Sensorimotor Control Research Articles

A sensory neuroprosthesis enhances recovery from treadmill-induced stumbles for individuals with lower limb loss

Over 50% of individuals with lower limb loss report a fear of falling and avoiding daily activities partly due to a lack of plantar sensation. Providing direct somatosensory feedback via neural stimulation holds promise for addressing this issue. In this study, three individuals with lower limb loss received a sensory neuroprosthesis (SNP) that provided plantar somatosensory feedback corresponding to prosthesis-floor interactions perceived as arising from the missing foot generated by electrically activating the peripheral nerves in the residuum. Participants walked on a treadmill while receiving perturbations involving brief increases in the belt speed. Perturbations were initiated during early stance and randomly delivered to intact and prosthetic sides with the SNP active or inactive. With the SNP active, participants exhibited decreased trunk angular sway and peak trunk flexion angular velocity during recovery from both prosthetic and intact side perturbations. For prosthetic side perturbations, peak ground reaction force magnitudes decreased when the SNP was active. For intact side perturbations, peak ground reaction force magnitudes increased on the prosthetic side’s first recovery step after the perturbation, which resulted in a more symmetric recovery because the force approached the response on the intact side’s first recovery step following a prosthetic side perturbation. These results suggest participants integrated the feedback from the SNP into their sensorimotor control for maintaining stability and gained confidence in relying on their prosthetic limb during recovery. Restoring plantar sensation with a SNP for individuals with lower limb loss could lead to reduced risk of falling by improving recovery from trips.

Hypergravity is more challenging than microgravity for the human sensorimotor system

The importance of gravity for human motor control is well established, but it remains unclear how the central nervous system accounts for gravitational changes to perform complex motor skills. We tested the hypothesis that microgravity and hypergravity have distinct effects on the neuromuscular control of reaching movements compared to normogravity. To test the influence of gravity levels on sensorimotor planning and control, participants (n = 9) had to reach toward visual targets during parabolic flights. Whole-body kinematics and muscular activity were adjusted in microgravity, allowing arm reaching to be as accurate as in normogravity. However, we observed in hypergravity a systematic undershooting, which likely resulted from a lack of reorganization of muscle activations. While new studies are necessary to clarify whether hypergravity impairs the internal model of limb dynamics, our findings provide new evidence that hypergravity creates a challenge that the human sensorimotor system is unable to solve in the short term.

Cross-cutting effect of type 2 diabetes on the sensorimotor control of balance

Cross-cutting effect of type 2 diabetes on the sensorimotor control of balance

The Effectiveness of Cervical Sensorimotor Control Training for the Management of Chronic Neck Pain Disorders: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis aimed to evaluate the effectiveness of cervical sensorimotor control training for the management of chronic neck pain (NP) disorders compared to no treatment, or other conservative or non-conservative treatments. The review was conducted following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines (PROSPERO registration number: CRD42022381714). A comprehensive database search was performed (until November 2023) for randomized controlled trials (RCTs) and clinical trials evaluating the effects of cervical sensorimotor control training on several subjective and objective outcomes in adults with chronic NP (traumatic or non-traumatic origin). Data on study and patient characteristics, outcome measures, and effects on primary and secondary outcomes were extracted. Seven RCTs (409 participants) were included, of which 6 qualified for meta-analysis. Low-certainty evidence suggests that cervical sensorimotor control training is more effective for reducing pain (standardized mean difference (SMD): 0.48; 95% confidence interval (CI): 0.07 to 0.89) and improving cervicocephalic kinesthesia at short term than no treatment, and for reducing kinesiophobia at intermediate term compared to other treatment modalities. No significant between-group differences were found for other outcomes and follow-ups (very low-to-moderate-certainty evidence). Considering the significant improvements in cervicocephalic kinesthesia, cervical sensorimotor control training could be an important element in the rehabilitation of patients with chronic NP disorders. However, the current evidence in the literature is scarce to draw conclusions regarding its effectiveness as a stand-alone rehabilitation program.

Occlusal acuity and bite force in young adults.

Occlusal tactile acuity (OTA) and bite force are essential components of the sensorimotor control of oral behaviors. While these variables have been studied independently, it has not yet been revealed whether compressive force impacts the occlusal perception mediated by the mechanoreceptive afferents in the periodontal ligament. The present study examined the effect of repetition and maximum bite force on OTA by testing nine aluminum foils of different thicknesses together with a sham test with no foil, three times each, in randomized order in 36 healthy individuals. In addition, the 40 μm foil was tested three more times at the start of each session to evaluate possible short-term effects. This test session was repeated with and without an interspersed maximum bite force task in between. The results demonstrated that repeated measurements increased OTA significantly (p = 0.033); a change mainly driven by the 40 μm thickness, whereas maximum bite force tests did not affect OTA (p = 0.097). Collectively, the results suggest that the enhanced OTA may be attributed to repetition-mediated learning and neuroplasticity within the pathways related to OTA. Furthermore, the compressive bite force may have induced a short-term change that lasted seconds and was not detected by the subsequent OTA measurements or may have altogether inhibited the facilitatory effect of repeated OTA. This underscores the potential for future research to explore the implications of compressive force and pain on OTA in patient populations, which could provide valuable insights into the adaptive mechanisms of the sensorimotor system in pathological conditions.

The multisensory control of sequential actions

Many motor tasks are comprised of sequentially linked action phases, as when reaching for, lifting, transporting, and replacing a cup of coffee. During such tasks, discrete visual, auditory and/or haptic feedback are typically associated with mechanical events at the completion of each action phase, as when breaking and subsequently making contact between the cup and the table. An emerging concept is that important sensorimotor control operations, that affect subsequent action phases, are centred on these discrete multisensory events. By predicting sensory feedback at the completion of action phases, and comparing with the actual feedback that arises, task performance can be continuously monitored. If errors are detected, the sensorimotor system can quickly respond with task-protective corrective actions. The aim of this study was to investigate how discrete multisensory feedback at the completion of action phases are used in these control operations. To investigate this question, 42 healthy human participants (both male and female) performed a visually guided sequential reaching task where auxiliary discrete visual, auditory and/or haptic feedback was associated with the completion of action phases. Occasionally however, this feedback was removed in one or two modalities. The results show that although the task was visually guided, its control was critically influenced by discrete auditory and haptic feedback. Multisensory integration effects occurred, that enhanced the corrective actions, when auditory feedback was unexpectedly removed along with haptic or visual feedback. This multisensory enhancement may facilitate the ability to detect errors during sequential actions and amplify task-protective corrective actions.

Pharyngeal mechanosensory neurons control food swallow in Drosophila melanogaster

As the early step of food ingestion, the swallow is under rigorous sensorimotor control. Nevertheless, the mechanisms underlying swallow control at a molecular and circuitry level remain largely unknown. Here, we find that mutation of the mechanotransduction channel genes nompC, Tmc, or piezo impairs the regular pumping rhythm of the cibarium during feeding of the fruit fly Drosophila melanogaster. A group of multi-dendritic mechanosensory neurons, which co-express the three channels, wrap the cibarium and are crucial for coordinating the filling and emptying of the cibarium. Inhibition of them causes difficulty in food emptying in the cibarium, while their activation leads to difficulty in cibarium filling. Synaptic and functional connections are detected between the pharyngeal mechanosensory neurons and the motor circuit that controls swallow. This study elucidates the role of mechanosensation in swallow, and provides insights for a better understanding of the neural basis of food swallow.

Pharyngeal mechanosensory neurons control food swallow in Drosophila melanogaster.

As the early step of food ingestion, the swallow is under rigorous sensorimotor control. Nevertheless, the mechanisms underlying swallow control at a molecular and circuitry level remain largely unknown. Here, we find that mutation of the mechanotransduction channel genes nompC, Tmc, or piezo impairs the regular pumping rhythm of the cibarium during feeding of the fruit fly Drosophila melanogaster. A group of multi-dendritic mechanosensory neurons, which co-express the three channels, wrap the cibarium and are crucial for coordinating the filling and emptying of the cibarium. Inhibition of them causes difficulty in food emptying in the cibarium, while their activation leads to difficulty in cibarium filling. Synaptic and functional connections are detected between the pharyngeal mechanosensory neurons and the motor circuit that controls swallow. This study elucidates the role of mechanosensation in swallow, and provides insights for a better understanding of the neural basis of food swallow.

Does aberrant electrocortical dynamics pattern imply atypical balance control in adolescents with idiopathic scoliosis?

Adolescent idiopathic scoliosis (AIS) is a developmental disorder described as a three-dimensional spine deformity with multifactorial etiology. The multifactorial model of AIS suggests that the patient population is diverse. Identifying individuals with sensorimotor control impairments could enable personalized treatments, potentially leading to improved outcomes for those with AIS. We hypothesize that abnormal electrocortical dynamics within the sensorimotor cortex will be related to less efficient balance control in standing during ankle proprioception alteration in the absence or presence of vision. To test this hypothesis, the balance control performance of adolescents with AIS will be assessed on a force platform by computing the root mean square value of the scalar distance between the center of pressure and the center of gravity. Electroencephalography will be recorded while challenging balance control by altering ankle proprioception in the presence and absence of visual cues. Time-frequency analyses will be calculated to determine alpha, and beta band power in both conditions. Pilot data from 13 participants with AIS were analyzed to support our hypothesis. Three participants with less efficient balance control showed electrocortical dynamics changes, such as an increase in beta band power in the presence and absence of vision and a decrease in alpha band power in the presence of vision compared to the AIS group with efficient balance control. These findings support our hypothesis of suboptimal sensorimotor information processing in the subgroup of adolescents with AIS with less efficient balance control, which could have significant implications for developing personalized treatments for AIS.

Imaging-genomic spatial-modality attentive fusion for studying neuropsychiatric disorders.

Multimodal learning has emerged as a powerful technique that leverages diverse data sources to enhance learning and decision-making processes. Adapting this approach to analyzing data collected from different biological domains is intuitive, especially for studying neuropsychiatric disorders. A complex neuropsychiatric disorder like schizophrenia (SZ) can affect multiple aspects of the brain and biologies. These biological sources each present distinct yet correlated expressions of subjects' underlying physiological processes. Joint learning from these data sources can improve our understanding of the disorder. However, combining these biological sources is challenging for several reasons: (i) observations are domain specific, leading to data being represented in dissimilar subspaces, and (ii) fused data are often noisy and high-dimensional, making it challenging to identify relevant information. To address these challenges, we propose a multimodal artificial intelligence model with a novel fusion module inspired by a bottleneck attention module. We use deep neural networks to learn latent space representations of the input streams. Next, we introduce a two-dimensional (spatio-modality) attention module to regulate the intermediate fusion for SZ classification. We implement spatial attention via a dilated convolutional neural network that creates large receptive fields for extracting significant contextual patterns. The resulting joint learning framework maximizes complementarity allowing us to explore the correspondence among the modalities. We test our model on a multimodal imaging-genetic dataset and achieve an SZ prediction accuracy of 94.10% (p < .0001), outperforming state-of-the-art unimodal and multimodal models for the task. Moreover, the model provides inherent interpretability that helps identify concepts significant for the neural network's decision and explains the underlying physiopathology of the disorder. Results also show that functional connectivity among subcortical, sensorimotor, and cognitive control domains plays an important role in characterizing SZ. Analysis of the spatio-modality attention scores suggests that structural components like the supplementary motor area, caudate, and insula play a significant role in SZ. Biclustering the attention scores discover a multimodal cluster that includes genes CSMD1, ATK3, MOB4, and HSPE1, all of which have been identified as relevant to SZ. In summary, feature attribution appears to be especially useful for probing the transient and confined but decisive patterns of complex disorders, and it shows promise for extensive applicability in future studies.

Reliability of Sensorimotor Control Tests in Individuals with Adolescent Idiopathic Scoliosis

Background: The presence of sensorimotor control deficits in adolescent idiopathic scoliosis compared to typically developed adolescents is supported by the literature but lacks reliability studies for assessment in this population. This study aimed to assess the reliability of eight sensorimotor control tests, in terms of static and dynamic balance, joint position sense (JPS) tests of the extremities and the spine, and a functional upper extremity proprioceptive test in adolescent idiopathic scoliosis subjects. Methods: Sixty adolescent idiopathic scoliosis subjects were divided into four groups. Each group underwent two tests by the same examiner, repeated at 15 min intervals. Reliability was measured using the intraclass correlation coefficient (ICC), standard error of measurement (SEM), and smallest detectable difference (SDD). Results: The results showed high reliability for the upper extremity functional proprioception test, for the dynamic and static balance test, and for the spinal lateral flexion joint position sense test in both directions. On the other hand, the shoulder external rotation, knee extension, elbow flexion, and spinal flexion joint position sense tests demonstrated poor reliability in adolescent idiopathic scoliosis subjects. Conclusions: Therapists are recommended to use the functional upper extremity proprioception test, the Fukuda test, the static balance test using a force footplate, and the spinal lateral flexion joint position sense test for assessing treatment progress in this population.

Preliminary report: Reduced hand sensory and motor function in persons living with heart failure.

Despite the growing evidence highlighting reduced functional independence in persons living with heart failure (PwHF), the underlying mechanisms that lead to reduced functional independence in this patient population are unknown. Given the association between functional independence and fine motor skills, which are functionally related to hand sensory and motor functions, we hypothesized that PwHF exhibit reduced sensory and motor function of hands compared to healthy individuals. We recruited a total of 10 PwHF (age: 57.6 ± 12.5 years old, four females) and a total of age- & sex-matched healthy control individuals (age: 58.2 ± 12.2 years old, four females). Participants performed a wide range of tests assessing the level of independence, fitness, cognitive function, and hand sensorimotor function. While the level of independence was comparable between two groups, PwHF exhibited reduced sensory and motor function. Compared to healthy participants, the ability to identify an object via tactile and proprioceptive inputs was reduced in PwHF, though the tactile mechanoreceptor function showed normal integrity. Similarly, PwHF exhibited a decline in manipulating small objects and steady grip force production. Heart failure seems to have repercussions that extend to the sensorimotor control of hand actions in advance to a decline in functional independence. These results underscore the need of further investigation as to the underlying mechanisms of reduced sensorimotor function, potential intervention targets, and determine whether assessments of hand sensorimotor function can serve as a vehicle to quantify restoration of self-care functionality.

The state of the science for potential contributors to musculoskeletal injury following concussion: Mechanisms, gaps, and clinical considerations

Concussion is a common mild traumatic brain injury affecting athletic, military, and general populations. While unrestricted medical clearance often occurs within 1-month, emerging evidence indicates prolonged sensorimotor control deficiencies and greater musculoskeletal injury risk after a concussion. Various theoretical frameworks and original studies indicate potential neurophysiological alterations affecting sensory input, sensorimotor integration, and neuromotor output, though the exact mechanisms remain unclear. This commentary aims to briefly review the literature on contributors to sensory and neuromotor deficiencies potentially related to musculoskeletal injury risk, recommend future research avenues to better understand these factors, and highlight current and future clinical applications.

NeuroMechFly v2: simulating embodied sensorimotor control in adult Drosophila.

Discovering principles underlying the control of animal behavior requires a tight dialogue between experiments and neuromechanical models. Such models have primarily been used to investigate motor control with less emphasis on how the brain and motor systems work together during hierarchical sensorimotor control. NeuroMechFly v2 expands Drosophila neuromechanical modeling by enabling vision, olfaction, ascending motor feedback and complex terrains that can be navigated using leg adhesion. We illustrate its capabilities by constructing biologically inspired controllers that use ascending feedback to perform path integration and head stabilization. After adding vision and olfaction, we train a controller using reinforcement learning to perform a multimodal navigation task. Finally, we illustrate more bio-realistic modeling involving complex odor plume navigation, and fly-fly following using a connectome-constrained visual network. NeuroMechFly can be used to accelerate the discovery of explanatory models of the nervous system and to develop machine learning-based controllers for autonomous artificial agents and robots.

Divided Attention Has Limited Effects on Speech Sensorimotor Control.

When vowel formants are externally perturbed, speakers change their production to oppose that perturbation both during the ongoing production (compensation) and in future productions (adaptation). To date, attempts to explain the large variability across individuals in these responses have focused on trait-based characteristics such as auditory acuity, but evidence from other motor domains suggests that attention may modulate the motor response to sensory perturbations. Here, we test the extent to which divided attention impacts sensorimotor control for supralaryngeal articulation. Neurobiologically healthy speakers were exposed to random (Experiment 1) or consistent (Experiment 2) real-time auditory perturbation of vowel formants to measure online compensation and trial-to-trial adaptation, respectively. In both experiments, participants completed two conditions: one with a simultaneous visual distractor task to divide attention and one without this secondary task. Divided visual attention slightly reduced online compensation, but only starting > 300 ms after vowel onset, well beyond the typical duration of vowels in speech. Divided attention had no effect on adaptation. The results from both experiments suggest that the use of sensory feedback in typical speech motor control is a largely automatic process unaffected by divided visual attention, suggesting that the source of cross-speaker variability in response to formant perturbations likely lies within the speech production system rather than in higher-level cognitive processes. Methodologically, these results suggest that compensation for formant perturbations should be measured prior to 300 ms after vowel onset to avoid any potential impact of attention or other higher-order cognitive factors.

Effect of a Sensorimotor Training Program for Aerial Maneuvers in Junior Surfers

The purpose of this study was to examine the impact of a sensorimotor training program on maximum ankle dorsiflexion (ankle DF), coordination, dynamic balance and postural control, and lower-limb muscle power, in competitive junior surfers, and its relation to parameters of sensorimotor control required to perform aerial maneuvers. Twelve junior competitive surfers followed a 7-week sensorimotor training program, being assessed pre- and post-program with the knee-to-wall test (KW), Y-Balance test—lower quarter (YBT-LQ), and the countermovement jump test (CMJ). Post-training assessment revealed positive effects on the KW (ankle DF) distance, which increased approximately 2 cm (p &lt; 0.001) for both ankles, and all scores for the YTB-LQ (coordination, dynamic balance, and postural control) variables increased, being significant (p &lt; 0.005) for some reach distances (YBT-LQ—Anterior Left, YBT-LQ—Postero-medial Left, and YTB-LQ Anterior Right). YBT-LQ Anterior Reach Asymmetry also improved by decreasing 1.62 cm (p &lt; 0.001) and the CMJ height (lower limb muscle power) increased 2.89 cm (p &lt; 0.001). The training program proved to effectively enhance parameters of physical performance for this sample, including ankle DF, coordination, dynamic balance, postural control, and lower limb muscle power. This tailored-made task approach can help to optimize surfing performance capabilities and contribute to reducing the risk of injuries while performing aerials.

Body ownership alterations in stroke emerge from reduced proprioceptive precision and damage to the frontoparietal network.

Stroke patients often experience alterations in their subjective feeling of ownership for the affected limb, which can hinder motor function and interfere with rehabilitation. In this study, we aimed at disentangling the complex relationship between sensory impairment, body ownership (BO), and motor control in stroke patients. We recruited 20 stroke patients with unilateral upper limb sensory deficits and 35 age-matched controls. Participants performed a virtual reality reaching task with a varying displacement between their real unseen hand and a visible virtual hand. We measured reaching errors and subjective ownership ratings as indicators of hand ownership. Reaching errors were modeled using a probabilistic causal inference model, in which ownership for the virtual hand is inferred from the level of congruency between visual and proprioceptive inputs and used to weigh the amount of visual adjustment to reaching movements. Stroke patients were more likely to experience ownership over an incongruent virtual hand and integrate it into their motor plans. The model explained this tendency in terms of a decreased capability of detecting visuo-proprioceptive incongruences, proportionally to the amount of proprioceptive deficit. Lesion analysis further revealed that BO alterations, not fully explained by the proprioceptive deficit, are linked to frontoparietal network damage, suggesting a disruption in higher-level multisensory integration functions. Collectively, our results show that BO alterations in stroke patients can be quantitatively predicted and explained in a computational framework as the result of sensory loss and higher-level multisensory integration deficits. Swiss National Science Foundation (163951).

Reduced resting-state periodic beta power in adults who stutter is related to sensorimotor control of speech execution

ObjectiveThe primary aim of the current study was to determine whether adults who stutter (AWS) present with anomalous periodic beta (β) rhythms when compared to typically fluent adults in the eyes-open resting state. A second aim was to determine whether lower β power in the RS is related to a measure of β event-related desynchronization (ERD) during syllable sequence execution. MethodsEEG data was collected from 128 channels in a 5 min, eyes-open resting state condition and from a syllable sequence repetition task. Temporal independent component analysis (ICA) was used to separate volume conducted EEG sources and to find a set of component weights common to the RS and syllable repetition task. Both traditional measures of power spectral density (PSD) and parameterized spectra were computed for components showing peaks in the β band (13–30 Hz). Parameterization was used to evaluate separable components adjusted for the 1/f part of the spectrum. ResultsICA revealed frontal-parietal midline and lateral sensorimotor (μ) components common to the RS and a syllable repetition task with peaks in the β band. The entire spectrum for each component was modeled using the FOOOF algorithm. Independent samples t-tests revealed significantly lower periodic β in midline central-parietal and lateral sensorimotor components in AWS. Regression analysis suggested a significant relationship between left periodic sensorimotor β power in the RS and ERD during syllable sequence execution. ConclusionsFindings suggest that periodic β peaks in the spectrum are related to hypothesized underlying pathophysiological differences in stuttering, including midline rhythms associated the default mode network (DMN) and lateral sensorimotor rhythms associated with the control of movement.

Resting state network changes induced by experimental inaudible infrasound exposure and associations with self-reported noise sensitivity and annoyance.

The effects of prolonged infrasound (IS) exposure on brain function and behavior are largely unknown, with only one prior study investigating functional connectivity (FC) changes. In a long-term randomized-controlled trial, 38 participants were exposed to inaudible airborne IS (6Hz, 80-90 dB) or sham devices for four weeks (8h/night). We assessed FC changes in resting-state networks (auditory, default mode (DMN), sensorimotor (SMN), and executive control (ECN)), and explored IS 'sensitivity' as a predictor of identified significant FC changes. We also examined correlations between somatic symptoms and FC. IS exposure led to decreased FC in the right precuneus (DMN) and increased FC in the Vermis IV and V (SMN). In the ECN, we observed increased FC in the right frontal middle gyrus (BA8) and the right inferior parietal lobe, and decreased FC in another region of the right frontal middle gyrus. Changes in the ECN (right inferior parietal lobe) were negatively associated with self-reported annoyance from IS/low-frequency noise. A significant negative association was found between FC changes in the DMN (right precuneus) and somatic symptoms. Our study is the first to investigate prolonged IS exposure effects on brain FC, revealing changes in the vDMN, SMN, and ECN, but not in the auditory network. Future studies should assess annoyance and sensitivity markers, fine-grained measures of somatic symptoms, and stratify samples by sensitivity to uncover individual differences in response to IS.

Functional Roles of Sensorimotor Alpha and Beta Oscillations in Overt Speech Production.

Power decreases, or desynchronization, of sensorimotor alpha and beta oscillations (i.e., alpha and beta ERD) have long been considered as indices of sensorimotor control in overt speech production. However, their specific functional roles are not well understood. Hence, we first conducted a systematic review to investigate how these two oscillations are modulated by speech motor tasks in typically fluent speakers (TFS) and in persons who stutter (PWS). Eleven EEG/MEG papers with source localization were included in our systematic review. The results revealed consistent alpha and beta ERD in the sensorimotor cortex of TFS and PWS. Furthermore, the results suggested that sensorimotor alpha and beta ERD may be functionally dissociable, with alpha related to (somato-)sensory feedback processing during articulation and beta related to motor processes throughout planning and articulation. To (partly) test this hypothesis of a potential functional dissociation between alpha and beta ERD, we then analyzed existing intracranial electro-encephalography (iEEG) data from the primary somatosensory cortex (S1) of picture naming. We found moderate evidence for alpha, but not beta, ERD's sensitivity to speech movements in S1, lending supporting evidence for the functional dissociation hypothesis identified by the systematic review.