The importance of observing the master's hand: Action Observation Training promotes the acquisition of new musical skills.

Introduction: Via mirror mechanism, motor training approaches based on the alternation of action observation and execution (i.e., Action Observation Training-AOT) promote the acquisition of motor abilities. Previous studies showed that both visual and auditory stimuli may elicit a common motor representation of music-related gestures; however, the potentialities of AOT for the acquisition of musical skills are still underexplored. Methods: Twenty-one music-naïve participants underwent two blocks of training: AOT and Key-light Observation Training (KOT). AOT consisted of the observation of a melodic sequence played on a keyboard with the right hand by an expert model, followed by participant's imitation. Observation and execution were repeated six consecutive times (T1-T6). KOT followed the same procedure, except for the visual content of the stimulus, depicting the sequential highlighting of the piano keys corresponding to the melody. The rate of correct notes (C), the trainee-model similarity of key-pressure strength (S), and the trainee-model consistency of note duration (R) were collected across T1-T6. Results: Both AOT and KOT improved musical performance. Noteworthy, AOT showed a higher learning magnitude relative to KOT in terms of C and S. Discussion: Action Observation Training promotes the acquisition of key elements of melodic sequences, encompassing not only the accurate sequencing of notes but also their expressive characteristics, such as key-pressure dynamics. The convergence of listening and observation of actions onto a shared motor representation not only explains several pedagogical approaches applied in all musical cultures worldwide, but also enhances the potential efficacy of current procedures for music training.

Effectiveness of action observation treatment based on pathological model in hemiplegic children: a randomized-controlled trial.

BACKGROUND: Action observation treatment (AOT) is an innovative therapeutic approach consisting in the observation of actions followed by their subsequent repetition. The standard version of AOT consists in the observation/imitation of a typically developed individual, which is proposed as model (TDM-AOT). AIM: This study aims to compare the effectiveness of AOT based on a pathological ameliorative model (PAM-AOT) versus TDM-AOT in improving upper limb ability in children with unilateral cerebral palsy (UCP). DESIGN: The study consists in a prospective randomized controlled, evaluator-blinded trial (RCT), with two active arms, designed to evaluate the effectiveness of AOT based on pathological model (PAM-AOT) as compared to a standard AOT based on TDM (TDM-AOT). SETTING: The 3-week AOT program was administered in a clinical setting. For some patients, the treatment was delivered at participant's home with the remote support of the physiotherapist (tele-rehabilitation). POPULATION: Twenty-six children with UCP (mean age 10.5±3.09 years; 14 females) participated in the study, with the experimental group observing a pathological model and the control group observing a typically developed model. METHODS: Motor assessments included unimanual and bimanual ability measures conducted at T0 (baseline, before the treatment), T1 (3 weeks after T0), T2 (8-12 weeks after treatment) and T3 (24-28 weeks after treatment); a subset of 16 patients also underwent fMRI motor assessment. Generalized Estimating Equations models were used for statistical analysis. RESULTS: Both groups showed significant improvement in bimanual function (GEE, Wald 106.16; P<0.001) at T1 (P<0.001), T2 (P<0.001), and T3 (P<0.001). Noteworthy, the experimental group showed greater improvement than the control group immediately after treatment (P<0.013). Both groups exhibited similar improvement in unimanual ability (GEE, Wald 25.49; P<0.001). The fMRI assessments revealed increased activation of ventral premotor cortex after treatment in the experimental compared with control group (GEE, Wald 6.26; P<0.012). CONCLUSIONS: Overall, this study highlights the effectiveness of PAM-AOT in achieving short-term improvement of upper limb ability in children with UCP. CLINICAL REHABILITATION IMPACT: These findings have significant implications for rehabilitative interventions based on AOT in hemiplegic children, by proposing a non-traditional approach focused on the most functional improvement achievable by imitating a pathological model.

Brain activation during processing of mouth actions in patients with disorders of consciousness.

In the past 2 decades, several attempts have been made to promote a correct diagnosis and possible restorative interventions in patients suffering from disorders of consciousness. Sensory stimulation has been proved to be useful in sustaining the level of arousal/awareness and to improve behavioural responsiveness with a significant effect on oro-motor functions. Recently, action observation has been proposed as a stimulation strategy in patients with disorders of consciousness, based on neurophysiological evidence that the motor cortex can be activated not only during action execution but also when actions are merely observed in the absence of motor output, or during listening to action sounds and speech. This mechanism is provided by the activity of mirror neurons. In the present study, a group of patients with disorders of consciousness (11 males, 4 females; median age: 55 years; age range: 19-74 years) underwent task-based functional MRI in which they had, in one condition, to observe and listen to the sound of mouth actions, and in another condition, to listen to verbs with motor or abstract content. In order to verify the presence of residual activation of the mirror neuron system, the brain activations of patients were compared with that of a group of healthy individuals (seven males, eight females; median age: 33.4 years; age range: 24-65 years) performing the same tasks. The results show that brain activations were lower in patients with disorders of consciousness compared with controls, except for primary auditory areas. During the audiovisual task, 5 out of 15 patients with disorders of consciousness showed only residual activation of low-level visual and auditory areas. Activation of high-level parieto-premotor areas was present in six patients. During the listening task, three patients showed only low-level activations, and six patients activated also high-level areas. Interestingly, in both tasks, one patient with a clinical diagnosis of vegetative state showed activations of high-level areas. Region of interest analysis on blood oxygen level dependent signal change in temporal, parietal and premotor cortex revealed a significant linear relation with the level of clinical functioning, assessed with coma recovery scale-revised. We propose a classification of the patient's response based on the presence of low-level and high-level activations, combined with the patient's functional level. These findings support the use of action observation and listening as possible stimulation strategies in patients with disorders of consciousness and highlight the relevance of combined methods based on functional assessment and brain imaging to provide more detailed neuroanatomical specificity about residual activated areas at both cortical and subcortical levels.

Lesion mapping and functional characterization of hemiplegic children with different patterns of hand manipulation.

Brain damage in children with unilateral cerebral palsy (UCP) affects motor function, with varying severity, making it difficult the performance of daily actions. Recently, qualitative and semi-quantitative methods have been developed for lesion classification, but studies on mild to moderate hand impairment are lacking. The present study aimed to characterize lesion topography and preserved brain areas in UCP children with specific patterns of hand manipulation. A homogeneous sample of 16 UCP children, aged 9 to 14 years, was enrolled in the study. Motor assessment included the characterization of the specific pattern of hand manipulation, by means of unimanual and bimanual measures (Kinematic Hand Classification, KHC; Manual Ability Classification System, MACS; House Functional Classification System, HFCS; Melbourne Unilateral Upper Limb Assessment, MUUL; Assisting Hand Assessment, AHA). The MRI morphological study included multiple methods: (a) qualitative lesion classification, (b) semi-quantitative classification (sq-MRI), (c) voxel-based morphometry comparing UCP and typically developed children (VBM-DARTEL), and (d) quantitative brain tissue segmentation (q-BTS). In addition, functional MRI was used to assess spared functional activations and cluster lateralization in the ipsilesional and contralesional hemispheres of UCP children during the execution of simple movements and grasping actions with the more affected hand. Lesions most frequently involved the periventricular white matter, corpus callosum, posterior limb of the internal capsule, thalamus, basal ganglia and brainstem. VMB-DARTEL analysis allowed to detect mainly white matter lesions. Both sq-MRI classification and q-BTS identified lesions of thalamus, brainstem, and basal ganglia. In particular, UCP patients with synergic hand pattern showed larger involvement of subcortical structures, as compared to those with semi-functional hand. Furthermore, sparing of gray matter in basal ganglia and thalamus was positively correlated with MUUL and AHA scores. Concerning white matter, q-BTS revealed a larger damage of fronto-striatal connections in patients with synergic hand, as compared to those with semi-functional hand. The volume of these connections was correlated to unimanual function (MUUL score). The fMRI results showed that all patients, but one, including those with cortical lesions, had activation in ipsilesional areas, regardless of lesion timing. Children with synergic hand showed more lateralized activation in the ipsilesional hemisphere both during grasping and simple movements, while children with semi-functional hand exhibited more bilateral activation during grasping. The study demonstrates that lesion localization, rather than lesion type based on the timing of their occurrence, is more associated with the functional level of hand manipulation. Overall, the preservation of subcortical structures and white matter can predict a better functional outcome. Future studies integrating different techniques (structural and functional imaging, TMS) could provide further evidence on the relation between brain reorganization and specific pattern of manipulation in UCP children.

Ventrolateral prefrontal neurons of the monkey encode instructions in the 'pragmatic' format of the associated behavioral outcomes.

The prefrontal cortex plays an important role in coding rules and producing context-appropriate behaviors. These processes necessarily require the generation of goals based on current context. Indeed, instructing stimuli are prospectively encoded in prefrontal cortex in relation to behavioral demands, but the coding format of this neural representation is, to date, largely unknown. In order to study how instructions and behaviors are encoded in prefrontal cortex, we recorded the activity of monkeys (Macaca mulatta) ventrolateral prefrontal neurons in a task requiring to perform (Action condition) or withhold (Inaction condition) grasping actions on real objects. Our data show that there are neurons responding in different task phases, and that the neuronal population discharge is stronger in the Inaction condition when the instructing cue is presented, and in the Action condition in the subsequent phases, from object presentation to action execution. Decoding analyses performed on neuronal populations showed that the neural activity recorded during the initial phases of the task shares the same type of format with that recorded during the final phases. We propose that this format has a pragmatic nature, that is instructions and goals are encoded by prefrontal neurons as predictions of the behavioral outcome.

Activation of Cerebellum, Basal Ganglia and Thalamus During Observation and Execution of Mouth, hand, and foot Actions.

Humans and monkey studies showed that specific sectors of cerebellum and basal ganglia activate not only during execution but also during observation of hand actions. However, it is unknown whether, and how, these structures are engaged during the observation of actions performed by effectors different from the hand. To address this issue, in the present fMRI study, healthy human participants were required to execute or to observe grasping acts performed with different effectors, namely mouth, hand, and foot. As control, participants executed and observed simple movements performed with the same effectors. The results show that: (1) execution of goal-directed actions elicited somatotopically organized activations not only in the cerebral cortex but also in the cerebellum, basal ganglia, and thalamus; (2) action observation evoked cortical, cerebellar and subcortical activations, lacking a clear somatotopic organization; (3) in the territories displaying shared activations between execution and observation, a rough somatotopy could be revealed in both cortical, cerebellar and subcortical structures. The present study confirms previous findings that action observation, beyond the cerebral cortex, also activates specific sectors of cerebellum and subcortical structures and it shows, for the first time, that these latter are engaged not only during hand actions observation but also during the observation of mouth and foot actions. We suggest that each of the activated structures processes specific aspects of the observed action, such as performing internal simulation (cerebellum) or recruiting/inhibiting the overt execution of the observed action (basal ganglia and sensory-motor thalamus).

Fast-Spiking Interneurons of the Premotor Cortex Contribute to Initiation and Execution of Spontaneous Actions.

Planning and execution of voluntary movement depend on the contribution of distinct classes of neurons in primary motor and premotor areas. However, timing and pattern of activation of GABAergic cells during specific motor behaviors remain only partly understood. Here, we directly compared the response properties of putative pyramidal neurons (PNs) and GABAergic fast-spiking neurons (FSNs) during spontaneous licking and forelimb movements in male mice. Recordings centered on the face/mouth motor field of the anterolateral motor cortex (ALM) revealed that FSNs fire longer than PNs and earlier for licking, but not for forelimb movements. Computational analysis revealed that FSNs carry vastly more information than PNs about the onset of movement. While PNs differently modulate their discharge during distinct motor acts, most FSNs respond with a stereotyped increase in firing rate. Accordingly, the informational redundancy was greater among FSNs than PNs. Finally, optogenetic silencing of a subset of FSNs reduced spontaneous licking movement. These data suggest that a global rise of inhibition contributes to the initiation and execution of spontaneous motor actions.SIGNIFICANCE STATEMENT Our study contributes to clarifying the causal role of fast-spiking neurons (FSNs) in driving initiation and execution of specific, spontaneous movements. Within the face/mouth motor field of mice premotor cortex, FSNs fire before pyramidal neurons (PNs) with a specific activation pattern: they reach their peak of activity earlier than PNs during the initiation of licking, but not of forelimb, movements; duration of FSNs activity is also greater and exhibits less selectivity for the movement type, as compared with that of PNs. Accordingly, FSNs appear to carry more redundant information than PNs. Optogenetic silencing of FSNs reduced spontaneous licking movement, suggesting that FSNs contribute to the initiation and execution of specific spontaneous movements, possibly by sculpting response selectivity of nearby PNs.

Influence of sport expertise in facilitating and inhibiting the recognition of the opponent's intentions in sailing.

Starting from the proposed role of the mirror neuron system in the recognition of the intention underlying the actions of others, an experimental paradigm was implemented to test the role of sailing motor expertise in predicting the outcome of a competitor's action. It was hypothesized that subjects with experience in sailing would correctly interpret the maneuver performed due to the activation of domain specific motor representations of the same movements and that subjects who practiced a sport different from sailing would perform worse because of the activation of irrelevant motor patterns. For doing so, a series of video clips, in which a professional sailor performed a tack or a feint, have been manipulated so that the video clips would stop at the moment of the dunkin, namely, when the boat acquires speed to tack or continue straight ahead. The task consisted in predicting whether the action following the dunkin was an actual tack or a feint. The performance of 87 subjects, divided into three subgroups (sailors, tennis players, sedentary), was evaluated in terms of accuracy in identifying the sailor's intentions and correlated to age, gender, manual dominance, education, job, hours spent weekly playing videogames, and experience in playing sports. Results showed that the percentage of correct identifications of the intention to do a tack or feint was the highest in the group of sailors and the lowest in tennis players. An inverse relation between tennis experience and ability in recognizing the sailor's intention was found in the group of tennis players. Gender, age, manual dominance, education, job, and experience with videogames were not found to be correlated with performance. Findings support the possible implication of the mirror neuron system in maneuver detection in sailing and may be a starting point for the development of psychological training in this sport.

Decoding point-light displays and fully visible hand grasping actions within the action observation network.

Action observation typically recruits visual areas and dorsal and ventral sectors of the parietal and premotor cortex. This network has been collectively termed as extended action observation network (eAON). Within this network, the elaboration of kinematic aspects of biological motion is crucial. Previous studies investigated these aspects by presenting subjects with point-light displays (PLDs) videos of whole-body movements, showing the recruitment of some of the eAON areas. However, studies focused on cortical activation during observation of PLDs grasping actions are lacking. In the present functional magnetic resonance imaging (fMRI) study, we assessed the activation of eAON in healthy participants during the observation of both PLDs and fully visible hand grasping actions, excluding confounding effects due to low-level visual features, motion, and context. Results showed that the observation of PLDs grasping stimuli elicited a bilateral activation of the eAON. Region of interest analyses performed on visual and sensorimotor areas showed no significant differences in signal intensity between PLDs and fully visible experimental conditions, indicating that both conditions evoked a similar motor resonance mechanism. Multivoxel pattern analysis (MVPA) revealed significant decoding of PLDs and fully visible grasping observation conditions in occipital, parietal, and premotor areas belonging to eAON. Data show that kinematic features conveyed by PLDs stimuli are sufficient to elicit a complete action representation, suggesting that these features can be disentangled within the eAON from the features usually characterizing fully visible actions. PLDs stimuli could be useful in assessing which areas are recruited, when only kinematic cues are available, for action recognition, imitation, and motor learning.

Effectiveness of action observation therapy based on virtual reality technology in the motor rehabilitation of paretic stroke patients: a randomized clinical trial.

BACKGROUND: The rehabilitation of paretic stroke patients uses a wide range of intervention programs to improve the function of impaired upper limb. A new rehabilitative approach, called action observation therapy (AOT) is based on the discovery of mirror neurons and has been used to improve the motor functions of adult stroke patients and children with cerebral palsy. Recently, virtual reality (VR) has provided the potential to increase the frequency and effectiveness of rehabilitation treatment by offering challenging and motivating tasks.  METHODS: The purpose of the present project is to design a randomized controlled six-month follow-up trial (RCT) to evaluate whether action observation (AO) added to standard VR (AO + VR) is effective in improving upper limb function in patients with stroke, compared with a control treatment consisting of observation of naturalistic scenes (CO) without any action content, followed by VR training (CO + VR). DISCUSSION: AO + VR treatment may provide an addition to the rehabilitative interventions currently available for recovery after stroke and could be utilized within standard sensorimotor training or in individualized tele-rehabilitation. TRIAL REGISTRATION: The trial has been prospectively registered on ClinicalTrials.gov. NCT05163210 . 17 December 2021.

Structural connectivity associated with the sense of body ownership: a diffusion tensor imaging and disconnection study in patients with bodily awareness disorder.

The brain mechanisms underlying the emergence of a normal sense of body ownership can be investigated starting from pathological conditions in which body awareness is selectively impaired. Here, we focused on pathological embodiment, a body ownership disturbance observed in brain-damaged patients who misidentify other people's limbs as their own. We investigated whether such body ownership disturbance can be classified as a disconnection syndrome, using three different approaches based on diffusion tensor imaging: (i) reconstruction of disconnectome maps in a large sample (N = 70) of stroke patients with and without pathological embodiment; (ii) probabilistic tractography, performed on the age-matched healthy controls (N = 16), to trace cortical connections potentially interrupted in patients with pathological embodiment and spared in patients without this pathological condition; (iii) probabilistic 'in vivo' tractography on two patients without and one patient with pathological embodiment. The converging results revealed the arcuate fasciculus and the third branch of the superior longitudinal fasciculus as mainly involved fibre tracts in patients showing pathological embodiment, suggesting that this condition could be related to the disconnection between frontal, parietal and temporal areas. This evidence raises the possibility of a ventral self-body recognition route including regions where visual (computed in occipito-temporal areas) and sensorimotor (stored in premotor and parietal areas) body representations are integrated, giving rise to a normal sense of body ownership.

The Imitation Game in Children With Tourette Syndrome: A Lack of Impulse Control to Mirror Environmental Stimuli.

The learning process in humans requires continuous contacts with environmental stimuli, especially during neurodevelopmental growth. These functions are assisted by the coding potential of mirror neurons to serve social interactions. This ability to learn imitating the observed behavior is no longer necessary during adulthood, and control mechanisms prevent automatic mirroring. However, children with Gilles de la Tourette syndrome could encounter coding errors at the level of the mirror neurons system as these cortical regions are themselves the ones affected in the syndrome. Combined with impulsivity, the resulting sign would be a manifest echopraxia that persists throughout adulthood, averting these individuals from the appraisal of a spot-on motor control.

Decoding grip type and action goal during the observation of reaching-grasping actions: A multivariate fMRI study.

During execution and observation of reaching-grasping actions, the brain must encode, at the same time, the final action goal and the type of grip necessary to achieve it. Recently, it has been proposed that the Mirror Neuron System (MNS) is involved not only in coding the final goal of the observed action, but also the type of grip used to grasp the object. However, the specific contribution of the different areas of the MNS, at both cortical and subcortical level, in disentangling action goal and grip type is still unclear. Here, twenty human volunteers participated in an fMRI study in which they performed two tasks: (a) observation of four different types of actions, consisting in reaching-to-grasp a box handle with two possible grips (precision, hook) and two possible goals (open, close); (b) action execution, in which participants performed grasping actions similar to those presented during the observation task. A conjunction analysis revealed the presence of shared activated voxels for both action observation and execution within several cortical areas including dorsal and ventral premotor cortex, inferior and superior parietal cortex, intraparietal sulcus, primary somatosensory cortex, and cerebellar lobules VI and VIII. ROI analyses showed a main effect for grip type in several premotor and parietal areas and cerebellar lobule VI, with higher BOLD activation during observation of precision vs hook actions. A grip x goal interaction was also present in the left inferior parietal cortex, with higher BOLD activity during precision-to-close actions. A multivariate pattern analysis (MVPA) revealed a significant accuracy for the grip model in all ROIs, while for the action goal model, significant accuracy was observed only for left inferior parietal cortex ROI. These findings indicate that a large network involving cortical and cerebellar areas is involved in the processing of type of grip, while final action goal appears to be mainly processed within the inferior parietal region, suggesting a differential contribution of the areas activated in this study.

Visual response of ventrolateral prefrontal neurons and their behavior-related modulation.

The ventral part of lateral prefrontal cortex (VLPF) of the monkey receives strong visual input, mainly from inferotemporal cortex. It has been shown that VLPF neurons can show visual responses during paradigms requiring to associate arbitrary visual cues to behavioral reactions. Further studies showed that there are also VLPF neurons responding to the presentation of specific visual stimuli, such as objects and faces. However, it is largely unknown whether VLPF neurons respond and differentiate between stimuli belonging to different categories, also in absence of a specific requirement to actively categorize or to exploit these stimuli for choosing a given behavior. The first aim of the present study is to evaluate and map the responses of neurons of a large sector of VLPF to a wide set of visual stimuli when monkeys simply observe them. Recent studies showed that visual responses to objects are also present in VLPF neurons coding action execution, when they are the target of the action. Thus, the second aim of the present study is to compare the visual responses of VLPF neurons when the same objects are simply observed or when they become the target of a grasping action. Our results indicate that: (1) part of VLPF visually responsive neurons respond specifically to one stimulus or to a small set of stimuli, but there is no indication of a "passive" categorical coding; (2) VLPF neuronal visual responses to objects are often modulated by the task conditions in which the object is observed, with the strongest response when the object is target of an action. These data indicate that VLPF performs an early passive description of several types of visual stimuli, that can then be used for organizing and planning behavior. This could explain the modulation of visual response both in associative learning and in natural behavior.

Some evidence on Gerstmann's syndrome: A case study on a variant of the clinical disorder.

We describe the case of a bilingual patient with persistent symptoms largely, although not fully, consistent with those that are usually reported in Gerstmann's syndrome. Twenty months after a spontaneous primary intracranial hemorrhage, the patient was evaluated with a series of neuropsychological tasks and underwent an MRI investigation based on Diffusion Tensor Imaging probabilistic tractography. The patient suffered from dysgraphia (difficulty in the access to the graphemic representation of letter forms), autotopoagnosia (difficulties in locating body parts on verbal command), right-left confusion (difficulties in localizing right and left side of symmetrical body parts), and number processing/calculation impairments (predominant difficulties on transcoding tasks). Probabilistic tractography revealed a relatively spared superior longitudinal fasciculus and severe damage to the subcortical white matter connecting the angular gyrus with other parietal regions, such as the intraparietal sulcus and the supramarginal gyrus. Within the framework of the contemporary cognitive accounts of Gerstmann's syndrome, the case supports the assumption of an anatomical intraparietal disconnection more than a functional Grundstörung (core impairment).

Grasping and Manipulation: Neural Bases and Anatomical Circuitry in Humans.

Neurophysiological and neuroimaging evidence suggests a significant contribution of several brain areas, including subdivisions of the parietal and the premotor cortex, during the processing of different components of hand and arm movements. Many investigations improved our knowledge about the neural processes underlying the execution of reaching and grasping actions, while few studies have directly investigated object manipulation. Most studies on the latter topic concern the use of tools to achieve specific goals. Yet, there are very few studies on pure manipulation performed in order to explore and recognize objects, as well as on manipulation performed with a high level of manual dexterity. Another dimension that is quite neglected by the available studies on grasping and manipulation is, on the one hand, the contribution of the subcortical nodes, first of all the basal ganglia and cerebellum, to these functions, and, on the other hand, recurrent connections of these structures with cortical areas. In the first part, we have reviewed the parieto-premotor and subcortical circuits underlying reaching and grasping in humans, with a focus on functional neuroimaging data. Then, we have described the main structures recruited during object manipulation. We have also reported the contribution of recent structural connectivity techniques whereby the cortico-cortical and cortico-subcortical connections of grasping-related and manipulation-related areas in the human brain can be determined. Based on our review, we have concluded that studies on cortical and subcortical circuits involved in grasping and manipulation might be promising to provide new insights about motor learning and brain plasticity in patients with motor disorders.

Reorganization of action observation and sensory-motor networks after action observation therapy in children with congenital hemiplegia: A pilot study.

New rehabilitation programs based on action observation therapy (AOT) are effective in improving motor function in children with congenital hemiplegia. In this pilot study we tested the potential effects of AOT on the reorganization of the motor system by functional magnetic resonance imaging (fMRI). As part of a randomized trial, eight subjects (age range: 6.2-14.5 years) with congenital hemiplegia were randomly assigned to an experimental (EG) or control (CG) group. All children underwent a clinical and neurophysiological assessment with Assisting Hand Assessment (AHA), MRI, and fMRI at baseline (T0), 1(T1), and 8(T2) weeks after the end of 3-week treatment. For the EG, AOT consisted in the observation of uni/bimanual goal-directed actions followed by their execution. CG watched same-duration computer games and then performed the same actions in the same order used in the EG. fMRI study was carried out using two different paradigms, for exploring sensory-motor network (SMN) localization and action observation network (AON). The pattern of brain activation was generally similar between T0 and T1 for both groups, while it was more widespread at T2, compared to T0 and T1, in the EG. This enlargement was coupled with functional improvement at AHA. Single-subject analysis shows a reduction of lateralization indexes both for the AON and the SMN. This pilot study, despite the small sample, showed the fMRI feasibility for providing relevant biomarkers of brain plasticity for monitoring the AOT response in children with congenital hemiplegia. The study was registered at http://www.clinicaltrials.gov (identifier NCT01016496).

Activation of cerebellum and basal ganglia during the observation and execution of manipulative actions.

Studies on action observation mostly described the activation of a network of cortical areas, while less investigation focused specifically on the activation and role of subcortical nodes. In the present fMRI study, we investigated the recruitment of cerebellum and basal ganglia during the execution and observation of object manipulation performed with the right hand. The observation conditions consisted in: (a) observation of manipulative actions; (b) observation of sequences of random finger movements. In the execution conditions, participants had to perform the same actions or movements as in (a) and (b), respectively. The results of conjunction analysis showed significant shared activations during both observation and execution of manipulation in several subcortical structures, including: (1) cerebellar lobules V, VI, crus I, VIIIa and VIIIb (bilaterally); (2) globus pallidus, bilaterally, and left subthalamic nucleus; (3) red nucleus (bilaterally) and left thalamus. These findings support the hypothesis that the action observation/execution network also involves subcortical structures, such as cerebellum and basal ganglia, forming an integrated network. This suggests possible mechanisms, involving these subcortical structures, underlying learning of new motor skills, through action observation and imitation.

Explicit Motor Imagery for Grasping Actions in Children With Spastic Unilateral Cerebral Palsy.

Background: Motor Imagery (MI) refers to mental simulation of a motor action without producing any overt movement. Previous studies showed that children with Unilateral Cerebral Palsy (UCP) are impaired in implicit MI, as demonstrated by the performance of Hand Laterality Judgment tasks. The aim of this study was to examine the specificity of explicit MI deficits in UCP children. Methods: A group of UCP children (n = 10; aged 9-14) performed a mental chronometry task consisting in grasping an object and placing it into a container, or in imagining to perform the same action. As control, a group of typically developing (TD) children, matched by age, performed the same task. Movement durations for executed and imagined trials were recorded. A subgroup of 7 UCP children and 10 TD children also underwent a session of functional MRI to examine the activation of parieto-frontal areas typically associated to MI processes, during the imagination of reaching-grasping actions performed with the paretic hand. Results: Behavioral results revealed the existence of a correlation between executed and imagined movement durations both in TD and UCP groups. Moreover, the regression analysis in TD children showed that higher scores in mental chronometry tasks were positively correlated to increased bilateral activation of the intraparietal sulcus (IPS), superior parietal lobule (SPL), and dorsal premotor (PMd) cortex. A similar analysis revealed in the UCP group a positive correlation between a higher score in the mental chronometry task and bilateral activations of IPS, and to activation of contralesional, right PMd, and putamen during imagination of grasping movements. Conclusions: These results provide new insights on the relationship between MI capacity and motor deficits in UCP children, suggesting the possibility of the use of explicit MI training to improve patient's upper limb motor functions.