Modulation of the Activity of the Cerebellum in Autism (MACA)
- Conditions
- Autism Spectrum Disorder
- Interventions
- Device: tDCS
- Registration Number
- NCT05781412
- Lead Sponsor
- Beatriz Catoira
- Brief Summary
Research on the involvement of the cerebellum in social understanding behavior and the mentalizing brain system has just begun. Knowledge about the neurobiology of social understanding is important for understanding the ways to manipulate these processes. Like cerebral tDCS, cerebellar tDCS could then be used to enhance more complex processes, such as mentalizing, in healthy individuals. It can eventually also be examined as a therapeutic tool for patients with mentalizing difficulties such as patients with ASD. In this study, it is examined whether anodal tDCS at the right posterior cerebellum influences social understanding and which cerebro-cerebellar networks play a role in this process.
- Detailed Description
Autism Spectrum Disorders (ASD) are a group of lifelong neurodevelopmental disorders characterized by social and communicative difficulties and repetitive and stereotyped behaviors. Research has shown that cerebellar abnormalities are among the most important etiological factors for ASD. The cerebellum is found to be most frequently involved in tasks where participants must remember or imagine past or future autobiographical events, judge persons or situations based on behavioral sentences, make trait inferences of others using stories, words or faces, and describe persons or objects based on behavioral or object pictures. Recent research has also provided evidence on the involvement of the posterior areas of the cerebellum in social cognition.
Specifically, the areas crus I and crus II, located at the lateral hemispheres of the posterior cerebellum, are associated with more complex cognitive and social processes, such as mentalizing. Mentalizing is the cognitive ability to attribute mental states, such as desires, intentions, and beliefs, to other people. This ability is needed to understand and predict other people's behavior and is the main component of social cognition. Problems with mentalizing, including the attribution of false beliefs to others, are characteristic for autism spectrum disorder (ASD). A sequencing task (that included social and non social conditions) showing that cerebellar patients performed worse than healthy participants.
Facial emotion recognition refers to the ability to derive emotional meaning from facial expressions and has been shown to underlie social competency. Recent literature reviews have reported significant facial emotion recognition impairments in individuals with ASD. These impairments take various forms, such as a reduced accuracy in labeling facial emotions or reduced specificity in rating facial emotions of varying intensity . Thus, there is evidence suggesting that ASD is associated with a selective impairment in facial emotion recognition.
Transcranial direct current stimulation (tDCS) is a noninvasive technique that can produce long-lasting changes in the excitability and spontaneous activity of the stimulated brain areas. Therefore, tDCS is investigated as a possible treatment for different psychiatric diseases. Cerebellar tDCS have shown to also produce prolonged changes successfully at the neural and behavioral level. However, due to the high density of neurons in the cerebellum and diffuse connections to the cerebrum, it is more difficult to understand the working mechanisms of cerebellar as compared to cerebral tDCS. In addition, the electrical current will spread across more neurons in the cerebellum by cerebellar tDCS and will functionally affect the cerebral regions to which these cerebellar neurons are connected as well. Therefore, the type of behavioral effect, such as an improvement of performance after anodal tDCS or an impairment of performance after cathodal tDCS, is harder to predict for cerebellar than cerebral tDCS.
Modulation of social understanding with tDCS has been studied by stimulating the key mentalizing regions mPFC and TPJ. In healthy participants, an improvement on tasks was found that required the enhancement or inhibition of representation of the self or of others, which is important for mentalizing, after anodal tDCS at the TPJ compared to sham tDCS or cathodal tDCS. The effect of cerebellar tDCS on social understanding using action sequences has not yet been examined.
Recruitment & Eligibility
- Status
- RECRUITING
- Sex
- All
- Target Recruitment
- 100
Not provided
Not provided
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description H-AQ_anodalstimulation tDCS non diagnosed autistic participant,anodal stimulation on the first session, sham stimulation on the second sesion ASD_anodalstimulation tDCS ASD participant, anodal stimulation on the first session, sham stimulation on the second sesion H-AQ_shamstimulation tDCS non diagnosed autistic participant, sham stimulation on the first session, anodal stimulation on the second sesion NT_anodalstimulation tDCS Neurotypical participant, anodal stimulation on the first session, sham stimulation on the second sesion ASD_shamstimulation tDCS ASD participant, sham stimulation on the first session, anodal stimulation on the second sesion NT_shamstimulation tDCS Neurotypical participant, sham stimulation on the first session, anodal stimulation on the second sesion
- Primary Outcome Measures
Name Time Method PS_RT assessment will begin 10 minutes after stimulation and last up to 15 minutes Reaction Time in the pictorial sequencing time
PS_accuracy assessment will begin 10 minutes after stimulation and last up to 15 minutes Accuracy in the pictorial sequencing task
ER_accuracy assessment will begin 20 minutes after stimulation and last up to 5 minutes Accuracy in the emotion recognition task
Brain activity at the emotion recognition task assessment will begin 20 minutes after stimulation and last up to 5 minutes Brain activity (fMRI) in regions of interest/whole brain analysis. Differences between stimulation and sham, between task conditions and between sessions as well as possible interactions in between those factors and covariates (AQ scores, age, gender...)
ER_RT assessment will begin 20 minutes after stimulation and last up to 5 minutes Reaction Times in the emotion recognition task
Brain activity at resting state assesment will begin concurrent with stimulation and last up to 20 minutes Brain activity (fMRI) in regions of interest/whole brain analysis. Differences between stimulation and sham, between task conditions and between sessions as well as possible interactions in between those factors and covariates (AQ scores, age, gender...)
Brain activity at the pictorial sequencing task assessment will begin 10 minutes after stimulation and last up to 15 minutes Brain activity (fMRI) in regions of interest/whole brain analysis. Differences between stimulation and sham, between task conditions and between sessions as well as possible interactions in between those factors and covariates (AQ scores, age, gender...)
White matter integrity in the cerebellum assessment will begin immediately after stimulation and last up to 10 minutes White matter integrity matrix (FA, MD, RD) in the cerebellum using tract-based spatial statistics in the cerebellum \& differences between groups
- Secondary Outcome Measures
Name Time Method Connectivity_ERtask assessment will begin 20 minutes after stimulation and last up to 5 minutes Brain connectivity (fMRI) analysis on the emotion recognition task
Connectivity_stimulation assesment will begin concurrent with stimulation and last up to 20 minutes Brain connectivity (fMRI) analysis during stimulation
Connectivity_PStask assessment will begin 10 minutes after stimulation and last up to 15 minutes Brain connectivity (fMRI) analysis on the pictorial sequencing task
Fiber tractography between the cerebellum and the default mode/ mentalizing network assessment will begin immediately after stimulation and last up to 10 minutes Fiber tractography (Diffusion weighted imaging) between the cerebellum and the default mode / mentalizing network, by extraction of white matter integrity parameters on each fiber tract
ROI-based structural connectivity assessment will begin immediately after stimulation and last up to 10 minutes Structural connectivity (DWI) between ROIs from the default mode/mentalizing network
Whole brain structural network construction assessment will begin immediately after stimulation and last up to 10 minutes Structural connectivity (DWI) within the whole brain using graph theory
Trial Locations
- Locations (1)
UZ Brussel
🇧🇪Jette, Brussels, Belgium