Figure - available from: Brain Topography
This content is subject to copyright. Terms and conditions apply.
Cortical and cerebellar activations related to the contrasts Exe Mouth Goal > Move (A, A1), Exe Hand Goal > Move (B, B1), Exe Foot Goal > Move (C, C1). Whole-brain statistical parametric maps are rendered on a 3D MNI ch2 brain template (MRIcron software; https://www.nitrc.org/projects/mricron). Cerebellar activations are shown on a flat map of the cerebellum (SUIT, http://www.diedrichsenlab.org). Statistical threshold set at p < 0.001 (FWE corrected at cluster level)
Source publication
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 p...
Citations
... In our study, we found hand-related activity in ipsilateral lobules V, VI, and VIIIa/b and foot-related activity in ipsilateral lobules I-IV and VIIIb (Figure 2). Similar results have been demonstrated by several motor (Grodd et al. 2001;Spencer et al. 2007;Stoodley 2012;Ashida et al. 2019;Errante et al. 2023;Reddy et al. 2024) and sensory (Bushara et al. 2001;Takanashi et al. 2003;Ashida et al. 2019) studies of the cerebellum. Of these studies, only two use a whole-brain field of view and report additional results in regions outside the cerebellum, and both reflect motor task designs that may additionally involve sensory feedback (Errante et al. 2023;Reddy et al. 2024). ...
... Similar results have been demonstrated by several motor (Grodd et al. 2001;Spencer et al. 2007;Stoodley 2012;Ashida et al. 2019;Errante et al. 2023;Reddy et al. 2024) and sensory (Bushara et al. 2001;Takanashi et al. 2003;Ashida et al. 2019) studies of the cerebellum. Of these studies, only two use a whole-brain field of view and report additional results in regions outside the cerebellum, and both reflect motor task designs that may additionally involve sensory feedback (Errante et al. 2023;Reddy et al. 2024). Our finding of contralateral activation (during the right-hand stimulus only) has also been previously . ...
Non-painful tactile sensory stimuli are processed in the cortex, subcortex, and brainstem. Recent functional magnetic resonance imaging (fMRI) studies have highlighted the value of whole-brain, systems-level investigation for examining pain processing. However, whole-brain fMRI studies are uncommon, in part due to challenges with signal to noise when studying the brainstem. Furthermore, the differentiation of small sensory brainstem structures such as the cuneate and gracile nuclei necessitates high resolution imaging. To address this gap in systems-level sensory investigation, we employed a whole-brain, multi-echo fMRI acquisition at 3T with multi-echo independent component analysis (ME-ICA) denoising and brainstem-specific modeling to enable detection of activation across the entire sensory system. In healthy participants, we examined patterns of activity in response to non-painful brushing of the right hand, left hand, and right foot, and found the expected lateralization, with distinct cortical and subcortical responses for upper and lower limb stimulation. At the brainstem level, we were able to differentiate the small, adjacent cuneate and gracile nuclei, corresponding to hand and foot stimulation respectively. Our findings demonstrate that simultaneous cortical, subcortical, and brainstem mapping at 3T could be a key tool to understand the sensory system in both healthy individuals and clinical cohorts with sensory deficits.
... [25][26][27][28] Interestingly, it has also been demonstrated the existence of "audio-visual" MNs, activated by the action sound in both monkeys 29 and humans. 30 In humans, also listening to action-related sentences (e.g., "grasp a glass") elicits a somatotopic activation of the premotor cortex. 31 On the basis of its properties, it has been hypothesized that the MNS plays a crucial role in imitation learning of new actions, 32 thus providing the theoretical framework for using AOT to support motor rehabilitation in patients with stroke, 33,34 Parkinson's disease, 35,36 aphasia, 37 and cerebral palsy. ...
... The activations found in healthy participants using the AV paradigm are consistent with those reported in previous studies on observation of mouth actions 24,27,56 and listening to action sound. 30 In particular, in the present study, goal-related actions activated bilaterally low-level visual and auditory areas in the occipito-temporal cortex, plus other sectors of the premotor and parietal cortex. AV intransitive actions activated a brain pattern similar to that described for goal-related actions, except the parietal cortex. ...
In the past two decades several attempts have been made to promote a correct diagnosis and possible restorative interventions in patients suffering from Disorders of Consciousness (DOC). Sensory stimulation has been proved to be useful in sustaining the level of arousal/awareness and to improve behavioral responsiveness with a significant effect on oro-motor functions. Recently, action observation has been proposed as a stimulation strategy in DOC patients, 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 DOC (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, 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, brain activations of patients were compared with that of a group of healthy individuals (7 males, 8 females; median age: 33.4 years; age range: 24-65 years) preforming the same tasks. The results show that brain activations were lower in DOC patients compared with controls, except for primary auditory areas. During the audiovisual task, 5 out of 15 DOC patients showed only residual activation of low-level visual and auditory areas. Activation of high-level parieto-premotor areas was present in 6 patients. During the listening task, 3 patients showed only low-level activations, and 6 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 (BOLD) 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 patient’s functional level. These findings support the use of action observation and listening as possible stimulation strategies in DOC patients 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.
... AO and MI are motor-cognitive mechanisms that share substrates with movement execution, relying on the process of movement preparation and involving the premotor cortex (ventral and dorsal), supplementary motor area (SMA), pre-SMA, inferior frontal gyrus (IFG), superior and inferior parietal lobule (SPL and IPL), intraparietal area, and the primary motor cortex (M1) [10,11,14,15]. Recent fMRI studies in humans, have provided supportive evidence for the involvement of cortical-cerebellar and cortico-striatal (e.g., striatum, SNT) networks, like motor execution [16,17]. This suggests the possible contribution of the cerebellum and basal ganglia to an extended mirror neuron system [11]. ...
Action observation (AO) and motor imagery (MI) has emerged as promising tool for physiotherapy intervention in Parkinson’s disease (PD). This narrative review summarizes why, how, and when applying AO and MI training in individual with PD. We report the neural underpinning of AO and MI and their effects on motor learning. We examine the characteristics and the current evidence regarding the effectiveness of physiotherapy interventions and we provide suggestions about their implementation with technologies. Neurophysiological data suggest a substantial correct activation of brain networks underlying AO and MI in people with PD, although the occurrence of compensatory mechanisms has been documented. Regarding the efficacy of training, in general evidence indicates that both these techniques improve mobility and functional activities in PD. However, these findings should be interpreted with caution due to variety of the study designs, training characteristics, and the modalities in which AO and MI were applied. Finally, results on long-term effects are still uncertain. Several elements should be considered to optimize the use of AO and MI in clinical setting, such as the selection of the task, the imagery or the video perspectives, the modalities of training. However, a comprehensive individual assessment, including motor and cognitive abilities, is essential to select which between AO and MI suite the best to each PD patients. Much unrealized potential exists for the use AO and MI training to provide personalized intervention aimed at fostering motor learning in both the clinic and home setting.
Motor-task functional magnetic resonance imaging (fMRI) is crucial in the study of several clinical conditions, including stroke and Parkinson’s disease. However, motor-task fMRI is complicated by task-correlated head motion, which can be magnified in clinical populations and confounds motor activation results. One method that may mitigate this issue is multi-echo independent component analysis (ME-ICA), which has been shown to separate the effects of head motion from the desired BOLD signal but has not been tested in motor-task datasets with high amounts of motion. In this study, we collected an fMRI dataset from a healthy population who performed a hand grasp task with and without task-correlated amplified head motion to simulate a motor-impaired population. We analyzed these data using three models: single-echo (SE), multi-echo optimally combined (ME-OC), and ME-ICA. We compared the models’ performance in mitigating the effects of head motion on the subject level and group level. On the subject level, ME-ICA better dissociated the effects of head motion from the BOLD signal and reduced noise. Both ME models led to increased t-statistics in brain motor regions. In scans with high levels of motion, ME-ICA additionally mitigated artifacts and increased stability of beta coefficient estimates, compared to SE. On the group level, all three models produced activation clusters in expected motor areas in scans with both low and high motion, indicating that group-level averaging may also sufficiently resolve motion artifacts that vary by subject. These findings demonstrate that ME-ICA is a useful tool for subject-level analysis of motor-task data with high levels of task-correlated head motion. The improvements afforded by ME-ICA are critical to improve reliability of subject-level activation maps for clinical populations in which group-level analysis may not be feasible or appropriate, for example in a chronic stroke cohort with varying stroke location and degree of tissue damage.
