimulation protocols had any causal effect upon behaviour when targeted to the control site (vertex). In this study, our hypotheses for our human TMS study were derived from our observations in NHPs; this approach might inspire further translational research through investigation of homologous brain regions and tasks across species using similar neuroscientific methodologies to advance the neural mechanism of recognition memory in primates.
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Córtex Pré-Frontal Dorsolateral , Estimulação Magnética Transcraniana , Animais , Humanos , Macaca , Rememoração Mental , Córtex Pré-Frontal , Reconhecimento PsicológicoRESUMO
Interoception concerns the perception of the body's internal state. Despite the importance of this ability for health and aspects of higher-order cognition, its measurement remains problematic. Most studies of interoception employ one of two tasks: the heartbeat counting or heartbeat discrimination task. These tasks are thought to index common abilities, an assertion often used to justify the use of a single measure of cardiac interoception. However, mixed findings regarding the relationship between performance on these tasks raises the question of whether they can be used interchangeably to assess interoceptive accuracy, confidence and awareness ('metacognition'). The present study employed a meta-analytical approach to assess the association between these tasks. Pooled findings from 22 studies revealed a small relationship between accuracy scores on the measures. Additional analyses demonstrated a moderate relationship between confidence ratings but no association between measures of interoceptive awareness. These findings question the interchangeable use of the two tasks.
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Frequência Cardíaca , Interocepção , Conscientização , Cognição , Coração , HumanosRESUMO
According to dual-process theory, recognition memory performance draws upon two processes, familiarity and recollection. The relative contribution to recognition memory are commonly distinguished in humans by analyzing receiver-operating-characteristics (ROC) curves; analogous methods are more complex and very rare in animals but fast familiarity and slow recollective-like processes (FF/SR) have been detected in nonhuman primates (NHPs) based on analyzing recognition error response time profiles. The relative utility of these methods to investigate familiarity and recollection/recollection-like processes across species is uncertain; indeed, even how comparable the FF/SR measures are across humans and NHPs remains unclear. Therefore, in this study a broadly similar recognition memory task was exploited in both humans and a NHP to investigate the time course of the two recognition processes. We first show that the FF/SR dissociation exists in this task in human participants and then we demonstrate a similar profile in the NHP which suggests that FF/SR processes are comparable across species. We then verified, using ROC-derived indices for each time-bin in the FF/SR profile, that the ROC and FF/SR measures are related. Hence, we argue that the FF/SR approach, procedurally easier in nonhuman animals, can be used as a decent proxy to investigate these two recognition processes in future animal studies, important given that scant data exists as to the neural basis underlying recollection yet many of the most informative techniques primarily exist in animal models.