Role Of Sensory Feedback Research Articles

Vestibular input modulates stepping balance reactions early in the pre-step phase through to post-recovery.

Compensatory stepping reactions to recover balance are frequently performed, however, the role of sensory feedback in regulating these responses is not fully understood. Specifically, it is unknown whether vestibular input influences compensatory stepping. Here, we aimed to assess whether step responses utilize vestibular input by combining medio-lateral galvanic vestibular stimulation (GVS) with step-inducing balance perturbations via unpredictable anterior-posterior platform translations. Step responses were assessed for any lateral differences due to the illusory sense of left (LGVS) or rightward (RGVS) postural motion in terms of pre-step weight-shifts, center of mass (COM) motion and step-placement as well as lateral stability when recovering balance. GVS evoked clear differences from the pre-step phase onwards, in an asymmetrical pattern depending on the GVS direction relative to the right step-leg side. RGVS induced a leftwards postural shift to create a larger stability margin to the right (p<0.0007), opposing the illusory motion and reducing the fall towards the unsupported side during the step; however, RGVS caused no change in step-width. Conversely, LGVS evoked a leftward step placement (p<0.0001) in the direction of the mis-sensed motion, but without any rightward shift in postural motion. This asymmetry is consistent with vestibular input predictively modulating pre-step lateral weight-shifts and foot-placement in accordance with step mechanics, specifically in controlling frontal plane stability when lifting the foot to step.

Role of sensory feedback in postural control of the patients with diabetic neuropathy

Role of sensory feedback in postural control of the patients with diabetic neuropathy

The role of sensory feedback from carpal sinus hairs in locomotor kinematics of rats (Rattus norvegicus, Rodentia) during walking on narrow substrates

Carpal sinus hairs on the forearms are assumed to have evolved within the stem lineage of Theria. The presence and similar position of these specialized tactile hairs in scansorial and terrestrial species as well as earlier studies on rats indicate a biological role in sensing substrate irregularities in high structured environments to ensure the dynamic stability of the body during locomotion. While these sensors were considered as one functional unit until so far, the present study deals with the biological role of the single tactile hairs of the trident, assuming a role in sensing substrate diameters and adapting limb coordination and body posture to different arboreal inclinations. To investigate the influence of each hair, we studied the locomotion of rats on poles of two different diameters whereby we selectively removed individual carpal sinus hairs. The rats walked at speeds ranging from 0.12 m/s to 0.58 m/s. Normal-light high-speed cameras and x-ray fluoroscopy visualized the hairs and body dynamics during locomotion. The time lag between first contact of the hairs to the branch until contact of the forepaw was 56–108 ms. Within this time window the pronation/supination of the paw and anterior body posture are adjusted to the substrate diameter. We presume that the most proximal sinus hair (located between the medial and lateral one) senses the paw-substrate distance through the increasing bend from its first branch-contact until the contact of the paw. The medial and the lateral hairs touch the pole sides and thereby, may collect information about the properties of the small-diameter substrate. The removal of single hairs from the group results in minor changes of kinematic parameters, but locomotor stability is seriously impaired when more than one hair is cut. The kinematic responses span from a more crouched body posture and higher forearm pronation to paw slipping, muscle tremor or complete refusal to walk on the narrow substrate.

Object Recognition via Evoked Sensory Feedback during Control of a Prosthetic Hand.

Haptic and proprioceptive feedback is critical for sensorimotor integration when we use our hand to perform daily tasks. Here, we evaluated how externally evoked haptic and proprioceptive feedback and myoelectric control strategies affected the recognition of object properties when participants controlled a prosthetic hand. Fingertip haptic sensation was elicited using a transcutaneous nerve stimulation grid to encode the prosthetic's fingertip forces. An array of tactors elicited patterned vibratory stimuli to encode tactile-proprioceptive kinematic information of the prosthetic finger joint. Myoelectric signals of the finger flexor and extensor were used to control the position or velocity of joint angles of the prosthesis. Participants were asked to perform object property (stiffness and size) recognition, by controlling the prosthetic hand with concurrent haptic and tactile-proprioceptive feedback. With the evoked feedback, intact and amputee participants recognized the object stiffness and size at success rates ranging from 50% to 100% in both position and velocity control with no significant difference across control schemes. Our findings show that evoked somatosensory feedback in a non-invasive manner can facilitate closed-loop control of the prosthetic hand and allowed for simultaneous recognition of different object properties. The outcomes can facilitate our understanding on the role of sensory feedback during bidirectional human-machine interactions, which can potentially promote user experience in object interactions using prosthetic hands.

Sensory Prediction of Limb Movement Is Critical for Automatic Online Control.

Fast, online control of movement is an essential component of human motor skills, as it allows automatic correction of inaccurate planning. The present study explores the role of two types of concurrent signals in error correction: predicted visual reafferences coming from an internal representation of the hand, and actual visual feedback from the hand. While the role of sensory feedback in these corrections is well-established, much less is known about sensory prediction. The relative contributions of these two types of signals remain a subject of debate, as they are naturally interconnected. We address the issue in a study that compares online correction of an artificially induced, undetected planning error. Two conditions are tested, which only differ with respect to the accuracy of predicted visual reafferences. In the first, “Prism” experiment, a planning error is introduced by prisms that laterally displace the seen hand prior to hand movement onset. The prism-induced conflict between visual and proprioceptive inputs of the hand also generates an erroneous prediction of visual reafferences of the moving hand. In the second, “Jump” experiment, a planning error is introduced by a jump in the target position, during the orienting saccade, prior to hand movement onset. In the latter condition, predicted reafferences of the hand remained intact. In both experiments, after hand movement onset, the hand was either visible or hidden, which enabled us to manipulate the presence (or absence) of visual feedback during movement execution. The Prism experiment highlighted late and reduced correction of the planning error, even when natural visual feedback of the moving hand was available. In the Jump experiment, early and automatic corrections of the planning error were observed, even in the absence of visual feedback from the moving hand. Therefore, when predicted reafferences were accurate (the Jump experiment), visual feedback was processed rapidly and automatically. When they were erroneous (the Prism experiment), the same visual feedback was less efficient, and required voluntary, and late, control. Our study clearly demonstrates that in natural environments, reliable prediction is critical in the preprocessing of visual feedback, for fast and accurate movement.

Flexible Spiking CPGs for Online Manipulation During Hexapod Walking.

Neural signals for locomotion are influenced both by the neural network architecture and sensory inputs coordinating and adapting the gait to the environment. Adaptation relies on the ability to change amplitude, frequency, and phase of the signals within the sensorimotor loop in response to external stimuli. However, in order to experiment with closed-loop control, we first need a better understanding of the dynamics of the system and how adaptation works. Based on insights from biology, we developed a spiking neural network capable of continuously changing amplitude, frequency, and phase online. The resulting network is deployed on a hexapod robot in order to observe the walking behavior. The morphology and parameters of the network results in a tripod gait, demonstrating that a design without afferent feedback is sufficient to maintain a stable gait. This is comparable to results from biology showing that deafferented samples exhibit a tripod-like gait and adds to the evidence for a meaningful role of network topology in locomotion. Further, this work enables research into the role of sensory feedback and high-level control signals in the adaptation of gait types. A better understanding of the neural control of locomotion relates back to biology where it can provide evidence for theories that are currently not testable on live insects.

Sensory feedback in music performer–instrument interactions

Musical performance involves the production of highly accurate sequences of movements in space and time. During a performance, real-time auditory, visual, somatosensory (tactile and kinematic), and movement-related information of the outcome of an action provided within the different sensory systems is integrated into a coherent percept and fed back to the motor system. These sensory feedback mechanisms are, therefore, crucial to maintaining the fluency of production. However, how and to what extent do these feedback mechanisms influence music performance and learning? A growing area of research has investigated the role of different types of sensory feedback on the musicians’ performance. The aim of this integrative review is to overview the recent literature on the role of sensory feedback on music performance, focusing particularly on the individual interaction between musician and instrument. In the first section, we review recent findings regarding the role of auditory, visual, and somatosensory (tactile and kinesthetic) feedback on music performance considering each sensory modality separately. To finalize, we briefly discuss the implications of these findings to support learning and pedagogical practice.

Making sense of renewable energy: Practical knowledge, sensory feedback and household understandings in a Scottish island microgrid

Technology-mediated energy feedback is a common demand management intervention aiming to encourage shedding and shifting practices, whereby householders potentially alter their energy consumption in response to factors including fluctuating electricity prices, and changing weather conditions. Due to issues of intermittent generation and mismatched supply and demand, shifting and shedding practices are particularly important in renewable-based grids. Yet energy feedback is based on an information-deficit model of householders which, among other issues, privileges certain forms of information and knowledge over others––namely the institutionalised and the quantifiable over the practical and the sensory. Drawing on social practice theory, this paper presents qualitative research from the Isle of Eigg, Scotland, which is the site of a microgrid deriving roughly 90 percent of its electricity from renewable sources. This empirical material is used to explore the mundane, tacit and corporeal forms of practical knowledge householders draw on to understand energy consumption and generation, and in particular the role of sensory feedback––what people can see, hear, touch, or otherwise sense. The analysis finds that islanders draw on heat- and weather-based forms of sensory feedback that help them to understand domestic energy consumption, and renewable generation, respectively. Meanwhile, energy monitors find limited utility, with conventional energy feedback used largely to formalise and supplement practical forms of knowledge developed through islanders’ bodily engagement with the environment, and lived experience. The research suggests that heat- and weather-based forms of sensory feedback are of potential relevance to the challenge of intermittency faced by renewable grids.

Beyond Motor Noise: Considering Other Causes of Impaired Reinforcement Learning in Cerebellar Patients.

Motor and reinforcement learning have been classically linked to functionally independent brain networks centered on the cerebellum and the basal ganglia, respectively. In a recent study published in eNeuro , Therrien et al. (2018) showed that increasing motor noise in healthy subjects disrupts reinforcement learning. However, this impairment remained well below that detected in cerebellar patients even when motor noise in healthy subjects was adjusted to match that observed in the patients. This suggests that impaired reinforcement learning following cerebellar damage cannot be solely accounted for by altered motor noise in these patients. Based on recent anatomic and functional evidence, we argue that the cerebellum may directly contribute to reinforcement learning, consistent with its tight connections with the basal ganglia. The ability to adapt to changes occurring in the environment is a fundamental feature of human behavior, which relies on both sensory and reward feedbacks. On the one hand, the role of sensory feedback has been largely considered by studying how motor commands adapt to visual perturbations (e.g., a visuomotor rotation), a process called error-based learning (Shadmehr et al., 2010; Wolpert et al., 2011; Kim et al., 2018; Roemmich and Bastian, 2018). This type of motor learning involves the computation of sensory prediction errors (SPEs), namely, the difference between predicted and actual sensory outcome (Tseng et al., 2007; Schlerf and Ivry, 2012; Shadmehr, 2017, 2018). On the other hand, the role of reward feedback has been mostly investigated in tasks that require learning what action to select or not, by updating reward predictions based on previous experience, a process named reinforcement learning (Lee et al., 2012; Derosiere et al., 2017a,b; Gershman and Daw, 2017; O’Doherty et al., 2017). A central …

Sensory Feedback and Animal Locomotion: Perspectives from Biology and Biorobotics: An Introduction to the Symposium.

The successful completion of many behaviors relies on sensory feedback. This symposium brought together researchers using novel techniques to study how different stimuli are encoded, how and where multimodal feedback is integrated, and how feedback modulates motor output in diverse modes of locomotion (aerial, aquatic, and terrestrial) in a diverse range of taxa (insects, fish, tetrapods), and in robots. Similar to biological organisms, robots can be equipped with integrated sensors and can rely on sensory feedback to adjust the output signal of a controller. Engineers often look to biology for inspiration on how animals have evolved solutions to problems similar to those experienced in robotic movement. Similarly, biologists too must proactively engage with engineers to apply computer and robotic models to test hypotheses and answer questions on the capacity and roles of sensory feedback in generating effective movement. Through a diverse group of researchers, including both biologists and engineers, the symposium attempted to catalyze new interdisciplinary collaborations and identify future research directions for the development of bioinspired sensory control systems, as well as the use of robots to test hypotheses in neuromechanics.

Allocation of attention to real-time visual speech feedback in a digital mirror

The role of sensory feedback in speech motor control is typically investigated by observing the behavioral and/or neurological response to experimental feedback perturbation. The function of feedback and its use in typical control is therefore inferred from responses under atypical conditions. The present study avoided perturbation, using eye tracking and a digital mirror (continuous video relay from a webcam) to examine how speakers attend to real-time visual feedback across normal speech and non-speech tasks. Fixation locations and durations were recorded during a period of rest prior to task onset (no-task condition), a recitation of the ABC’s, a re-telling of a popular children’s story (Goldilocks and the Three Bears), and parallel clear speech versions of the latter two tasks. Analysis of gaze showed that participants overall seemed to avoid fixating on their self-image, and that avoidance increased during speech tasks compared to non-speech “rest.” Across the two content areas (ABC’s vs. storytelling), participants’ self-gaze was concentrated more heavily on speech-relevant areas during storytelling, and no differences in gaze were observed between casual and clear speech. These data suggest an increased role for sensory feedback during complex linguistic tasks, as well as indicating an overall aversion towards realistic visual self-feedback.

Perspectives on classical controversies about the motor cortex.

Primary motor cortex has been studied for more than a century, yet a consensus on its functional contribution to movement control is still out of reach. In particular, there remains controversy as to the level of control produced by motor cortex ("low-level" movement dynamics vs. "high-level" movement kinematics) and the role of sensory feedback. In this review, we present different perspectives on the two following questions: What does activity in motor cortex reflect? and How do planned motor commands interact with incoming sensory feedback during movement? The four authors each present their independent views on how they think the primary motor cortex (M1) controls movement. At the end, we present a dialogue in which the authors synthesize their views and suggest possibilities for moving the field forward. While there is not yet a consensus on the role of M1 or sensory feedback in the control of upper limb movements, such dialogues are essential to take us closer to one.

Neural Network Underlying Intermanual Skill Transfer in Humans

Physical practice with one hand results in performance gains of the other (un-practiced) hand, yet the role of sensory feedback and underlying neurophysiology is unclear. Healthy subjects learned sequences of finger movements by physical training with their right hand while receiving real-time movement-based visual feedback via 3D virtual reality devices as if their immobile left hand was training. This manipulation resulted in significantly enhanced performance gain with the immobile hand, which was further increased when left-hand fingers were yoked to passively follow right-hand voluntary movements. Neuroimaging data show that, during training with manipulated visual feedback, activity in the left and right superior parietal lobule and their degree of coupling with motor and visual cortex, respectively, correlate with subsequent left-hand performance gain. These results point to a neural network subserving short-term motor skill learning and may have implications for developing new approaches for learning and rehabilitation in patients with unilateral motor deficits.

Hip proprioceptive feedback influences the control of mediolateral stability during human walking.

Active control of the mediolateral location of the feet is an important component of a stable bipedal walking pattern, although the roles of sensory feedback in this process are unclear. In the present experiments, we tested whether hip abductor proprioception influenced the control of mediolateral gait motion. Participants performed a series of quiet standing and treadmill walking trials. In some trials, 80-Hz vibration was applied intermittently over the right gluteus medius (GM) to evoke artificial proprioceptive feedback. During walking, the GM was vibrated during either right leg stance (to elicit a perception that the pelvis was closer mediolaterally to the stance foot) or swing (to elicit a perception that the swing leg was more adducted). Vibration during quiet standing evoked leftward sway in most participants (13 of 16), as expected from its predicted perceptual effects. Across the 13 participants sensitive to vibration, stance phase vibration caused the contralateral leg to be placed significantly closer to the midline (by ∼2 mm) at the end of the ongoing step. In contrast, swing phase vibration caused the vibrated leg to be placed significantly farther mediolaterally from the midline (by ∼2 mm), whereas the pelvis was held closer to the stance foot (by ∼1 mm). The estimated mediolateral margin of stability was thus decreased by stance phase vibration but increased by swing phase vibration. Although the observed effects of vibration were small, they were consistent with humans monitoring hip proprioceptive feedback while walking to maintain stable mediolateral gait motion.

P33. Noisy galvanic vestibular stimulation improves dynamic walking stability in healthy subjects

Introduction We examined the effect of galvanic vestibular stimulation (GVS) delivered as zero-mean white noise current (noisy GVS) on the walking performance in healthy subjects. Methods The walking performance of 15 healthy subjects (mean age 23.0±1.3 years) at slow, preferred and fast walking speed was examined during two different conditions: (1) walking with eyes closed and zero amplitude sham noisy GVS, and (2) walking with eyes closed and non-zero amplitude noisy GVS set to 80% of the individual sensory threshold for GVS. We examined 10 gait parameters: stride time, stride length, base of support, swing time percentage, double support time percentage as well as the CV of stride time, stride length and base of support, gait asymmetry and bilateral phase synchronization. Results Noisy GVS significantly improved stride time CV by 34% ( p p p p p Conclusion Noisy GVS is effective in improving locomotion function in healthy subjects. It predominantly targets the variability and bilateral coordination characteristics of the walking pattern, which are critically linked to dynamic walking stability. The predominant impact of noisy GVS during slow walking supports the principle of a speed-depended role of sensory feedback in locomotion control.

Neuromechanical model of reflexes and locomotor rhythms in the crayfish leg

The role of sensory feedback in the production of locomotor rhythms has been discussed for a hundred years [1], but a detailed description has emerged only recently with the coupling of neurophysiological and behavioral experiments and neuromechanical models [2]. In both cats and stick insects, this combination has helped clarify the role of proprioceptive feedback in determining the stance-swing transition during walking. The role of sensory feedback in posture and locomotor control of the crayfish leg has been intensively investigated over the last 25 years, and the neural circuitry governing leg elevation and depression movements during static posture and walking has been described [3]. We have developed a hybrid neuromechanical experiment consisting of an AnimatLab neuromechanical model (http://www.animatlab.com) of the crayfish thorax and 5th leg linked to the corresponding sensory and motor nerves of the living crayfish thoracic nervous system. We found that lifting the model leg would evoke resistance reflexes in tonically active preparations similar to those seen in intact resting animals, whereas the reflex reversed sign to become assistive during a locomotor rhythm. Moreover, the rhythm had a much higher frequency with the sensory feedback closed than when the loop was opened. To help determine whether the known circuitry can account for postural reflexes and reflex-assisted walking, we linked the same neuromechanical model of the crayfish leg to a model of the neural circuit that controls leg levation and depression (Figure 1). We found that an appropriately 'tuned' model could replicate the hybrid experimental results, and that this depended on the proper balance between the strength (gain) of the assistance reflex and the strength and stability of the half-center oscillator. To increase the intrinsic CPG frequency, the leg levation assistance reflex had to be sufficiently sensitive and strong to reset the CPG earlier in the interval between depression and levation motor bursts. The CPG had to be sufficiently robust to produce a stable low-frequency burst pattern without reflex input, but be able to reset in response to appropriately timed input. Figure 1 Neuromechanical model. Body model is at left, showing thorax and left 5th leg with hinges, CBCO stretch receptor, and Dep (red) and Lev (blue) muscles identified. Circuit is at right, with Dep MNs, INs, and muscles in red, and Lev in blue. Muscles and ... Figure 2 Model responses under open loop (left) and closed loop (right) conditions. Closing the feedback loop increased the burst frequency of the Lev/Dep CPG.

Functional synchronization in repetitive bimanual prehension movements

To examine the mechanisms of functional bimanual synchronization in goal-directed movements, we studied the movement kinematics of motorically unimpaired subjects while they performed repetitive prehension movements (either unimanually or bimanually) to small food items. Compared to unimanual conditions, bimanual movement execution yielded a significantly prolonged mouth contact phase. We hypothesized that this threefold prolongation led to a proper functional synchronization of the movement onsets of both hands at the beginning of each new movement cycle. That these temporal adjustments occurred in the movement phase with maximal haptic input points to the importance of sensory feedback for bimanual coordination. These results are discussed with respect to the important role of sensory feedback in the timing of coordinated bimanual movements. Furthermore, we propose that time-based coordinating schemas, which are implemented by the cerebellum and the posterior parietal cortex using sensory feedback, underlie functional inter-limb coordination.

Is Head-on-Trunk Extension a Proprioceptive Mediator of Postural Control and Sit-to-Stand Movement Characteristics?

ABSTRACT During stance, head extension increases postural sway, possibly due to interference with sensory feedback. The sit-to-stand movement is potentially destabilizing due to the development of momentum as the trunk flexes forward and the body transitions to a smaller base of support. It is unclear what role head orientation plays in the postural and movement characteristics of the sit-to-stand transition. The authors assessed how moving from sitting to standing with head-on-trunk extension compared with moving with the head neutral or flexed, or with moving with the head facing forward in space (which would involve head-on-trunk extension, but not head-in-space extension) in healthy, young participants. Head-on-trunk extension increased center of pressure variability, but decreased movement velocities, movement duration, and trunk flexion compared with flexed and neutral head-on-trunk orientations. Similarities in movement characteristics between head-on-trunk extension and the forward head-in-space orientation suggest that stabilizing the head in space does not fully counteract the postural and movement changes due to head-on-trunk extension. Findings suggest that proprioceptive feedback from the neck muscles contributes to the regulation of posture and movement, and therefore should not be overlooked in research on the role of sensory feedback in postural control.

Reflexes and preflexes: on the role of sensory feedback on rhythmic patterns in insect locomotion

Neuromuscular systems are stabilized and controlled by both feedforward and feedback signals. Feedforward pathways driven by central pattern generators (CPGs), in conjunction with preflexive mechanical reaction forces and nonlinear muscle properties, can produce stable stereotypical gaits. Feedback is nonetheless present in both slow and rapid running, and preflexive mechanisms can join with neural reflexes originating in proprioceptive sensors to yield robust behavior in uncertain environments. Here, we develop a single degree-of-freedom neuromechanical model representing a joint actuated by an agonist/antagonist muscle pair driven by motoneurons and a CPG in a periodic rhythm characteristic of locomotion. We consider two characteristic feedback modes: phasic and tonic. The former encodes states such as position in the timing of individual spikes, while the latter can transmit graded measures of force and other continuous variables as spike rates. We use results from phase reduction and averaging theory to predict phase relationships between CPG and motoneurons in the presence of feedback and compare them with simulations of the neuromechanical model, showing that both phasic and tonic feedback can shift motoneuronal timing and thereby affect joint motions. We find that phase changes in neural activation can cooperate with preflexive displacement and velocity effects on muscle force to compensate for externally applied forces, and that these effects qualitatively match experimental observations in the cockroach.

Modulation, individual variation and the role of lingual sensory afferents in the control of prey transport in the lizardPogona vitticeps

Most organisms feed on a variety of food items that may differ dramatically in their physical and behavioural characteristics (e.g. mobility, mass, texture, etc.). Thus the ability to modulate prey transport behaviour in accordance with the characteristics of the food appears crucial. Consequently, prey reduction and transport movements must be adjusted to the natural variation in material properties of the food, between and within feeding sequences and transport cycles. Here we describe an investigation of (1) the ability of the agamid lizard Pogona vitticeps to modulate prey transport kinematics when feeding on a range of food items differing in their physical characteristics and (2) the role of sensory feedback in controlling jaw and tongue movements by bilateral transection of the lingual trigeminal sensory afferents. Our findings demonstrate that P. vitticeps modulates the kinematics of its feeding behaviour in response to the mechanical demands imposed by different food types. In addition, transection of the trigeminal sensory afferents has an effect on the movements of jaws and tongue during transport, and increases the duration of transport cycles needed to process a given food type. However, after transection, transport cycles were still different for different food types suggesting that other sources of sensory information are also used to modulate prey transport in the lizard P. vitticeps.