What neurological diseases tell us about procedural perceptual-motor learning? A systematic review of the literature.

INTRODUCTION: Procedural perceptual-motor learning of sequences (PPMLS) provides perceptual-motor skills in many activities of daily living. Based on behavioral and neuroimaging results, theoretical models of PPMLS postulate that the cortico-striatal loop, the cortico-cerebellar loop and the hippocampus are specifically involved in the early stage of PPMLS while the cortico-striatal loop would be specifically involved in the late stage of PPMLS. Hence, current models predict that the early stage of PPMLS should be impaired in Parkinson's disease (PD: lesion of the cortico-striatal loop), in cerebellar disease (CD: lesion of the cortico-cerebellar loop) and in Alzheimer's disease (AD: lesion of the hippocampus), whereas the late stage of PPMLS should be specifically impaired in PD. OBJECTIVE: The aim of the study is (1) to draw a complete picture of experimental results on PPMLS in PD, CD and AD (2) to understand heterogeneity of results as regard to participant and task characteristics. METHOD: This review is based on the guideline proposed by the PRISMA statement. RESULTS: Our review reveals (1) that the experimental results clarify the theoretical models and (2) that the impairment of PPMLS depends on both the personal characteristics of the participants and the characteristics of the task to-be-learnt rather than on the disease itself. CONCLUSION: Our results highlight that these characteristics should be more carefully considered to understand the heterogeneity of results across studies on PPMLS and the effects of rehabilitation programs.

Procedural learning and retention of audio-verbal temporal sequence is altered in children with developmental coordination disorder but cortical thickness matters.

Rhythmic abilities are impaired in developmental coordination disorder (DCD) but learning deficit of procedural skills implying temporal sequence is still unclear. Current contradictory results suggest that procedural learning deficits in DCD highly depend on learning conditions. The present study proposes to test the role of sensory modality of stimulations (visual or auditory) on synchronization, learning, and retention of temporal verbal sequences in children with and without DCD. We postulated a deficit in learning particularly with auditory stimulations, in association with atypical cortical thickness of three regions of interesting: sensorimotor, frontal and parietal regions. Thirty children with and without DCD (a) performed a synchronization task to a regular temporal sequence and (b) practiced and recalled a novel non-regular temporal sequences with auditory and visual modalities. They also had a magnetic resonance imaging to measure their cortical thickness. Results suggested that children with DCD presented a general deficit in synchronization of a regular temporal verbal sequence irrespective of the sensory modality, but a specific deficit in learning and retention of auditory non-regular verbal temporal sequence. Stability of audio-verbal synchronization during practice correlated with cortical thickness of the sensorimotor cortex. For the first time, our results suggest that synchronization deficits in DCD are not limited to manual tasks. This deficit persists despite repeated exposition and practice of an auditory temporal sequence, which suggests a possible alteration in audio-verbal coupling in DCD. On the contrary, control of temporal parameters with visual stimuli seems to be less affected, which opens perspectives for clinical practice.

Benefits of a Dance Intervention on Balance in Adolescents with Cerebral Palsy.

AIMS: Cerebral palsy (CP) impacts motor functions such as balance, limits of stability and walking, and may also affect other functions such as attention and rhythm production. Motor and non-motor deficits lead to difficulties in daily life activities. The main objective of this study was to evaluate the effects of a dance intervention on balance in adolescents with CP. The secondary objectives were to evaluate the effects of this intervention on walking speed, attention, and rhythm production. METHODS: A pre-post design study with a double baseline was conducted on ten adolescents with CP in order to assess the effects of a 10-week dance intervention. The dance intervention focused on improving balance and limits of stability. Outcomes on static and dynamic balance were evaluated with clinical and laboratory tests before and after the intervention. Walking speed, attention, and rhythm production were also evaluated before and after the intervention. RESULTS: Balance improved after the dance intervention as assessed with both the clinical tests and a laboratory test. Rhythm production also improved after the dance intervention. CONCLUSIONS: Results suggest that a 10-week dance intervention is an effective activity to improve static and dynamic balance as well as rhythmic production in adolescents with CP.

Atypical inter-hemispheric communication correlates with altered motor inhibition during learning of a new bimanual coordination pattern in developmental coordination disorder.

Impairment of motor learning skills in developmental coordination disorder (DCD) has been reported in several studies. Some hypotheses on neural mechanisms of motor learning deficits in DCD have emerged but, to date, brain-imaging investigations are scarce. The aim of the present study is to assess possible changes in communication between brain areas during practice of a new bimanual coordination task in teenagers with DCD (n = 10) compared to matched controls (n = 10). Accuracy, stability and number of mirror movements were computed as behavioural variables. Neural variables were assessed by electroencephalographic coherence analyses of intra-hemispheric and inter-hemispheric fronto-central electrodes. In both groups, accuracy of the new coordination increased concomitantly with right intra-hemispheric fronto-central coherence. Compared to typically developing teenagers, DCD teenagers presented learning difficulties expressed by less stability, no stabilization of the new coordination and a greater number of mirror movements despite practice. These measures correlated with reduced inter-hemispheric communication, even after practice of the new coordination. For the first time, these findings provide neuro-imaging evidence of a kind of inter-hemispheric 'disconnection' related to altered inhibition of mirror movements during motor learning in DCD.

Impaired corticomuscular coherence during isometric elbow flexion contractions in humans with cervical spinal cord injury.

After spinal cord injury (SCI), the reorganization of the neuromuscular system leads to increased antagonist muscles' co-activation-that is, increased antagonist vs. agonist muscles activation ratio-during voluntary contractions. Increased muscle co-activation is supposed to result from reduced cortical influences on spinal mechanisms inhibiting antagonist muscles. The assessment of the residual interactions between cortical and muscles activity with corticomuscular coherence (CMC) in participants with SCI producing different force levels may shed new lights on the regulation of muscle co-activation. To achieve this aim, we compared the net joint torque, the muscle co-activation and the CMC ~ 10 and ~ 20 Hz with both agonist and antagonist muscles in participants with SCI and healthy participants performing actual isometric elbow flexion contractions at three force levels. For all participants, overall CMC and muscle co-activation decreased with the increase in the net joint torque, but only CMC ~ 10 Hz was correlated with muscle co-activation. Participants with SCI had greater muscle co-activation and lower CMC ~ 10 Hz, at the highest force levels. These results emphasize the importance of CMC as a mechanism that could take part in the modulation of muscle co-activation to maintain a specific force level. Lower CMC ~ 10 Hz in SCI participants may reflect the decreased cortical influence on spinal mechanisms, leading to increased muscle co-activation, although plasticity of the corticomuscular coupling seems to be preserved after SCI to modulate the force level. Clinically, the CMC may efficiently evaluate the residual integrity of the neuromuscular system after SCI and the effects of rehabilitation.

Age-related changes in post-movement beta synchronization during a selective inhibition task.

Post-movement beta synchronization (PMBS) modulations have been related to sensory reafferences after movement initiation and inhibitory processes after movement interruption. Although these processes have been separately studied in young and old adults, little is known about the age-related changes in PMBS during selective inhibitory control (i.e. stop a part of an action). The present study examines the age-related modulations of PMBS associated with sensory reafferences and inhibitory processes in selective inhibitory control. Young (n = 17) and old (n = 13) participants performed a switching task first engaging bimanual finger tapping then requiring to stop the left while maintaining the right unimanual tapping (i.e. selective inhibition) at an imperative stimulus. Age groups were compared on behavioral (mean, variability and percentage of errors of inter-tap interval during and after the switching) and electrophysiological (time-frequency and source estimations in the 14-30 Hz beta frequency range) data time-locked on the imperative stimulus. Behaviorally, old adults showed larger variability and percentage of errors during the switching but performed as well as young adults after the switching. Electrophysiologically, PMBS significantly increased after the switching in the old compared to the young group within bilateral frontal and parietal areas. Our results show that the effort to maintain selective inhibition involves increased brain activation in old compared to young adults. The larger PMBS within frontal and parietal regions in old adults may reflect an age-related brain compensation enabling to efficiently maintain post-switching inhibition.

An enhanced experimental procedure to rationalize on the impairment of perception of action capabilities.

It is well documented that changes in the physiological states of the perceiver-actor influence the perception of action capabilities. However, because experimental procedures of most studies involved a limitless availability for stimuli visual encoding and perceptual strategies, it remains difficult to adopt a single position among the large range of alternative interpretations for impaired perception. A reaching-to-grasp paradigm under breathing restriction was adapted from Graydon et al. (Cogn Emot 26:1301-1305, 2012) to standardize the time for encoding of stimuli information and narrowed the involvement of perceptual strategies. In the present study, we propose a highly controlled environment where the discrete information is presented during 300 ms, congruently with neurophysiological studies focused on visuomotor transformation. An underestimation of the perception of action capabilities is found under breath restriction, suggesting that 300 ms for stimuli encoding is sufficient to induce altered visuomotor brain transformations when limiting the involvement of perceptual strategies. This result suggests that such behavior could refer to an impaired brain potentiation of the perceptual occurrence, providing strong hypotheses on the brain dynamics of sensorimotor integration that underlie impaired perception of action capabilities in stressful situations.

Is there a link between sensorimotor coordination and inter-manual coordination? Differential effects of auditory and/or visual rhythmic stimulations.

The purpose of this study was to test how the sensory modality of rhythmic stimuli affects the production of bimanual coordination patterns. To this aim, participants had to synchronize the taps of their two index fingers with auditory and visual stimuli presented separately (auditory or visual) or simultaneously (audio-visual). This kind of task requires two levels of coordination: (1) sensorimotor coordination, which can be measured by the mean asynchrony between the beat of the stimulus and the corresponding tap and by mean asynchrony stability, and (2) inter-manual coordination, which can be assessed by the accuracy and stability of the relative phase between the right-hand and left-hand taps. Previous studies show that sensorimotor coordination is better during the synchronization with auditory or audio-visual metronomes than with visual metronome, but it is not known whether inter-manual coordination is affected by stimulation modalities. To answer this question, 13 participants were required to tap their index fingers in synchrony with the beat of auditory and/or visual stimuli specifying three coordination patterns: two preferred inphase and antiphase patterns and a non-preferred intermediate pattern. A first main result demonstrated that inphase tapping had the best inter-manual stability, but the worst asynchrony stability. The second main finding revealed that for all patterns, audio-visual stimulation improved the stability of sensorimotor coordination but not of inter-manual coordination. The combination of visual and auditory modalities results in multisensory integration, which improves sensorimotor coordination but not inter-manual coordination. Both results suggest that there is dissociation between processes underlying sensorimotor synchronization (anticipation or reactivity) and processes underlying inter-manual coordination (motor control). This finding opens new perspectives to evaluate separately the possible sensorimotor and inter-manual coordination deficits present in movement disorders.

Motor Adaptation Deficits in Children with Developmental Coordination Disorder and/or Reading Disorder.

Procedural learning has been mainly tested through motor sequence learning tasks in children with neurodevelopmental disorders, especially with isolated Developmental Coordination Disorder (DCD) and Reading Disorder (RD). Studies on motor adaptation are scarcer and more controversial. This study aimed to compare the performance of children with isolated and associated DCD and RD in a graphomotor adaptation task. In total, 23 children with RD, 16 children with DCD, 19 children with DCD-RD, and 21 typically developing (TD) children wrote trigrams both in the conventional (from left to right) and opposite (from right to left) writing directions. The results show that movement speed and accuracy were more impacted by the adaptation condition (opposite writing direction) in children with neurodevelopmental disorders than TD children. Our results also reveal that children with RD have less difficulty adapting their movement than children with DCD. Children with DCD-RD had the most difficulty, and analysis of their performance suggests a cumulative effect of the two neurodevelopmental disorders in motor adaptation.

The long-term impact of irradiation on functional connectivity in brain circuits involved in memory processes after pediatric posterior fossa tumor.

PURPOSE: Memory is one of the main specific cognitive domains impaired with attention and processing speed after a pediatric brain tumor. This work explored the long-term impact of radiotherapy in children with posterior fossa tumor (PFT) on brain connectivity in neural circuits involved in memory using resting-state functional magnetic resonance imaging (rs-fMRI). METHODS: A total of 20 irradiated and 15 non-irradiated PFT survivors, and 21 healthy controls, prospectively included in the IMPALA study (NCT04324450), performed memory tests assessing episodic, procedural, and working memories and were subjected to an rs-fMRI. We manually contoured main structures involved in memory to explore connectivity at rest in a seed-to-voxel analysis. The groups were compared and differences in connectivity were correlated with behavioral scores and irradiation doses. RESULTS: The performance of all mnesic tasks was lower in PFT survivors with a greater alteration in working and episodic memory in irradiated patients. Irradiated survivors had atypical connectivities in all memory circuits compared to controls and in cortico-caudate and cortico-cerebellar circuits compared to non-irradiated survivors. Non-irradiated survivors had only atypical connectivities in the cortico-cerebellar circuits compared to controls. In irradiated survivors, atypical connectivities in cortico-hippocampal circuits were linked with episodic memory scores and dose of irradiation to the left hippocampus and in cortico-striatal circuits with procedural memory scores and dose of irradiation to the striatum. CONCLUSION: The results of this study highlight that irradiation has a long-term impact on brain connectivity in brain circuits involved in memory after pediatric PFT with a specific radiation-dose effect in supratentorial structures.

Which factors modulate spontaneous motor tempo? A systematic review of the literature.

Intentionally or not, humans produce rhythmic behaviors (e.g., walking, speaking, and clapping). In 1974, Paul Fraisse defined rhythmic behavior as a periodic movement that obeys a temporal program specific to the subject and that depends less on the conditions of the action (p. 47). Among spontaneous rhythms, the spontaneous motor tempo (SMT) corresponds to the tempo at which someone produces movements in the absence of external stimuli, at the most regular, natural, and pleasant rhythm for him/her. However, intra- and inter-individual differences exist in the SMT values. Even if several factors have been suggested to influence the SMT (e.g., the age of participants), we do not yet know which factors actually modulate the value of the SMT. In this context, the objectives of the present systematic review are (1) to characterize the range of SMT values found in the literature in healthy human adults and (2) to identify all the factors modulating the SMT values in humans. Our results highlight that (1) the reference value of SMT is far from being a common value of 600 ms in healthy human adults, but a range of SMT values exists, and (2) many factors modulate the SMT values. We discuss our results in terms of intrinsic factors (in relation to personal characteristics) and extrinsic factors (in relation to environmental characteristics). Recommendations are proposed to assess the SMT in future research and in rehabilitative, educative, and sport interventions involving rhythmic behaviors.

A preliminary study of the different memory systems in neurofibromatosis type 1: What is impaired and what is spared?

BACKGROUND: Since 1990's, the cognitive profile of children with a neurofibromatosis type 1 (NF1) has been refined by many different studies. Children with NF1 may exhibit a variety of cognitive dysfunctions. Memory difficulties have been reported, but the results are contradictory and, compared to other cognitive functions, memory has been less evaluated. OBJECTIVE: The aim of this study was to investigate the memory profile in NF1 with a particular population, children with NF1 without attention deficit hyperactivity disorder (ADHD). METHODS: Eighteen children with NF1 without ADHD and eighteen typically developing aged from 8 to 12.6 years were compared in terms of both their verbal and visual working memory, anterograde memory, and procedural perceptual-motor memory. We also assessed semantic and autobiographical memory. RESULTS: Our results indicate the existence of memory difficulties in children with NF1 without ADHD in verbal working and anterograde memory but not in terms of the visual domain. They also experienced difficulties recalling personal memories but these were improved by cueing. However, semantic memory and procedural perceptual-motor memory was preserved. CONCLUSIONS: These results highlight a difference between memory systems in children with NF1 without ADHD and the importance to assess the different memory systems, the nature of information and the processes in long-term memory in NF1 population. However, our results raise questions about the possible links between these difficulties and the executive functions. The specifics of memory profile in children with NF1 must be taken into consideration in these children's clinical follow-up, in order to understand their learning difficulties and to make adaptations to their care.

Impact of a pediatric posterior fossa tumor and its treatments on motor procedural learning.

INTRODUCTION: Posterior fossa tumor (PFT) survivors have difficulty learning new skills. Procedural memory is a skill learning system that allows, through training, the automatization of procedures and progressive improvement of performance. It underlies most of the motor procedures in everyday life that we perform automatically, such as riding a bike or writing. Motor procedural memory is divided into two components: motor sequence learning involving mainly cortico-striatal networks, and motor adaptation involving mainly cortico-cerebellar networks. The aim of this work was to explore the impact of a tumor and its treatment during childhood on procedural learning hypothesizing that sequence learning would be impaired in PFT survivors who have been treated with radiotherapy, whereas motor adaptation would be impaired in all PFT survivors. METHOD: 22 irradiated survivors of PFT, 17 non-irradiated survivors and 21 healthy controls from the IMPALA study (NCT04324450) performed a motor sequence learning task and a motor adaptation task. Doses received by striatal and cerebellar structures were reported from the initial dosimetry plans. RESULTS: Sequence learning was preserved in both tumor groups, but at the individual level 7/22 irradiated, and 4/17 non-irradiated participants failed to learn the motor sequence. Motor adaptation was impaired in both tumor groups, predominantly in the irradiated group. CONCLUSION: This study sheds new light on the long-term impact of PFT treatments in childhood on a rarely-studied part of memory, which is perceptual-motor procedural learning. Our results suggest that the cerebellum and striatum could be considered as organs at risk with regard to procedural learning.

Brain responses to handwritten and printed letters differentially depend on the activation state of the primary motor cortex.

Previous studies demonstrated that visual perception of handwritten letters activates the left primary motor cortex more strongly than printed letters. Here, we used EEG to record cortical responses evoked by single letters to directly test if their visual processing is actually influenced by their motor content. We manipulated the "motor familiarity" of letters that we considered high for letters written by the observers themselves, medium for letters written by other individuals, and low for printed, machine designed letters. In order to relate the effects of motor familiarity to the activation of the primary motor cortex, we also directly manipulated its availability during the visual task: we computed Event-Related Potentials (ERPs) over the posterior cortex during a dual task where participants had to observe the letters while performing unrelated self-paced brief movements of the right hand approximately every 5s (allowing the primary motor cortex to successively activate and "idle"). At 300-350 ms and 500-600 ms after stimulus onset, the amplitude of the ERP components markedly reflected the level of motor familiarity of the observed letter. Nonetheless, this was true only when the primary motor cortex was in an "idling" state: when the motor cortex was in an activation state, this motor familiarity effect was dropped. This clearly indicates that, at these latencies, the motor information embedded in letters is processed in the brain and that this processing depends on the activation state of the left primary motor cortex.

Increased intensity of unintended mirror muscle contractions after cervical spinal cord injury is associated with changes in interhemispheric and corticomuscular coherences.

Mirror contractions refer to unintended contractions of the contralateral homologous muscles during voluntary unilateral contractions or movements. Exaggerated mirror contractions have been found in several neurological diseases and indicate dysfunction or lesion of the cortico-spinal pathway. The present study investigates mirror contractions and the associated interhemispheric and corticomuscular interactions in adults with spinal cord injury (SCI) - who present a lesion of the cortico-spinal tract - compared to able-bodied participants (AB). Eight right-handed adults with chronic cervical SCI and ten age-matched right-handed able-bodied volunteers performed sets of right elbow extensions at 20% of maximal voluntary contraction. Electromyographic activity (EMG) of the right and left elbow extensors, interhemispheric coherence over cerebral sensorimotor regions evaluated by electroencephalography (EEG) and corticomuscular coherence between signals over the cerebral sensorimotor regions and each extensor were quantified. Overall, results revealed that participants with SCI exhibited (1) increased EMG activity of both active and unintended active limbs, suggesting more mirror contractions, (2) reduced corticomuscular coherence between signals over the left sensorimotor region and the right active limb and increased corticomuscular coherence between the right sensorimotor region and the left unintended active limb, (3) decreased interhemispheric coherence between signals over the two sensorimotor regions. The increased corticomuscular communication and decreased interhemispheric communication may reflect a reduced inhibition leading to increased communication with the unintended active limb, possibly resulting to exacerbated mirror contractions in SCI. Finally, mirror contractions could represent changes of neural and neuromuscular communication after SCI.

Atypical connectivity in the cortico-striatal network in NF1 children and its relationship with procedural perceptual-motor learning and motor skills.

INTRODUCTION: Neurofibromatosis type 1 (NF1) is considered a model of neurodevelopmental disorder because of the high frequency of learning deficits, especially developmental coordination disorder. In neurodevelopmental disorder, Nicolson and Fawcett formulated the hypothesis of an impaired procedural learning system that has its origins in cortico-subcortical circuits. Our aim was to investigate the relationship between cortico-striatal connectivity and procedural perceptual-motor learning performance and motor skills in NF1 children. METHODS: Seventeen NF1 and 18 typically developing children aged between 8 and 12 years old participated in the study. All were right-handed and did not present intellectual or attention deficits. In all children, procedural perceptual-motor learning was assessed using a bimanual visuo-spatial serial reaction time task (SRTT) and motor skills using the Movement Assessment Battery for Children (M-ABC). All participants underwent a resting-state functional MRI session. We used a seed-based approach to explore cortico-striatal connectivity in somatomotor and frontoparietal networks. A comparison between the groups' striato-cortical connectivity and correlations between connectivity and learning (SRTT) and motor skills (M-ABC) were performed. RESULTS: At the behavioral level, SRTT scores are not significantly different in NF1 children compared to controls. However, M-ABC scores are significantly impaired within 9 patients (scores below the 15th percentile). At the cerebral level, NF1 children present a higher connectivity in the cortico-striatal regions mapping onto the right angular gyrus compared to controls. We found that the higher the connectivity values between these regions, differentiating NF1 and controls, the lower the M-ABC scores in the whole sample. No correlation was found for the SRTT scores. CONCLUSION: NF1 children present atypical hyperconnectivity in cortico-striatal connections. The relationship with motor skills could suggest a sensorimotor dysfunction already found in children with developmental coordination disorder. These abnormalities are not linked to procedural perceptual-motor learning assessed by SRTT.

Visual-processing deficits in children with neurofibromatosis type 1: A clinical marker of reading difficulties.

Today's estimates indicate that nearly 50% of children with Neurofibromatosis type 1 (NF1) suffer from reading disabilities, with a high impact on their academic achievement. In addition to the well-documented importance of phonological skills in reading acquisition and neurodevelopmental disorders, visual-attention processes also appear as important factors in learning to read. The present study aimed at assessing the role of visual-processing dysfunction in the high prevalence of reading disabilities in NF1 children and providing a useful tool for clinician in the early detection of reading impairment in this neurogenetic disorder. Forty-two children with NF1 and 42 typically developing children (TD) participated in the study. All were right-handed and did not present intellectual disability or attention deficit hyperactivity disorder. Visual-attention processes were assessed with the Developmental Eye Movement (DEM) test, together with the NF1 children's reading level. NF1 children with and without reading disabilities were then compared. The results showed that visual-processing deficits were highly present among the NF1 children included in our study. Furthermore, poor readers with NF1 presented an increased risk of visual-processing deficits compared to peers. This finding supports the role of visual-processing deficits in the reading difficulties encountered in nearly half of children with NF1. Finally, in NF1 children without intellectual or attention disability, visual-processing deficits emerge as one of the clinical markers of reading disabilities. The study holds important clinical implications both for the identification, by providing a useful screening tool, and the management of reading disabilities in NF1 children.

A prospective behavioral and imaging study exploring the impact on long-term memory of radiotherapy delivered for a brain tumor in childhood and adolescence.

BACKGROUND: Posterior fossa tumors represent two thirds of brain tumors in children. Although progress in treatment has improved survival rates over the past few years, long-term memory impairments in survivors are frequent and have an impact on academic achievement. The hippocampi, cerebellum and cerebellar-cortical networks play a role in several memory systems. They are affected not only by the location of the tumor itself and its surgical removal, but also by the supratentorial effects of complementary treatments, particularly radiotherapy. The IMPALA study will investigate the impact of irradiation doses on brain structures involved in memory, especially the hippocampi and cerebellum. METHODS/DESIGN: In this single-center prospective behavioral and neuro-imaging study, 90 participants will be enrolled in three groups. The first two groups will include patients who underwent surgery for a posterior fossa brain tumor in childhood, who are considered to be cured, and who completed treatment at least 5 years earlier, either with radiotherapy (aggressive brain tumor; Group 1) or without (low-grade brain tumor; Group 2). Group 3 will include control participants matched with Group 1 for age, sex, and handedness. All participants will perform an extensive battery of neuropsychological tests, including an assessment of the main memory systems, and undergo multimodal 3 T MRI. The irradiation dose to the different brain structures involved in memory will be collected from the initial radiotherapy dosimetry. DISCUSSION: This study will provide long-term neuropsychological data about four different memory systems (working memory, episodic memory, semantic memory, and procedural memory) and the cognitive functions (attention, language, executive functions) that can interfere with them, in order to better characterize memory deficits among the survivors of brain tumors. We will investigate the correlations between neuropsychological and neuroimaging data on the structural (3DT1), microstructural (DTI), functional (rs-fMRI), vascular (ASL) and metabolic (spectroscopy) impact of the tumor and irradiation dose. This study will thus inform the setting of dose constraints to spare regions linked to the development of cognitive and memory functions. TRIAL REGISTRATION: ClinicalTrials.gov: NCT04324450, registered March 27, 2020, updated January 25th, 2021. Retrospectively registered, https://www.clinicaltrials.gov/ct2/show/NCT04324450.

Behavioural and cerebral asymmetries of mirror movements are specific to rhythmic task and related to higher attentional and executive control.

Mirror movements (MM) refer to the involuntary movements or contractions occurring in homologous muscles contralateral to the unilateral voluntary movements. This behavioural manifestation increases in elderly. In right-handed adults, some studies report asymmetry in MM production, with greater MM in the right dominant hand during voluntary movements of the left non-dominant hand than the opposite. However, other studies report contradictory results, suggesting that MM asymmetry could depend on the characteristics of the task. The present study investigates the behavioural asymmetry of MM and its associated cerebral correlates during a rhythmic task and a non-rhythmic task using low-force contractions (i.e., 25 % MVC). We determined the quantity and the intensity of MM using electromyography (EMG) and cerebral correlates through electroencephalography (EEG) in right-handed healthy young and middle-aged adults during unimanual rhythmic vs. non-rhythmic tasks. Overall, results revealed (1) behavioural asymmetry of MM specific to the rhythmic task and irrespective of age, (2) cerebral asymmetry of motor activations specific to the rhythmic task and irrespective of age and (3) greater attentional and executive activations in the rhythmic task compared to the non-rhythmic task. In line with our hypotheses, behavioural and cerebral motor asymmetries of MM seem to be specific to the rhythmic task. Results are discussed in terms of cognitive-motor interactions: greater attentional and executive control required in the rhythmic tasks could contribute to the increased occurrence of involuntary movements in both young and middle-aged adults.