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Introduction: Motor difficulties are frequent in autistic children and associated with diverse social behavior, possibly due to atypical neural processing subserving internal action models. This systematic review synthesizes results from current functional magnetic resonance imaging (fMRI) research of brain activation during execution, imitation and observation of naturalistic actions in autistic children and adolescents (<18 years).

Methods: Peer-reviewed articles in English published between 2000 and 2025 reporting task-related fMRI in diagnosed autistic vs. typically developing youth (<18 years) were evaluated. Eight studies (with a total of 129 autistic and 128 typically developing participants) were identified, divided into action execution (n = 1), observation (n = 4), and imitation (n = 3).

Results: Between-group differences included reduced cerebellar activations for execution in autistic children; higher activity in left-lateralized motor processing regions for imitation; and lower activity in temporoparietal, posterior cingulate and anterior prefrontal cortex for observation.

Discussion: Findings suggest that atypical brain activation during action execution, observation and imitation in autistic youth is frequent and largely support the notion of aberrant formation and use of motor representations in autism development. Although, due to the limited number of studies, small samples, variability in fMRI pipelines, and task specific nature of the results, interpretations require caution and further investigations are warranted.

Folate receptor alpha (FRα) is a high-affinity transporter responsible for delivering folate (vitamin B9) into the central nervous system (CNS), supporting the synthesis of nucleic acids, amino acids, lipids, and signaling molecules through one-carbon transfer pathways. Beyond its transport function, upon activation by folate, FRα modulates extracellular signaling, regulates membrane and cytosolic proteins, and gene transcription. Disruption of FRα, whether functional or structural, can impair CNS folate availability and lead to developmental abnormalities or neurological dysfunction, with the clinical consequences depending on the timing, severity, and presumably on the individual genetic background. Together, these insights position FRα as both a multifunctional regulator of cellular fate and a key molecular interface connecting folate metabolism, brain development, and neurobehavioral outcomes. This narrative review synthesizes the current state of knowledge on FRα, highlighting its roles in neuronal and glial differentiation, CNS maturation, and neural plasticity, while also examining the links between impaired FRα function and a spectrum of developmental and neuropsychiatric conditions. It also outlines the need for broader population-based studies to evaluate the diagnostic value of FRα autoantibodies and the therapeutic potential of folate supplementation.

Sequential manual actions involving object manipulation, whether performed ourselves or observed in others, are a fundamental part of our daily lives. Motor representations within internal action models have been linked to both action execution and observation, but it is less clear how brain activity associated with planning, execution and observation of complex sequential actions differs and overlap. Here, using event-related fMRI, we examined brain activity during sequential manual action in planning, execution and observation in a sample of healthy adults (N = 28). Comparing actions under different task complexity (complex, rotation > baseline, no rotation), we found increased activation in parietal, precentral and sensory-motor regions during action execution planning. Execution of complex actions engaged ipsilateral parieto-frontal regions, while observation activated parietal regions. Planning to observe complex actions engaged occipito-parietal, precentral and cerebellar regions. Importantly, across all four conditions, we found a significant overlap in brain activity in the bilateral intraparietal sulcus. This suggests that the inferior parietal lobe is an important node for complex sequential manual actions.

Motor impairments are common in individuals with autism spectrum disorder (ASD) although less is known about the neural mechanisms related to such difficulties. This review provides an outline of functional magnetic resonance imaging (fMRI) findings associated with execution and observation of naturalistic actions in autistic adults. Summarized outcomes revealed that adults with ASD recruit similar brain regions as neurotypical adults during action execution and during action observation, although with a difference in direction and/or magnitude. For action execution, this included higher and lower activity bilaterally in the precentral cortex, the parietal cortex, the inferior frontal gyrus (IFG), the middle temporal gyrus (MTG), the occipital cortex, and the cerebellum. For action observation, differences mainly concerned both higher and lower activity in bilateral IFG and right precentral gyrus, and lower activity in MTG. Activity overlaps between action execution and observation highlight atypical recruitment of IFG, MTG, precentral, and parieto-occipital regions in ASD. The results show atypical recruitment of brain regions subserving motor planning and/or predictive control in ASD. Atypical brain activations during action observation, and the pattern of activity overlaps, indicate an association with difficulties in understanding others' actions and intentions.

Sensorimotor difficulties are common in children with autism spectrum disorder, and it has been suggested that motor planning problems underlie their atypical movements. At early school-age, motor planning development typically involves changes in visuomotor integration, a function known to be affected in autism spectrum disorder. However, there is a lack of detailed characterization of typical motor planning development during this stage, and how motor planning develops in children with autism spectrum disorder is largely unknown. This longitudinal kinematic study examined goal-directed sequential manual movements in children with autism spectrum disorder and in typically developing children across ages 7, 8, and 9 years. We manipulated goal-difficulty and availability of initial visual information to investigate visuomotor integration and chaining of subparts during movement performance. The results revealed emerging group differences at older age, suggesting atypical motor planning development in children with autism spectrum disorder. Notably, unlike the typically developing group, availability of initial visual information did not facilitate motor planning for the autism spectrum disorder group. The results show that motor planning differences in autism spectrum disorder appear related to atypical visuomotor integration and global processing of sensorimotor information. The findings also emphasize the importance of considering developmental aspects in research and practice related to motor problems in children with autism spectrum disorder.

Jaw-head movement coordination develops during adolescence. However, functional adjustments during this period remain poorly understood. This study aimed to characterize jaw and head movement adjustments in early adolescents and compare this to adults. Three-dimensional optical cameras captured jaw and head movements during maximum jaw opening-closing and chewing. Twenty (8 females, 12 males) adolescents (mean 13.5 yr, standard deviation [SD] 8 months) and 20 (9 females, 11 males) adults (mean 28.2 yr, SD 80 months) participated. Outcomes included jaw and head movement magnitudes, movement cycle time, time to first peak value, and initial phase. Functional data analysis and Wilcoxon rank-sum tests were employed. Adolescents showed larger head magnitude in jaw opening-closing and smaller jaw magnitude than did adults during chewing in the first movement cycle. Adolescents exhibited longer time to peak and time of first movement cycle during jaw opening-closing. During chewing, adolescents showed a longer initial phase, time to peak for consecutive cycles, and movement cycle time. For both age groups, the first cycle differed from consecutive cycles in jaw and head movement magnitudes and cycle times. Compared to adults, adolescents displayed pronounced spatiotemporal initial jaw-head movement adjustments during jaw function, particularly in the first movement cycle. Jaw-head coordination refines from early adolescence into adulthood.

Introduction: Improvements in obstetric/neonatal care have increased the survival rates of extremely-preterm-born (EP), though followed by an increased number, and degrees, of white matter injury (WMI), and long-lasting neurodevelopmental impairments. Study aim: to investigate consequences of EP birth on the evolving white matter microstructure and myelination; and its causative role on acquired IQ and sensory-motor functions.

Participants and methods: Two MRI methods (3T; DTI and SyMRI) used to calculate white matter properties and associations with IQ and sensory-motor functions in children born FT and EP at 12-y. In total N = 57 children; 32 FT (GA 38-42), and 25 EP (GA 22- <27) successfully performed MRI and administered WISC-V and Beery visual-motor integration (VMI) test. DTI used for analyzing fractional anisotropy (FA), mean diffusivity (MD), axial- (AD) and radial diffusivity (RD). SyMRI (T1-T2-R1-R2 and PD) for analyzing myelin segmentation, white-matter (WM), gray-matter (GM), cerebrospinal fluid (CSF), and brain parenchyma volume (BPV).

Results: Children born EP had significant smaller total brain (BPV), less GM, WM and more CSF/ICV compared to FT born. GA correlated positively with brain volumes, myelin, and with IQ and Beery-WMI. For EPs myelin correlated positively with GA, WISC-V and Beery-VMI. EPs had significant higher RD and AD compared to FT, no significant FA difference found. Within EP-group, myelin content correlated positively with FA and negatively with RD and AD.

Conclusion: These findings suggest that EP births is associated with high-risk for long-lasting, globally compromised white matter myelination and microstructural organization which causes adverse cognitive and sensory-motor functions.

Motor issues are frequently observed accompanying core deficits in autism spectrum disorder (ASD). Impaired motor behavior has also been linked to cognitive and social abnormalities, and problems with predictive ability have been suggested to play an important, possibly shared, part across all these domains. Brain imaging of sensory-motor behavior is a promising method for characterizing the neurobiological foundation for this proposed key trait. The present functional magnetic resonance imaging (fMRI) developmental study, involving children/youth with ASD, typically developing (TD) children/youth, and neurotypical adults, will investigate brain activations during execution and observation of a visually guided, goal-directed sequential (two-step) manual task. Neural processing related to both execution and observation of the task, as well as activation patterns during the preparation stage before execution/observation will be investigated. Main regions of interest include frontoparietal and occipitotemporal cortical areas, the human mirror neuron system (MNS), and the cerebellum.

Introduction: Children with autism spectrum disorder (ASD) frequently display atypical motor functioning. This longitudinal study investigated atypical visuomotor integration in the development of action planning as one possible source.

Participants and Methods: Fourteen children with ASD and 17 typically developing (TD) controls participated three times over the ages 7 (T1) to 9 (T3) years. 3D kinematic registrations were made during performance of a manual sequential peg-rotation task with either visible or occluded goal-display condition before onset. Time, condition, and group differences were analyzed on onset-latency, part peak velocity in reach-to-grasp (PPV-RtG), remaining angle of peg-rotation at goal (p-RA), and fitting-duration.

Results: Time-point generated significant (p < 0.05) main effects for all variables. Stratifying by condition revealed shorter latency (both groups), higher PPV-RtG (visual-condition TD-group), lower p-RA (visual-condition TD-group; occluded-condition ASD-group), and shorter fitting-duration (visual-condition TD-group; occluded-condition both groups) with increasing age. Group generated significant main effects for fitting-duration. Stratifying by condition revealed longer fitting-durations (both conditions), and increased p-RA (occluded-condition at T1; visible-condition at T3) in the ASD-group. Condition generated significant main effects for all variables except fitting-duration. Stratifying by group revealed shorter latency (both groups), higher PPV-RtG (TD-group at T3), and reduced p-RA (TD-group at T3) in the visual-condition.

Conclusions: The results show different sensory-motor integration in the children with ASD, characterized by not benefitting from pre-existing visual information in action planning in accordance with their TD peers, particularly evident at 9 years. Our findings, based on longitudinal data, support suggestions that visuomotor integration underpinning action planning may operate differently in ASD.

Introduction: Motor planning deviances may negatively affect interpersonal motor interactions in ASD, although detailed studies are sparse. This study examined motor planning kinematics in an interpersonal and non-interpersonal context in 9-year-old children with ASD and neurotypical peers.

Patients and methods: Twelve children with ASD and 17 controls performed two different sequential manual tasks (preferred hand): grasping and placing a peg on a wooden disc (non-interpersonal) or in the hand of an examiner (interpersonal). Three-dimensional kinematic recordings of arm/hand movements were performed. Group and task differences were explored for total movement duration (MD), and for peak velocity (PV) and placement of peak velocity (PPV) during reach-to-grasp and transport-to-place movements, respectively.

Results: Task differences were found in terms of longer MD and higher transport-to-place-PV in the disc- compared to hand-task. An interaction effect was evident for reach-to-grasp-PPV, where the control-group, but not ASD, had earlier reach-to-grasp-PPV and longer relative deceleration in the hand-task compared to the disc-task.

Conclusion: Results show that the interpersonal context influenced initial reach-to-grasp motor planning in the control-group, but not the ASD-group. Later in the sequential movement (transport-to-place), the interpersonal context seemed to influence motor planning independent of group. Taken together, this indicates support towards a more careful peg-placing in the interpersonal hand-task in the control-group but much less clearly so in the ASD-group.

Relevance for users and families: Atypical motor planning may influence motor interaction with peers. Investigations of motor planning and movement organization in ASD could thus inform interventions also targeting interpersonal exchange.