The Cerebellum

Background: Transcranial direct current stimulation (tDCS) is increasingly used as an adjunct to rehabilitation for young people with cerebral palsy (CP), yet considerable variability exists in clinical response. Individualised electric field modelling provides an opportunity to estimate the distribution of electrical fields generated by the stimulation delivered to the brain and explore potential relationships with functional outcomes. Methods: Structural MRI scans from nineteen participants (10-16 years) from a previously published randomised controlled trial (ISRCTN74235136) investigating the effects of tDCS combined with motor training, underwent participant-specific finite element modelling using SimNIBS. Electric field strength was quantified within anatomically defined motor regions of interest, including the primary motor cortex (M1), dorsal premotor cortex (PMd), supplementary motor area (SMA), and a combined motor network. Global grey matter electric field metrics and stimulation focality were also extracted. Results: Estimated electric field strength differed significantly across motor regions (p<0.001), with PMd receiving significantly greater stimulation than both M1 and SMA. Electric field strength within a control region (primary visual cortex) was significantly lower than within M1 (p<0.001). Despite inter-individual variability in regional and global electric field metrics, no significant associations were observed between estimated electric field strength or focality and changes in function following intervention. Conclusion: Individualised electric field modelling demonstrated that an M1-targeted tDCS montage preferentially stimulated PMd rather than M1 in young people with CP. These findings highlight the importance of subject-specific modelling when characterising current distribution and suggest that variability in electric field strength alone does not explain variability in behavioural response.

The cerebellar nuclei (CN) has demonstrated its influence on cognitive behavior via the cerebello-cortico circuit, yet the role of CN critical period mechanisms and how they may influence cognitive behavior, such as parvalbumin (PV) expressing interneurons enwrapped by perineuronal nets (PNNs), is still unclear. Therefore, we investigated the role of the lateral CN (LCN) PV cell calcium activity while animals performed a visual discrimination touchscreen cognitive task. All animals received the PV cell calcium indicator GCaMP6f at postnatal day 21 (P21). We targeted the LCN critical period by manipulating neural activity in male mice using the inhibitory Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) from postnatal day 21 to 35 or by injecting an Hapln1-AAV vector to selectively target LCN PNN development. After animals completed the visual discrimination task, cerebellar tissue was collected for viral recovery and antibody staining for PNN components, Hapln1 and aggrecan. Results revealed DREADD animals showed improved reversal learning, an increase in calcium response to learning-related activity and altered PNN expression (Hapln1 and aggrecan). Hapln1 treated animals displayed a decrease in final day acquisition performance, lower reversal performance compared to DREADD groups, a decrease in reversal calcium learning-related activity, and an increase in PNN expression (Hapln1). Together, these data provide further evidence of LCN mechanisms associated with learning as well as the importance of understanding region-specific critical periods of plasticity.

Background: Infant muscle tone reflects early central nervous system integrity and has been associated with later motor and cognitive development, including autism traits. The cerebellum regulates both motor control and higher-order socio-cognitive functions and has been repeatedly implicated in autism, but its role in linking infant muscle tone to adolescent autistic traits has not previously been studied in a large, prospective population cohort. Methods: We used data from the prospective Generation R Study. Infant muscle tone (hypotonia and hypertonia) was assessed via Prechtl examination, and third-trimester fetal transcerebellar diameter was measured using ultrasound n=6,842). Cerebellar morphology at ages 6, 10, and 14 years (n=4,861) was measured using structural MRI. Linear mixed-effects models tested associations between infant muscle tone and 35 anatomical and 10 functional cerebellar regions. Causal mediation models tested whether cerebellar volume mediated associations between infant muscle tone and adolescent autistic traits at age 14 (Social Responsiveness Scale). Results: Hypotonia predicted larger vermis IX volumes across childhood (beta=0.037, pFDR =0.043). Hypertonia showed an age-dependent association with left lateral lobule IX (beta=-0.0027, pFDR =0.041), with differences diminishing with age. Third-trimester transcerebellar diameter did not predict postnatal muscle tone. Given its significant main effect, vermis IX volume was tested as a mediator, but did not mediate the pathway to adolescent autistic traits. However, infant hypotonia showed a small direct association with elevated autistic traits at age 14, specific to girls (beta=0.0255, p=0.020). Conclusions: Infant muscle tone is associated with localized differences in cerebellar volumes. These associations are specific to vermal and left hemispheric lobule IX, a region commonly implicated in spinocerebellar postural control, axial stability, and higher-order sensorimotor integration. Furthermore, infant muscle tone was not predicted by prenatal cerebellar diameter, and cerebellar volumes did not mediate the association between infant hypotonia and adolescent autistic traits in our study. Future research should further investigate these findings in clinical populations, integrating longitudinal whole-brain, multi-modal imaging to clarify the association between infant muscle tone, the cerebellar functioning, and autistic traits.

Objectives: Transcranial magnetic stimulation (TMS) is widely used to probe corticospinal excitability by eliciting motor evoked potential (MEP)s in targeted muscles, with MEP characteristics such as magnitude and latency reflecting the physiological state of the pathways being stimulated. Although numerous studies have examined MEP reliability in upper extremity muscles, less is known about the reliability of this measurement across the lower extremity. We hypothesized that inter-session, test-retest reliability of MEPs recorded simultaneously from multiple lower-limb muscles, from a single TMS location, would differ by muscle, stimulation intensity, and quantification method. Materials and Methods: Ten healthy participants (5 males, 5 females) completed three TMS sessions separated by atleast one week. At each session, the stimulation hotspot was identified using a five-location virtual grid anchored at the vertex, with electromyography (EMG) recorded from all eight muscles of interest at each grid location; the grid location producing the largest and most consistent MEPs in the tibialis anterior (TA), the primary target muscle, was selected as the stimulation site and held constant across all three sessions. MEPs were then recorded bilaterally from the TA, soleus, rectus femoris, and biceps femoris muscles at two stimulation intensities (110% and 120% resting motor threshold (RMT)). MEP size was quantified using mean rectified magnitude and peak-to-peak amplitude, and inter-session reliability was assessed using intraclass correlation coefficients (ICC). Bland-Altman analysis was used to characterize the range of measurement variability across all eight muscles. Results: MEP size differed across sessions, and reliability varied by muscle, intensity, and quantification method. The highest reliability was observed in the right TA, the muscle used to establish the stimulation hotspot, using mean rectified magnitude at 120% RMT. Reliability was comparatively lower in the seven non-target muscles recorded from the same fixed stimulation site, indicating that MEP consistency was not uniform across the lower-limb musculature. Conclusions: MEP reliability in the lower extremity depends heavily on the muscle, stimulation intensity, and quantification method used, and is highest in the muscle for which the stimulation site was optimized. These findings support the interpretation that coil positioning targeted to a specific muscle yields more consistent responses in that muscle than in others recorded from the same fixed site, and underscore the importance of careful muscle selection and hotspot optimization when designing TMS protocols for longitudinal or clinical lower-limb research.

Spinal muscular atrophy (SMA) is caused by a deficiency in the survival motor neuron (SMN) protein, resulting in degeneration of spinal motor neurons (MNs). However, persistent neurological deficits despite postnatal SMN-restoring therapies suggest that recovery of sensorimotor and supraspinal circuits may be incomplete. The cerebellum has recently emerged as a supraspinal contributor to motor deficits in the severe SMN{Delta}7 mouse model, yet it remains unclear whether cerebellar pathology is a conserved and therapeutically reversible feature across severe SMA mouse models and clinical subtypes. Here, we identify cerebellar pathology in Taiwanese SMA mice, characterized by hypoplasia, disrupted organization and loss of Purkinje cells (PCs), altered synaptic circuitry, and impaired cerebellar cortical output. Unlike the previously described p53-dependent PC degeneration in SMN{Delta}7 mice, cerebellar pathology in Taiwanese SMA mice was associated with developmental disorganization and external granule layer (EGL)-restricted p53 activation. Human cerebellar tissue mirrored this distinction, with p53 activation found in PCs from SMA Type I and in the EGL from SMA Type 0 individuals, indicating that cerebellar pathology arises through distinct mechanisms across severe forms of SMA. Importantly, two SMN-restoring strategies produced divergent therapeutic outcomes. In SMN{Delta}7 mice, AAV9-SMN prevented PC degeneration yet incompletely restored cerebellar circuitry. AAV9-SMN-treated Taiwanese mice developed severe ataxia-like deficits, retained profound cerebellar pathology, and survived to approximately one month of age. In contrast, systemic risdiplam rescued cerebellar pathology, motor behavior, and survival in both models. Together, these findings identify cerebellar pathology as a conserved yet distinct feature across severe forms of SMA and reveal cell type-specific tropism as a critical determinant of therapeutic outcome. More broadly, these findings suggest that successful recovery requires restoration of distributed supraspinal circuit integrity in addition to rescue of spinal motor pathways.

Generalization is a key cognitive process that allows humans to flexibly apply prior knowledge to guide new behaviors. Difficulties with generalization and flexibility are observed across neurodevelopmental disorders, especially autism, limiting adaptive function and quality of life. Cognitive-behavioral treatment benefits some but not all autistic individuals. As treatment requires application of learned skills to everyday life, variability in generalization ability may limit intervention success in autism. While cognitive substrates of learning and generalization are well established, their potential for explaining clinical outcomes is not known. Here, we combined a category learning task with computational modelling to distinguish two learning strategies underlying generalization -- prototype abstraction vs. exemplar memorization -- and tested whether individual differences in these learning strategies predicted real-world intervention outcomes in autistic youth. Fifty-four participants completed the category learning task at two pre-intervention timepoints, and then completed Unstuck and On Target:14-22 intervention targeting flexible problem solving, goal setting, and planning. We found that participants who consistently relied on prototype abstraction (N=26) were subsequently more likely to benefit from the intervention, showing improvement in parent- and self-reported flexibility. These findings identify prototype abstraction as a clinically relevant cognitive capacity that may help explain individual differences in intervention response and support the tailoring of interventions. More broadly, they demonstrate the value of linking basic cognitive mechanisms to clinical outcomes and may inform strategies to enhance the effectiveness of cognitive-behavioral interventions for youth with developmental disabilities.

AIM: To evaluate whether selective motor control quantified from spontaneous infant movement recordings provides diagnostic and prognostic information for cerebral palsy (CP) beyond established movement-based assessments. METHOD: This multicenter diagnostic and prognostic accuracy study included 302 infants (151 with CP) with spontaneous movement recordings obtained between 10 and 20 weeks corrected age from cohorts in Australia and the United States. All eligible infants with CP were included, and a comparison sample without CP was randomly selected. Recordings were scored using the Baby Observational Selective Control Appraisal (BabyOSCAR), Motor Optimality Score Revised (MOS-R), and General Movements Assessment (GMA). Outcomes at 2 years or older included CP diagnosis, Gross Motor Function Classification System (GMFCS) level, and motor distribution. RESULTS: BabyOSCAR discriminated CP diagnosis (area under the curve [AUC] 0.98), including children later classified in GMFCS level I. Among infants with CP, BabyOSCAR discriminated GMFCS levels I - II from III - V (AUC 0.89). BabyOSCAR absolute asymmetry also discriminated unilateral CP from all other infants (AUC 0.90). Diagnostic discrimination was also observed for MOS-R (AUC 0.94) and GMA (AUC 0.86). INTERPRETATION: Quantifying selective motor control from brief infant movement recordings may provide complementary early information about CP diagnosis, functional level, and motor distribution.

Background: People with chronic stroke retain the capacity to learn new motor skills, yet how preserved motor learning is expressed during practice remains incompletely understood. Sequence learning provides a useful model for examining these within-session learning dynamics and their neural basis after stroke. Objective: To characterize a temporally resolved behavioral phenotype of motor sequence learning in chronic stroke and establish its neural context using task-based functional MRI (fMRI). Methods: Twenty-four individuals with chronic stroke and 14 neurologically healthy controls performed a bimanual force-tracking sequence-learning task during functional MRI. Performance convergence was defined as the sequence-specific reduction in the accuracy difference between the paretic and less-affected hands across practice. Neural activity was evaluated using whole-brain, region-of-interest, and functional-connectivity analyses following preprocessing tailored to structurally heterogeneous stroke lesions. Results: Stroke participants demonstrated significant performance convergence despite persistent motor impairment, indicating preserved expression of sequence learning during practice that was not detected by conventional behavioral measures. Lesion-aware fMRI identified robust task-related activation and preserved stage-dependent modulation within cerebellar, premotor, and striatal learning networks, together with reduced bilateral putaminal activity after stroke. However, preregistered analyses found no reproducible associations between individual differences in performance convergence and learning-related activation or functional connectivity. Conclusions: Performance convergence provides a sensitive, temporally resolved behavioral phenotype of preserved motor sequence learning in chronic stroke that complements conventional endpoint measures. Together, performance convergence and task-based functional MRI provide a framework for investigating individual differences in motor learning capacity and their implications for rehabilitation responsiveness.

Hand dexterity impairment is a major contributor to long-term disability after acquired brain injury, yet the white matter substrates supporting residual dexterity remain incompletely understood. We investigated diffusion MRI markers of hand dexterity in individuals with chronic stroke (n = 9) and traumatic brain injury (TBI; n = 8) using complementary tract-specific and whole- brain approaches. Partial least squares regression (PLSR) was used to evaluate the cross-validated predictive relevance of bilateral corticospinal tract (CST) diffusion and tractometry features, while quantitative anisotropy (QA)-based correlational tractography was used to identify distributed white matter pathways associated with dexterity performance measured using Box and Block Test (BBT) and MusicGlove Dexterity Test(MGDT). In stroke, CST features predicted BBT performance (Q2 = 0.69, r = 0.85, permutation p = .010) and, more modestly, MGDT performance (Q2= 0.22, r = 0.72, permutation p = .008). In contrast, CST-based models showed no predictive relevance for dexterity outcomes in TBI. Whole-brain connectometry revealed that better dexterity after stroke was associated with greater QA across distributed pathways extending beyond the CST, including commissural, association, and projection fibers. Box and Block Test performance was prominently associated with callosal and cingulum-related pathways, whereas MusicGlove performance showed greater representation of CST and projection pathways. In TBI, significant connectometry findings for the BBT similarly implicated distributed commissural and association pathways, whereas no significant pathways were identified for the MusicGlove test. Together, these findings suggest that the structural correlates of hand dexterity extend beyond the CST and vary across dexterity measures and injury populations. Although preliminary given the small cohorts, the complementary tractometry and connectometry findings support a network-level characterization of residual hand function after acquired brain injury and motivate validation in larger cohorts.

ObjectiveStroke-related corticospinal tract (CST) disruption causes lasting hand impairments, but many stroke survivors retain some residual CST connections. In neurotypical adults, motor cortex (M1) TMS interventions can strengthen CST transmission when coupled to EEG brain states reflecting heightened M1 excitability. Because stroke alters the relationship between these brain states and cortical excitability, we aimed to identify poststroke brain states that accurately capture ipsilesional M1 excitability. We hypothesized that heightened ipsilesional M1 excitability would be represented by a common, group-level EEG pattern and a participant- specific, personalized pattern. MethodsWe acquired single-pulse TMS-EEG-EMG datasets in 15 chronic stroke survivors with residual CST connections. We then identified group-level and individual-specific EEG power patterns that distinguished between high and low ipsilesional M1 excitability states. ResultsAt the group level, bilateral sensorimotor mu power was significantly suppressed during high versus low excitability states, but this suppression did not correlate with hand impairment severity or trait-level ipsilesional M1 excitability. At the individual level, spatiotemporally varied EEG activity patterns distinguished between excitability states, but these patterns were only present in 60% of individuals. Conclusion and SignificanceThis study is the first to systematically characterize poststroke EEG brain states reflecting ipsilesional M1 excitability. Findings suggest that individual-specific EEG patterns may inconsistently index ipsilesional M1 excitability and instead identify bilateral sensorimotor mu power suppression as a group-level excitability marker that is present across the full spectrum of poststroke hand impairment. HighlightsO_LIWe analyzed TMS-EEG-EMG to identify group and individual level ipsilesional motor cortical excitability states in chronic stroke C_LIO_LIBilateral sensorimotor mu suppression marked heightened ipsilesional motor cortical excitability across hand impairment severity C_LIO_LI60% participants had individual level scalp patterns linked to motor cortical excitability states, challenging their reliability C_LI

Children and adolescents with hearing loss frequently encounter reduced auditory access and delayed language development, factors that may influence the maturation of executive functions. This study examined developmental differences in planning, a core executive function, in 98 children and adolescents with hearing loss or normal hearing aged 7 to18 years using the Tower of London task. Compared to normal hearing peers, participants with hearing loss made more unnecessary moves and rule violations and initiated problem-solving more rapidly, suggesting reduced preplanning efficiency and increased impulsivity. These group differences were most pronounced in adolescents, who showed faster initiation and greater movement inefficiency than age-matched normal hearing participants. Within the hearing loss group, adolescents displayed higher accuracy and longer initiation times than children, reflecting developmental improvements despite persistent gaps relative to hearing peers. Language development age did not alter the main effects. Findings indicate that reduced early auditory and language access may contribute to differences in planning development, highlighting the need for targeted executive functions support in educational and clinical settings for youth with hearing loss.

AVATAR therapy is an effective relational therapy for persistent distressing auditory verbal hallucinations (voices). A digital representation of the embodied persecutory voice (avatar) is created and used in a series of dialogues in which the voice hearer is supported to be more assertive and the avatar concedes power. In the first mediation analysis of AVATAR therapy examining the role of power-related constructs, we investigate whether treatment effects on total severity, frequency, and distress of voices are mediated by changes in beliefs about voices and the self, voice relationship appraisals and anxiety. Mediation effects were evaluated in relation to decomposing treatment offer and treatment receipt effects using both Intention to treat (ITT) and Complier Average Causal Effect (CACE) analyses. One hundred and fifty participants from AVATAR1, a randomised control trial (RCT) comparing AVATAR therapy to Supportive Counselling took part in this study, with their baseline and end of treatment (12 weeks) data used. As hypothesised, across both ITT and CACE analyses, reductions in perceived voice omnipotence and increased assertiveness in relation to voices emerged as consistent mediators of AVATAR therapy on reductions in overall severity, frequency and distress of auditory hallucinations compared to SC, whereas voice malevolence, perceived power differential, self-esteem and anxiety did not. Exploratory analysis also indicated that increases in acceptance and autonomy in relation to voices mediated the impact of AVATAR therapy on overall voice severity and distress. This mediation analysis refines our understanding of AVATAR therapy and highlights agency, voice omnipotence and acceptance as intervention targets.

Kinaesthetic motor imagery (kMI) is widely used in sport to enhance motor performance by engaging cortical sensorimotor networks. Neurofeedback may further support kMI, but the optimal neural target to reinforce remains unclear. Maximal sensorimotor event-related desynchronisation (SMR-ERD) represents a relevant target as it may index sensorimotor cortex engagement, yet sport expertise has been associated with reduced SMR-ERD, potentially reflecting neural efficiency. The optimal neurofeedback target may therefore depend on sport expertise, movement expertise, and individual kMI ability. This study examined how these factors influence sensorimotor activity during kMI. We compared 17 basketball players (Experts) and 16 individuals without formal basketball training (Novices). kMI ability and frequency of use were assessed using questionnaires, while SMR-ERD was quantified using electroencephalography (EEG) during kMI. Participants imagined either a basketball-specific movement (Free throw), for which only Experts had extensive experience, or a generic movement (Box lifting), familiar to both groups. Experts reported greater kMI ability and more frequent kMI use than Novices. Only Experts exhibited significant and sustained SMR-ERD during kMI. Moreover, SMR-ERD was stronger in Experts than Novices specifically during Free throw kMI, corresponding to their movement of expertise. Nonetheless, within the Expert group, higher kMI ability was associated with reduced SMR-ERD. These findings suggest that sport expertise initially enhances voluntary recruitment of sensorimotor networks during kMI, whereas greater kMI ability may subsequently promote neural efficiency, resulting in reduced overall sensorimotor cortical activation. These results highlight the need to tailor kMI-based neurofeedback training to users' sport expertise and kMI ability levels.

Motor sequence performance improves during and between brief practice bouts (micro-online and offline gains). We compared both metrics across two groups: one exposed to an implicit motor sequence, and one not. Micro-online gains drove sequence-specific learning and positively correlated with overall skill. However, micro-offline gains were comparable between groups and did not track sequence-specific learning. We conclude that implicit motor sequence learning is driven by micro-online rather than micro-offline gains.

Unipolar brush cells (UBCs) are excitatory interneurons that have a characteristic dendritic brush that amplifies and extends incoming signals in the cerebellum. UBCs transform synaptic input through their ionotropic and metabotropic glutamate receptors. Differential regulation of receptor subunits is a critical developmental process, but how the expression of glutamatergic receptors changes in UBCs as they develop is unclear. NMDA-type glutamate receptors (NMDARs) are particularly important for development and plasticity. We examined the expression of NMDAR subunits during development and tested whether signaling through these receptors is necessary for the development of the elaborate dendritic structure and unusual synaptic function of UBCs. Whole-cell patch clamp recordings from UBCs in acute brain slices revealed tonic and synaptic NMDAR-mediated currents in early postnatal UBCs that decrease during development. RNAscope in situ hybridization revealed differential developmental regulation of GluN2C/D subunits. Cell-type specific constitutive NMDAR knockout had no apparent effect on dendritic brush development, but increased UBC number in adulthood, suggesting a role in programmed cell death. Both pharmacological blockade or genetic deletion of NMDARs produced a paradoxical increase in excitability, which was calcium dependent and was occluded by inhibition of calcium activated potassium channels. Thus, NMDA receptors are dispensable for migration and dendritic development but may be involved in cell death pathways. Their functional roles include synaptic signaling as well as providing a tonic calcium flux that dampens excitability in developing UBCs and may influence transformations of vestibular signals essential for smooth movements and balance.

Background: Low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) over the contralesional primary motor cortex is widely used for post-stroke upper-limb rehabilitation, but treatment response varies substantially. This systematic review and meta-analysis aimed to quantify the efficacy of contralesional LF-rTMS and to examine whether baseline motor impairment severity and corticospinal tract (CST) integrity modify treatment effects. Methods: We searched seven databases from inception to July 2026 for randomized controlled trials of contralesional LF-rTMS ([&le;]1 Hz) versus sham after stroke, with comparable rehabilitation in both arms. The primary outcome was the change in Fugl-Meyer Assessment for the upper extremity (FMA-UE) scores. Random-effects meta-analysis used restricted maximum likelihood estimation with Knapp-Hartung adjustment. Effect modification was examined through meta-regression and biomarker-stratified analyses, and neurophysiological outcomes were also synthesized. Results: Thirty trials (33 comparisons, 1,668 participants) were included. LF-rTMS produced greater FMA-UE improvement than sham (mean difference 4.11 points, 95% CI 2.83-5.39; Hedges g 0.64, 95% CI 0.45-0.84), with substantial heterogeneity. Baseline severity did not significantly modify the effect in continuous meta-regression. However, exploratory within-trial biomarker-stratified analyses suggested larger effects in participants with preserved CST integrity or positive motor-evoked potential (MEP) status. LF-rTMS also shortened MEP latency and central motor conduction time, but these measures could not be validated as surrogate endpoints. Conclusions: Contralesional LF-rTMS provides a statistically significant but modest improvement in post-stroke upper-limb motor recovery. Baseline clinical severity alone may not identify responders, whereas CST integrity is an exploratory, hypothesis-generating candidate biomarker. It requires confirmation in adequately powered biomarker-stratified trials before it can inform clinical decisions. Trial Registration The study was registered with the International Prospective Register of Systematic Reviews (PROSPERO: CRD420261441561).

Sport-related concussions (SRC) are heterogenous injuries that produce a variety of symptoms and recovery trajectories. This heterogenous nature and focus on group-level analyses in current literature may obscure individual level results that could better inform clinical SRC management. In a prospective case-control study, we used diffusion magnetic resonance imaging (dMRI) to quantify longitudinal, whole-brain microstructural white matter changes reflecting axonal injury and inflammation and structural network-level alterations following SRC in adolescent athletes. Differential tractography assessed individual white matter track changes from acute injury to clinical recovery on an individual level. Acutely after SRC, but not after recovery, concussed adolescents demonstrated increased (i) quantitative anisotropy, (ii) restricted diffusion imaging, and (iii) isotropy, indicating increased microstructural disruptions early after injury. At the network level, differences were seen not acutely but after clinical recovery: whole brain network structure was more similar with reduced capacity for information spread among the concussed adolescents compared with controls. At the individual level, consistent patterns of damaged white matter tracks persisted in the concussed males but not in the concussed females. These results indicate that adolescent athlete brains are impacted acutely at the microstructural level following SRC, but that macroscale network disruptions appear after microstructure damage resolution, and they can persist beyond clinical recovery. Sex differences in the brains microstructural response to SRC, highlight the need for future research to include individualized and sex-stratified analyses to guide targeted SRC management.

Animal transcranial direct current stimulation (tDCS) studies typically use intensities exceeding clinical levels, and the off-line behavioral effects of weak electric fields in rodents remain unclear. We examined whether repeated anodal tDCS, calibrated by electric-field simulation to approximate human-equivalent weak fields, facilitates motor recovery after focal photothrombotic ischemic stroke (PIT) in rats. Simulation estimated that 50 A produced a maximum field of [~]1.96 V/m in the targeted motor cortex, matching clinically relevant intensities. Under isoflurane anesthesia, rats received anodal tDCS at 50 A, 250 A, or 1 mA (5 min/day, 5 days/week, 2 weeks), or sham; motor recovery was assessed weekly by beam-walking for 4 weeks. A linear mixed-effects model revealed significant time, group, and time x group effects. The 50 A group outperformed the PIT group at 1 week, and the 1 mA group at 2 weeks, with no differences thereafter. Low-current tDCS accelerates early post-stroke motor recovery, supporting weak-field neuromodulation.

Developmental dyslexia is a specific, highly prevalent and often debilitating reading and spelling disorder with unknown neurocomputational mechanisms. Here we discovered, in a preregistered functional magnetic resonance imaging study optimized for the subcortical sensory pathway, that dyslexia is characterized by altered predictive coding in left-hemispheric auditory sensory pathway nuclei. The neurocomputational alterations were related to one of the two main dyslexia risk scores, indicating a crucial role for dyslexia pathophysiology.

This paper introduces a sensorimotor learning framework for a corticocerebellar network, grounded in the perspective of population dynamics. Using an optimal control theory approach, the cerebellum model enhances preparatory activity through premotor input, allowing the motor cortex to reach the desired initial conditions for movement more efficiently. Unlike traditional motor learning approaches that focus on acquiring new skills, this paradigm emphasizes automatization of already executable behaviors through repetition driven by intrinsic motivation. The proposed model is evaluated using a center-out reaching task, demonstrating that the role of the cerebellum is to shorten the preparatory period required for the successful execution of the movement. These findings suggest that corticocerebellar interactions play a crucial role in optimizing motor preparation, offering insight into the neural mechanisms underlying movement efficiency.