Sensorimotor Conditions Research Articles

Multi-session transcutaneous spinal cord stimulation prevents chloride homeostasis imbalance and the development of hyperreflexia after spinal cord injury in rat

Spasticity is a complex and multidimensional disorder that impacts nearly 75% of individuals with spinal cord injury (SCI) and currently lacks adequate treatment options. This sensorimotor condition is burdensome as hyperexcitability of reflex pathways result in exacerbated reflex responses, co-contractions of antagonistic muscles, and involuntary movements. Transcutaneous spinal cord stimulation (tSCS) has become a popular tool in the human SCI research field. The likeliness for this intervention to be successful as a noninvasive anti-spastic therapy after SCI is suggested by a mild and transitory improvement in spastic symptoms following a single stimulation session, but it remains to be determined if repeated tSCS over the course of weeks can produce more profound effects. Despite its popularity, the neuroplasticity induced by tSCS also remains widely unexplored, particularly due to the lack of suitable animal models to investigate this intervention. Thus, the basis of this work was to use tSCS over multiple sessions (multi-session tSCS) in a rat model to target spasticity after SCI and identify the long-term physiological improvements and anatomical neuroplasticity occurring in the spinal cord. Here, we show that multi-session tSCS in rats with an incomplete (severe T9 contusion) SCI (1) decreases hyperreflexia, (2) increases the low frequency-dependent modulation of the H-reflex, (3) prevents potassium-chloride cotransporter isoform 2 (KCC2) membrane downregulation in lumbar motoneurons, and (4) generally augments motor output, i.e., EMG amplitude in response to single pulses of tSCS, particularly in extensor muscles. Together, this work displays that multi-session tSCS can target and diminish spasticity after SCI as an alternative to pharmacological interventions and begins to highlight the underlying neuroplasticity contributing to its success in improving functional recovery.

Grasping Virtual Objects Benefits Lower Aptitude Learners’ Acquisition of Foreign Language Vocabulary

Theories of embodied cognition describe language acquisition and representation as dependent on sensorimotor experiences that are collected during learning. Whereas native language words are typically acquired through sensorimotor experiences, foreign language (L2) words are often learned by reading, listening or repeating bilingual word lists. Recently, grasping referent objects has been demonstrated to serve as a useful sensorimotor strategy for L2 vocabulary learning. The effects of grasping virtual objects, however, remain unknown. In a virtual reality cave, we trained adult participants (N = 46) having low language aptitude and high language aptitude on novel L2 words under three conditions. In an audiovisual (baseline) condition, participants were presented with written and spoken L2 words. In an audiovisual observation condition, participants additionally saw virtual visual objects that corresponded to the meanings of L2 words. In an audiovisual, an observation, and a grasping condition, participants were asked to grasp the virtual objects. Participants’ word learning was assessed in free and cued recall tests administered immediately after training. Relative to baseline learning, simply viewing virtual objects during learning benefitted both groups. As expected, grasping virtual objects was found to benefit vocabulary retention in low language aptitude learners. Interestingly, this benefit was not observed in high language aptitude learners. Language learning aptitude scores correlated with vocabulary learning outcomes in both audiovisual learning conditions, but not in the sensorimotor condition, suggesting that grasping altered the typical relationship between aptitude and language learning performance. The findings are interpreted in terms of differences in the extent to which procedural and declarative memory systems are accessed in low language aptitude and high language aptitude learners during sensorimotor-based vocabulary learning. Additionally, the results suggest that simulated interactions without tangible feedback can benefit learning. This outcome expands our understanding of how physical experience extends cognition and paves the way for the application of sensorimotor enrichment strategies to virtual environments.

Neural correlates of temporal recalibration to delayed auditory feedback of active and passive movements.

When we perform an action, its sensory outcomes usually follow shortly after. This characteristic temporal relationship aids in distinguishing self- from externally generated sensory input. To preserve this ability under dynamically changing environmental conditions, our expectation of the timing between action and outcome must be able to recalibrate, for example, when the outcome is consistently delayed. Until now, it remains unclear whether this process, known as sensorimotor temporal recalibration, can be specifically attributed to recalibration of sensorimotor (action-outcome) predictions, or whether it may be partly due to the recalibration of expectations about the intersensory (e.g., audio-tactile) timing. Therefore, we investigated the behavioral and neural correlates of temporal recalibration and differences in sensorimotor and intersensory contexts. During fMRI, subjects were exposed to delayed or undelayed tones elicited by actively or passively generated button presses. While recalibration of the expected intersensory timing (i.e., between the tactile sensation during the button movement and the tones) can be expected to occur during both active and passive movements, recalibration of sensorimotor predictions should be limited to active movement conditions. Effects of this procedure on auditory temporal perception and the modality-transfer to visual perception were tested in a delay detection task. Across both contexts, we found recalibration to be associated with activations in hippocampus and cerebellum. Context-dependent differences emerged in terms of stronger behavioral recalibration effects in sensorimotor conditions and were captured by differential activation pattern in frontal cortices, cerebellum, and sensory processing regions. These findings highlight the role of the hippocampus in encoding and retrieving newly acquired temporal stimulus associations during temporal recalibration. Furthermore, recalibration-related activations in the cerebellum may reflect the retention of multiple representations of temporal stimulus associations across both contexts. Finally, we showed that sensorimotor predictions modulate recalibration-related processes in frontal, cerebellar, and sensory regions, which potentially account for the perceptual advantage of sensorimotor versus intersensory temporal recalibration.

Daytime impulsiveness, attention, and learning in the restless legs syndrome.

Restless legs syndrome (RLS) is a sensorimotor condition characterized by disturbing sensations and the desire to move, often localized in the legs. Cognitive changes and impulsivity can be present in RLS, although the potential effect of commonly co-occurring attention-deficit/hyperactivity disorders (ADHD) or dopamine agonist (DA) use on these are unclear. Twenty-three RLS patients and 22 healthy controls were included. Rey Auditory Verbal Learning Test (RAVLT), Continuous Performance Test (CPT), Beck Depression Inventory (BDI), Epworth Sleepiness Scale (ESS), State and Trait Anxiety Inventory (STAI), and Adult Attention Deficit Self-Evaluation Scale (ASRS) were administered. Performance was compared between RLS patients and controls accounting for the presence of attention-deficit/hyperactivity disorder (ADHD) and DA use. Age, education, BDI, ESS, STAI, and ASRS scores were similar for control and RLS groups. Control and RLS groups performed similarly on auditory verbal learning and general attention tests. In the CPT, commission error was significantly higher and response time was significantly shorter in the RLS group compared to controls (p = .014 and p = .010, respectively). These significant differences persisted after adjusting for ADHD and DA usage. In this study, RLS patients were more impulsive than the healthy individuals independent of ADHD and DA use. However, learning and attention performances of the patients are not affected.

Case Report: Modulation of Effective Connectivity in Brain Networks after Prosthodontic Tooth Loss Repair

INTRODUCTION. Recent neuroimaging studies suggest that dental loss replacements induce changes in neuroplasticity as well as in correlated connectivity between brain networks. However, as the typical temporal delay in detecting brain activity by neuroimaging cannot account for the influence one neural system exerts over another in a context of real activation (“effective” connectivity), it seems of interest to approach this dynamic aspect of brain networking in the time frame of milliseconds by exploiting electroencephalographic (EEG) data. MATERIAL AND METHODS. The present study describes one subject who received a new prosthodontic provisional implant in substitution for previous dental repairs. Two EEG sessions led with a portable device were recorded before and after positioning the new dental implant. By following MATLAB-EEGLAB processing supported by the plugins FIELDTRIP and SIFT, the independent component analysis (ICA) derived from EEG raw signals was rendered as current density fields and interpolated with the dipoles generated by each electrode for a dynamic study of the effective connectivity. One more recording session was undertaken six months after the placement of the final implant. RESULTS. Compared to the baseline, the new prosthodontic implant induced a novel modulation of the neuroplasticity in sensory-motor areas which was maintained following the definitive implant after six months, as revealed by changes in the effective connectivity from the basal strong enslavement of a single brain area over the others, to an equilibrate inter-related connectivity evenly distributed along the frontotemporal regions of both hemispheres. CONCLUSIONS. The rapid shift of the effective connectivity after positioning the new prosthodontic implant and its substantial stability after six months suggest the possibility that synaptic modifications, induced by novel sensory motor conditions, modulate the neuroplasticity and reshape the final dynamic frame of the interarea connectivity. Moreover, given the viability of the EEG practice, this approach could be of some interest in assessing the association between oral pathophysiology and neuronal networking.

Buprenorphine, a partial opioid agonist, prevents modulation of H-reflex induced by pulsed electromagnetic stimulation in spinal cord injured rats

Our recent study revealed that spinal electromagnetic stimulation (sEMS) applied at low (0.2 Hz) frequencies may improve diminished transmission in damaged spinal cord in spinal cord injured (SCI) rats. We have recently begun a pilot study investigating the effects of sEMS in non-injured and SCI humans. One unexpected result was the reduction of chronic low back pain (CLBP), reported by some patients following sEMS treatment. Chronic low back pain is one of the main causes of disability affecting the general population. Opioids are the most common drugs prescribed to US adults with CLBP. To optimize parameters for sEMS for pain treatment, in this study we used the SCI animal model and examined effects of sEMS applied at lumbosacral level on parameters and frequency-dependent depression (FDD) of Hoffmann H-reflex responses, known as common neurophysiological measures for evaluation of sensorimotor condition and plasticity in humans. We have also examined the interactive effects of sEMS and the opiate partial agonist Buprenorphine on the parameters of H-reflex in naïve and SCI rats. Consistent with previous reports, chronic SCI resulted in a marked decrease of threshold intensity required to evoke H-reflex and a lesser rate of FDD of the H-response in adult rats. Our current study revealed the optimum parameters of spinal EMS for best recovery of the properties of the H-reflex in chronic SCI animals. Here we demonstrate that electro-magnetic stimulation applied at spinal L4-L5 level with a pulsed mode (pulse at 20 Hz frequency for 5 sec with 25 sec break between pulses, total 40 trains for 20 min; PSEMS) reversed effects of SCI on key parameters of H-reflex: i.e. (1) restored the threshold intensity of electric current applied at tibial nerve to evoke the H-reflex and (2) recovered FDD properties of the H-reflex in SCI rats. Importantly, subcutaneous injections of Buprenorphine, prior to PSEMS administration, abolished the ability of PSEMS to recover both threshold intensity and FDD of the H-reflex in chronic SCI animals. These results suggest that a semi-synthetic opioid Buprenorphine and PSEMS might share common sites of action. We thus conclude that PSEMS might carry potential as a non-invasive treatment approach for chronic low back pain.

A new approach of inducing proprioceptive illusion by transcutaneous electrical stimulation

BackgroundNeurotraumas or neurodegenerative diseases often result in proprioceptive deficits, which makes it challenging for the nervous system to adapt to the compromised sensorimotor conditions. Also, in human machine interactions, such as prosthesis control and teleoperation, proprioceptive mismatch limits accuracy and intuitiveness of controlling active joints in robotic agents. To address these proprioceptive deficits, several invasive and non-invasive approaches like vibration, electrical nerve stimulation, and skin stretch have been introduced. However, proprioceptive modulation is still challenging as the current solutions have limitations in terms of effectiveness, usability, and consistency. In this paper, we propose a new way of modulating proprioception using transcutaneous electrical stimulation. We hypothesized that transcutaneous electrical stimulation on elbow flexor muscles will induce illusion of elbow joint extension.MethodEight healthy human subjects participated in the study to test the hypothesis. Transcutaneous electrodes were placed on different locations targeting elbow flexor muscles on human subjects and experiments were conducted to identify the best locations for electrode placement, and best electrical stimulation parameters, to maximize induced proprioceptive effect. Arm matching experiments and Pinocchio illusion test were performed for quantitative and qualitative analysis of the observed effects. One-way repeated ANOVA test was performed on the data collected in arm matching experiment for statistical analysis.ResultsWe identified the best location for transcutaneous electrodes to induce the proprioceptive illusion, as one electrode on the muscle belly of biceps brachii short head and the other on the distal myotendinous junction of brachioradialis. The results for arm-matching and Pinocchio illusion tests showed that transcutaneous electrical stimulation using identified electrode location and electrical stimulation parameters evoked the illusion of elbow joint extension for all eight subjects, which supports our hypothesis. On average, subjects reported 6.81° angular illusion of elbow joint extension in arm-matching tests and nose elongated to 1.78 × height in Pinocchio illusion test.ConclusionsTranscutaneous electrical stimulation, applied between the the synergistic elbow flexor muscles, consistently modulated elbow joint proprioception with the illusion of elbow joint extension, which has immense potential to be translated into various real-world applications, including neuroprosthesis, rehabilitation, teleoperation, mixed reality, and etc.

Speech Intensity Response to Altered Intensity Feedback in Individuals With Parkinson's Disease.

Purpose Hypophonia (low speech intensity) is the most common speech symptom experienced by individuals with Parkinson's disease (IWPD). Previous research suggests that, in IWPD, there may be abnormal integration of sensory information for motor production of speech intensity. In the current study, intensity of auditory feedback was systematically manipulated (altered in both positive and negative directions) during sensorimotor conditions that are known to modulate speech intensity in everyday contexts in order to better understand the role of auditory feedback for speech intensity regulation. Method Twenty-six IWPD and 24 neurologically healthy controls were asked to complete the following tasks: converse with the experimenter, start vowel production, and read sentences at a comfortable loudness, while hearing their own speech intensity randomly altered. Altered intensity feedback conditions included 5-, 10-, and 15-dB reductions and increases in the feedback intensity. Speech tasks were completed in no noise and in background noise. Results IWPD displayed a reduced response to the altered intensity feedback compared to control participants. This reduced response was most apparent when participants were speaking in background noise. Specific task-based differences in responses were observed such that the reduced response by IWPD was most pronounced during the conversation task. Conclusions The current study suggests that IWPD have abnormal processing of auditory information for speech intensity regulation, and this disruption particularly impacts their ability to regulate speech intensity in the context of speech tasks with clear communicative goals (i.e., conversational speech) and speaking in background noise.

Validating the use of functional Near-Infrared Spectroscopy in monkeys: The case of brain activation lateralization in Papio anubis

Hemispheric asymmetries have long been seen as characterizing the human brain; yet, an increasing number of reports suggest the presence of such brain asymmetries in our closest primate relatives. However, most available data in non-human primates have so far been acquired as part of neurostructural approaches such as MRI, while comparative data in humans are often dynamically acquired as part of neurofunctional studies. In the present exploratory study in baboons (Papio anubis), we tested whether brain lateralization could be recorded non-invasively using a functional Near-Infrared Spectroscopy (fNIRS) device in two contexts: motor and auditory passive stimulations. Under light propofol anaesthesia monitoring, three adult female baboons were exposed to a series of (1) left- versus right-arm passive movement stimulations; and (2) left- versus right-ear versus stereo auditory stimulations while recording fNIRS signals in the related brain areas (i.e., motor central sulcus and superior temporal cortices respectively). For the sensorimotor condition our results show that left-arm versus right-arm stimulations induced typical contralateral difference in hemispheric activation asymmetries in the three subjects. For the auditory condition, we also revealed typical human-like patterns of hemispheric asymmetries in one subject, namely a leftward lateralization for right ear stimulations for all three channels. Overall, our findings support the use of fNIRS to investigate brain processing in non-human primates from a functional perspective, opening the way for the development of non-invasive procedures in non-human primate brain research.

Cognitive profile in Restless Legs Syndrome: A signal-to-noise ratio account.

Restless legs syndrome (RLS) is a common neurological disorder characterized by a sensorimotor condition, where patients feel an uncontrollable urge to move the lower limbs in the evening and/or during the night. RLS does not only have a profound impact on quality of life due to the disturbed night-time sleep, but there is growing evidence that untreated or insufficiently managed RLS might also cause cognitive changes in patients affected by this syndrome. It has been proposed that RLS is caused by alterations in the signal-to-noise ratio (SNR) and in dopamine (DA) neurotransmission in the nervous system. Based on this evidence, we propose the “SNR-DA hypothesis” as an explanation of how RLS could affect cognitive performance. According to this hypothesis, variations/reductions in the SNR underlie RLS-associated cognitive deficits, which follow an inverted U-shaped function: In unmedicated patients, low dopamine levels worsen the SNR, which eventually impairs cognition. Pharmacological treatment enhances DA levels in medicated patients, which likely improves/normalizes the SNR in case of optimal doses, thus restoring cognition to a normal level. However, overmedication might push patients past the optimal point on the inverted U-shaped curve, where an exaggerated SNR potentially impairs cognitive performance relying on cortical noise such as cognitive flexibility. Based on these assumptions of SNR alterations, we propose to directly measure neural noise via “1/f noise” and related metrics to use transcranial random noise stimulation (tRNS), a noninvasive brain stimulation method which manipulates the SNR, as a research tool and potential treatment option for RLS.

Translation, Validity, and Reliability of the Upper Extremity Fugl-Meyer Assessment (FMA-UE) in Persian Speaking Stroke Patients

Objectives: Fugl-Meyer Assessment (FMA) is the common scale for clinical and functional evaluation of sensorimotor conditions and related Upper Extremity (UE) dysfunction after stroke. This study was done to translate and cross-culturally adjust the original upper extremity FMA (FMA-UE) into Persian and to evaluate the psychometric properties of the translated version. Methods: A procedure of forward/backward translation based on the published guidelines was adopted and two independent bilingual translators performed the translations in each stage. The conceptual and semantic equivalence was obtained through a consensus between experts. Consecutive stroke patients (n=47, male=63%) with a mean age of 61.54±10.9 years were recruited. Content, face, and concurrent validity was calculated using the content validity index, a cognitive interview, and correlation with the Wolf Motor Function Test (WMFT). Internal consistency and intra-rater reliability were determined by calculating Cronbach’s alpha and the Intra-Class Correlation coefficient (ICC2.1). Results: During the forward translation and cultural adjustment, some wording changes were performed. In the forward translation, the most challenging clarifications are related to anatomical terms and positions. The total FMA-Persian score demonstrated acceptable internal consistency (α=0.86) and intra-rater reliability (ICC2.1=0.96). Joint passive motion showed the lowest reliability among all domains. The FMA motor subscales showed a floor effect, while sensation, joint passive motion, and pain domains showed ceiling effects. The correlation between the FMA-UE score and the WMFT was 0.78 (P<0.001). Discussion: The FMA-UE translation and adjustment were performed successfully into the Persian language. The results of the current study found FMA-UE as an acceptable, reliable, and valid instrument for evaluating the upper limb function after stroke in Persian-speaking patients. However, it should be noted that floor and ceiling effects are respectively present in the domains of the motor subscales and for sensation, passive motion, and pain.

Back to reality: differences in learning strategy in a simplified virtual and a real throwing task.

Virtual environments have been widely used in motor neuroscience and rehabilitation, as they afford tight control of sensorimotor conditions and readily afford visual and haptic manipulations. However, typically, studies have only examined performance in the virtual testbeds, without asking how the simplified and controlled movement in the virtual environment compares to behavior in the real world. To test whether performance in the virtual environment was a valid representation of corresponding behavior in the real world, this study compared throwing in a virtual set-up with realistic throwing, where the task parameters were precisely matched. Even though the virtual task only required a horizontal single-joint arm movement, similar to many simplified movement assays in motor neuroscience, throwing accuracy and precision were significantly worse than in the real task that involved all degrees of freedom of the arm; only after 3 practice days did success rate and error reach similar levels. To gain more insight into the structure of the learning process, movement variability was decomposed into deterministic and stochastic contributions. Using the tolerance-noise-covariation decomposition method, distinct stages of learning were revealed: While tolerance was optimized first in both environments, it was higher in the virtual environment, suggesting that more familiarization and exploration was needed in the virtual task. Covariation and noise showed more contributions in the real task, indicating that subjects reached the stage of fine-tuning of variability only in the real task. These results showed that while the tasks were precisely matched, the simplified movements in the virtual environment required more time to become successful. These findings resonate with the reported problems in transfer of therapeutic benefits from virtual to real environments and alert that the use of virtual environments in research and rehabilitation needs more caution.NEW & NOTEWORTHY This study compared human performance of the same throwing task in a real and a matched virtual environment. With 3 days' practice, subjects improved significantly faster in the real task, even though the arm and hand movements were more complex. Decomposing variability revealed that performance in the virtual environment, despite its simplified hand movements, required more exploration. Additionally, due to fewer constraints in the real task, subjects could modify the geometry of the solution manifold, by shifting the release position, and thereby simplify the task.

0797 Restless Legs Syndrome and Perceived Olfactory and Taste Dysfunction: A Community-Based Study

Abstract Introduction Restless legs syndrome (RLS), an under-recognized sensorimotor condition worldwide, is thought to be a prodromal symptom of Parkinson’s disease as suggested by previous evidences. However, its association with prodromal chemosensory impairments, including olfactory or taste dysfunction, has remained largely unknown. Few studies of small sample sizes were conducted in predominantly Caucasian populations and results were inconsistent. Methods We performed a cross-sectional analysis including 90,337 Chinese adults free of neurodegenerative diseases in the Kailuan study in 2016. Presence of RLS was defined using revised RLS diagnostic criteria and further verified by Cambridge-Hopkins questionnaire for RLS. Perceived olfactory and taste dysfunction was collected via a questionnaire. The association between RLS and perceived olfactory and taste dysfunction was assessed using logistic regression model, adjusting for potential cofounders such as age, sex, smoking, alcohol consumption sleep conditions and medical history. Results RLS was associated with high odds of having perceived olfactory and/or taste dysfunction (adjusted odds ratio =5.92; 95% confidence interval, 3.11, 11.3). The significant association persisted when using Cambridge-Hopkins questionnaire for RLS (adjusted odds ratio =5.55; 95% confidence interval, 2.37-13.0) or when excluding participants with major chronic diseases. Conclusion RLS was associated with increased odds of perceived olfactory and taste dysfunction. Support This research was supported by start-up grant from the College of Health and Human Development and the Department of Nutritional Sciences, Pennsylvania State University, the Institute for CyberScience Seed Grant Program, Pennsylvania State University, and Natural Science Foundation of Hebei Province (H2018209318).

Randomized pilot trial for the efficacy of the MMF07 foot massager and heat therapy for restless legs syndrome.

BackgroundRestless Legs Syndrome (RLS) is a sensorimotor condition with a wide range of severity. Symptoms negatively affect sleep and quality of life. Pharmacologic options are not universally effective and side effects are common. Objective data regarding non-pharmacologic treatment is limited. The study objective was to evaluate the efficacy of the MMF07 foot massager and heat therapy on the severity of RLS symptoms.MethodsIn this pilot randomized controlled trial, twenty-eight patients with diagnosed, bothersome RLS were randomized to four treatment arms: no active intervention (n = 7), foot massager (n = 8), heat therapy (n = 6), and foot massager plus heat therapy (n = 7). Participants completed the RLS Severity Scale, RLS Quality of Life questionnaire, and the Medical Outcomes Study Sleep scale at the baseline visit and at the 4-week follow up visit.ResultsFour weeks post randomization, participants in the massager group had significant improvement in the RLS severity score (average difference: -9.0, 95% CI: -16.3, -1.7, p = 0.017) and sleep scale (average difference: -22.0, 95% CI: -36.5, -7.5, p = 0.005) compared to the no intervention group. The heat alone group had a significant improvement in the sleep scale compared to the no-intervention group (average difference: -17.4, 95% CI: -32.5, -2.3, p = 0.026). Quality of life improved in the massage only group compared to control (average difference 25.3, 95% CI: -2.4, 53.0, p = 0.072).ConclusionsResults suggest that the MMF07 foot massage device and heat therapy may be feasible and effective treatment options to improve RSL symptoms.

Auditory influence on postural control during stance tasks in different acoustic conditions.

Postural stability might be influenced by auditory input as humans utilize spatiotemporal information to localise sound sources. Earlier studies investigated the acoustic influence on posture but unfortunately experimental setup, room acoustics and conditions of participants varied widely. This study aimed at recording body sway velocity under clearly defined acoustic conditions in a homogenous group of young healthy participants. Thirty participants performed five stance tasks (standing eyes open/closed, standing on a foam support eyes open/closed, Tandem Romberg test eyes closed) under four acoustic conditions (in quiet, with a loudspeaker presenting continuous/interrupted noise, with ear protectors) in two different rooms (long/short reverberation time). Body sway velocity was determined close to body's centre of gravity. Postural stability decreased significantly when continuous noise was applied and increased significantly when interrupted noise was presented in the reverberant room. The usage of ear protectors increased body sway velocity compared to quietness in both rooms. An impaired auditory input by plugging/acoustic masking reduced postural control. Interrupted noise seems to provide a continuously repeated feedback about the postural position in a reverberant room. Hence, the effect of hearing on posture highly depends on the structure of the auditory signal, the sensorimotor condition and the acoustic environment.

Topology highlights mesoscopic functional equivalence between imagery and perception: The case of hypnotizability

The functional equivalence (FE) between imagery and perception or motion has been proposed on the basis of neuroimaging evidence of large spatially overlapping activations between real and imagined sensori-motor conditions. However, similar local activation patterns do not imply the same mesoscopic integration of brain regions, which can be described by tools from Topological Data Analysis (TDA). On the basis of behavioral findings, stronger FE has been hypothesized in the individuals with high scores of hypnotizability scores (highs) with respect to low hypnotizable participants (lows) who differ between each other in the proneness to modify memory, perception and behavior according to specific imaginative suggestions. Here we present the first EEG evidence of stronger FE in highs. In fact, persistent homology shows that the highs EEG topological asset during real and imagined sensory conditions is significantly more similar than the lows. As a corollary finding, persistent homology shows lower restructuring of the EEG asset in highs than in lows during both sensory and imagery tasks with respect to basal conditions. Present findings support the view that greater embodiment of mental images may be responsible for the highs greater proneness to respond to sensori-motor suggestions and to report involuntariness in action. In addition, findings indicate hypnotizability-related sensory and cognitive information processing and suggest that the psycho-physiological trait of hypnotizability may modulate more than one aspect of the everyday life.

Familiarization with treadmill walking: How much is enough?

Treadmill-based gait analysis is widely used to investigate walking pathologies and quantify treatment effects on locomotion. Differential sensorimotor conditions during overground vs. treadmill walking necessitate initial familiarization to treadmill walking. Currently, there is no standardized treadmill acclimatization protocol and insufficient familiarization potentially confounds analyses. We monitored initial adaptations to treadmill walking in 40 healthy adults. Twenty-six walking parameters were assessed over 10 minutes with marker-based kinematic analysis and acclimatization profiles were generated. While 16 walking parameters demonstrated initial acclimatization followed by plateau performance, ten parameters remained stable. Distal lower limb control including ankle range of motion, toe trajectory and foot clearance underwent substantial adaptations. Moreover, intralimb coordination and gait variability also demonstrated acclimatization, while measures of symmetry and interlimb coordination did not. All parameters exhibiting a plateau after acclimatization did so within 6–7 minutes (425 strides). Older participants and those naïve to treadmill walking showed adaptations with higher amplitudes but over similar timescales. Our results suggest a minimum of 6 minutes treadmill acclimatization is required to reach a stable performance, and that this should suffice for both older and naïve healthy adults. The presented data aids in optimizing treadmill-based gait analysis and contributes to improving locomotor assessments in research and clinical settings.

Restless Legs Syndrome in Children.

Restless legs syndrome (RLS) is a common pediatric condition that often goes undiagnosed. The genetics and pathophysiology of this sensorimotor condition are still not well understood. RLS can affect any part of the body, but the thighs and calves are the most commonly affected. Because of unpleasant sensations caused by RLS, these patients experience sleep disturbance and its consequences. The diagnosis of RLS is a clinical one. RLS occurs at a higher frequency and the symptoms are more severe in patients with iron deficiency; therefore, correcting iron deficiency improves the symptoms. Both pharmacologic and nonpharmacologic interventions can be effective in the treatment of children with RLS. However, in contrast to adults with RLS, most children with RLS are not treated with pharmacologic agents because the symptoms are not as severe as they are in adults. [Pediatr Ann. 2018;47(12):e504-e506.].

Bioelectronic Medicine-Ethical Concerns.

Bioelectronic medicine (BEM) offers exciting opportunities to treat diseases such as movement disorders and refractory inflammatory disease. The many variations of BEM allow for noninvasive aspects of treatment that might eliminate or reduce the need for pharmaceuticals; therefore, the term "electroceuticals" may be suitable. BEM has been effective for movement disorders and improvement of prosthetic devices. Based on this implication, there is an allowance to impact many focus areas that include but are not limited to autoimmune disease, sensory motor conditions, and neurological conditions. There are a wide array of ethical issues that relate to BEM, which include informed consent, research ethics, innovation, academic-industry relationships, intellectual property, and the conundrum that needs to be addressed when altering the brain such as the issues of autonomy and free beneficence and social justice. The major goal is to heighten awareness of ethical issues and facilitate a proactive ethical approach regarding BEM research.

Topology highlights mesoscopic functional equivalence between imagery and perception

The functional equivalence between mental images and perception or motion has been proposed on the basis of neuroimaging evidence of large spatially overlapping activations between real and imagined sensori-motor conditions. However, similar local activation patterns do not imply the same mesoscopic integration of brain regions active during imagery and perception or action. Here we present the first EEG evidence of topological equivalence between functional network organization at intermediate and global scales during tasks. We show that the degree of functional equivalence varies in the population and is associated with different magnitudes in the restructuring of the functional connectivity between imagery and real tasks. In particular, changes observed during imagery with respect to basal conditions account for the cognitive effort experienced during imagery, and subjects characterized by stronger functional equivalence exhibit smaller topological deviations in the imagination tasks performed after real tasks, thus showing learning effects. Altogether, our findings point to different sensori-cognitive information processing in the subjects showing different functional equivalence. We anticipate our results to be a starting point for a novel dynamical description of functional equivalence, which will be relevant for socio-cognitive theories of embodiment and cognitive formulations of how different selves emerge from neurophysiological assets.