Somatosensory & motor research最新文献

Aim: Hemispheric asymmetry is well established in tactile processing, with higher cortical responses observed on the contralateral side of the stimulation area. However, the effect of the interstimulus interval on lateralization is poorly understood. In this context, we aimed to reveal the effects of repeated non-painful tactile stimuli on brain responses and hemispheric lateralization via static ISIs.

Methods: Twenty-six healthy participants (13 females; mean age 22.2 ± 3.30 years) participated in the study. Tactile stimuli were delivered to the index fingertip of the right hand via a pneumatic stimulator with static ISIs (2s, 4s, and 8s applied as separate sessions). Electroencephalography was performed throughout the procedure. We determined the ROI and primarily analysed nine electrodes (Fz, Cz, Pz, F3, C3, P3, F4, C4, and P4). We measured the peak-to-peak maximum amplitudes (PP_maxN2P3) between N₂₀₀ and P₃₀₀, labelling N₂₀₀ as N₂ and P₃₀₀ as P₃.

Results: The results revealed no significant differences in the amplitudes of PP_maxN2P3 between the ipsilateral and contralateral hemispheres. Constant ISI manipulation altered the laterality of non-painful tactile stimuli. Furthermore, the amplitude of the brain responses would be higher in both the ipsilateral and contralateral hemispheres when the ISI increased. The evaluation of the duration of PP_maxN2P3 was prolonged in the frontal, central, and parietal areas.

Conclusion: The results indicate that manipulation of the interstimulus interval (ISI) can potentially negate the traditional contralateral advantage observed in tactile processing.

The maintenance of proprioception in upright standing posture and joint position sense accuracy (JPSA), is contingent on the coordination of sensory inputs made available to individuals during the task. Adding texture to augment cutaneous feedback on neuromuscular control of the ankle joint has yet to be studied in JPSA, thus motivating the purpose of this research to investigate the changes in ankle joint proprioception when wearing textured (FOTs) and non-textured orthoses (FOs) during a passive ankle joint position reproduction task in healthy young and middle-aged individuals (n = 48; 31 under 30 years, 17 over 30 years). Error accuracy, tibialis anterior and medial gastrocnemius muscle activity, and centre of pressure displacement were recorded from 48 participants while completing four ankle JPSA replication tasks (5°, 10° plantarflexion, 5°, 10° dorsiflexion) in stance. When the middle-aged participants (over 30 years) completed the dorsiflexion 5° JPSA task, a 31% error reduction was observed standing in FOTs compared to FOs. These results provide evidence supporting the effectiveness of adding cutaneous feedback to improve proprioception in middle-aged individuals.

Often, somatosensory and motor symptoms frequently co-occur in individuals with neurological conditions. These two systems exert reciprocal influences on one another; thus, an effective neurological rehabilitation protocol in clinical practice should concurrently address both motor and sensory assessment and training procedures. Although neurological rehabilitation guidelines emphasize the motor and sensory systems, it is valuable to examine contemporary approaches to their assessment and rehabilitation separately and in detail. In this review, we synthesize current neurological rehabilitation strategies for Stroke, Multiple Sclerosis, and Parkinson's Disease. In addition to outlining the clinical presentation of these pathologies, we provide a comprehensive overview of motor and sensory assessment methods as well as current rehabilitation approaches.

Purpose: To investigate the effects of Marmara propolis on the duration of sensory, deep sensory, and motor block recovery when used alone or in combination with bupivacaine in a rat sciatic nerve block model.

Materials and methods: Thirty-two Wistar-Albino rats were randomly divided into four groups (n = 8): Group Bupivacaine (Group B) received 0.2 mL of 0.5% bupivacaine perineurally; Group Propolis (Group P) received 30 mg/kg of Marmara propolis (0.2 ml) perineurally; Group Bupivacaine + Propolis (Group BP) received a combination of 0.2 mL bupivacaine and 30 mg/kg propolis perineurally; Group Bupivacaine + Propolis intraperitoneally (Group BPip) received 0.2 mL bupivacaine perineurally and 30 mg/kg propolis intraperitoneally. Sensory, deep sensory, and motor function recoveries were assessed every 5 min until full recovery.

Results: Group BP showed significantly longer recovery times for all three modalities compared to all other groups (p < 0.001). Group BPip also demonstrated prolonged deep sensory and motor recovery times compared to Groups B and P (p < 0.001). Group P exhibited the shortest recovery times across all measurements.

Conclusions: Marmara propolis, particularly when used in combination with bupivacaine, prolongs sensory, deep sensory, and motor block durations. These findings suggest that propolis may have both local and systemic adjuvant effects in regional anaesthesia applications.HIGHLIGHTS OF THE STUDYMarmara propolis significantly prolonged sensory, deep sensory, and motor block durations when administered perineurally in a rat sciatic nerve block model.Intraperitoneal administration of propolis also resulted in prolonged deep sensory and motor block recovery, indicating systemic analgesic activity.The combination of bupivacaine and propolis produced the longest block durations, suggesting a synergistic or adjuvant effect.This is the first study to investigate both local and systemic applications of propolis as an adjunct to regional anaesthesia.Findings support the potential use of propolis as a natural, plant-based adjuvant in peripheral nerve blocks.

Aim of the study: Brain-computer interfaces (BCIs) may help patients with severe neurological deficits communicate with the external world. Based on microelectrocorticography (µECoG) data recorded from the primary somatosensory cortex (S1) of unrestrained behaving rats, this study attempts to decode lever presses in a psychophysical detection task by using machine learning algorithms.

Materials and methods: 16-channel Pt-Ir microelectrode arrays were implanted on the S1 of two rats, and µECoG was recorded during a vibrotactile yes/no detection task. For this task, the rats were trained to press the right lever when they detected the vibrotactile stimulus and the left lever when they did not. The multichannel µECoG data was analysed offline by time-frequency methods and its features were used for binary classification of the lever press at each trial. Several machine learning algorithms were tested as such.

Results: The psychophysical sensitivities (A') were similar and low for both rats (0.58). Rat 2 (B'': -0.11) had higher bias for the right lever than Rat 1 (B'': - 0.01). The lever presses could be predicted with accuracies over 66% with all the tested algorithms, and the highest average accuracy (78%) was with the support vector machine.

Conclusion: According to the recent studies, sensory feedback increases the benefit of the BCIs. The current proof-of-concept study shows that lever presses can be decoded from the S1; therefore, this area may be utilised for a bidirectional BCI in the future.

Perineuronal nets (PNNs) are specialised extracellular matrix structures of the central nervous system that predominantly surround inhibitory interneurons. The development of PNNs is activity dependent and relies on sensory input to mature to an adult expression pattern, coinciding with the crysallization of synaptic circuitry following the closure of the developmental critical period. Our results of a neocortical characterisation demonstrate that the density of PNNs in the neocortex of the Long Evans rat was consistent across animals but varied as a function of the cortical region. Utilising a non-biased random effect model, it was shown that the retrosplenial granular cortex had the highest PNN density and the intermediate endopiriform cortex had the lowest. Given the importance of mystacial vibrissae to the behaviour of rodents, we further analysed the laminar distribution of PNNs within the primary somatosensory cortex (S1). Our results revealed that the layer IV, the 'barrel' region, contained the highest density of PNNs. Within S1, PNN density was consistent across all subregions. S1 had a significantly higher density of PNNs compared with the primary motor (M1) cortex, and PNN levels did not show lateralisation in either M1 or S1. Independent of cortical location, we observed a novel class of relatively large, brightly stained neurons ensheathed by PNNs, which were present exclusively along the layer VI-white matter border. A better understanding of PNNs and their distribution can assist in our understanding of how PNN manipulation can affect neurological conditions such as schizophrenia, epilepsy, stroke, central nervous system injuries, and degenerative processes.

Purpose: The H reflex recruitment curve represents the gold standard for quantifying changes in spinal circuitries. However, there is no agreement on how many stimulations should be applied for each parameter. Thus, we explored the impact of varying the number of stimulations (3, 6, 9, 12 and 15 stimuli per intensity) on between-day reliability of soleus H reflex.

Materials and methods: Twenty healthy participants (11 males, 9 females; age: 22.4 ± 2.3 years) visited the laboratory on two days for H-recruitment curves construction, using a 3 s inter-stimuli interval. To explore whether H reflex parameters differed between days, without varying the number of stimulations, paired-sample t tests were performed. Relative and absolute reliability were calculated using the intraclass correlation coefficients (ICCs) and the coefficients of variation (CVs), respectively.

Results: M_max, H_max/M_max, H slope, H_thresh, current at 50% of H_max and current at H_max were not significantly different between days (all p > 0.05). ICCs of M_max, H_max/M_max and H_thresh were all good (0.79-0.89). H slope ICCs were moderate (0.56-0.73) between 3 and 12, but good (0.75) with 15 stimulations. Current at H_max ICCs were moderate (0.55-0.0.73) with all stimulations, except with 9 (good: 0.76). CVs of the current at H_max were all moderate (between 5-to-10%). H_thresh CV was poor (>10%) with three, but moderate for other stimulations. M_max, H_max/M_max and H slope CVs were generally poor.

Conclusions: 9 stimulations are required to ensure higher between-day reliability of H reflex parameters, except for H slope that requires 15 stimulations.

Aim of the study: Sensory gating is a human higher cognitive function that serves to suppress excessive sensory information and prevent brain overactivity. To elucidate this function, a paired-pulse stimulation paradigm has been used while recording electroencephalography (EEG), and evaluated as an amplitude ratio of responses to a second stimulus (S2) over responses to the first stimulus (S1). The present study investigated the effects of the inter-stimulus interval (ISI) and inter-trial interval (ITI) on somatosensory gating using somatosensory-evoked potentials (SEPs).

Methods: In Experiment 1, ISI was set at five conditions: 200, 400, 600, 800, and 1000 ms. In Experiment 2, ITI was set at four conditions: 1, 2, 4, and 8 s.

Results: ISI affected the S2/S1 amplitude ratios of P22 and N27 at C3' and N30 at Fz, and these S2/S1 amplitude ratios decreased the most under the 200 and 400-ms conditions. ITI affected the S2/S1 amplitude ratios of P22, N27, and N60 at C3', and especially, the somatosensory gating did not work under the 1-s condition. These results suggest that not all SEP components are modulated in the same manner with changing ISI and ITI. The effects of ISI and ITI independently affected the somatosensory gating.

Conclusions: Based on our findings, preferable parameters are 200-400 ms for ISI and 4 s or longer for ITI to evaluate the functional mechanisms on somatosensory gating in SEPs.

Objective: To investigate the relationship between newly identified senataxin (SETX) gene mutations and the clinical manifestation of Amyotrophic Lateral Sclerosis (ALS), enhancing understanding of the genetic underpinnings associated with this disorder.

Methods: A cohort study was conducted at Nanfang Hospital, involving comprehensive genetic sequencing of ALS patients to identify novel SETX mutations. Homology modelling and structural analysis were employed to predict the functional impacts of these mutations on the senataxin protein. Clinical assessments, including symptom evaluation, age of onset, and progression rate, were integrated with electrophysiological studies to establish correlations between genetic variants and clinical outcomes.

Results: Ten novel SETX mutations were identified, expanding the genetic landscape of ALS. These mutations exhibited diverse impacts on clinical presentations, with patients showing variability in onset age, symptom severity, and progression rates. Computational modelling suggested that certain mutations cause significant structural changes in senataxin, potentially affecting its RNA/DNA helicase function. Electrophysiological findings consistently revealed nerve conduction abnormalities, indicating that these mutations may influence neuronal excitability and contribute to ALS pathogenesis.

Conclusion: The discovery of novel SETX mutations provides valuable insights into the genetic and clinical complexity of ALS. This study underscores the importance of genetic screening for SETX mutations and suggests potential personalised therapeutic approaches targeting senataxin dysfunction. By elucidating genotype-phenotype correlations, these findings contribute to the broader understanding of ALS and offer pathways for developing targeted interventions to address the challenges posed by this disabling disease.

Purpose: The objective assessment of the upper limbs of stroke survivors is challenging. Serious game-based assessments may allow for an objective assessment of this population. The present work aims to investigate the validity of the metrics provided by the Upper Extremity Smart Exercises-Innovative Treatment (USE-IT) assessment method for upper limb rehabilitation.

Materials and methods: Thirty-three stroke survivors were included in this study. We assessed the stroke survivors using The Fugl-Meyer Upper Extremity Scale (FM-UE), The Wolf Motor Function Test (WMFT), The Action Research Arm Test (ARAT), ABILHAND, ACTIVLIM, and the USE-IT. Validity was assessed by examining the correlation of the USE-IT metrics with the clinical scales.

Results: All clinical scales and the Global Reaching Map total score, one of the two outputs of the USE-IT assessment method, were found to be moderately correlated (|r| = 0.52-0.69) (p < .05). The other outputs of the USE-IT assessment method, the Local Reaching Map total score, showed a correlation with the Fugl-Meyer Assessment Upper Arm (FM-UA), The Action Research Arm Test (ARAT) Grip, and the Wolf Motor Function Test (WMFT) parameters (|r| = 0.34-0.38) (p < .05).

Conclusions: This study showed that the USE-IT assessment is well correlated with commonly used clinical scales for the upper limb motor function in stroke survivors. Therefore, the USE-IT is a valid game-based system for assessing upper limb impairment in stroke survivors.