Role Of Proprioception Research Articles

Mechanically evoked spike responses of pentascolopidial chordotonal organs of Drosophila melanogaster larvae.

Mechanosensitive ensembles of neurons in insects, known as chordotonal organs (COs), function in proprioception, the detection of sound and substrate vibrations. Here, we characterized the mechanical sensitivity of the lateral pentascolopidial CO (lch5) of Drosophila melanogaster larvae to establish its postulated role in proprioception. We developed a physiologically realistic method to replicate proprioceptive input to lch5 by pulling the apodeme (tendon) to which the tips of the neurons attach. We found that lch5 sensory neurons respond transiently with a short latency to the velocity component of stretch displacements and the release of stretch (relaxation). In the mechanosensory mutant inactive, lch5 has a decreased response to mechanical stimuli and a lower overall spontaneous spike rate. Finally, we simulated the input that lch5 receives during crawling and observed spike rate changes of peristaltic body contraction. We provide a characterization of proprioceptive feedback in D. melanogaster larvae and firmly establish the proprioceptive function of lch5 in larval locomotion.

Phosphatidic acid is an endogenous negative regulator of PIEZO2 channels and mechanical sensitivity

Mechanosensitive PIEZO2 ion channels play roles in touch, proprioception, and inflammatory pain. Currently, there are no small molecule inhibitors that selectively inhibit PIEZO2 over PIEZO1. The TMEM120A protein was shown to inhibit PIEZO2 while leaving PIEZO1 unaffected. Here we find that TMEM120A expression elevates cellular levels of phosphatidic acid and lysophosphatidic acid (LPA), aligning with its structural resemblance to lipid-modifying enzymes. Intracellular application of phosphatidic acid or LPA inhibits PIEZO2 but not PIEZO1 activity. Extended extracellular exposure to the non-hydrolyzable phosphatidic acid and LPA analog carbocyclic phosphatidic acid (ccPA) also inhibits PIEZO2. Optogenetic activation of phospholipase D (PLD), a signaling enzyme that generates phosphatidic acid, inhibits PIEZO2 but not PIEZO1. Conversely, inhibiting PLD leads to increased PIEZO2 activity and increased mechanical sensitivity in mice in behavioral experiments. These findings unveil lipid regulators that selectively target PIEZO2 over PIEZO1, and identify the PLD pathway as a regulator of PIEZO2 activity.

Proprioceptive engagement of the human cerebellum studied with 7T-fMRI

Abstract Proprioception, the process of perceiving our bodies in space, is a key aspect of self-perception. The cerebellar cortex is believed to play a critical role in proprioception. However, our understanding of the functional involvement of the cerebellum in proprioception remains limited due to the intricate, thin, and highly folded structure of the human cerebellar cortex, which is more challenging to resolve using in-vivo MRI compared to the cerebral cortex. In this study, we employed high-resolution, B1-shimmed, functional magnetic resonance imaging (fMRI) at 7T to investigate proprioceptive involvement of the cerebellum in humans. We used two tasks designed to differentially require proprioceptive information processing: midline-contralateral-finger-touch and simultaneous-unilateral-finger-flexing. We assessed responses to these tasks across three gradient directions inspired by the mesoscale cerebellar functional organisation, akin to laminar and columnar fMRI approaches in the cerebral cortex. Movements requiring higher proprioceptive engagement, in the midline-contralateral-finger-touch task, elicited stronger activations in both anterior and posterior lobe motor areas of the cerebellum (lobules V and VIIIa/b). We identified distinct activation patterns for the two tasks within these cerebellar motor regions, which may reflect differing functional roles of these motor areas. Midline-contralateral-finger-touch responses were found more medial than simultaneous-unilateral-finger-flexing responses in lobule V and deeper into the cerebellar fissures in lobule VIII. These findings contribute to a deeper understanding of cerebellar functional organisation, the cerebellar involvement in proprioception and may offer insights into addressing proprioceptive deficits associated with neurological conditions.

Role of proprioception in corrective visually-guided movements: larger movement errors in both arms of a deafferented individual compared to control participants.

Proprioception plays an important role in both feedforward and feedback processes underlying movement control. This has been shown with individuals who suffered a profound proprioceptive loss and use vision to partially compensate for the sensory loss. The purpose of this study was to specifically examine the role of proprioception in feedback motor responses to visual perturbations by examining voluntary arm movements in an individual with a rare case of selective peripheral deafferentation (GL). We compared her left and right hand movements with those of age-matched female control participants (70.0 years ± 0.2 SEM) during a reaching task. Participants were asked to move their unseen hand, represented by a cursor on the screen, quickly and accurately to reach a visual target. A visual perturbation could be pseudorandomly applied, at movement onset, to either the target position (target jump) or the cursor position (cursor jump). Results showed that despite the continuous visual feedback that was provided, GL produced larger errors in final position accuracy compared to control participants, with her left nondominant hand being more erroneous after a cursor jump. We also found that the proprioceptively-deafferented individual produced less spatially efficient movements than the control group. Overall, these results provide evidence of a heavier reliance on proprioceptive feedback for movements of the nondominant hand relative to the dominant hand, supporting the view of a lateralization of the feedback processes underlying motor control.

Fascial plane blocks: from microanatomy to clinical applications.

In the last 20 years, advancements in the understanding of fasciae have significantly transformed anaesthesia and surgery. Fascial plane blocks (FPBs) have gained popularity due to their validated safety profile and relative ease. They are used in various clinical settings for surgical and nonsurgical indications. Growing evidence suggests a link between the microscopic anatomy of fasciae and their mechanism of action. As a result, knowledge of these aspects is urgently needed to better optimise pain management. The purpose of this review is to summarise the different microscopic aspects of deep/muscular fascia to expand our understanding in the performance of FPBs. There is ample evidence to support the role of FPBs in pain management. However, the exact mechanism of action remains unclear. Fasciae are composed of various structural elements and display complex anatomical characteristics at the microscopic level. They include various cell types embedded within an extracellular matrix abundant in collagens and hyaluronan. Increasingly, numerous studies demonstrated their innervation that contributes to their sensory functions and their role in proprioception, motor coordination and pain perception. Lastly, the diversity of the cellular and extracellular matrix, with their viscoelastic properties, is essential to understanding the FPBs' mechanism of action. Physicians must be aware of the role of fascial microscopic anatomy and better understand their properties to perform FPBs in a conscious manner and enhance pain management.

Minimal impact of chronic proprioceptive loss on implicit sensorimotor adaptation and perceived movement outcome.

Implicit sensorimotor adaptation keeps our movements well calibrated amid changes in the body and environment. We have recently postulated that implicit adaptation is driven by a perceptual error: the difference between the desired and perceived movement outcome. According to this perceptual realignment model, implicit adaptation ceases when the perceived movement outcome-a multimodal percept determined by a prior belief conveying the intended action, the motor command, and feedback from proprioception and vision-is aligned with the desired movement outcome. Here, we examined the role of proprioception in implicit motor adaptation and perceived movement outcome by examining individuals who experience deafferentation (i.e., individuals with impaired proprioception and touch). We used a modified visuomotor rotation task designed to isolate implicit adaptation and probe perceived movement outcomes throughout the experiment. Surprisingly, both implicit adaptation and perceived movement outcome were minimally impacted by chronic deafferentation, posing a challenge to the perceptual realignment model of implicit adaptation.NEW & NOTEWORTHY We tested six individuals with chronic somatosensory deafferentation on a novel task that isolates implicit sensorimotor adaptation and probes perceived movement outcome. Strikingly, both implicit motor adaptation and perceptual movement outcome were not significantly impacted by chronic deafferentation, posing a challenge for theoretical models of adaptation that involve proprioception.

A pilot study: effect of somatosensory loss on motor corrections in response to unknown loads in a reaching task by chronic stroke survivors.

Despite recent studies indicating a significant correlation between somatosensory deficits and rehabilitation outcomes, how prevailing somatosensory deficits affect stroke survivors' ability to correct their movements and recover overall remains unclear. To explore how major deficits in somatosensory systems impede stroke survivors' motor correction to various external loads, we conducted a study with 13 chronic stroke survivors who had hemiparesis. An inertial, elastic, or viscous load, which was designed to impose perturbing forces with various force profiles, was introduced unexpectedly during the reaching task using a programmable haptic robot. Participants' proprioception and cutaneous sensation were also assessed using passive movement detection, finger-to-nose, mirror, repositioning, and Weinstein pressure tests. These measures were then analyzed to determine whether the somatosensory measures significantly correlated with the estimated reaching performance parameters, such as initial directional error, positional deviation, velocity deviations, and speed of motor correction were measured.Of 13 participants, 5 had impaired proprioception, as they could not recognize the passive movement of their elbow joint, and they kept showing larger initial directional errors even after the familiarization block. Such continuously found inaccurate initial movement direction might be correlated with the inability to develop the spatial body map especially for calculating the initial joint torques when starting the reaching movement. Regardless of whether proprioception was impaired or not, all participants could show the stabilized, constant reaching movement trajectories. This highlights the role of proprioception especially in the execution of a planned movement at the early stage of reaching movement.

Proprioception and Mechanoreceptors in Osteoarthritis: A Systematic Literature Review.

Osteoarthritis (OA) is one of the most common chronic diseases in the world. It is frequently accompanied by high levels of persistent pain, as well as substantial impairments in function and functional capacity. This review aims to systematically analyze the changes in proprioception and related mechanoreceptors in OA patients. Studies from September 2013 to September 2023 were identified by conducting searches on the PubMed, Web of Science, and Scopus electronic databases following the PRISMA statement. One reviewer independently assessed and screened the literature, extracted the data, and graded the studies. The body of evidence underwent an evaluation and grading process using the ROBINS-I tool, which was specifically designed to assess the risk of bias in non-randomized studies of interventions. Results were summarized using descriptive methods. A search through 37 studies yielded 14 clinical studies that were ultimately included. The primary focus of the studies was on the knee joint, particularly the posterior cruciate ligament (PCL). The studies found that PCL in OA patients had impaired proprioceptive accuracy, possibly due to changes in mechanoreceptors (Ruffini, Pacini, and Golgi Mazzoni corpuscles). This suggests that dysfunctional articular mechanoreceptors, especially in severe cases of OA, may contribute to reduced proprioception. Dynamic stabilometry also identified significant proprioceptive deficits in patients with knee articular cartilage lesions, underscoring the impact of such lesions on knee proprioception. Literature data have shown that proprioceptive accuracy may play an important role in OA, particularly in the knee PCL and cartilage. However, the role of proprioception and related mechanoreceptors needs to be further clarified. Future studies focusing on the relationship between proprioception, OA disease, and symptoms, considering age and gender differences, and exploring OA joints other than the knee should be conducted to improve clinical and surgical outcomes in cases where proprioception and mechanoreceptors are impaired in OA patients.

Scapholunate and lunotriquetral joint dynamic stabilizers and their role in wrist neuromuscular control and proprioception

Recent research interest has grown in exploring the role of muscles, isometric contraction, proprioception, and neuromuscular control in addressing dynamic scapholunate and lunotriquetral joint instability, marking a shift in the understanding of wrist stability. To present a comprehensive review of the carpal ligaments anatomy and wrist biomechanics, with a particular focus on the role of proprioception in dynamic carpal stability and their role in managing scapholunate (SL) and lunotriquetral (LTq) dynamic instabilities. We conducted a systematic search of the literature and review of the most relevant papers published and indexed in pubmed, related to wrist biomechanics, proprioception and its contribution to carpal dynamic stability. The study involved a comprehensive review of neuromuscular mechanisms in dynamic stabilization of the carpus, based on cadaver studies. The 3D position of the scaphoid, triquetrum, and capitate was monitored before and after tendon loading. The extensor carpi ulnaris (ECU) and the flexor carpi radialis (FCR) are identified as the primary pronators of the midcarpal joint. The ECU's pronation effect can potentially strain the scapholunate ligament, while the supinator muscles, the abductor pollicis longus (APL), the extensor carpi radialis longus (ECRL), and the flexor carpi ulnaris (FCU), have a protective role, particularly in cases of scapholunate ligament dysfunctions. The FCR, despite being a pronator of the distal row, has a beneficial effect as it provokes supination of the scaphoid. Comprehending carpal dysfunctions and instabilities hinges on understanding carpal anatomy and normal biomechanics. Proprioception, encompassing joint position sensation and neuromuscular control, is pivotal for stability. Biomechanical research informs tailored muscle strengthening for specific carpal issues. Supinator muscles should be strengthened for SL injuries, and ECU-focused strengthening and proprioceptive training are key for dynamic LTq instabilities. Ongoing research should delve into the intricate relationship between carpal ligaments, muscles, and proprioception to enhance wrist stability.

Identifying the white matter pathways involved in multiple sclerosis-related tremor using diffusion tensor imaging.

Tremor affects up to 45% of patients with Multiple Sclerosis (PwMS). Current understanding is based on insights from other neurological disorders, thus, not fully addressing the distinctive aspects of MS pathology. To characterize the brain white matter (WM) correlates of MS-related tremor using diffusion tensor imaging (DTI). In a prospective case-control study, PwMS with tremor were assessed for tremor severity and underwent MRI scans including DTI. PwMS without tremor served as matched controls. After tract selection and segmentation, the resulting diffusivity measures were used to calculate group differences and correlations with tremor severity. This study included 72 PwMS. The tremor group (n = 36) exhibited significant changes in several pathways, notably in the right inferior longitudinal fasciculus (Cohen's d = 1.53, q < 0.001) and left corticospinal tract (d = 1.32, q < 0.001), compared to controls (n = 36). Furthermore, specific tracts showed a significant correlation with tremor severity, notably in the left medial lemniscus (Spearman's coefficient [rsp] = -0.56, p < 0.001), and forceps minor of corpus callosum (rsp = -0.45, p < 0.01). MS-related tremor is associated with widespread diffusivity changes in WM pathways and its severity correlates with commissural and sensory projection pathways, which suggests a role for proprioception or involvement of the dentato-rubro-olivary circuit.

Exercise-based intervention as a nonsurgical treatment for patients with carpal instability: A case series

BackgroundAlthough the important roles of proprioception and neuromuscular control in carpal instabilities under laboratory conditions have been recognized, only a few studies have translated this knowledge into a routine clinical practice. PurposeThis study aimed to evaluate the results of a personalized rehabilitation in patients with carpal instability on functionality and pain intensity. Study designThis was a case series study. MethodsThis case series included 39 adults (mean age: 38.2 ± 14.0 years; 16/23 females/males) diagnosed with carpal instability (radial or ulnar) with indication for orthopedic treatment. The disabilities of the arm, shoulder, and hand questionnaire was used to assess upper limb functionality. Pain perception was assessed using a visual analog scale. Exercise-based physiotherapy interventions were performed according to the clinical needs of the patients for at least 6 weeks (2-3 sessions per week). For the treatment of radial instability (n = 13), strengthening exercises of the abductor pollicis longus, extensor carpi radialis longus, flexor carpi radialis, and pronator quadratus muscles were prescribed. For the treatment of ulnar instability (n = 24), extensor carpi ulnaris and pronator quadratus were trained. All patients underwent proprioceptive training in open kinetic chain and closed kinetic chain, as well as strengthening of the unaffected hand. Changes before and after treatment were compared using the nonparametric Wilcoxon signed rank test. ResultsA significant improvement with a large effect size in disabilities of the arm, shoulder, and hand (P < .001; d = 2.9) and visual analog scale (P < .001; d = 3.2) scores were obtained after treatment. Moreover, the changes were greater than the minimal clinically important difference of 10.8 and 1.4, respectively. Similar results were found when patients with radial instability and ulnar instability were analyzed separately. ConclusionsPersonalized training with specific proprioception and strengthening exercises produces improvements in functionality and pain perception in our cohort of people with carpal instability. These results highlight the importance of multicomponent exercise in the treatment of wrist instability. Future randomized clinical trials should further investigate the effectiveness of this protocol.

Postural Responses to Achilles Tendon Vibration Depend on Feet Positioning.

Mechanical vibration of the Achilles tendon is widely used to analyze the role of proprioception in postural control. The response to this tendon vibration (TV) has been analyzed in the upright posture, but the feet positions have varied in past research. Moreover, investigators have addressed only temporal parameters of the center of pressure (CoP). We investigated the effect of TV on both temporal and spectral characteristics of the CoP motion. Eighteen healthy young adults, stood barefoot, with one foot on each side of a dual platform, wearing glasses with opaque lenses. We applied 20seconds of Achilles TV (bilaterally with inertial vibrators at a frequency of 80Hz and an amplitude of .2-.5mm). We analyzed CoP signals pre-vibration (PRE,4-seconds), during vibration (VIB,20 seconds), and after vibration cessation (REC,20 seconds). We repeated this protocol in natural and standardized positions (15° feet angular opening). For determining CoP amplitude and velocity, we divided the 20seconds into five phases of fourseconds each and calculated spectral parameters for the whole 20-second signals. There was an adaptation process in the speed of the CoP mediolateral (p < .01) and anteroposterior (p < .01) and in the displacement of the CoP anteroposterior (p < .01), with higher values in the VIB condition. Velocity and displacement decreased progressively in the REC condition. Median and peak frequencies were higher in the VIB condition when compared to the REC condition, but only in the mediolateral direction (p = .01). The standardized foot position led to increased speed in CoP mediolateral, anteroposterior, and mediolateral displacement (p < .01). CoP spectral characteristics were not affected by foot positioning. We concluded that adaptation of CoP motion in the presence of TV and after its cessation are observable both in time and frequency domains. Feet positioning influenced CoP motion in the presence of TV and after its cessation but it did not affect its spectral characteristics.

Lumbar joint position sense measurement of patients with low back pain.

Lumbar position sense can be assessed by measurement instruments including the goniometer, isokinetic dynamometry, and electronic motion monitoring equipment, which have demonstrated relatively high reliability. This literature provides a comprehensive overview of influencing factors of lumbar position sense measurement, including repositioning method, fatigue degree, and posture during the reposition. It highlights the significant role of muscle proprioception, which contributes to greater accuracy in active reposition compared to passive reposition. The differences in lumbar position sense with different measurement positions may be explained by the presence of mechanoreceptors in the load-bearing structures of the lumbar spine, especially in the facet joint capsules. These mechanoreceptors play a crucial role in providing sensory feedback and proprioceptive information pertaining to the position and movement of the lumbar spine. Individuals with low back pain (LBP) demonstrate alterations in lumbar position sense compared to those without LBP. The auto motor sensory feedback transmission mechanism of patients with non-specific LBP was more unstable than that of healthy people. These findings suggest that lumbar position sense may play a potential role in the development and perpetuation of LBP. At present, the commonly used clinical assessment methods for determining position sense include both active and passive repositioning. However, neither method exhibits high sensitivity and specificity, leading to the poor comparability of relevant studies and posing challenges for clinical application.

Locomotion modulates olfactory learning through proprioception in C. elegans

Locomotor activities can enhance learning, but the underlying circuit and synaptic mechanisms are largely unknown. Here we show that locomotion facilitates aversive olfactory learning in C. elegans by activating mechanoreceptors in motor neurons, and transmitting the proprioceptive information thus generated to locomotion interneurons through antidromic-rectifying gap junctions. The proprioceptive information serves to regulate experience-dependent activities and functional coupling of interneurons that process olfactory sensory information to produce the learning behavior. Genetic destruction of either the mechanoreceptors in motor neurons, the rectifying gap junctions between the motor neurons and locomotion interneurons, or specific inhibitory synapses among the interneurons impairs the aversive olfactory learning. We have thus uncovered an unexpected role of proprioception in a specific learning behavior as well as the circuit, synaptic, and gene bases for this function.

Genetic exploration of roles of acid-sensing ion channel subtypes in neurosensory mechanotransduction including proprioception.

Although acid-sensing ion channels (ASICs) are proton-gated ion channels responsible for sensing tissue acidosis, accumulating evidence has shown that ASICs are also involved in neurosensory mechanotransduction. However, in contrast to Piezo ion channels, evidence of ASICs as mechanically gated ion channels has not been found using conventional mechanoclamp approaches. Instead, ASICs are involved in the tether model of mechanotransduction, with the channels gated via tethering elements of extracellular matrix and intracellular cytoskeletons. Methods using substrate deformation-driven neurite stretch and micropipette-guided ultrasound were developed to reveal the roles of ASIC3 and ASIC1a, respectively. Here we summarize the evidence supporting the roles of ASICs in neurosensory mechanotransduction in knockout mouse models of ASIC subtypes and provide insight to further probe their roles in proprioception.

Contrasting action and posture coding with hierarchical deep neural network models of proprioception.

Biological motor control is versatile, efficient, and depends on proprioceptive feedback. Muscles are flexible and undergo continuous changes, requiring distributed adaptive control mechanisms that continuously account for the body's state. The canonical role of proprioception is representing the body state. We hypothesize that the proprioceptive system could also be critical for high-level tasks such as action recognition. To test this theory, we pursued a task-driven modeling approach, which allowed us to isolate the study of proprioception. We generated a large synthetic dataset of human arm trajectories tracing characters of the Latin alphabet in 3D space, together with muscle activities obtained from a musculoskeletal model and model-based muscle spindle activity. Next, we compared two classes of tasks: trajectory decoding and action recognition, which allowed us to train hierarchical models to decode either the position and velocity of the end-effector of one's posture or the character (action) identity from the spindle firing patterns. We found that artificial neural networks could robustly solve both tasks, and the networks'units show tuning properties similar to neurons in the primate somatosensory cortex and the brainstem. Remarkably, we found uniformly distributed directional selective units only with the action-recognition-trained models and not the trajectory-decoding-trained models. This suggests that proprioceptive encoding is additionally associated with higher-level functions such as action recognition and therefore provides new, experimentally testable hypotheses of how proprioception aids in adaptive motor control.

The role of core endurance and proprioception on knee functionality in patients with patellofemoral pain

Background/Aim: Patellofemoral pain (PFP) is one of the most common musculoskeletal diagnoses which is considered to be a complex and multifactorial problem. We aimed to determine how the deficiencies in body/core muscle strength and proprioception may affect PFP development.&#x0D; Methods: Fifty patients with diffuse anterior knee pain and/or diagnosed with chondromalacia patella in the study group and 50 healthy adults in the control group were included in this prospective cross-sectional study. The patients with knee disorders except for chondromalacia patella, those who had lower extremity and spinal surgery, and/or had physical therapy in the last 3-months were excluded from the study. Active proprioceptive repositioning test and the prone-bridge test and side-bridge tests was used for primarily assessment of core muscles capacity. The knee functionality was evaluated with Kujala's knee score, and physical activity levels were evaluated with the short form of the International Physical Activity Questionnaire.&#x0D; Results: The mean age, weight, and median of body mass index were higher in the patient group while active working patients were significantly higher in control group. (p=0.041) The mean of Kujala, Prone-bridge, Side-bridge (right and left) tests were significantly higher in the control group than the patient group. (p=0.012) The mean Flex-30 test was significantly higher in the patient group than control group. (p=0.037) In the study group, there were very strong correlation between hyperextension of body and Kujala tests and between hyperextension of body and prone-bridge tests (p&lt;0.05) while, there was a very strong correlation between hyperextension of body and flex-30 tests in the control group. (p&lt;0.05)&#x0D; Conclusion: As our body has a closed kinetic chain system, it is obvious that core musculature has great importance on the knee joint. In the current study, we demonstrated the importance of core musculature both in the sense of motor and sensory on the functionality of knee joint in PFP.

Proprioceptive contribution to oculomotor control in humans.

Stretch receptors in the extraocular muscles (EOMs) inform the central nervous system about the rotation of one's own eyes in the orbits. Whereas fine control of the skeletal muscles hinges critically on proprioceptive feedback, the role of proprioception in oculomotor control remains unclear. Human behavioural studies provide evidence for EOM proprioception in oculomotor control, however, behavioural and electrophysiological studies in the macaque do not. Unlike macaques, humans possess numerous muscle spindles in their EOMs. To find out whether the human oculomotor nuclei respond to proprioceptive feedback we used functional magnetic resonance imaging (fMRI). With their eyes closed, participants placed their right index finger on the eyelid at the outer corner of the right eye. When prompted by a sound, they pushed the eyeball gently and briefly towards the nose. Control conditions separated out motor and tactile task components. The stretch of the right lateral rectus muscle was associated with activation of the left oculomotor nucleus and subthreshold activation of the left abducens nucleus. Because these nuclei control the horizontal movements of the left eye, we hypothesized that proprioceptive stimulation of the right EOM triggered left eye movement. To test this, we followed up with an eye‐tracking experiment in complete darkness using the same behavioural task as in the fMRI study. The left eye moved actively in the direction of the passive displacement of the right eye, albeit with a smaller amplitude. Eye tracking corroborated neuroimaging findings to suggest a proprioceptive contribution to ocular alignment.

Innervation of human superficial fascia.

The superficial fascia has only recently been recognized as a specific anatomical structure. Furthermore, whereas it is actually recognized that the innervation of the deep/muscular fascia plays a key role in proprioception and nociception, there are very few studies that have analyzed these characteristics in the superficial fascia. In this work, our group analyzed two different anatomical districts (abdomen and thigh), from volunteer patients, undergoing surgery procedures. Each sample was processed for histological analysis by Hematoxylin&Eosin, and by immunohistochemistry stainings (in 5-micron-paraffin embedded section and in cryosectioned free floating samples), with antibodies specific for nerve fibers: S100 antibody for myelinating and non-myelinating Schwann cells, PGP9.5 antibody as pan-neuronal marker, tyrosine hydroxylase for autonomic innervation. The results revealed a huge innervation: the nervous structures were found above all around blood vessels and close to adipocytes, but they penetrated also in the connective tissue itself and are found in the midst of fibro-adipose tissue. The tissue is pervaded by both thin (mean diameter of 4.8 ± 2.6 μm) and large nerve fiber bundles of greater diameter (21.1 ± 12.2 μm). The ratio S100/TH positivity was equal to 2.96, with a relative percentage of autonomic innervation with of 33.82%. In the light of these findings is evident that the superficial fasciae have a clear and distinct anatomical identity and a specific innervation, which should be considered to better understand their role in thermoregulation, exteroception and pain perception. The knowledge of the superficial fascia may improve grading and developing of different manual approach for treatments of fascial dysfunctions, and the understanding of how some factors like temperature or manual therapies can have an impact on sensitivity of the fascia.

Understanding implicit sensorimotor adaptation as a process of proprioceptive re-alignment.

Multiple learning processes contribute to successful goal-directed actions in the face of changing physiological states, biomechanical constraints, and environmental contexts. Amongst these processes, implicit sensorimotor adaptation is of primary importance, ensuring that movements remain well-calibrated and accurate. A large body of work on reaching movements has emphasized how adaptation centers on an iterative process designed to minimize visual errors. The role of proprioception has been largely neglected, thought to play a passive role in which proprioception is affected by the visual error but does not directly contribute to adaptation. Here, we present an alternative to this visuo-centric framework, outlining a model in which implicit adaptation acts to minimize a proprioceptive error, the distance between the perceived hand position and its intended goal. This proprioceptive re-alignment model (PReMo) is consistent with many phenomena that have previously been interpreted in terms of learning from visual errors, and offers a parsimonious account of numerous unexplained phenomena. Cognizant that the evidence for PReMo rests on correlational studies, we highlight core predictions to be tested in future experiments, as well as note potential challenges for a proprioceptive-based perspective on implicit adaptation.