The Cerebellum

Background: Infants with extremely low birth weight (ELBW) are at high risk for neurodevelopmental impairment, but the relationship between cerebellar structure and later developmental outcome remains incompletely defined. Methods: In this retrospective single-center study, we examined total cerebellar volume on clinically acquired brain magnetic resonance imaging (MRI) in ELBW infants while accounting for postmenstrual age (PMA) at imaging. Results: Of 65 infants screened, 42 were included. Mean gestational age at birth was 25.54 {+/-} 1.68 weeks, mean birth weight was 733.2 {+/-} 118.7 g, and mean PMA at MRI was 43.02 {+/-} 6.53 weeks (range, 31.57--68.00). Mean cerebellar volume was 22.17 {+/-} 9.63 cm. Independently adjudicated developmental outcomes comprised normal development in 16 infants, isolated or specific impairment in 12, and moderate/severe impairment in 14. Unadjusted cerebellar volumes did not differ across developmental groups (P = 0.490) or qualitative MRI categories (P = 0.875). However, the PMA-by-developmental-category interaction was significant (P = 0.002), with estimated cross-sectional slopes of 1.72, 1.56, and 0.39 cm per week, respectively. The interaction remained significant within 36--46 weeks PMA (n = 29; P = 0.011) and after adjustment for small-for-gestational-age (SGA) status. Sensitivity analyses indicated uncertainty in the stability of the interaction. Conclusions: These findings suggest that age-informed cerebellar volumetric patterns may provide developmental information not evident from average volumes alone and support prospective validation with standardized imaging and developmental assessments. As a result, cerebellar volumes obtained early in life may hold prognostic information for ELBW infants.

Background: Response to Comprehensive Behavioral Intervention for Tics (CBIT), the first-line treatment for tic disorders, is suboptimal. We conducted Phase 1 of a two-phase, milestone-driven trial to determine if augmenting CBIT with repetitive transcranial magnetic stimulation (TMS) to supplementary motor area (SMA) could safely engage targeted sensorimotor circuitry and improve tic controllability. Methods: In a 3-arm, double-blind, sham-controlled randomized trial (NCT04578912), 50 youth (ages 12-21) with moderate-to-severe tics received 10 sessions of either 1Hz rTMS, continuous theta burst stimulation (cTBS), or sham stimulation to the SMA, immediately followed by CBIT. Primary outcomes were safety, feasibility, and neural target engagement (fMRI SMA activation and resting-state functional connectivity [RSFC]). Secondary outcomes included change in tic controllability, tic frequency at rest, and urges. Results: The CBIT+TMS intervention was safe and feasible (96% completion). Treatment-related adverse events were mild-to-moderate and occurred more frequently in the 1Hz rTMS group (27% of sessions) vs. cTBS (14.7%) and sham (11.3%). While task-based SMA activation remained unchanged, cTBS demonstrated robust neural target engagement, reducing SMA-primary motor cortex (M1) RSFC and putamen-M1 RSFC. Conversely, 1Hz rTMS blunted the cortico-striatal connectivity reductions observed in the sham group. All groups exhibited significant reductions in tic frequency and improved controllability. Premonitory urges increased in the 1Hz rTMS group but decreased in sham and cTBS. Conclusions: SMA-directed cTBS is a safe, feasible augmentation that may amplify the neural effects of CBIT on sensorimotor circuitry. Findings identify cTBS as the preferred stimulation regimen for future efficacy testing. Clinical Trial Registration: ClinicalTrials.gov; Identifier: NCT04578912.

Computer mouse weight has been proposed to influence human motor performance, but existing evidence comes largely from small, short-duration controlled studies, leaving its relationship to performance during naturalistic gameplay unresolved. We analyzed one-week skill improvement in Aimlabs, a popular first-person shooter aim-training and assessment platform, among 9,067 players whose telemetry recorded a mouse-model change (switchers) during self-directed game use, using a 21-day baseline and 7-day follow-up; 4,991 players with a single mouse model (non-switchers) observed over matched pseudo-anchor intervals provided a secondary contextual comparison. Post-switch mouse weight was represented by eight bands spanning 35-124 g. The primary multivariable generalized additive regression model accounted for baseline skill, pre- and post-switch practice intensity, and pre- and post-switch mouse sensitivity, and allowed the association between weight band and improvement to vary with baseline skill, post-switch practice, and post-switch sensitivity. For each weight band, predicted mean one-week improvement was standardized to the observed distribution of these covariates among switchers and reported in percentile-rank points. Statistical significance was evaluated using 1,000 permutations in which observed mouse weights were randomly reassigned among switchers without replacement and the model was refitted to generate empirical null distributions for the weight-related test statistics. Predicted improvement differed significantly across the eight weight bands (p = 0.001). Pairwise comparisons identified significant differences between bands (p < 0.05), but no single band was associated with significantly greater predicted improvement than all seven others. In this large naturalistic cohort, predicted improvement was highest for players with 35-44 g mice, followed by 45-54 and 55-64 g, and several pairwise comparisons showed significantly greater improvement in lighter than in heavier weight bands. Across the examined baseline-skill profiles, the lowest predicted improvements occurred in either the 85-99 or 115-124 g band. Predicted improvement differed across weight bands at the 25th-percentile and median baseline-skill values (p = 0.002 and p = 0.003) but not at the 75th percentile (p = 0.153). However, the weight-band x baseline-skill interaction was not significant (p = 0.181), indicating that the analysis did not establish that weight-related differences varied by skill level.

ObjectiveRecovery from post-stroke aphasia is traditionally thought to plateau within a year after stroke. As such, no studies have characterized long-term recovery using comprehensive behavioral assessment and longitudinal functional MRI. We sought to characterize behavioral and neuroplastic changes over nearly six years in a patient with chronic post-stroke aphasia. MethodsA patient with chronic left hemisphere stroke underwent behavioral assessment and task-based fMRI at 9, 22, 33 and 71 months after stroke. Testing assessed auditory comprehension, semantic and phonological processing, naming, reading, spelling, motor speech, and executive function. Task-related activation during an adaptive semantic matching paradigm was quantified within language and semantic regions of interest. ResultsBehavior improved across multiple language domains. WAB-R Aphasia Quotient increased from 49.2 to 69.2, along with the large gains in word finding, connected speech, reading and spelling, whereas auditory comprehension remained relatively stable. fMRI demonstrated progressively increasing activation within left-hemisphere language regions, reaching normative range by the final assessment, along with increasing activation in semantic/executive regions. DiscussionRecovery of language production abilities can continue for years after stroke, supported by neuroplastic changes in the brain. Neurologists should inform stroke survivors that aphasia recovery can continue indefinitely after stroke.

Childhood cancer survivors (CS) treated with chemotherapy frequently experience long-term cognitive impairments, commonly referred to as CRCI. Whether these deficits reflect disrupted white matter microstructure, altered relationships between microstructure and cognition, or both remains unclear. Here, we applied the NODDI-Bingham model, which quantifies neurite density (NDI), isotropic free water (ISO), and orientation dispersion along primary (ODIp), secondary (ODIs), and total (ODIt) fiber axes, to characterize biophysically specific white matter microstructure in CS and examine its relationship to cognition. Twenty-one pediatric cancer survivors and 21 age-matched healthy controls (HC) underwent multi-shell diffusion MRI. Voxel-wise NODDI-Bingham analyses were performed within JHU atlas regions. Group differences were tested by ANCOVA, and associations between microstructure and cognition were examined with the NIH Toolbox Crystallized, Fluid, and Early Childhood composites using group-specific regressions. Confirmatory analyses were performed in an age-matched subsample of the HCP (n = 679). Notably, CS showed reduced NDI in the corona radiata, cerebral peduncles, and corpus callosum, with elevated ODIt and ODIp in the middle cerebellar peduncle, pathways that subserve processing speed and interhemispheric integration, cognitive domains among the most vulnerable in CRCI. Group-specific regressions revealed qualitatively different relationships between microstructure and cognition: HC exhibited mixed positive and negative relationships across four of five metrics (138 clusters spanning approximately 305,000 voxels; peak Cohen's d up to 3.00), whereas CS showed a predominantly uniformly negative pattern (67 clusters across 57,000 voxels), with no positive clusters for ISO, ODIt, ODIp, or ODIs, thus highlighting that reduced dispersion and extracellular free water are linked to better cognitive performance in CS. HCP analyses reproduced the HC pattern across all five metrics at proportionally smaller effect sizes, ruling out sample-size effects. NODDI-Bingham identifies two aspects of chemotherapy-related white matter pathology that standard diffusion metrics cannot resolve. First, pediatric cancer survivors show selective elevation of ODIp and ODIt in the cerebellar peduncles and reduced NDI in the corona radiata and corpus callosum, localizing group-level injury to specific fanning and neurite density signatures. Second, whereas in healthy controls white matter shows mixed positive and negative relationships between microstructure and cognition, survivors retain only negative relationships for ODIp and ODIt and a diminished mixed pattern for NDI, such that in the chemotherapy-exposed brain, only reduced neurite density and increased primary-axis fanning relate to cognitive impairment. These findings implicate a biophysically specific restructuring of the relationships between white matter and cognition as a candidate mechanism for CRCI and support NODDI-Bingham as a targeted biomarker panel for monitoring and intervention trials.

Purpose: Stimulability testing involves the evaluation of multiple aspects of a patient's behavior, but the results are most frequently consolidated into a single domain (i.e., "stimulable"). The current study performs preliminary content, construct, concurrent, and predictive validation for the Multidimensional Stimulability Profile for Voice (MSP-V), a rating scale designed to measure multiple domains during stimulability testing (Degree of Change, Rapidity of Change, Generalization, Patient-rated Voice Quality, Patient-rated Voice Feel, and an overall rating of Stimulability Level). Methods: 78 patients with voice disorders (24 functional, 15 structural, 39 neurological) were administered the MSP-V by five speech-language pathologists (SLPs). Content validity was evaluated via the Content Validity Index (CVI) completed by nine voice-specialized SLPs. Construct validity was evaluated via exploratory factor analysis. Concurrent validity was assessed by determining whether MSP-V domains scaled in the expected direction compared to categorical stimulability ratings (e.g., "Highly stimulable" vs. "Stimulable"). Predictive validity was assessed by examining the relationship between MSP-V domains and voice disorder diagnosis, return to voice therapy, and patient-reported practice outside of therapy. Results: The CVI reached the critical value for clinician-rated and patient-rated domains. Two distinct factors were identified during EFA, one consisting of clinician-rated domains and the other of patient-rated domains. All MSP-V domains showed the expected directional relationships as categorical stimulability ratings. No domains differed significantly between disorder etiologies. The Rapidity of Change and Stimulability Level domains both significantly predicted return for voice therapy, where participants who rated lower on each domain were more likely to return to for voice therapy. No domains were predictive of patient-reported practice. Conclusions: The MSP-V is a clinically feasible tool with emerging content, construct, concurrent, and predictive validity that could be used to provide increased clarity and precision in stimulability testing documentation for research and practice.

BackgroundThe balance between excitatory and inhibitory neuronal signalling (E/I balance), proposed as a key mechanism controlling neuronal activity, is disrupted in many neurodevelopmental conditions. One such condition is Neurofibromatosis Type 1, a monogenic neurodevelopmental disorder characterised by increased inhibitory tone. While previous research suggests that E/I balance may be altered in infancy, it is unknown whether E/I balance remains altered during adolescence in NF1. Here we investigated this question using the aperiodic exponent of the resting electroencephalogram (EEG) power spectrum, a proposed electrophysiological index of E/I balance. MethodThe aperiodic exponent of the EEG power spectrum ( 1/f) was estimated for 16 adolescents with NF1 diagnosis aged 11-16, and 16 age- and sex-matched neurotypical controls. General linear models (GLM) were fit to estimate effects of NF1 diagnosis, age and their interaction on aperiodic exponent. We also estimated the peak dominant frequency and power in oscillatory activity of the EEG signal and fitted the same structure of GLM models. Cognitive assessments across domains of memory, executive function and attention were also analysed with GLM to examine brain-cognition associations. ResultsThe NF1 group had higher aperiodic exponent compared to neurotypical controls, but the aperiodic exponent was not associated with cognitive performance. After accounting for aperiodic activity, the NF1 group also had lower dominant oscillatory frequency than the control group. There was no significant interaction between NF1 diagnosis and age on PAF. There were no group differences in peak alpha power. ConclusionsWe demonstrate for the first time that the alterations to aperiodic activity in NF1 are consistent with the proposed mechanism of increased inhibitory tone. These findings show the potential of this paradigm for future pharmacological and brain stimulation trials investigating treatment-related changes in cortical function.

Inhibitory control deficits have long been proposed as a central neurocognitive mechanism underlying childhood Attention Deficit/Hyperactivity Disorder (ADHD). However, neuroimaging findings remain heterogeneous, partly due to methodological variability across developmental samples and experimental paradigms. The present study aimed to characterize the neural architecture of motor response inhibition in typically developing (TD) children and identify reproducible functional abnormalities associated with pediatric ADHD using stringent, developmentally specific inclusion criteria. We conducted two coordinate-based meta-analyses using Activation Likelihood Estimation (ALE). Following a systematic literature search (up to August 2026), we identified 23 task-based fMRI studies reporting inhibitory-control-related activation in TD children (237 foci) and 17 studies comparing children with ADHD and TD peers (114 foci) during the Stop-Signal Task or Go/No-Go Task. All participants were younger than 18 years of age. Statistical significance was determined using cluster-level family-wise error (FWE) correction. In TD children, ALE revealed a robust inhibitory-control network encompassing the bilateral anterior insula (AI), inferior frontal gyrus (IFG), and the midline pre-supplementary motor area (preSMA) and anterior cingulate cortex (ACC). This spatial organization closely resembled the canonical inhibitory-control network consistently observed in adults, suggesting that the core neural architecture supporting motor inhibition is already detectably organized during development. In the between-group analysis, children with ADHD exhibited significant hypoactivation primarily within the preSMA. Notably, this region demonstrated striking spatial overlap with the preSMA cluster reliably recruited in TD children during motor inhibition. These findings provide convergent support for inhibitory-control models of ADHD and identify altered preSMA recruitment as one of the most consistent functional abnormalities associated with pediatric ADHD. While the neural infrastructure supporting inhibitory control is broadly established during childhood, children with ADHD exhibit reduced recruitment of a key cortical node within this network during motor inhibition demands.

Neurofeedback shows promise as a clinical intervention, but its effectiveness is hindered by variability of response across individuals. One factor influencing neurofeedback success may be endogenous brain states, particularly the baseline power within target frequency bands. Transcranial alternating current stimulation (tACS) provides a potential mechanism to modulate these baseline frequency bands. This study explored whether tACS could effectively enhance participants' ability to gain neurofeedback control by increasing lateralised posterior alpha activity prior to engagement in a covert spatial attention-based neurofeedback task. Participants completed three counterbalanced sessions: 1) alpha tACS and active neurofeedback, 2) alpha tACS and sham neurofeedback, 3) gamma (40Hz) tACS and active neurofeedback. Neurofeedback performance was assessed via lateralised posterior alpha power shifts and Posner task reaction times. We identified no difference in reaction times or lateralised alpha power shifts across conditions. While participants reliably demonstrated lateralised posterior alpha patterns, consistent with the covert spatial attention neurofeedback protocol, no advantage of active neurofeedback over sham was observed. The lack of significant effects underscores the need for further rigorous tACS studies to identify the parameters essential for successful neural entrainment, and to evaluate its potential in enhancing neurofeedback efficacy.

Background and Purpose: Neonatal hypoxia-ischemia (NHI) is a leading cause of mortality and long-term neurodevelopmental disability. Therapeutic hypothermia (TH) is currently the only established treatment for NHI; however, its efficacy remains limited, underscoring the need for adjunctive neuroprotective strategies. Lactate is now regarded as a major metabolic substrate of the brain and has previously been shown to exert neuroprotective effects following experimental NHI. We investigated whether lactate enhances hypothermia-induced neuroprotection and evaluated the optimal timing of administration and potential underlying mechanisms. Methods: Postnatal day 7 Wistar rats were subjected to NHI using the Rice-Vannucci model and treated with TH alone (2h at 32{degrees}C), sodium L-lactate alone, or combined L-lactate-TH. Animals underwent longitudinal magnetic resonance imaging (MRI) and behavioral assessments, complemented by histological, immunohistochemical, and Western blot analyses, including assessment of protein lactylation. The effect of sodium L-lactate administration timing relative to TH was also evaluated. Results: Lactate significantly enhanced the neuroprotective effects of TH, particularly when administered before hypothermia, resulting in greater lesion recovery, reduced neuroinflammation and apoptotic cell death, preserved neuronal integrity, and improved long-term motor and cognitive outcomes. Combined treatment preserved neuronal lactate transporter, prevented NHI-induced astrocytic glutamate transporter upregulation, modulated lactylation markers, supporting coordinated metabolic and epigenetic adaptations following NHI. Conclusions: Early lactate administration enhances the neuroprotective efficacy of TH following NHI. These findings identify lactate as a promising adjunct to TH and support its translational potential as a metabolic strategy to improve outcomes following NHI brain injury.

Chronic spatial neglect after right-hemisphere stroke reflects network dysfunction, with recovery influenced by structural connectivity. Music recruits coordinated bi-hemispheric activity and may promote interhemispheric communication after stroke. Following our pilot study in post-stroke aphasia, we asked whether classical music modulates connectivity and behavior in chronic neglect. Three patients completed a crossover protocol comparing two weeks of daily audiovisual classical music with an audiobook control, with neglect, mood, quality-of-life, diffusion MRI, and resting-state high-density EEG measures. All showed right superior longitudinal fasciculus II disconnection with preserved callosal pathways. In N2, line bisection shifted leftward across all five lines after music, together with increased posterior interhemispheric theta-band weighted symbolic mutual information (wSMI), then deteriorated into the pathological range after the audiobook, without mood improvement. N1 showed mixed behavioral effects, with mood and quality of life improving after music. N3 showed no significant spatial improvement and worsened mood after music. These heterogeneous responses motivate larger studies of connectional predictors. The findings support the feasibility of classical music as an adjunct to neglect rehabilitation and suggest that cognitive changes may occur independently of mood, while the audiobook cannot be considered an inert control.

The cerebellum plays an emerging, but understudied, role in neurodevelopmental disorders (NDDs). Mutations in CHD8 cause a monogenic NDD (CHD8-NDD) characterized by autism and other manifestations, and prior work in Chd8 mutant mice reported cerebellar abnormalities, raising the possibility of cerebellar contribution to CHD8-NDD. To comprehensively characterize the impact of Chd8 haploinsufficiency on cerebellar development and function, we profiled the postnatal day 12 (P12) cerebellum of germline Chd8+/- mice using transcriptomic, morphological, and electrophysiological approaches. Gross cerebellar morphology was unaffected, but single-nucleus RNA sequencing revealed transcriptomic signatures of pathophysiology across cell types, including accelerated maturation of molecular layer interneurons and granule cells, and altered myelination state of oligodendrocytes. Purkinje cells (PCs) showed the strongest transcriptomic burden of any cell type and, consistent with this, exhibited altered morphology and electrophysiological properties. Bulk RNA sequencing confirmed that transcriptomic pathology persists into adulthood, indicating lasting impacts on both neuronal and glial gene expression. Together, these results capture cell-type-specific cerebellar perturbations associated with Chd8 haploinsufficiency and support the cerebellum as a relevant site of pathology in CHD8-NDD.

Rehabilitation is the cornerstone of clinical care following spinal cord injury (SCI) and is frequently incorporated into preclinical studies to evaluate emerging therapies. However, the variables that influence the effectiveness of rehabilitation interventions in rodent models remain poorly characterized, limiting the translational value of preclinical research. Here, we performed a meta-analysis of 150 preclinical studies comprising more than 3000 rodents and 292 effect sizes to identify such factors associated with successful rehabilitation after SCI. Rehabilitation improved functional outcomes across multiple behavioral domains, with larger effects observed in thoracic than cervical injury models. Meta-regression identified environmental enrichment as the most effective strategy, particularly when combined with task-specific training. Longer rehabilitation duration was associated with improved recovery, whereas greater daily exposure to forced rehabilitation was associated with smaller gains. In contrast, prolonged access to voluntary rehabilitation did not show this relationship. Rehabilitation improved outcomes when initiated at all time points after injury, with greater benefits when initiated during the late subacute and intermediate phases. Rehabilitation approaches associated with higher stress burden produced reduced benefits, suggesting that stress may limit rehabilitation-induced recovery. Collectively, these findings identify rehabilitation type, duration, and delivery context as important determinants of recovery after SCI and support a broad therapeutic window for intervention. Our results favor low-stress, voluntary rehabilitation strategies that promote sustained engagement and provide principles for designing effective and biologically appropriate rehabilitation strategies, potentially improving translational success for emerging SCI therapies. One Sentence SummarySustained voluntary rehabilitation promotes functional recovery across stages of experimental spinal cord injury, whereas prolonged forced training may reduce its benefits.

Functional recovery after spinal cord injury depends on whether reorganizing descending circuits form adaptive, task-specific relays rather than maladaptive ones. The corticospinal tract undergoes competitive, activity-dependent refinement during a defined juvenile window, so the timing and polarity of cortical activity may dictate whether injured circuits rewire usefully. Whether biasing cortical activity during this window can steer reorganization toward recovery, and whether naturalistic rehabilitation supplies the activity such steering requires, remain unknown. In juvenile rats we delivered excitatory or inhibitory chemogenetic receptors, or a control vector, to the forelimb motor cortex at postnatal day 5, induced a right cervical hemisection at postnatal day 14, and gave oral clozapine-N-oxide during nightly rough-and-tumble play from postnatal day 20 to 50. Play, the rehabilitation common to all groups, did not differ between them, isolating cortical-activity polarity as the manipulated variable. Outcomes spanned forelimb dexterity, reaching kinematics, cortical output by intracortical microstimulation, descending architecture by intersectional viral tracing, and frequency-dependent depression of the Hoffmann reflex. In untreated injured animals, cortical output re-lateralized maladaptively toward the intact forelimb, driving the ipsilateral (intact) limb in 11 of 15 evoked responses and 3 of 5 animals. Excitation preserved selective drive to the impaired forelimb (38 of 39 responses; concordant-site proportion Kruskal-Wallis H = 9.08, exact P = 0.0031), and pure ipsilateral re-lateralization was absent from all nine treated animals (3 of 5 control versus 0 of 9 treated; Fisher's exact P = 0.027). Across behavioural, kinematic, and anatomical measures a consistent excitatory > control > inhibitory gradient emerged. Excitation enhanced wrist elevation and forward extension during reaching, restored frequency-dependent depression of the Hoffmann reflex, and selectively recruited three parallel lesion-bypassing relays: interhemispheric cortico-cortical-spinal, cortico-reticulo-spinal, and cortico-propriospinal (ipsilesional cortical relay neurons F(2,14) = 56.96, P < 0.0001). Inhibition yielded the weakest behavioural recovery and least relay recruitment, and did not restore contralesional cortical drive. Cortical-activity polarity during a juvenile window thus acts as a developmental switch governing whether descending reorganization is adaptive or maladaptive. Guided excitation, paired with behaviourally meaningful activity, reshapes diffuse sprouting into structured, lesion-bypassing relays and corrects the spontaneous re-lateralization that otherwise misdirects recovery. These findings provide a translational rationale for activity-paired neuromodulation in paediatric spinal cord injury.

Axonal action potential propagation critically depends on tightly regulated intra and extracellular electrolyte concentrations and acid base homeostasis. Experimental studies have demonstrated that changes in extracellular sodium, potassium, and calcium concentrations alter axonal excitability and conduction properties. However, it remains unknown whether small variations in electrolyte concentrations within the physiological range are associated with measurable changes in nerve conduction velocity in humans. In this study, data from neurologically healthy children who underwent both nerve conduction studies and blood gas analysis were analyzed to investigate the relationship between electrolyte concentrations and median motor nerve conduction velocity. Nerve conduction velocity was significantly negatively correlated with ionized calcium concentration and positively correlated with sodium concentration, whereas no significant correlation was observed for potassium. In an a priori defined multiple linear regression model, ionized calcium, sodium, and bicarbonate remained significantly associated with nerve conduction velocity after correction for multiple testing. These findings indicate that even small variations in electrolyte concentrations within the physiological range are associated with measurable differences in peripheral nerve conduction velocity and suggest an additional contribution of acid base status to nerve conduction.

3q29 deletion (3q29Del) is a genetic risk variant for autism spectrum disorder and schizophrenia that often results in developmental delays, cognitive disability, and impaired fine motor function. People with 3q29Del have reduced cerebellar volume, which correlates with symptom severity, and many 3q29Del-associated phenotypes also commonly occur after cerebellar injury or dysfunction. However, it is unknown whether the existing 3q29Del mouse model recapitulates the cerebellar dysfunction observed in humans. To characterize cerebellar phenotypes and uncover pathological differences in the 3q29Del mouse model, we investigated cerebellar structure, motor and vocal behaviors, protein expression, and mitochondrial function. We found uniformly reduced cerebellar volume in 3q29Del mice. Behavioral assays revealed vocal impairments in 3q29Del pups, fine motor impairments in adult mice, and reduced social mating calls in adult male mice. Proteomic analysis revealed enrichment of synaptic and mitochondrial proteins among the differentially expressed proteins in 3q29Del cerebellum tissue. Furthermore, mitochondria from 3q29Del mouse cerebellum displayed reduced oxygen flux and increased electron leak. These results recapitulate many human 3q29Del phenotypes in the 3q29Del mouse model and indicate mitochondrial dysfunction as a potential driver of 3q29Del pathology. Our findings also point to cerebellar involvement in 3q29Del phenotypes and provide a foundation for further research on cerebellar development in 3q29Del.

Bimanual coordination is essential for many skilled everyday actions and requires maintaining specific spatiotemporal relationships between the two hands according to task demands. However, the contribution of the primary motor cortices (M1s) to learning such relationships is only partially understood. Conventional bimanual tasks necessarily engage both M1s in controlling the moving hands, making learning-related changes difficult to distinguish from those associated with movement execution. To reduce this effector-related confound, we used a unimanual and bimanual rhythmic coordination paradigm in which participants learned the same novel 90-degree relative-phase relationship by coordinating either hand with a virtual partner and compared these conditions with conventional bimanual practice. In three experiments, performance accuracy and stability improved during practice and improved further after a 6-h retention interval with comparable time-dependent changes across unimanual and bimanual trained groups. In Experiment 2, motor-evoked potentials measured before and after training revealed an overall increase in corticospinal excitability across both M1s under unimanual and bimanual training. In Experiment 3, bidirectional dual-site paired-pulse stimulation revealed effector-dependent changes in interhemispheric inhibition, in which bimanual practice produced no reliable directional modulation, whereas unimanual practice produced asymmetric changes that depended on the trained hand. Neither corticospinal excitability nor interhemispheric inhibition showed a consistent relationship with behavioral improvement. Together, these findings demonstrate comparable behavioral learning of a novel spatiotemporal coordination relationship across bimanual and unimanual contexts, while showing that behavioral improvement is not straightforwardly reflected in M1 neurophysiological changes. Causal intervention studies are therefore needed to determine whether and when M1 contributes directly to acquisition of novel coordination relationships.

Spinal cord injury (SCI) is an incurable neurological condition in which post-traumatic edema contributes to secondary ischemic damage because the spinal cord is confined within the rigid vertebral canal. However, glymphatic transport in the healthy and injured spinal cord remains poorly characterized. We hypothesized that spinal cerebrospinal (CSF) and glymphatic transport is shaped by anatomy, administration route, and molecular size of the tracer; is disrupted after SCI; and is further impaired by loss of aquaporin-4 (AQP4). CSF tracers were administered by cisterna magna or lumbar intrathecal injection to anesthetized adult C57BL/6 mice. Dynamic contrast-enhanced MRI, ex vivo fluorescence imaging, and histology were used to characterize tracer distribution, influx, and clearance. Constrictions of the spinal subarachnoid space at C3-C7, T6-T12 and L5-S1 spinal segments accelerated contrast-agent dispersion, demonstrating that local anatomy regulates spinal CSF transport. Tracer influx into the cord itself occurred primarily along periarterial pathways.Tracer distribution depended on the administration route: cisterna magna injection preferentially labeled white matter in the upper spinal cord, whereas lumbar injection preferentially labeled grey matter in the lower spinal cord. Gadobutrol and ovalbumin penetrated and dispersed throughout the parenchyma, whereas fibrinogen remained confined to the meninges. Under physiological conditions, intraparenchymal tracers cleared within 24 h. SCI was modeled using a minimally invasive NMDA-induced lesion at T11 that produced focal necrosis while preserving the dura and vertebral structures. Glymphatic transport, lesion volume, and motor recovery were compared between wild-type and AQP4-knockout mice using imaging, the Basso Mouse Scale, and voluntary wheel running. After SCI, intrathecal contrast propagated more rapidly, especially at T7-T8 segments and at the S1 segment, but tissue clearance was profoundly impaired, with tracer retention persisting for up to seven days. AQP4-knockout mice showed greater clearance impairment, larger lesions, and poorer motor recovery than wild-type controls compared at 24 h. These findings define major determinants of spinal glymphatic transport and show that accelerated tracer propagation after SCI does not indicate effective clearance. Instead, SCI produces glymphatic dysfunction that is exacerbated by loss of AQP4 and associated with greater tissue damage and functional impairment. The results extend the glymphatic framework to the spinal cord and identify fluid-clearance pathways as potential therapeutic targets for limiting edema and secondary injury. Future studies should determine whether restoring glymphatic function improves neurological recovery after SCI.

Discourse analysis can reliably predict real-world communicative success, yet is rarely implemented clinically, due to challenges in manually generating stimulus-specific main concept inventories (MCIs) and scoring patient narratives. We evaluated whether automatically derived macrolinguistic (main concept, sentiment) and microlinguistic (fluency, lexical, syntactic) features extracted from movie clip narrations can augment the clinical assessment of discourse in aphasia. The MCIs generated directly from each clip's video, audio and subtitles using a vision-language model approximated the main concepts healthy controls produced. Group classification (control: n=51; aphasia: n=54) based on the discourse features was excellent (AUC=0.95, 95% CI [0.90, 0.99]), with macrolinguistic features showing the largest group differences (main concept completeness: d=-1.84, 95% CI [-2.30, -1.38]) and strongest associations with aphasia severity (semantic distance to inventory: r=-0.79, 95% CI [-0.87, -0.66]). Findings support the feasibility and scalability of automated criterion-based discourse assessment using ecological stimuli, and highlight its potential for clinical implementation.

Background: Immediate transcranial evoked potentials (iTEPs) are ultra-early electroencephalographic responses elicited by single-pulse transcranial magnetic stimulation (TMS) of the primary motor cortical hand area (M1-HAND). Their characteristic latency, waveform, and sensitivity to short-interval intracortical inhibition suggest a close relationship to the cortical generators of indirect corticospinal volleys (I-waves). Here, we tested the hypothesis that iTEPs constitute a fundamental physiological response of human motor cortex and therefore generalize across motor representations, including the leg representation (M1-LEG). Methods: Single-pulse TMS was delivered over the motor cortical representation of the right tibialis anterior (TA) in 16 healthy volunteers. In a subset of participants (n=10), stimulus-response curves and paired-pulse short-interval intracortical inhibition (SICI) measures were obtained. Results: TMS of M1-LEG elicited reproducible iTEPs consisting of a slow positive deflection with superimposed high-frequency peaks with topographic maxima in electrodes adjacent to the stimulation site. M1-LEG iTEPs emerged close to active motor threshold and increased in prevalence and amplitude with increasing stimulation intensity. Paired-pulse stimulation produced consistent SICI of the second and third iTEP peaks. M1-LEG stimulation also evoked conventional later TEPs with latencies and polarities closely resembling those recorded after M1-HAND stimulation. Conclusions: TMS of the human M1-LEG elicits robust iTEPs that closely resemble those recorded from M1-HAND in their timing, intensity dependence, and sensitivity to intracortical inhibition. These findings indicate that iTEPs are not specific to M1-HAND but reflect a general physiological response of human motor cortex closely linked to corticospinal I-wave generation. This broadens their utility as a non-invasive probe of excitatory and inhibitory circuit dynamics throughout the human motor system.