Mammalian sensory systems are traditionally viewed as hierarchical pathways in which subcortical nuclei relay signals from peripheral receptors to the cortex, where sensory information is contextualized for perception and behaviour. However, the auditory pathway contains an unusually large number of anatomically complex, recurrently connected subcortical nuclei that transmit heavily pre-processed information to the cortex. Emerging evidence shows that the auditory system functions as an integrated cortical-subcortical networkthat is heavily influenced by non-auditory inputs and extensive bidirectional connectivity at nearly all levels. Subcortical structures are not passive relays but active participants in computations traditionally attributed to cortex, including adaptive coding of sound statistics, multisensory integration, encoding of behavioural relevance and action, and learning. Although certain transformations occur hierarchically - such as brainstem spatial processing - sensitivity to most sound features forms a continuum across the auditory pathway, with modulation by other sensory, motor and cognitive systems at every stage. The degree of subcortical pre-processing may explain why emergent cortical properties are harder to identify in audition than in vision, in which cortical and subcortical receptive field properties are more distinct. This distributed circuit organization opens new avenues for understanding how the brain constructs perception and guides behaviour from the fusion of sensory evidence and contextual knowledge.

Distress, not symptoms: Reframing psychological difficulties in neurodegenerative diseases of the motor system.

This study investigated the neurophysiological mechanisms linking visual body perception to motor output in females with adolescent idiopathic scoliosis (AIS), specifically examining how altered body schema influences corticospinal excitability. A two-stage paradigm was employed in participants with AIS and healthy controls. First, psychophysical thresholds for detecting spinal curvature were estimated. Second, single-pulse transcranial magnetic stimulation (TMS) was applied over the primary motor cortex (100-125 ms post-stimulus) to assess motor system reactivity to body-relevant stimuli. Corticospinal excitability was recorded via motor evoked potentials (MEPs) from intrinsic hand muscles as a proxy for motor readiness during the observation of spinal distortions. Results revealed that AIS patients exhibited significantly lower perceptual thresholds than controls, indicating hypersensitivity to spinal curvature that correlated with subjective self-perception (Trunk Appearance Perception Scale; TAPS). TAPS scores did not correlate significantly with participants' Cobb angles, indicating that subjective body schema distortion operates independently of mechanical deformity severity. In addition, TMS revealed that AIS patients reached peak corticospinal excitability at their lower perceptual threshold, whereas healthy controls demonstrated peak excitability only when spinal curvatures exceeded their detection thresholds. These findings suggest that AIS involves an increased corticospinal gain in response to body-relevant stimuli. Rather than serving purely as a detection mechanism, the motor system in AIS exhibits a heightened readiness that is tightly coupled with the perception of spinal distortions. Such sensorimotor reorganization suggests that motor excitability is adaptively recalibrated to the patient's lived physical experience.

Intrinsic neural architecture of implicit self-evaluation bivalence: Evidence from resting-state ALFF and dynamic functional connectivity.

Empathy for pain can reduce activity in the observer's motor system, but the neural processes that shape this response remain unclear. Here we show that observing another person in pain reduces corticospinal excitability and increases perceived pain intensity when viewed from a first-person perspective, but not from a third-person perspective. This motor suppression is absent when noxious events are applied to a non-biological object. Using single-pulse, paired-pulse, and dual-site transcranial magnetic stimulation, we find no detectable change in local motor cortical inhibitory or facilitatory circuits, but observe a pain-specific reduction in the connectivity index between the inferior frontal gyrus and primary motor cortex. This effect covaries with perceived pain intensity and motor suppression and is site-specific relative to a Vertex control condition. Bayesian network modeling further suggests that perceived pain intensity predicts both unpleasantness and motor excitability. Together, these findings suggest that pain appraisal may be associated with frontal-motor interactions during pain empathy.

Functional electrical stimulation (FES) has been recognized for decades as a method to retrain the motor system after stroke. Benefits of FES rehabilitation can be enhanced by (1) combining FES with task-oriented therapy (i.e. FES therapy (FEST)), (2) timing FES with the user's volitional motor intention and (3) incorporating multiple trained tasks, as opposed to high repetitions of single tasks. Using a novel wearable FES technology, we tested therapy incorporating these elements in two chronic stroke survivors. Our group has developed the NeuroLife Sleeve, a wearable forearm sleeve that contains a high-density grid of embedded FES electrodes, that may be controlled by an operator or by the wearer's own electromyographic (EMG) signals. The system enables rapid software-based switching between stimulation configurations for different functional movements without repeated electrode repositioning. During eight weeks of FEST, intention-driven FES enabling multiple movements was delivered via operator control twice weekly and EMG control once weekly. At the end of the therapy period, subjects A and B had both improved their scores: Box and Blocks Test (A: +5, B: +7), the Action Research Arm Test (A: +7, B: +12), the Fugl Meyer Upper Extremity section (A: +11, B: +9), and the 9-Hole Peg Test (A: 158s, B: 54s, both previously unable). Clinical improvements persisted during the 10-week follow-up period, during which FES exposure was reduced by more than 80%. This case report provides a proof-of-concept demonstration of the NeuroLife Sleeve to support FEST and preliminary evidence that intention-driven FEST may support motor recovery in chronic stroke survivors. The NeuroLife Sleeve is a novel device designed to deliver this therapy through the easily donned wearable sleeve interface, support for both operator-triggered and EMG-controlled FES paradigms, and efficient transitions between tasks with programmable FES placement and parameters. Because both control modes were used throughout the intervention, the relative therapeutic contribution of each cannot be distinguished. We retrospectively registered the trial with ClinicalTrials.gov (16/01/2024, NCT06207240).

Transcutaneous auricular vagus nerve stimulation (taVNS) is a promising noninvasive neuromodulation technique with growing therapeutic relevance. Although increasingly combined with physical therapy in neurorehabilitation, its mechanistic effects during active movement remain poorly understood, as most physiology studies examine taVNS at rest, overlooking the dynamic neural activity engaged during movement. This study aimed to determine the neurophysiological basis for pairing taVNS bursts with movement. Thirty-six healthy adults (10 females, 26 males) completed two experiments where 2 s taVNS bursts were delivered. The first experiment assessed autonomic [heart rate (HR), galvanic skin response (GSR)], neuromodulatory (pupil diameter), and cortical [electroencephalography (EEG) spectral slope] responses during a randomized trial design involving three stimulation conditions (taVNS, earlobe sham, no stimulation) and two behavioral contexts [movement (go) vs still (no-go)]. The second experiment evaluated corticospinal excitability by measuring transcranial magnetic stimulation (TMS)-induced motor evoked potentials (MEPs) during taVNS. taVNS increased TMS-induced MEP amplitudes, indicating transient facilitation of corticospinal output when stimulation coincides with an engaged motor system. Concordantly, EEG sensorimotor activity was enhanced by taVNS during movement but not during stillness. In contrast, pupil diameter showed a clear phasic response to stimulation in both movement and still conditions, consistent with state-independent neuromodulatory engagement. Autonomic indices were not additionally modulated by phasic taVNS beyond movement-related changes. These findings identify a state-dependent window in which taVNS preferentially boosts task-engaged motor circuitry rather than producing nonspecific autonomic activation, providing mechanistic support for movement-paired stimulation protocols and highlighting pupil, EEG, and MEPs as sensitive biomarkers of phasic taVNS effects.

Adaptation to stimulus duration causes a repulsive aftereffect on the perceived duration of subsequent stimuli. Most studies investigating duration adaptation have found that the effect is confined to the adapted modality, highlighting unimodal components of duration processing. Here, we use adaptation to test whether motor and auditory duration processing rely on partially shared neural mechanisms by looking for a transfer of the duration aftereffect between these modalities. We asked participants to estimate the perceived duration of auditory stimuli following auditory or motor adaptation. While we replicated the unimodal effects of auditory adaptation, we report that motor adaptation did not produce the typical repulsive aftereffect. We interpret this result as evidence that duration processing by the motor and auditory systems is based on independent mechanisms.

Embodied cognition theories propose that conceptual knowledge is grounded in sensorimotor experience, but evidence for motor involvement in semantic memory retrieval for natural items remains inconsistent. Across two pre-registered experiments, we investigated whether motor dual-tasks and body posture manipulations affect semantic recall for natural manipulable concepts (fruits) versus non-manipulable concepts (colors) during semantic fluency (SF) tasks. In Experiment 1, 46 young adults performed SF while executing concurrent motor sequences with either upper limbs or lower limbs as control. In Experiment 2, 46 young adults completed the same task while adopting either restricted or unrestricted control postures. Contrary to predictions of interference, Experiment 1 revealed facilitation: participants retrieved fruits significantly faster during upper limbs motor tasks compared to control dual-task, with no effects for the color category. This facilitation affected retrieval speed rather than semantic network structure, suggesting that semantically congruent movement might prime semantic recall, consistent with theories proposing that unbound motor feature activation facilitates conceptual access. Experiment 2 showed no significant posture effects on SF measures for either category. These findings support a weak embodiment perspective where motor systems influence semantic retrieval processes rather than core representations themselves. The context-dependent nature of the effects highlights that embodied influences on semantic memory are more flexible and task-sensitive than previously assumed. Motor involvement in semantic processing appears to depend critically on the specific relationship between concurrent motor activity and the conceptual domain being accessed, challenging assumptions about robust, context-independent embodied effects.

Multi-timescale motor circuit dynamics underlie adaptive and efficient exploratory behavior.

Brain health disorders (BHDs) remain a concern for people with HIV (PWH) despite antiretroviral therapy access and viral suppression. The contribution of HIV to brain health is often obscured by comorbidities in high-income settings which are less prevalent in sub-Saharan Africa. Neurofilament light chain (NfL), a biomarker of axonal injury, may offer insight into underlying mechanisms. 338 virally-suppressed PWH and 250 people without HIV (PWoH) completed a Research Domain Criteria-informed battery assessing cognitive, sensorimotor, and social processing systems. Demographically-adjusted norms were derived from PWoH. Serostatus differences in impairment (≥ 1SD below the mean) were examined using multivariable logistic regression. Additional models examined associations between NfL (plasma, cerebrospinal fluid [CSF]) and task performance. PWH were similar to PWoH in age (43.9 vs. 43.5yrs), sex (female, 54 vs. 46%), and education (6.1 vs. 5.8yrs). PWH had higher odds of impairment in the cognitive control and attention (Color Trails, Symbol Digit) and sensorimotor (Grooved Pegboard) domains. Plasma NfL was associated with sensorimotor impairment in both groups. Similar trends held in CSF NfL but did not reach statistical significance, likely due to sample size (n = 85). Cognitive and sensorimotor difficulties are common in PWH in Rakai, independent of typical Western confounders. The profile of impairment differs from reports in high-income settings where declarative memory deficits are often observed. NfL was associated with sensorimotor impairment, suggesting that NfL may capture ongoing axonal injury and motor system vulnerability in PWH and PWoH. These findings suggest NfL's potential as a biomarker of sensorimotor impairment in sub-Saharan Africa.

Prescribed performance synchronization control of dual-PMSM motion system via novel sliding mode control and adaptive extended state observer.

The need for sophisticated and dependable prognostic systems for Induction Motors (IM) working under dynamic load and speed circumstances has increased due to the quick expansion of Electric Vehicles (EVs). Real-time defect prediction is limited by traditional multi-sensor data fusion techniques like concatenation, weighted averaging, or rule-based fusion, which are unable to determine which sensor is more informative at any given time. Additionally, early deterioration signs are missed by traditional models because they are unable to capture long-range temporal correlations across heterogeneous data. Additionally, these models have vanishing-gradient problems, which cause little but significant changes to be overlooked. An innovative prognostic learning system for integrated defect detection and remaining useful life (RUL) prediction in electric vehicle induction motors is presented in this work. It is based on Temporal Attention Fusion Long Short-Term Memory (TAF-LSTM) architecture. The suggested method successfully combines multi-domain feature extraction, long-sequence modeling, and temporal attention mechanisms to capture contextual fluctuations, gradual degradation patterns, and transient fault signals across several sensor channels. 99.9% fault diagnosis accuracy is demonstrated by experimental validation utilizing multi-sensor operating data. Additionally, for RUL prediction, the model obtains a Mean Squared Error (MSE) of 0.25 and a Root Mean Squared Error (RMSE) of 0.50, demonstrating extremely precise prognostic performance. These findings demonstrate that the suggested TAF-LSTM architecture provides a real-time, scalable, and dependable motor health monitoring solution with substantial promise for next-generation predictive maintenance in electric vehicles.

Preclinical studies suggest that lysergic acid diethylamide (LSD) may induce lasting changes in brain function and learning ability, but evidence in humans is uncertain. Motor learning, in particular, has clinical relevance but has not been investigated in human studies of psychedelics. Forty-five healthy subjects (24 women) participated in this randomized crossover trial comparing 100 µg LSD with a placebo. For up to one week after dosing, we investigated LSD's post-acute neurophysiological effects using auditory tetanization with electroencephalography (EEG), paired associative stimulation (PAS) with transcranial magnetic stimulation (TMS), peripheral levels of brain-derived neurotrophic factor (BDNF). Additionally, online and offline motor learning were assessed one day after dosing with a sequence typing task. Questionnaires assessed perceived stress and cognitive flexibility one week after dosing. We found that offline motor learning significantly improved the day after LSD. One week after LSD, perceived stress was reduced and aspects of cognitive flexibility were increased. EEG data showed that LSD acutely decreased amplitudes of N1 and P2 auditory event-related potentials and still modulated P2 one week later. Motor-evoked potentials measured with TMS showed increased amplitude and faster latency under LSD. LSD did not alter BDNF levels. Our findings encourage future studies on LSD and learning and additionally highlight important challenges in the measurement of long-term potentiation in humans. The observed acute and lasting changes in neural signals provide insight into LSD's effects on the auditory and motor systems.

A Narrative Review of the Psychiatric Aspects of Deep-Brain Stimulation for Movement Disorders: a Role for Consultation-Liaison Psychiatrists.

Acute intermittent hypoxia (AIH) elicits respiratory motor plasticity in the phrenic, intercostal, and hypoglossal motor pools, and has emerged as a promising therapeutic strategy to improve respiratory function in people with neuromuscular disorders that compromise breathing. Although we recently reported that time-of-day regulates moderate AIH (PaO2 ∼40-50 mmHg) induced respiratory motor plasticity, it is unknown if diurnal effects on AIH-induced phrenic (pLTF) or ventilatory (vLTF) long-term facilitation are mediated via the endogenous circadian clock vs other factors. Since many biological rhythms are driven by the endogenous clock, and clock genes (including the essential clock gene Bmal1) are rhythmically expressed in the phrenic motor system, we hypothesized that the molecular clock within respiratory motor neurons exerts time-of-day effects on pLTF and vLTF in Sprague-Dawley rats (3-6 month old males). Intrapleural injections of small-interfering RNAs (siRNAs) were used to selectively knock down Bmal1 within respiratory motor neurons by ∼30%. AIH consisting of 15, 1-min hypoxic episodes (FIO2 = 0.09) was delivered in the mid-rest (i.e. light) or mid-active (i.e. dark) phases, and pLTF (Δintegrated phrenic burst amplitude) and vLTF (ΔV̇E/V̇CO2) were assessed in rats given siRNAs targeting Bmal1 vs non-targeting controls. In mid-rest phase, pLTF was reduced and vLTF abolished in rats given siBmal1 vs non-targeting siRNA. However, siBmal1 had no significant effect on either pLTF or vLTF in mid-active phase. Thus, the phrenic motor neuron circadian clock regulates AIH-induced respiratory motor plasticity in a time-of-day-dependent manner. It is important to consider circadian biology in future studies of AIH-induced respiratory motor plasticity.

Arthrogryposis multiplex congenita (AMC) is a diverse group of conditions characterized by multiple joint contractures. Although individually rare, these disorders are estimated to affect 1 in 3000-5000 live births. Their common pathophysiological mechanism is fetal akinesia, a sustained reduction of fetal movement that may arise from intrinsic disturbances-such as central nervous system malformations, motor neuronopathies, neuropathies, neuromuscular junction defects, congenital myopathies, muscular dystrophies, or metabolic diseases-or from extrinsic factors including uterine constraint, maternal illness, infections, or toxic exposures. Reduced fetal motion leads to relatively uniform clinical manifestations, known as the fetal akinesia deformation sequence (FADS), which is characterized by craniofacial anomalies, pulmonary hypoplasia, growth restriction, and contractures. Currently, AMC is classified by clinical features, such as distal arthrogryposis or lethal congenital contracture syndromes. However, advances in molecular genetics have shown wide variability among conditions classified into the same category. Prognosis is widely variable, ranging from lethal perinatal forms to non-progressive mild conditions. This review discusses AMC etiologies from a topographic standpoint, considering the different levels of the motor system involved, by combining current clinical, genetic, and pathophysiological information.

Functional Neurological Disorder (FND) is a common and disabling condition at the interface of neurology and psychiatry, characterized by motor, sensory, seizure-like, or cognitive symptoms that are incongruent with recognized neurological disease but associated with substantial impairment. Despite its frequency and marked female predominance, FND remains underdiagnosed and often misunderstood. This narrative review synthesizes evidence from neurobiological, biomarker, and treatment studies, with attention to predictive coding, salience network dysfunction, impaired sense of agency, stress-related mechanisms, and sex- and gender-related vulnerability. Current evidence supports a model of FND as a disorder of distributed brain network dysfunction involving abnormal interactions among salience, limbic, motor, and self-monitoring systems. Predictive coding and impaired agency models provide clinically useful frameworks for understanding symptom generation, although they remain mechanistic hypotheses rather than definitive causal explanations. Candidate biomarkers, including functional connectivity alterations, autonomic dysregulation, and HPA axis measures, offer pathophysiological insight but remain insufficiently validated for routine diagnosis. Female predominance likely reflects interacting biological, psychological, and sociocultural mechanisms rather than a single neuroendocrine pathway. This review contributes an integrated, clinically oriented framework linking neurobiology, biomarkers, sex/gender vulnerability, and treatment in FND. Current evidence supports multidisciplinary care combining diagnostic communication, specialized physiotherapy, psychotherapy, and coordinated follow-up, while future research should prioritize standardized phenotyping, longitudinal designs, and multimodal biomarker validation.

Susceptibility-matched padding improves the quality of cervical and lumbar spinal fMRI.

Interindividual variability in resting motor threshold (RMT) reflects baseline differences in corticospinal tract excitability and brain sensitivity to transcranial magnetic stimulation (TMS). However, the impact of baseline motor system neural oscillation on RMT remains unknown. We used a cross-sectional observational study. RMTs and resting-state electroencephalograms were collected in a single experimental session from 95 participants in our study. The characteristics of neural oscillations are reflected by power spectral density (PSD) and phase locking value (PLV) in different bands. We found significant weak-to-moderate negative correlations of RMT with delta-band PSD in bilateral central and frontal regions, as well as theta-band PLV in bilateral central regions. Together, these measures accounted for approximately 18.5% of the variance in RMT. Our findings enhance the understanding of how resting-state neural oscillations modulate the brain's sensitivity to TMS and provide new insights for developing more effective TMS strategies.