Bilateral Sensorimotor Cortex Research Articles

Beta-Band Oscillations Represent Auditory Beat and Its Metrical Hierarchy in Perception and Imagery.

With magnetoencephalography, we examined β-band oscillatory activities around 20 Hz while participants listened to metronome beats and imagined musical meters such as a march and waltz. We demonstrated that β-band event-related desynchronization in the auditory cortex differentiates between beat positions, specifically between downbeats and the following beat. This is the first demonstration of β-band oscillations related to hierarchical and internalized timing information. Moreover, the meter representation in the β oscillations was widespread across the brain, including sensorimotor and premotor cortices, parietal lobe, and cerebellum. The results extend current understanding of the role of β oscillations in neural processing of predictive timing.

A Neural Substrate for Behavioral Inhibition in the Risk for Major Depressive Disorder

Behavioral inhibition (BI) is an early developing trait associated with cautiousness and development of clinical depression and anxiety. Little is known about the neural basis of BI and its predictive importance concerning risk for internalizing disorders. We looked at functional connectivity of the default-mode network (DMN) and salience network (SN), given their respective roles in self-relational and threat processing, in the risk for internalizing disorders, with an emphasis on determining the functional significance of these networks for BI. We used functional magnetic resonance imaging to scan, during the resting state, children and adolescents 8 to 17 years of age who were either at high familial risk (HR; n= 16) or low familial risk (LR; n= 18) for developing clinical depression and/or anxiety. Whole-brain DMN and SN functional connectivity were estimated for each participant and compared across groups. We also compared the LR and HR groups on levels of BI and anxiety, and incorporated these data into follow-up neurobehavioral correlation analyses. The HR group, relative to the LR group, showed significantly decreased DMN connectivity with the ventral striatum and bilateral sensorimotor cortices. Within the HR group, trait BI increased as DMN connectivity with the ventral striatum and sensorimotor cortex decreased. The HR and LR groups did not differ with respect to SN connectivity. Our findings show, in the risk for internalizing disorders, a negative functional relation between brain regions supporting self-relational processes and reward prediction. These findings represent a potential neural substrate for behavioral inhibition in the risk for clinical depression and anxiety.

Brain structural correlates of sensory phenomena in patients with obsessive–compulsive disorder

Sensory phenomena (SP) are uncomfortable feelings, including bodily sensations, sense of inner tension, "just-right" perceptions, feelings of incompleteness, or "urge-only" phenomena, which have been described to precede, trigger or accompany repetitive behaviours in individuals with obsessive-compulsive disorder (OCD). Sensory phenomena are also observed in individuals with tic disorders, and previous research suggests that sensorimotor cortex abnormalities underpin the presence of SP in such patients. However, to our knowledge, no studies have assessed the neural correlates of SP in patients with OCD. We assessed the presence of SP using the University of São Paulo Sensory Phenomena Scale in patients with OCD and healthy controls from specialized units in São Paulo, Brazil, and Barcelona, Spain. All participants underwent a structural magnetic resonance examination, and brain images were examined using DARTEL voxel-based morphometry. We evaluated grey matter volume differences between patients with and without SP and healthy controls within the sensorimotor and premotor cortices. We included 106 patients with OCD and 87 controls in our study. Patients with SP (67% of the sample) showed grey matter volume increases in the left sensorimotor cortex in comparison to patients without SP and bilateral sensorimotor cortex grey matter volume increases in comparison to controls. No differences were observed between patients without SP and controls. Most patients were medicated. Participant recruitment and image acquisition were performed in 2 different centres. We have identified a structural correlate of SP in patients with OCD involving grey matter volume increases within the sensorimotor cortex; this finding is in agreement with those of tic disorder studies showing that abnormal activity and volume increases within this region are associated with the urges preceding tic onset.

Assessments of Muscle Oxygenation and Cortical Activity Using Functional Near-infrared Spectroscopy in Healthy Adults During Hybrid Activation.

Hybrid activation (HA), patterned electrical stimulation (ES) superimposed on attempted voluntary movement in close synchrony, can augment muscle force output. It has been proposed for limb function restoration and neuromodulation. Limited studies have been performed to investigate the influences of HA on muscle oxygenation and brain cortical activity. The present study investigates muscle oxygenation and cortical activity during isometric knee extension tasks with voluntary contraction (VOL) only, ES only, and with HA at three stimulation intensities, namely 10 mA (HA-I), 30 mA (HA-II), and 50 mA (HA-III). A frequency-domain near-infrared spectroscopy system was employed to assess the muscle oxygenation in the vastus lateralis as well as the cortical activity from the bilateral sensorimotor cortices (SMCs), premotor cortices (PMCs), and supplementary motor areas (SMAs). Our results show that the increased ES contribution during HA significantly increased O2 demand in working muscle, implying that the intervention of ES accelerates the muscle metabolism during muscle contraction. For cortical activation, ES only had a similar cortical activation pattern to that during VOL but with lower activation in SMCs, PMCs, and SMAs. Augmented sensorimotor activation was observed during the HA-II condition. The enhanced level of cortical activation during HA was not only affected by the ES contribution within HA but also related to the functional specificity of cortical areas. Our results suggest that HA can effectively enhance the muscle oxygen demand as well as the activation of cortical regions, and that the ES contribution within HA is a key factor.

Progesterone mediates brain functional connectivity changes during the menstrual cycle—a pilot resting state MRI study

The growing interest in intrinsic brain organization has sparked various innovative approaches to generating comprehensive connectivity-based maps of the human brain. Prior reports point to a sexual dimorphism of the structural and functional human connectome. However, it is uncertain whether subtle changes in sex hormones, as occur during the monthly menstrual cycle, substantially impact the functional architecture of the female brain. Here, we performed eigenvector centrality (EC) mapping in 32 longitudinal resting state fMRI scans of a single healthy subject without oral contraceptive use, across four menstrual cycles, and assessed estrogen and progesterone levels. To investigate associations between cycle-dependent hormones and brain connectivity, we performed correlation analyses between the EC maps and the respective hormone levels. On the whole brain level, we found a significant positive correlation between progesterone and EC in the bilateral dorsolateral prefrontal cortex (DLPFC) and bilateral sensorimotor cortex. In a secondary region-of-interest analysis, we detected a progesterone-modulated increase in functional connectivity of both bilateral DLPFC and bilateral sensorimotor cortex with the hippocampus. Our results suggest that the menstrual cycle substantially impacts intrinsic functional connectivity, particularly in brain areas associated with contextual memory-regulation, such as the hippocampus. These findings are the first to link the subtle hormonal fluctuations that occur during the menstrual cycle, to significant changes in regional functional connectivity in the hippocampus in a longitudinal design, given the limitation of data acquisition in a single subject. Our study demonstrates the feasibility of such a longitudinal Resting-state functional Magnetic Resonance Imaging (rs-fMRI) design and illustrates a means of creating a personalized map of the human brain by integrating potential mediators of brain states, such as menstrual cycle phase.

Early lexico-semantic modulation of motor related areas during action and non-action verb processing

Although action verb processing deficits have been described in diseases affecting the motor system, research on temporal processing in this area has not been reported. In this study, action and non-action verb processing was contrasted in healthy volunteers using electro-encephalography. These data may serve as a control condition for further research in motor disorders. Latency and amplitude evaluations as well as source reconstruction were applied on event-related potentials. Action verbs evoked higher activation in bilateral sensorimotor areas from 155 to 174 ms and in bilateral dorsolateral prefrontal cortex (DLPFC) from 219 to 238 ms. Hand action verb processing activates the motor programmes of the actions the verbs refer to. This seems not restricted to the core (pre)motor cortical areas of the brain. A broad motor brain network is hypothesized to be involved. While sensorimotor activation seems essential for action verb understanding, this cannot be concluded for DLPFC activation. • Single verb processing evokes a peak in activity at 165 ms post-stimulus onset. • Bilateral sensorimotor cortex is activated by hand action verbs from 155 to 174 ms. • Sensorimotor activation is automatic and necessary for action verb understanding. • Bilateral dorsolateral prefrontal cortex contributes to hand action verb processing. • Embodied theories of cognition are confirmed.

A selective involvement of putamen functional connectivity in youth with internet gaming disorder

Brain cortico-striatal circuits have consistently been implicated in the pathology of addiction related disorders. We applied a reliable seed-based analysis of the resting-state brain activity to comprehensively delineate the subdivisions of striatal functional connectivity implicated in internet gaming disorder. Among twelve right-handed male adolescents with internet gaming disorder and 11 right-handed and gender-matched healthy controls, we examined group differences in the functional connectivity of dorsal and ventral subdivisions of the caudate nucleus and putamen, as well as the association of these connectivity indices with behavioral measures of internet use. Adolescents with internet gaming disorder showed significantly reduced dorsal putamen functional connectivity with the posterior insula-parietal operculum. More time spent playing online games predicted significantly greater functional connectivity between the dorsal putamen and bilateral primary somatosensory cortices in adolescents with internet gaming disorder, and significantly lower functional connectivity between the dorsal putamen and bilateral sensorimotor cortices in healthy controls. The dorsal putamen functional connectivity was significantly and specifically different in adolescents with internet gaming disorder. The findings suggest a possible biomarker of internet gaming disorder.

Intrinsic coupling modes in source-reconstructed electroencephalography.

Intrinsic coupling of neuronal assemblies constitutes a key feature of ongoing brain activity, yielding the rich spatiotemporal patterns observed in neuroimaging data and putatively supporting cognitive processes. Intrinsic coupling has been investigated in electrophysiological recordings using two types of functional connectivity measures: amplitude and phase coupling. These two coupling modes differ in their likely causes and functions, and have been proposed to provide complementary insights into intrinsic neuronal interactions. Here, we investigate the relationship between amplitude and phase coupling in source-reconstructed electroencephalography (EEG). Volume conduction is a key obstacle for connectivity analysis in EEG-we therefore also test the envelope correlation of orthogonalized signals and the phase lag index. Functional connectivity between six seed source regions (bilateral visual, sensorimotor, and auditory cortices) and all other cortical voxels was computed. For all four measures, coupling between homologous sensory areas in both hemispheres was significantly higher than with other voxels at the same physical distance. The frequency of significant coupling differed between sensory areas: 10 Hz for visual, 30 Hz for auditory, and 40 Hz for sensorimotor cortices. By contrasting envelope correlations and phase locking values, we observed two distinct clusters of voxels showing a different relationship between amplitude and phase coupling. Large clusters contiguous to the seed regions showed an identity (1:1) relationship between amplitude and phase coupling, whereas a cluster located around the contralateral homologous regions showed higher phase than amplitude coupling. These results show a relationship between intrinsic coupling modes that is distinct from the effect of volume conduction.

Functional connectivity density alterations in schizophrenia.

Background: Schizophrenia is characterized by altered resting-state functional connectivity. Most previous studies have focused on changes in connectivity strengths; however, the alterations in connectivity density in schizophrenia remain largely unknown. Here, we aimed to investigate changes in resting-state functional connectivity density (rsFCD) in schizophrenia.Methods: A total of 95 schizophrenia patients and 93 sex- and age-matched healthy controls (HCs) underwent resting-state functional MRI examinations. The rsFCD, which reflects the total number of functional connections between a given brain voxel and all other voxels in the entire brain, was calculated for each voxel of each subject. Voxel-based comparisons were performed to identify brain regions with significant rsFCD differences between patients and controls (P < 0.05, corrected).Results: Compared with HCs, patients with schizophrenia showed significantly increased rsFCD in the bilateral striatum and hippocampus and significantly decreased rsFCD in the bilateral sensorimotor cortices and right occipital cortex. However, the rsFCD values of these brain regions were not correlated with antipsychotic dosage, illness duration, or clinical symptom severity.Conclusions: The striatal and hippocampal regions and parietal-occipital regions exhibited completely different changes in rsFCD in schizophrenia, which roughly correspond to dopamine activity in these regions in schizophrenia. These findings support the connectivity disorder hypothesis of schizophrenia and increase our understanding of the neural mechanisms of schizophrenia.

Cortical activation and inter-hemispheric sensorimotor coherence in individuals with arm dystonia due to childhood stroke

ObjectiveDystonia is a disabling motor disorder often without effective therapies. To better understand the genesis of dystonia after childhood stroke, we analyzed electroencephalographic (EEG) recordings in this population. MethodsResting spectral power of EEG signals over bilateral sensorimotor cortices (Powrest), resting inter-hemispheric sensorimotor coherence (Cohrest), and task-related changes in power (TRPow) and coherence (TRCoh) during wrist extension were analyzed in individuals with dystonia (age 20±3years) and healthy volunteers (age 17±5years). ResultsIpsilesional TRPow decrease was significantly lower in patients than controls during the more affected wrist task. Force deficits of the affected wrist correlated with reduced alpha TRPow decrease on the ipsilesional and not the contralesional hemisphere. Cohrest was significantly lower in patients than controls, and correlated with more severe dystonia and poorer hand function. Powrest and TRCoh were similar between groups. ConclusionsThe association between weakness and cortical activation during wrist extension highlights the importance of ipsilesional sensorimotor activation on function. Reduction of Cohrest in patients reflects a loss of inter-hemispheric connectivity that may result from structural changes and neuroplasticity, potentially contributing to the development of dystonia. SignificanceCortical and motor dysfunction are correlated in patients with childhood stroke and may in part explain the genesis of dystonia.

Altered white matter integrity in the corpus callosum in fibromyalgia patients identified by tract-based spatial statistical analysis.

Although recent imaging studies of fibromyalgia (FM) have converged on a dysfunction of central pain processing as the primary pathophysiologic cause of the disorder, microstructural changes of the white matter (WM) suggestive of abnormalities in the anatomic connectivity of the brain have not been extensively examined. The aim of this study was to investigate WM integrity and its possible relationship to pain symptoms in women with FM. Nineteen FM patients and 21 age-, sex-, and education-matched healthy control subjects were included in the study and underwent diffusion-weighted imaging. Group differences in WM integrity, which were assessed via fractional anisotropy (FA), was investigated by applying tract-based spatial statistics. As compared with the healthy control group, the FM group showed a single cluster with lower FA in the left body of the corpus callosum, which was found to be connected to the bilateral sensorimotor cortices (P < 0.05, corrected for multiple comparisons). Furthermore, FA values in the cluster were negatively associated with sensory pain, as measured by the Short-Form McGill Pain Questionnaire, as well as with the relative magnitude of sensory pain versus affective pain (calculated by dividing the sensory score by the affective score). Findings of the current study demonstrated that patients with FM had disrupted WM microstructure in the body of the corpus callosum, which was associated with clinical pain intensity. Our results suggest that abnormal interhemispheric transfer might contribute to the heightened pain perception. Our findings further strengthen the hypothesis of centrally augmented pain processing in patients with FM.

Abnormal development of sensory-motor, visual temporal and parahippocampal cortex in children with learning disabilities and borderline intellectual functioning.

Borderline intellectual functioning (BIF) is a condition characterized by an intelligence quotient (IQ) between 70 and 85. BIF children present with cognitive, motor, social, and adaptive limitations that result in learning disabilities and are more likely to develop psychiatric disorders later in life. The aim of this study was to investigate brain morphometry and its relation to IQ level in BIF children. Thirteen children with BIF and 14 age- and sex-matched typically developing (TD) children were enrolled. All children underwent a full IQ assessment (WISC-III scale) and a magnetic resonance (MR) examination including conventional sequences to assess brain structural abnormalities and high resolution 3D images for voxel-based morphometry analysis. To investigate to what extent the group influenced gray matter (GM) volumes, both univariate and multivariate generalized linear model analysis of variance were used, and the varimax factor analysis was used to explore variable correlations and clusters among subjects. Results showed that BIF children, compared to controls have increased regional GM volume in bilateral sensorimotor and right posterior temporal cortices and decreased GM volume in the right parahippocampal gyrus. GM volumes were highly correlated with IQ indices. The present work is a case study of a group of BIF children showing that BIF is associated with abnormal cortical development in brain areas that have a pivotal role in motor, learning, and behavioral processes. Our findings, although allowing for little generalization to the general population, contribute to the very limited knowledge in this field. Future longitudinal MR studies will be useful in verifying whether cortical features can be modified over time even in association with rehabilitative intervention.

The impact of constraint induced movement therapy on brain activation in chronic stroke patients with upper extremity paralysis: An fMRI study

ABSTRACTThis study is designed to explore the impact of constraint‐induced movement therapy (CIMT) on brain activation in chronic stroke patients with upper extremity paralysis and seek valuable predictors of recovery. Six chronic stroke patients with right hand dysfunction and nine healthy control subjects participated in the study. The patient's hand function was assessed by the Action Research Arm Test and statistical significance was determined by a paired Student's t‐tests. We conducted functional magnetic resonance imaging and analyzed the data using Analysis of Functional Neuroimages software. After CIMT, function of the affected right hand improved continuously with no deterioration of left hand function. The bilateral primary sensorimotor, primary somatosensory, and somatosensory association cortex were evidently activated in response to paretic right hand movement with a tendency to transfer from the ipsilateral hemisphere to the contralateral hemisphere. Remarkably, the corpus striatum, thalamus, and cerebellum showed persistently increased bilateral activation throughout the whole process. Bilateral extrapyramidal structures including corpus striatum, thalamus, and cerebellum exhibited activation at low levels in response to movement of the unaffected left hand. Our results indicated that the bilateral primary sensorimotor cortex is the most highly activated brain region during CIMT. Furthermore, the hyperactivity of extrapyramidal structures plays an important facilitating role during recovery and represents a good predictor of recovery. A gradual rebalance of the activation of the neural network between the two cerebral hemispheres and a return to normal conditions was seen, which may be a positive sign for recovery. © 2014 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 24, 270–275, 2014

Alterations of resting-state regional and network-level neural function after acute spinal cord injury

ObjectThe purpose of this study was to investigate functional alterations of the brain in the early stage of spinal cord injury (SCI) and further investigate how these functional alterations relate to SCI patients’ sensorimotor functions. MethodsTwenty-five patients with SCI and 25 matched healthy controls underwent imaging by using resting-state functional magnetic resonance imaging (fMRI). The amplitude of low-frequency fluctuations (ALFF) were used to characterize regional neural function, and the seed-based functional connectivity (FC) was used to evaluate the functional integration of the brain network. ResultsCompared to healthy controls, patients with SCI showed decreased ALFF in the bilateral primary sensorimotor cortex, and increased ALFF in the bilateral cerebellum and right orbitofrontal cortex (OFC). The ALFF value in the left cerebellum was negatively correlated with the clinical total motor score in patients with SCI. Furthermore, SCI patients mainly showed decreased inter-hemispheric FC between the bilateral primary sensorimotor cortex, as well as increased intra-hemispheric FC within the motor network, including the primary sensorimotor cortex, premotor cortex, supplementary motor area (SMA), thalamus and cerebellum. Subsequent correlation analyses revealed that increased FC within the primary sensorimotor cortex, SMA, and cerebellum negatively correlated with the total American Spinal Cord Injury Association (ASIA) motor score. ConclusionsOur findings provide evidence that SCI can induce significant regional and network-level functional alterations in the early stage of the disease. We hypothesized these alterations may be an adaptive phenomenon following SCI, reflecting a compensatory mechanism during the early stage of SCI.

Amplitude differences in high-frequency fMRI signals between eyes open and eyes closed resting states.

Recent studies employing rapid sampling techniques have demonstrated that the resting state fMRI (rs-fMRI) signal exhibits synchronized activities at frequencies much higher than the conventional frequency range (<0.1 Hz). However, little work has investigated the changes in the high-frequency fluctuations between different resting states. Here, we acquired rs-fMRI data at a high sampling rate (TR = 400 ms) from subjects with both eyes open (EO) and eyes closed (EC), and compared the amplitude of fluctuation (AF) between EO and EC for both the low- and high-frequency components. In addition to robust AF differences in the conventional low frequency band (<0.1 Hz) in visual cortex, primary auditory cortex and primary sensorimotor cortex (PSMC), we also detected high-frequency (primarily in 0.1–0.35 Hz) differences. The high-frequency results without covariates regression exhibited noisy patterns. For the data with nuisance covariates regression, we found a significant and reproducible reduction in high-frequency AF between EO and EC in the bilateral PSMC and the supplementary motor area (SMA), and an increase in high-frequency AF in the left middle occipital gyrus (MOG). Furthermore, we investigated the effect of sampling rate by down-sampling the data to effective TR = 2 s. Briefly, by using the rapid sampling rate, we were able to detect more regions with significant differences while identifying fewer artifactual differences in the high-frequency bands as compared to the down-sampled dataset. We concluded that (1) high-frequency fluctuations of rs-fMRI signals can be modulated by different resting states and thus may be of physiological importance; and (2) the regression of covariates and the use of fast sampling rates are superior for revealing high-frequency differences in rs-fMRI signals.

Predictors and biomarkers of treatment gains in a clinical stroke trial targeting the lower extremity.

Behavioral measures are often used to distinguish subgroups of patients with stroke (eg, to predict treatment gains, stratify clinical trial enrollees, or select rehabilitation therapy). In studies of the upper extremity, measures of brain function using functional magnetic resonance imaging (fMRI) have also been found useful, but this approach has not been examined for the lower extremity. The current study hypothesized that an fMRI-based measure of cortical function would significantly improve prediction of treatment-induced lower extremity behavioral gains. Biomarkers of treatment gains were also explored. Patients with hemiparesis 1 to 12 months after stroke were enrolled in a double-blind, placebo-controlled, randomized clinical trial of ropinirole+physical therapy versus placebo+physical therapy, results of which have previously been reported (NCT00221390).(15) Primary end point was change in gait velocity. Enrollees underwent baseline multimodal assessment that included 19 measures spanning 5 assessment categories (medical history, impairment, disability, brain injury, and brain function), and also underwent reassessment 3 weeks after end of therapy. In bivariate analysis, 8 baseline measures belonging to 4 categories (medical history, impairment, disability, and brain function) significantly predicted change in gait velocity. Prediction was strongest, however, using a multivariate model containing 2 measures (leg Fugl-Meyer score and fMRI activation volume within ipsilesional foot sensorimotor cortex). Increased activation volume within bilateral foot primary sensorimotor cortex correlated positively with treatment-induced leg motor gains. A multimodal model incorporating behavioral and fMRI measures best predicted treatment-induced changes in gait velocity in a clinical trial setting. Results also suggest potential use of fMRI measures as biomarkers of treatment gains.

THU0314 Altered White Matter Integrity in Corpus Callosal Area in Fibromyalgia Identified with Tract Based Spatial Statistical Analysis

BackgroundAlthough recent imaging studies of fibromyalgia (FM) have converged on a dysfunction of central pain processing as a primary pathophysiology of the disorder, microstructural alteration suggestive of abnormal synaptic transmission...

Disrupted resting-state functional connectivity in minimally treated chronic schizophrenia

ObjectiveThe pathophysiology of chronic schizophrenia may reflect long term brain changes related to the disorder. The effect of chronicity on intrinsic functional connectivity patterns in schizophrenia without the potentially confounding effect of antipsychotic medications, however, remains largely unknown. MethodWe collected resting-state fMRI data in 21 minimally treated chronic schizophrenia patients and 20 healthy controls. We computed regional functional connectivity strength for each voxel in the brain, and further divided regional functional connectivity strength into short-range regional functional connectivity strength and long-range regional functional connectivity strength. General linear models were used to detect between-group differences in these regional functional connectivity strength metrics and to further systematically investigate the relationship between these differences and clinical/behavioral variables in the patients. ResultsCompared to healthy controls, the minimally treated chronic schizophrenia patients showed an overall reduced regional functional connectivity strength especially in bilateral sensorimotor cortex, right lateral prefrontal cortex, left insula and right lingual gyrus, and these regional functional connectivity strength decreases mainly resulted from disruption of short-range regional functional connectivity strength. The minimally treated chronic schizophrenia patients also showed reduced long-range regional functional connectivity strength in the bilateral posterior cingulate cortex/precuneus, and increased long-range regional functional connectivity strength in the right lateral prefrontal cortex and lingual gyrus. Notably, disrupted short-range regional functional connectivity strength mainly correlated with duration of illness and negative symptoms, whereas disrupted long-range regional functional connectivity strength correlated with neurocognitive performance. All of the results were corrected using Monte-Carlo simulation. ConclusionsThis exploratory study demonstrates a disruption of intrinsic functional connectivity without long-term exposure to antipsychotic medications in chronic schizophrenia. Furthermore, this disruption was connection–distance dependent, thus raising the possibility for differential neural pathways in neurocognitive impairment and psychiatric symptoms in schizophrenia.

Age-related decrease of functional connectivity additional to gray matter atrophy in a network for movement initiation

Healthy aging is accompanied by a decrease in cognitive and motor capacities. In a network associated with movement initiation, we investigated age-related changes of functional connectivity (FC) as well as regional atrophy in a sample of 232 healthy subjects (age range 18-85years). To this end, voxel-based morphometry and whole-brain resting-state FC were analyzed for the supplementary motor area (SMA), anterior midcingulate cortex (aMCC) and bilateral striatum (Str). To assess the specificity of age-related effects, bilateral primary sensorimotor cortex (S1/M1) closely associated with motor execution was used as control seeds. All regions showed strong reduction of gray matter volume with age. Corrected for this regional atrophy, the FC analysis revealed an age×seed interaction for each of the bilateral Str nodes against S1/M1 with consistent age-related decrease in FC with bilateral caudate nucleus and anterior putamen. Specific age-dependent FC decline of SMA was found in bilateral central insula and the adjacent frontal operculum. aMCC showed exclusive age-related decoupling from the anterior cingulate motor area. The present study demonstrates network as well as node-specific age-dependent FC decline of the SMA and aMCC to highly integrative cortical areas involved in cognitive motor control. FC decrease in addition to gray matter atrophy within the Str may provide a substrate for the declining motor control in elderly. Finally, age-related FC changes in both the network for movement initiation as well as the network for motor execution are not explained by regional atrophy in the healthy aging brain.

Motor skills training promotes motor functional recovery and induces synaptogenesis in the motor cortex and striatum after intracerebral hemorrhage in rats

We investigated the effects of motor skills training on several types of motor function and synaptic plasticity following intracerebral hemorrhage (ICH) in rats. Male Wistar rats were injected with collagenase into the left striatum to induce ICH, and they were randomly assigned to the ICH or sham groups. Each group was divided into the motor skills training (acrobatic training) and control (no exercise) groups. The acrobatic group performed acrobatic training from 4 to 28 days after surgery. Motor functions were assessed by motor deficit score, the horizontal ladder test and the wide or narrow beam walking test at several time points after ICH. The number of ΔFosB-positive cells was counted using immunohistochemistry to examine neuronal activation, and the PSD95 protein levels were analyzed by Western blotting to examine synaptic plasticity in the bilateral sensorimotor cortices and striata at 14 and 29 days after ICH. Motor skills training following ICH significantly improved gross motor function in the early phase after ICH and skilled motor coordinated function in the late phase. The number of ΔFosB-positive cells in the contralateral sensorimotor cortex in the acrobatic group significantly increased compared to the control group. PSD95 protein expression in the motor cortex significantly increased in the late phase, and in the striatum, the protein level significantly increased in the early phase by motor skills training after ICH compared to no training after ICH. We demonstrated that motor skills training improved motor function after ICH in rats and enhanced the neural activity and synaptic plasticity in the striatum and sensorimotor cortex.