Premotor Research Articles

Involvement of aSPOC in the online updating of reach-to-grasp to mechanical perturbations of hand transport.

Humans adjust their movement to changing environments effortlessly via multisensory integration of the effector's state, motor commands, and sensory feedback. It is postulated that frontoparietal (FP) networks are involved in the control of prehension, with dorsomedial (DM) and dorsolateral (DL) regions processing the reach and the grasp, respectively. This study tested (5F, 5M participants) the differential involvement of FP nodes (ventral premotor cortex - PMv, dorsal premotor cortex - PMd, anterior intraparietal sulcus - aIPS, and anterior superior parietal-occipital cortex - aSPOC) in online adjustments of reach-to-grasp coordination to mechanical perturbations that disrupted arm transport. We used event-related transcranial magnetic stimulation (TMS) to test whether the nodes of these pathways causally contribute to the processing of proprioceptive information when reaching for a virtual visual target at two different perturbation latencies. TMS over aSPOC selectively altered correction magnitude of arm transport during late perturbations, demonstrating that aSPOC processes proprioceptive inputs related to mechanical perturbations in a movement phase-dependent manner.Significance Statement Detailed knowledge regarding specific brain regions, the timing of their involvement, and roles in the online updating of sensory input during the control of the reach-to-grasp movement is critical for understanding the deficits resulting from various diseases, such as stroke, as well as for the development of effective intervention strategies. Our results provide evidence for the involvement of aSPOC in the modulation of the response to a mechanical perturbation of arm transport during the later stage of the movement, suggesting that this area participates in estimating the effector state based on proprioceptive input. Our results can provide key information for identifying brain targets of engagement in therapeutic applications of noninvasive brain stimulation to ameliorate motor deficits stemming from parietal damage.

Stereoelectroencephalographic exploration and surgical outcome in Lennox-Gastaut syndrome.

Lennox-Gastaut syndrome (LGS) is typically characterized by drug-resistant epilepsy and subsequent cognitive deterioration. Surgery is a rare but viable option for the control of seizures in a subset of patients with LGS. This study aimed to describe the organization of the epileptogenic zone network (EZN) in patients with LGS using stereoelectroencephalography (SEEG) and to report the outcome of post-SEEG treatment. A quantitative SEEG signal analysis was conducted in 14 consecutive patients with LGS, in whom a potentially localized EZN was suggested based on a comprehensive noninvasive evaluation. The EZN and the irritative zone network were identified using relevant biomarkers during ictal (epileptogenicity index and connectivity epileptogenicity index) and interictal (spikes and high-frequency oscillations) recordings. The applied post-SEEG treatments were assessed, including SEEG-guided radiofrequency thermocoagulation (RF-TC), surgery, and neurostimulation. The seizure onset patterns showed some specificity by seizure type, with 84% of tonic seizures involving low-voltage fast activity. The EZN of patients with LGS was often, but not always, complex and extensive, involving two or more lobes (79%) and both hemispheres (64%). The lateral neocortical structures, particularly the lateral premotor and dorsolateral prefrontal cortices, were identified as being most frequently involved in the EZN. Among the explored subcortical structures, only the pulvinar, central-lateral thalamic nucleus, and hypothalamic hamartoma belonged to the EZN. Twelve patients (86%) underwent SEEG-guided RF-TC, with 50% experiencing a >50% reduction in baseline seizure frequency. Four patients (29%) underwent curative surgery for significant involvement of a lesion in the EZN, and one case achieved an Engel class I outcome. This is the first quantitative SEEG study in patients with LGS to demonstrate the utility of SEEG in identifying patients who may benefit from surgery and to perform SEEG-guided RF-TC. Nevertheless, the indications for SEEG should be carefully assessed, as localized EZN is uncommon in LGS.

Spatio-temporal transformers for decoding neural movement control.

Deep learning tools applied to high-resolution neurophysiological data have significantly progressed, offering enhanced decoding, real-time processing, and readability for practical applications. However, the design of artificial neural networks to analyze neural activity in vivo remains a challenge, requiring a delicate balance between efficiency in low-data regimes and the interpretability of the results.
Approach:
To address this challenge, we introduce a novel specialized transformer architecture to analyze single-neuron spiking activity. The model is tested on multi-electrode recordings from the dorsal premotor cortex (PMd) of non-human primates performing a motor inhibition task.
Main Results
The proposed architecture provides an early prediction of the correct movement direction, achieving accurate results no later than 230 ms after the Go signal presentation across animals. Additionally, the model can forecast whether the movement will be generated or withheld before a Stop signal, unattended, is actually presented. To further understand the internal dynamics of the model, we compute the predicted correlations between time steps and between neurons at successive layers of the architecture, with the evolution of these correlations mirrors findings from previous theoretical analyses.
Significance
Overall, our framework provides a comprehensive use case for the practical implementation of deep learning tools in motor control research, highlighting both the predictive capabilities and interpretability of the proposed architecture.

Motor network reorganization associated with rTMS-induced writing improvement in writer's cramp dystonia.

Writer's cramp (WC) dystonia is an involuntary movement disorder with distributed abnormalities in the brain's motor network. Prior studies established the potential for repetitive transcranial magnetic stimulation (rTMS) to either premotor cortex (PMC) or primary somatosensory cortex (PSC) to modify symptoms. However, clinical effects have been modest with limited understanding of the neural mechanisms hindering therapeutic advancement of this promising approach. This study aimed to understand the motor network effects of rTMS in WC that correspond with behavioral efficacy. We hypothesized that behavioral efficacy is associated with modulation of cortical and subcortical regions of the motor network. In a double-blind, cross-over design, twelve WC participants underwent rTMS in one of three conditions (Sham-TMS, 10 Hz PSC-rTMS, 10 Hz PMC-rTMS) while engaged in a writing task to activate dystonic movements and measure writing fluency. Brain connectivity was evaluated using task-based fMRI after each TMS session. 10 Hz rTMS to PSC, but not PMC, significantly improved writing dysfluency. PSC-TMS also significantly weakened cortico-basal ganglia, cortico-cerebellum, and intra-cerebellum functional connectivity (FC), and strengthened striatal FC relative to Sham. Changes in PSC and SPC BOLD activity were associated with reduced dysfluent writing behavior. 10 Hz rTMS to PSC improved writing dysfluency by redistributing motor network connectivity and strengthening somatosensory-parietal connectivity. A key signature for effective stimulation at PSC and improvement in writing dysfluency may be strengthening of intra-cortical connectivity between primary somatosensory and superior parietal cortices. These findings offer mechanistic hypotheses to advance the therapeutic application of TMS for dystonia. 10 Hz repetitive TMS to somatosensory cortex reduces writing dysfluency in dystoniaIncreased somatosensory cortex activity correlates with reduced writing dysfluencyIn dystonia + sham-TMS, writing dysfluency correlates with cerebellar connectivity.10 Hz rTMS to somatosensory cortex induces reorganization of the motor network.

Altered cortical activation patterns in post-stroke patients during walking with two-channel functional electrical stimulation: a functional near-infrared spectroscopy observational study.

Restoration of independent walking ability is the primary objective of stroke rehabilitation; however, not all patients achieve this goal due to diverse impairments in the paretic lower limb and compensatory mechanisms that lead to an asymmetrical and mechanically inefficient gait. This investigation aimed to examine alterations in cortical activation in post-stroke patients while walking with a wearable two-channel functional electrical stimulation (FES) in comparison to walking without FES. This observational study was conducted to discern distinct activation patterns in 19 stroke patients during sessions with and without FES, while using functional near-infrared spectroscopy (fNIRS) to monitor changes in blood oxygen levels. Our findings revealed only a significant reduction in ΔOxy-Hb in the contralesional pre-motor cortex (z = -2.803, p = 0.005) during the FES-on walking sessions compared to the FES-off sessions. Furthermore, all regions in the FES-on session exhibited lower ΔOxy-Hb. Conversely, no significant differences were observed in ΔDeoxy-Hb. Moreover, a significant correlation was found between decrease in cPMC and the reduced cost time of walking under FES-on condition. The fNIRS analysis revealed diminished activation in the contralesional pre-motor cortex when walking with FES, implying that FES may facilitate a more automatic gait pattern while reducing a patient's reliance on contralesional cortical resources. The findings of this study lay the groundwork for long-term neural rehabilitation.

Peripheral neurofilament light chain and intracortical myelin in bipolar I disorder.

Neurofilament light chain (NfL) is a cytoskeletal protein that supports neuronal structure. Blood NfL levels are reported to be higher in diseases where myelin is damaged. Studies investigating intracortical myelin (ICM) in bipolar disorder (BD) have reported deficits in ICM maturation over age. This study investigated the association between ICM and peripheral blood NfL levels in BD. NfL was quantified using a high sensitivity ELISA kit in 72 BD and 71 healthy control (HC) participants. t-test was used to determine group difference in NfL levels between BD and HC, and ridge regression was performed to analyze NfL and ICM association in six brain regions that demonstrated ICM deficits including the dorsolateral motor cortex, dorsomedial motor cortex, dorsolateral premotor cortex, dorsomedial premotor cortex, caudal dorsolateral prefrontal cortex, caudal dorsomedial prefrontal cortex, and age in BD only. Regions within the occipital lobe and cingulum was also analyzed as control regions. BD individuals had higher serum NfL concentration compared to HC (p = 0.001). The ridge regression analysis including the six brain regions and age explained 26 % of the variance in NfL concentration, while the occipital lobe and cingulum along with age explained only 7 % and 2 % of the variance, respectively. This was a cross-sectional correlational study so causation cannot be inferred. Also, this study focused on a limited number of brain regions previously associated with changes in ICM in BD. This study corroborates previous research, which found increased NfL in CSF and blood in BD compared to HC. This demonstrates the potential utility of NfL as a marker of brain morphology deficits in BD.

Comparison of Brain Activation Between Different Modes of Motor Acquisition: A Functional Near-Infrared Study.

Different modes of motor acquisition, including motor execution (ME), motor imagery (MI), action observation (AO), and mirror visual feedback (MVF), are often used when learning new motor behavior and in clinical rehabilitation. The aim of this study was to investigate differences in brain activation during different motor acquisition modes among healthy young adults. This cross-sectional study recruited 29 healthy young adults. Participants performed a functional reaching and grasping task under ME, MI, AO, and MVF mode with their right arms at a frequency of 0.5Hz for 1min per task. Each task was performed three times in a random order. Brain activation in the supplementary motor area (SMA), premotor cortices (PMC), and primary motor cortices (M1) during tasks was measured using functional near-infrared spectroscopy through 16 source-detector channels. ME showed significant activation in bilateral PMC, M1, and right SMA, with higher activation in the contralateral M1. MI induced greater activity in the PMC and SMA, particularly in the ipsilateral regions. MVF resulted in significant activation in bilateral PMC, SMA, and M1. AO showed an increasing trend in brain activation, but no significant differences in any channels. Compared to AO, ME and MVF induced significantly greater brain activity in M1. Activation levels under MI and MVF were comparable to that of ME. MI and MVF induced greater activity in the PMC and SMA, and MVF showed significant activity in all brain areas, especially in the bilateral M1. These findings support the application of different motor acquisition strategies according to individual needs. When ME cannot be executed, such as for individuals with hemiparesis or severe impairments of both upper extremities, MI and MVF may be applied, respectively, to drive neuroplastic changes.

Ameliorative effect of <i>Vernonia amygdalina</i> on lead-induced neurotoxicity on the premotor cortex of adult Wistar rats

Ameliorative effect of <i>Vernonia amygdalina</i> on lead-induced neurotoxicity on the premotor cortex of adult Wistar rats

Long-term forced-use therapy after sensorimotor cortex lesions restores contralesional hand function and promotes its preference in Macaca mulatta.

Injury to one cerebral hemisphere can result in paresis of the contralesional hand and subsequent preference of the ipsilesional hand in daily activities. However, forced use therapy in humans can improve function of the contralesional paretic hand and increase its use in daily activities, although the ipsilesional hand may remain preferred for fine motor activities. Studies in monkeys have shown that minimal forced use of the contralesional hand, which was the preferred hand prior to brain injury, can produce remarkable recovery of function. Here we tested the hypothesis that long-term forced use of the contralesional hand during the post-lesion period can return it to preferred status. Four rhesus monkeys received tests of hand preference prior to surgical lesions of primary motor cortex, lateral premotor cortex and anterior parietal cortex (F2P2 lesion) contralateral to the preferred hand. Beginning two weeks after the lesion, forced use therapy involving contralateral hand reaches to acquire food targets occurred 3X weekly with at least 300 reaches/session until 24weeks post-lesion. Despite initial paresis of the contralesional hand, its manipulation skill returned to near pre-lesion levels or higher and all four monkeys returned to a contralesional hand preference late in the post-lesion period. Favorable reorganization of spared cortical and subcortical neural networks may promote recovery of hand function and preference. These results have relevance for the use of extensive forced-use therapy in humans who experience unilateral periRolandic injury to potentially support better recovery of contralesional hand function.

Brain Functional Characteristics in Football Players During Motor-Cognitive Dual Task: Insights From fNIRS.

Long-term training enables professional athletes to develop concentrated and efficient neural network organizations for specific tasks. This study used functional near-infrared spectroscopy to investigate task performance, brain functional characteristics, and their relationships in footballers during sport-specific motor-cognitive processes. Twenty-four footballers (athlete group, with 18 remaining of good signal quality) and 20 non-footballers (control group, with 16 remaining) completed four tasks: a single task (trigger buttons corresponding to the appearance direction of teammates with kicking actions), an N-back direction task, a dual task, and an N-back digit task. Brain activation, functional connectivity (FC), and lateralization were calculated, and their correlation with behavioral indicators was analyzed. Results showed that reaction times were shorter in footballers across all tasks. The activation value in the right dorsolateral prefrontal cortex (DLPFC) decreased during dual task compared to the resting state in the athlete group. The activation values in all brain regions (except left primary sensory cortex in the single task), right DLPFC (dual task), and left premotor cortex & left supplementary motor area (left PMC & left SMA, digit task) were significantly lower in the athlete group than in the control group. Footballers exhibited higher interhemispheric FC during the direction and digit tasks, and greater leftward bias in the DLPFC during the dual task. The FC between left prefrontal cortex (PFC) -left PMC & left SMA and within the left PFC region was significantly positively correlated with accuracy during the dual task. Footballers showed better task performance with less impact from load, lower central energy consumption and higher sensory-motor network connectivity during task execution, indicating a more efficient state. Enhancing brain function and related networks may improve athletes' reactive abilities and performance.

The Brain Activation of Two Motor Imagery Strategies in a Mental Rotation Task.

Background: Motor imagery includes visual imagery and kinesthetic imagery, which are two strategies that exist for mental rotation and are currently widely studied. However, different mental rotation tests can lead to different strategic performances. There are also many research results where two different strategies appear simultaneously under the same task. Previous studies on the comparative brain mechanisms of kinesthetic imagery and visual imagery have not adopted consistent stimulus images or mature mental rotation paradigms, making it difficult to effectively compare these types of imagery. Methods: In this study, we utilized functional near-infrared spectroscopy (fNIRS) to investigate the brain activation of sixty-seven young right-handed participants with different strategy preferences during hand lateral judgment tasks (HLJT). Results: The results showed that the accuracy of the kinesthetic imagery group was significantly higher than that of the visual imagery group, and the reaction time of the kinesthetic imagery group was significantly shorter than that of the visual imagery group. The areas significantly activated in the kinesthetic imagery group were wider than those in the visual imagery group, including the dorsolateral prefrontal cortex (BA9, 46), premotor cortex (BA6), supplementary motor area (SMA), primary motor cortex (BA4), and parietal cortex (BA7, 40). It is worth noting that the activation levels in the frontal eye fields (BA8), primary somatosensory cortex (BA1, 2, 3), primary motor cortex (BA4), and parietal cortex (BA40) of the kinesthetic imagery group were significantly higher than those in the visual imagery group. Conclusion: Therefore, we speculate that kinesthetic imagery has more advantages than visual imagery in the mental rotation of egocentric transformations.

Discovering the Neural Processes of Jazz Improvisation: A Research to Resource Article

Most jazz music contains some form of improvisation. Therefore, teaching improvisation, or spontaneous musical composition within a given context, remains an important task in music education. Discovering the neural processes involved in jazz improvisation might aid music educators who teach jazz improvisation and give researchers greater insight into overall creativity. Using functional magnetic resonance imaging to study jazz improvisers, researchers consistently found that the dorsolateral prefrontal cortex, superior temporal gyrus, premotor cortex, and pre-supplementary motor areas showed increased levels of activation when improvising. In this research to resource article, I suggest the role that each of these neural areas might play in jazz improvisation and how this knowledge might affect jazz pedagogy. Implications for music educators include the importance of creating a welcoming environment for students to experiment with jazz improvisation, developing efficient instrumental/vocal technique, and supporting the internal processes innate to improvisation.

Predicting upper limb motor recovery in subacute stroke patients via fNIRS-measured cerebral functional responses induced by robotic training

BackgroundNeural activation induced by upper extremity robot-assisted training (UE-RAT) helps characterize adaptive changes in the brains of poststroke patients, revealing differences in recovery potential among patients. However, it remains unclear whether these task-related neural activities can effectively predict rehabilitation outcomes. In this study, we utilized functional near-infrared spectroscopy (fNIRS) to measure participants’ neural activity profiles during resting and UE-RAT tasks and developed models via machine learning to verify whether task-related functional brain responses can predict the recovery of upper limb motor function.MethodsCortical activation and brain network functional connectivity (FC) in brain regions such as the superior frontal cortex, premotor cortex, and primary motor cortex were measured using fNIRS in 82 subacute stroke patients in the resting state and during UE-RAT. The Fugl-Meyer Upper Extremity Assessment Scale (FMA-UE) was chosen as the index for assessing upper extremity motor function, and clinical information such as demographic and neurophysiological data was also collected. Robust features were screened in 100 randomly divided training sets using the least absolute shrinkage and selection operator (LASSO) method. Based on the selected robust features, machine learning algorithms were used to develop clinical models, fNIRS models, and combined models that integrated both clinical and fNIRS features. Finally, Shapley Additive Explanations (SHAP) was applied to interpret the prediction process and analyze key predictive factors.ResultsCompared to the resting state, task-related FC is a more robust feature for modeling, with screening frequencies above 90%. The combined models built using artificial neural networks (ANNs) and support vector machines (SVMs) significantly outperformed the other algorithms, with an average AUC of 0.861 (± 0.087) for the ANN and an average correlation coefficient (r) of 0.860 (± 0.069) for the SVM. Furthermore, predictive factor analysis of the models revealed that FC measured during tasks is the most important factor for predicting upper limb motor function.ConclusionThis study confirmed that UE-RAT-induced FC can serve as an important predictor of rehabilitation, especially when combined with clinical information, further enhancing the accuracy of model predictions. These findings provide new insights for the early prediction of patients’ recovery potential, which may contribute to personalized rehabilitation decisions.

COMMON AND DISTINCT NEURAL CORRELATES OF SOCIAL INTERACTION PERCEPTION AND THEORY OF MIND.

Social cognition spans from perceiving agents and their interactions to making inferences based on theory of mind (ToM). Despite their frequent co-occurrence in real life, the commonality and distinction between social interaction perception and ToM at behavioral and neural levels remain unclear. Here, participants (N = 231) provided moment-by-moment ratings of four text and four audio narratives on social interactions and ToM engagement. Social interaction and ToM ratings were reliable (split-half r = .98 and .92, respectively) but only modestly correlated across time (r = .32). In a second sample (N = 90), we analyzed co-variation between normative social interaction and ToM ratings and functional magnetic resonance (fMRI) activity during narrative reading (text) and listening (audio). Social interaction perception and ToM activity maps generalized across text and audio presentation (r = .83 and .57 between unthresholded t maps, respectively). When ToM was held constant, merely perceiving social interactions activated all regions canonically associated with ToM under both modalities (FDR q < .01), including temporoparietal junction, superior temporal sulcus, medial prefrontal cortex, and precuneus. ToM activated these regions as well, indicating a shared, modality-general system for social interaction perception and ToM. Furthermore, ToM uniquely engaged lateral occipitotemporal cortex, left anterior intraparietal sulcus, and right premotor cortex. These results imply that perceiving social interactions automatically engages regions implicated in mental state inferences. In addition, ToM is distinct from social interaction perception in its recruitment of regions associated with higher-level cognitive processes, including action understanding and executive functions.

Assessing age-related changes in brain activity during isometric upper and lower limb force control tasks

Despite the widespread use of older adults (OA) as controls in movement disorder studies, the specific effects of aging on the neural control of upper and lower limb movements remain unclear. While functional MRI paradigms focusing on hand movements are widely used to investigate age-related brain changes, research on lower limb movements is limited due to technical challenges in an MRI environment. This study addressed this gap by examining both upper and lower limb movements in healthy young adults (YA) vs. OA. Sixteen YA and 20 OA, matched for sex, dominant side, and cognitive status, performed pinch grip and ankle dorsiflexion tasks, each requiring 15% of their maximum voluntary contraction. While both groups achieved the target force and exhibited similar force variability and accuracy, OA displayed distinct differences in force control dynamics, with a slower rate of force increase in the hand task and a greater rate of force decrease in the foot task. Imaging results revealed that OA exhibited more widespread activation, extending beyond brain regions typically involved in movement execution. In the hand task, OA showed increased activity in premotor and visuo-motor integration regions, as well as in the cerebellar hemispheres. During the foot task, OA engaged the cerebellar hemispheres more than YA. Collectively, results suggest that OA may recruit additional brain regions to manage motor tasks, possibly to achieve similar performance. Future longitudinal studies that track changes over time could help clarify if declines in motor performance lead to corresponding changes in brain activation.

Pallidal and motor cortical interactions determine gait initiation dynamics in Parkinson's disease.

Gait initiation is a fundamental human task, requiring one or more anticipatory postural adjustments (APA) prior to stepping. Deviations in amplitude and timing of APAs exist in Parkinson's disease (PD), causing dysfunctional postural control which increases the risk of falls. The motor cortex and basal ganglia have been implicated in the regulation of postural control, however, their dynamics during gait initiation, relationship to APA metrics, and response to pharmacotherapy such as levodopa are unknown. To address these questions, we streamed electrocorticography (ECoG) potentials from the premotor and primary motor cortices, as well as local field potentials (LFPs) from the globus pallidus in five people with PD exhibiting gait and balance dysfunction during a cued gait initiation task. Amplitude and timing of APA were evaluated with force plates and synchronized to the neural data. Subjects performed gait initiation trials under ON and LOW levodopa conditions to assess effects of medication on APA metrics and underlying neural dynamics. All subjects demonstrated pallidal and cortical oscillatory changes during different phases of gait initiation. Grouped analysis revealed that from quiet standing to the first foot step, pallidal beta power showed stepwise decrease and broadband gamma power increases, whereas cortical potentials showed low frequency (theta, alpha, beta) power decrease during gait initiation, regardless of medication state. The pallidum and motor cortices also became increasingly coherent during gait initiation compared to quiet standing prior to APA onset. Using linear mixed models, we found that while pallidal gamma powers are predictive of APA scaling, pallidal-cortical coherence (theta, alpha, beta) and premotor-M1 gamma coherence are predictive of APA timing. Our study is the first detailed characterization of basal-ganglia cortical circuit dynamics during human gait initiation. We identified significant pallidal motor cortical power and coherence changes that underlie the amplitude and timing of APA which appear to be independent of medication states of the study subjects. Our results provide evidence for a model where synchronized premotor and motor cortical activities transiently couple with the globus pallidus to regulate the timing of postural responses, and local pallidal activity regulate the amplitude of postural changes during gait initiation. It suggests that abnormal pallidal outflow and synchronization between the pallidum and motor cortices may be a pathophysiological mechanism underlying disordered postural response in Parkinson's disease.

A gradient of hemisphere-specific dorsal to ventral processing routes in parieto-premotor networks.

Networks in the parietal and premotor cortices enable essential human abilities regarding motor processing, including attention and tool use. Even though our knowledge on its topography has steadily increased, a detailed picture of hemisphere-specific integrating pathways is still lacking. With the help of multishell diffusion magnetic resonance imaging, probabilistic tractography, and the Graph Theory Analysis, we investigated connectivity patterns between frontal premotor and posterior parietal brain areas in healthy individuals. With a two-stage node characterization approach, we defined the network role of precisely mapped cortical regions from the Julich-Brain atlas. We found evidence for a third, left-sided, medio-dorsal subpathway in a successively graded dorsal stream, referencing more specialized motor processing on the left. Supplementary motor areas had a strongly lateralized connectivity to either left dorsal or right ventral parietal domains, representing an action-attention dichotomy between hemispheres. The left sulcal parietal regions primarily coupled with areas 44 and 45, mirrored by the inferior frontal junction (IFJ) on the right, a structural lateralization we termed as "Broca's-IFJ switch." We were able to deepen knowledge on gyral and sulcal pathways as well as domain-specific contributions in parieto-premotor networks. Our study sheds new light on the complex lateralization of cortical routes for motor activity in the human brain.

Identification of anticipatory brain activity in a time discrimination task

The purpose of this study was to investigate anticipatory functions in temporal cognition, identifying the presence of proactive brain processing specifically preceding a time discrimination task. To this aim, two discriminative response tasks (DRTs) were employed: a feature DRT and a temporal (T-DRT). While the F-DRT required discrimination among different geometrical shapes, the T-DRT required discrimination among different stimulus durations. Specifically, this study investigated the role of premotor and prefrontal cortices, and sensory visual areas in preparatory activity preceding time-processing by electroencephalographic methods and analyzing the event-related potential (ERP). ERP components associated with motor (the BP), cognitive (the pN), and sensory readiness (the vN) were analyzed on 21 participants completing the two DRTs. The results support the involvement of all considered brain areas in temporal cognition but extend this information by indicating that these areas can be engaged during the preparation phase before the stimulus is delivered. Furthermore, the T-DRT requires strong anticipatory activity in the PFC likely serving as a moderator of upcoming motor responses. Finally, visual areas were greatly engaged in the early phase of sensory readiness of the T-DRT probably to create top-down low-level representations of imminent events to facilitate perception.

Clinical and functional outcome for gliomas located in the primary and supplementary motor area. Surgical series and systematic Literature review

IntroductionThis retrospective study and review aim to investigate diffuse adult gliomas in the motor cortex (primary motor area, M1, and secondary motor area, M2, which includes the supplementary motor area and premotor cortex). It explores the relationships between the histologic and molecular profiles of the lesions, their location, and the type of resection performed, and correlates them with patients’ outcomes post-surgery. Material and MethodsAn Institutional retrospective review was conducted on a consecutive series of 200 selected patients with histologically confirmed Glioblastomas (GBM) treated surgically between September 2018 and February 2022. These patients were categorized into three subgroups: Group A (lesions contacting CST and/or M1), Group B (lesions related to SMA and pre-SMA), and Group C (lesions outside and distal to the Motor Pathways). The study examined the relationships between the histologic and molecular profiles of the gliomas, their locations, and the types of resections performed, correlating these data with patients’ postoperative prognoses. ResultsThe findings indicate that the three subgroups did not exhibit significant deterioration in clinical and functional status. Lesions in M1/CST and SMA locations were not inherently associated with poorer outcomes. Notably, lesions involving SMA had a higher preoperative volume compared to those in other areas (Group A: 24.5 ± 24.3 cm3; Group B: 30.1 ± 22.7 cm3; Group C: 19.91 ± 15.8 cm3; p = 0.025). ConclusionsThese results align with existing literature, suggesting that although transient motor worsening is expected post-surgery, gliomas in motor areas do not significantly impact survival or functional status. Additionally, the molecular patterns of these tumors do not differ from those of lesions in other brain regions.

Structure of subcortico-cortical tracts in middle-aged and older adults with autism spectrum disorder.

Middle-aged and older adults with autism spectrum disorder may be susceptible to accelerated neurobiological changes in striato- and thalamo-cortical tracts due to combined effects of typical aging and existing disparities present from early neurodevelopment. Using magnetic resonance imaging, we employed diffusion-weighted imaging and automated tract-segmentation to explore striato- and thalamo-cortical tract microstructure and volume differences between autistic (n = 29) and typical comparison (n = 33) adults (40 to 70years old). Fractional anisotropy, mean diffusivity, and tract volumes were measured for 14striato-cortical and 12 thalamo-cortical tract bundles. Data were examined using linear regressions for group by age effects and group plus age effects, and false discovery rate correction was applied. Following false discovery rate correction, volumes of thalamocortical tracts to premotor, pericentral, and parietal regions were significantly reduced in autism spectrum disorder compared to thalamo-cortical groups, but no group by age interactions were found. Uncorrected results suggested additional main effects of group and age might be present for both tract volume and mean diffusivity across multiple subcortico-cortical tracts. Results indicate parallel rather than accelerated changes during adulthood in striato-cortical and thalamo-cortical tract volume and microstructure in those with autism spectrum disorder relative to thalamo-cortical peers though thalamo-cortical tract volume effects are the most reliable.