Age, experience, injury, and the changing brain

Brain handedness associations depend on how and when handedness is measured

Hand preference is ubiquitous, intuitive, and often simplified to right- or left-handed. Accordingly, differences between right- and left-handed individuals in the brain have been established. Nevertheless, considering handedness as a binarized construct fails to capture the variability of brain-handedness associations across different domains or activities. Further, hand-use changes across generations (e.g., letter writing vs. texting) such that individuals of different ages live in different environments. As a result, brain-handedness associations may depend on how and when handedness is measured. We used two large datasets, the Human Connectome Project-Development (HCP-D; n = 465; age = 5-21 years) and Human Connectome Project-Aging (HCP-A; n = 368; age = 36-100 years), to investigate generational differences in brain-handedness associations. Nine items from the Edinburgh Handedness Inventory were associated with resting-state functional connectomes. We show that brain-handedness associations differed across the two cohorts. Moreover, these differences depended on the way handedness was measured. Given that brain-handedness associations differ across handedness measures and datasets, we caution against a one-size-fits-all approach to neuroimaging studies of this complex trait.

Computerized social cognitive training in the subacute phase after traumatic brain injury: A quasi-randomized controlled trial

OBJECTIVES

To assess the usefulness of a computerized tasks module designed for the rehabilitation of social cognition (SC) in acquired brain injury.

METHODS

Quasi-randomized controlled trial (ClinicalTrials.gov:NCT03479970) involving 45 patients with moderate-severe traumatic brain injury (TBI) in a subacute inpatient rehabilitation hospital. The experimental group (n = 28) received treatment with a computerized SC module in combination with a non-SC module. The control group (n = 26) only received a treatment with non-SC module.

RESULTS

Intragroup comparisons showed that the experimental group had better results for all SC measures, except for International Affective Picture System (IAPS). The control group improved for Facial Expressions of cEmotion-Stimuli and Tests (FEEST) and Moving Shapes Paradigm (MSP), showing no changes with respect to pretreatment in IAPS, MSP and Reading the Mind in the Eyes Test (RMET). Intergroup comparisons did not present differences between the two groups for pretreatment measures. Post-treatment comparison showed that the experimental group obtained better results for RMET than the control group.

CONCLUSION

The computerized SC module was useful for the rehabilitation of SC in patients with moderate-severe TBI in the subacute phase. The group that received combined rehabilitative treatment (SC + non-SC) obtained better results for SC than the group that received treatment intended only for non-SC.

Low-intensity transcranial ultrasound stimulation improves memory in vascular dementia by enhancing neuronal activity and promoting spine formation

Memory is closely associated with neuronal activity and dendritic spine formation. Low-intensity transcranial ultrasound stimulation (TUS) improves the memory of individuals with vascular dementia (VD). However, it is unclear whether neuronal activity and dendritic spine formation under ultrasound stimulation are involved in memory improvement in VD. In this study, we found that seven days of TUS improved memory in VD model while simultaneously increasing pyramidal neuron activity, promoting dendritic spine formation, and reducing dendritic spine elimination. These effects lasted for 7 days but disappeared on 14 d after TUS. Neuronal activity and dendritic spine formation strongly corresponded to improvements in memory behavior over time. In addition, we also found that the memory, neuronal activity and dendritic spine of VD mice cannot be restored again by TUS of 7 days after 28 d. Collectively, these findings suggest that TUS increases neuronal activity and promotes dendritic spine formation and is thus important for improving memory in patients with VD.

Longitudinal observations of the effects of ischemic stroke on binaural perception

Acute ischemic stroke, characterized by a localized reduction in blood flow to specific areas of the brain, has been shown to affect binaural auditory perception. In a previous study conducted during the acute phase of ischemic stroke, two tasks of binaural hearing were performed: binaural tone-in-noise detection, and lateralization of stimuli with interaural time- or level differences. Various lesion-specific, as well as individual, differences in binaural performance between patients in the acute phase of stroke and a control group were demonstrated. For the current study, we re-invited the same group of patients, whereupon a subgroup repeated the experiments during the subacute and chronic phases of stroke. Similar to the initial study, this subgroup consisted of patients with lesions in different locations, including cortical and subcortical areas. At the group level, the results from the tone-in-noise detection experiment remained consistent across the three measurement phases, as did the number of deviations from normal performance in the lateralization task. However, the performance in the lateralization task exhibited variations over time among individual patients. Some patients demonstrated improvements in their lateralization abilities, indicating recovery, whereas others' lateralization performance deteriorated during the later stages of stroke. Notably, our analyses did not reveal consistent patterns for patients with similar lesion locations. These findings suggest that recovery processes are more individual than the acute effects of stroke on binaural perception. Individual impairments in binaural hearing abilities after the acute phase of ischemic stroke have been demonstrated and should therefore also be targeted in rehabilitation programs.

Neuroanatomical dimensions in medication-free individuals with major depressive disorder and treatment response to SSRI antidepressant medications or placebo

Major depressive disorder (MDD) is a heterogeneous clinical syndrome with widespread subtle neuroanatomical correlates. Our objective was to identify the neuroanatomical dimensions that characterize MDD and predict treatment response to selective serotonin reuptake inhibitor (SSRI) antidepressants or placebo. In the COORDINATE-MDD consortium, raw MRI data were shared from international samples (N = 1,384) of medication-free individuals with first-episode and recurrent MDD (N = 685) in a current depressive episode of at least moderate severity, but not treatment-resistant depression, as well as healthy controls (N = 699). Prospective longitudinal data on treatment response were available for a subset of MDD individuals (N = 359). Treatments were either SSRI antidepressant medication (escitalopram, citalopram, sertraline) or placebo. Multi-center MRI data were harmonized, and HYDRA, a semi-supervised machine-learning clustering algorithm, was utilized to identify patterns in regional brain volumes that are associated with disease. MDD was optimally characterized by two neuroanatomical dimensions that exhibited distinct treatment responses to placebo and SSRI antidepressant medications. Dimension 1 was characterized by preserved gray and white matter (N = 290 MDD), whereas Dimension 2 was characterized by widespread subtle reductions in gray and white matter (N = 395 MDD) relative to healthy controls. Although there were no significant differences in age of onset, years of illness, number of episodes, or duration of current episode between dimensions, there was a significant interaction effect between dimensions and treatment response. Dimension 1 showed a significant improvement in depressive symptoms following treatment with SSRI medication (51.1%) but limited changes following placebo (28.6%). By contrast, Dimension 2 showed comparable improvements to either SSRI (46.9%) or placebo (42.2%) (β = -18.3, 95% CI (-34.3 to -2.3), P = 0.03). Findings from this case-control study indicate that neuroimaging-based markers can help identify the disease-based dimensions that constitute MDD and predict treatment response.

Multifaceted neural and vascular pathologies after pediatric mild traumatic brain injury

Dynamic changes in neurodevelopment and cognitive functioning occur during adolescence, including a switch from reactive to more proactive forms of cognitive control, including response inhibition. Pediatric mild traumatic brain injury (pmTBI) affects these cognitions immediately post-injury, but the role of vascular versus neural injury in cognitive dysfunction remains debated. This study consecutively recruited 214 sub-acute pmTBI (8-18 years) and age/sex-matched healthy controls (HC; N = 186), with high retention rates (>80%) at four months post-injury. Multimodal imaging (functional MRI during response inhibition, cerebral blood flow and cerebrovascular reactivity) assessed for pathologies within the neurovascular unit. Patients exhibited increased errors of commission and hypoactivation of motor circuitry during processing of probes. Evidence of increased/delayed cerebrovascular reactivity within motor circuitry during hypercapnia was present along with normal perfusion. Neither age-at-injury nor post-concussive symptom load were strongly associated with imaging abnormalities. Collectively, mild cognitive impairments and clinical symptoms may continue up to four months post-injury. Prolonged dysfunction within the neurovascular unit was observed during proactive response inhibition, with preliminary evidence that neural and pure vascular trauma are statistically independent. These findings suggest pmTBI is characterized by multifaceted pathologies during the sub-acute injury stage that persist several months post-injury.

Repeated mild traumatic brain injury causes sex-specific increases in cell proliferation and inflammation in juvenile rats

Childhood represents a period of significant growth and maturation for the brain, and is also associated with a heightened risk for mild traumatic brain injuries (mTBI). There is also concern that repeated-mTBI (r-mTBI) may have a long-term impact on developmental trajectories. Using an awake closed head injury (ACHI) model, that uses rapid head acceleration to induce a mTBI, we investigated the acute effects of repeated-mTBI (r-mTBI) on neurological function and cellular proliferation in juvenile male and female Long-Evans rats. We found that r-mTBI did not lead to cumulative neurological deficits with the model. R-mTBI animals exhibited an increase in BrdU + (bromodeoxyuridine positive) cells in the dentate gyrus (DG), and that this increase was more robust in male animals. This increase was not sustained, and cell proliferation returning to normal by PID3. A greater increase in BrdU + cells was observed in the dorsal DG in both male and female r-mTBI animals at PID1. Using Ki-67 expression as an endogenous marker of cellular proliferation, a robust proliferative response following r-mTBI was observed in male animals at PID1 that persisted until PID3, and was not constrained to the DG alone. Triple labeling experiments (Iba1+, GFAP+, Brdu+) revealed that a high proportion of these proliferating cells were microglia/macrophages, indicating there was a heightened inflammatory response. Overall, these findings suggest that rapid head acceleration with the ACHI model produces an mTBI, but that the acute neurological deficits do not increase in severity with repeated administration. R-mTBI transiently increases cellular proliferation in the hippocampus, particularly in male animals, and the pattern of cell proliferation suggests that this represents a neuroinflammatory response that is focused around the mid-brain rather than peripheral cortical regions. These results add to growing literature indicating sex differences in proliferative and inflammatory responses between females and males. Targeting proliferation as a therapeutic avenue may help reduce the short term impact of r-mTBI, but there may be sex-specific considerations.

Reorganization in the macaque interoceptive-allostatic network following anterior cingulate cortex damage

Accumulating evidence indicates that the adult brain is capable of significant structural change following damage-a capacity once thought to be largely limited to developing brains. To date, most existing research on adult plasticity has focused on how exteroceptive sensorimotor networks compensate for damage to preserve function. Interoceptive networks-those that represent and process sensory information about the body's internal state-are now recognized to be critical for a wide range of physiological and psychological functions from basic energy regulation to maintaining a sense of self, but the extent to which these networks remain plastic in adulthood has not been established. In this report, we used detailed histological analyses to pinpoint precise changes to gray matter volume in the interoceptive-allostatic network in adult rhesus monkeys (Macaca mulatta) who received neurotoxic lesions of the anterior cingulate cortex (ACC) and neurologically intact control monkeys. Relative to controls, monkeys with ACC lesions had significant and selective unilateral expansion of the ventral anterior insula and significant relative bilateral expansion of the lateral nucleus of the amygdala. This work demonstrates the capacity for neuroplasticity in the interoceptive-allostatic network which, given that changes included expansion rather than atrophy, is likely to represent an adaptive response following damage.

Prospective Study of Gray Matter Atrophy Following Pediatric Mild Traumatic Brain Injury

BACKGROUND AND OBJECTIVES

The clinical and physiologic time course for recovery following pediatric mild traumatic brain injury (pmTBI) remains actively debated. The primary objective of the current study was to prospectively examine structural brain changes (cortical thickness and subcortical volumes) and age-at-injury effects. A priori study hypotheses predicted reduced cortical thickness and hippocampal volumes up to 4 months postinjury, which would be inversely associated with age at injury.

METHODS

Prospective cohort study design with consecutive recruitment. Study inclusion adapted from American Congress of Rehabilitation Medicine (upper threshold) and Zurich Concussion in Sport Group (minimal threshold) and diagnosed by Emergency Department and Urgent Care clinicians. Major neurologic, psychiatric, or developmental disorders were exclusionary. Clinical (Common Data Element) and structural (3 T MRI) evaluations within 11 days (subacute visit [SA]) and at 4 months (early chronic visit [EC]) postinjury. Age- and sex-matched healthy controls (HC) to control for repeat testing/neurodevelopment. Clinical outcomes based on self-report and cognitive testing. Structural images quantified with FreeSurfer (version 7.1.1).

RESULTS

A total of 208 patients with pmTBI (age = 14.4 ± 2.9; 40.4% female) and 176 HC (age = 14.2 ± 2.9; 42.0% female) were included in the final analyses (>80% retention). Reduced cortical thickness (right rostral middle frontal gyrus; d = -0.49) and hippocampal volumes (d = -0.24) observed for pmTBI, but not associated with age at injury. Hippocampal volume recovery was mediated by loss of consciousness/posttraumatic amnesia. Significantly greater postconcussive symptoms and cognitive deficits were observed at SA and EC visits, but were not associated with the structural abnormalities. Structural abnormalities slightly improved balanced classification accuracy above and beyond clinical gold standards (∆+3.9%), with a greater increase in specificity (∆+7.5%) relative to sensitivity (∆+0.3%).

DISCUSSION

Current findings indicate that structural brain abnormalities may persist up to 4 months post-pmTBI and are partially mediated by initial markers of injury severity. These results contribute to a growing body of evidence suggesting prolonged physiologic recovery post-pmTBI. In contrast, there was no evidence for age-at-injury effects or physiologic correlates of persistent symptoms in our sample.

Multicompartmental models and diffusion abnormalities in paediatric mild traumatic brain injury

The underlying pathophysiology of paediatric mild traumatic brain injury and the time-course for biological recovery remains widely debated, with clinical care principally informed by subjective self-report. Similarly, clinical evidence indicates that adolescence is a risk factor for prolonged recovery, but the impact of age-at-injury on biomarkers has not been determined in large, homogeneous samples. The current study collected diffusion MRI data in consecutively recruited patients (n = 203; 8-18 years old) and age and sex-matched healthy controls (n = 170) in a prospective cohort design. Patients were evaluated subacutely (1-11 days post-injury) as well as at 4 months post-injury (early chronic phase). Healthy participants were evaluated at similar times to control for neurodevelopment and practice effects. Clinical findings indicated persistent symptoms at 4 months for a significant minority of patients (22%), along with residual executive dysfunction and verbal memory deficits. Results indicated increased fractional anisotropy and reduced mean diffusivity for patients, with abnormalities persisting up to 4 months post-injury. Multicompartmental geometric models indicated that estimates of intracellular volume fractions were increased in patients, whereas estimates of free water fractions were decreased. Critically, unique areas of white matter pathology (increased free water fractions or increased neurite dispersion) were observed when standard assumptions regarding parallel diffusivity were altered in multicompartmental models to be more biologically plausible. Cross-validation analyses indicated that some diffusion findings were more reproducible when ∼70% of the total sample (142 patients, 119 controls) were used in analyses, highlighting the need for large-sample sizes to detect abnormalities. Supervised machine learning approaches (random forests) indicated that diffusion abnormalities increased overall diagnostic accuracy (patients versus controls) by ∼10% after controlling for current clinical gold standards, with each diffusion metric accounting for only a few unique percentage points. In summary, current results suggest that novel multicompartmental models are more sensitive to paediatric mild traumatic brain injury pathology, and that this sensitivity is increased when using parameters that more accurately reflect diffusion in healthy tissue. Results also indicate that diffusion data may be insufficient to achieve a high degree of objective diagnostic accuracy in patients when used in isolation, which is to be expected given known heterogeneities in pathophysiology, mechanism of injury and even criteria for diagnoses. Finally, current results indicate ongoing clinical and physiological recovery at 4 months post-injury.

Staff and volunteers' perceptions of a Communication Enhanced Environment model in an acute/slow stream rehabilitation and a rehabilitation hospital ward: a qualitative description study within a before-and-after pilot study

PURPOSE

A lack of social interaction during early stroke recovery can negatively affect neurological recovery and health-related quality of life of patients with aphasia following stroke. A Communication Enhanced Environment (CEE) model was developed to increase patient engagement in language activities early after stroke. This study aimed to examine staff (n = 20) and volunteer (n = 2) perceptions of a CEE model and factors influencing the implementation and use of the model. This study formed part of a broader study that developed and embedded a CEE model on two hospital wards.

MATERIALS AND METHODS

Six focus groups and one interview with hospital staff were conducted and analysed using a qualitative description approach. Feedback emailed by volunteers was included in the data set.

RESULTS

Staff and volunteers perceived the CEE model benefitted themselves, the hospital system and patients. Staff identified a range of factors that influenced the implementation and use of the CEE model including individual staff, volunteer and patient factors, hospital features, the ease with which the CEE model could be used, and the implementation approach.

CONCLUSIONS

This study provides valuable insights into staff perceptions which may inform the implementation of interventions and future iterations of a CEE model.Implications for RehabilitationA CEE model may promote efficiency and increased patient engagement in stroke rehabilitation.The CEE model information session and aphasia communication partner training, and the provision of resources, may be useful strategies to increase staff confidence in using communication supporting strategies with patients with aphasia.Behaviour change and implementation science strategies may provide a framework to address barriers and promote facilitators to embed hospital-based interventions that require individual, ward, cultural and systems level change to reduce the evidence-based gap in clinical practice.

Memantine associated with ventricular-subcutaneous shunt promotes behavioral improvement, reduces reactive astrogliosis and cell death in juvenile hydrocephalic rats

Hydrocephalus is defined as the accumulation of cerebrospinal fluid in the brain ventricles. The usual treatment of hydrocephalus is surgical (shunt), but not all patients can undergo treatment immediately after diagnosis. Thus, neuroprotective measures were tested to minimize the tissue damage involved. Memantine is a non-competitive antagonist of the N-methyl-D-aspartate (NMDA) receptor, which has shown a neuroprotective action in neurodegenerative diseases. This study aimed to evaluate the neuroprotective response of memantine in animals treated with or without a ventricular-subcutaneous shunt. Seven-day-old male Wistar rats induced by intracisternal injection of kaolin were used, divided into five groups: intact control (n=10), hydrocephalic (n=10), hydrocephalic treated with memantine (20mg/kg/day) (n=10), hydrocephalic treated with shunt (n=10), hydrocephalic treated with shunt and memantine (20mg/kg/day) (n=10). Memantine administration was started on the day after hydrocephalus induction and continued until the last day of the experimental period, totaling 21 consecutive days of drug application. The CSF shunt surgery was performed seven days after hydrocephalus induction. Behavioral tests (open field, and modified Morris water maze), histological, and immunohistochemical evaluations were performed. Treatment with memantine resulted in significant improvement (p<0.05) in sensorimotor development, preservation of spatial memory, reduction of astrocytic reaction in the corpus callosum, cortex, and germinal matrix. When associated with the shunt, it has also been shown to reduce the cell death cascade. It is concluded that memantine is a promising adjuvant drug with beneficial potential for the treatment of lesions secondary to hydrocephalus.

3D patient-derived tumor models to recapitulate pediatric brain tumors In Vitro

Brain tumors are the leading cause of cancer-related deaths in children. Tailored therapies need preclinical brain tumor models representing a wide range of molecular subtypes. Here, we adapted a previously established brain tissue-model to fresh patient tumor cells with the goal of establishing3D in vitro culture conditions for each tumor type.Wereported our findings from 11 pediatric tumor cases, consisting of three medulloblastoma (MB) patients, three ependymoma (EPN) patients, one glioblastoma (GBM) patient, and four juvenile pilocytic astrocytoma (Ast) patients. Chemically defined media consisting of a mixture of pro-neural and pro-endothelial cell culture medium was found to support better growth than serum-containing medium for all the tumor cases we tested. 3D scaffold alone was found to support cell heterogeneity and tumor type-dependent spheroid-forming ability; both properties were lost in 2D or gel-only control cultures. Limited in vitro models showed that the number of differentially expressed genes between in vitro vs. primary tissues, are 104 (0.6%) of medulloblastoma, 3,392 (20.2%) of ependymoma, and 576 (3.4%) of astrocytoma, out of total 16,795 protein-coding genes and lincRNAs. Two models derived from a same medulloblastoma patient clustered together with the patient-matched primary tumor tissue; both models were 3D scaffold-only in Neurobasal and EGM 1:1 (v/v) mixture and differed by a 1-mo gap in culture (i.e., 6wk versus 10wk). The genes underlying the in vitrovs. in vivo tissue differences may provide mechanistic insights into the tumor microenvironment. This study is the first step towards establishing a pipeline from patient cells to models to personalized drug testing for brain cancer.

Patients' experiences of a Communication Enhanced Environment model on an acute/slow stream rehabilitation and a rehabilitation ward following stroke: a qualitative description approach

BACKGROUND

Patients in hospital following stroke express a desire to continue therapy tasks outside of treatment activities. However, they commonly describe experiences of boredom and inactivity. An enriched environment aims to provide opportunities for physical, cognitive and social activity and informed the development of a Communication Enhanced Environment (CEE) model to promote patient engagement in language activities.

PURPOSE

Explore patient perceptions of a CEE model, and barriers and facilitators to engagement in the model.

METHODS

A qualitative description study from a larger project that implemented a CEE model into acute and rehabilitation private hospital wards in Western Australia. Semi-structured interviews were conducted with seven patients, including four with aphasia, within 22 days post-stroke who had access to the CEE model.

RESULTS

Patients described variable experiences accessing different elements of the CEE model which were influenced by individual patient factors, staff factors, hospital features as well as staff time pressures. Those who were able to access elements of the CEE model described positive opportunities for engagement in language activities.

CONCLUSIONS

While findings are encouraging, further exploration of the feasibility of a CEE model in this complex setting is indicated to inform the development of this intervention.Implications for rehabilitationPatient access to a CEE model is challenging in a hospital setting.Patients who were able to access elements of the CEE model described positive opportunities for engagement in language activities.Patients' access to the CEE model was influenced by patient factors, staff factors, hospital features as well as staff time pressures.

Clinical Neurorehabilitation: Using Principles of Neurological Diagnosis, Prognosis, and Neuroplasticity in Assessment and Treatment Planning

Neurorehabilitation aspires to restore a person to his or her fullest potential after incurring neurological dysfunction. In medical rehabilitation, diagnosis involves assessment of medical conditions and their effects on functioning. It is usually a team effort that involves an amalgam of diagnostic assessments by multiple disciplines, leading to a collection of rehabilitative treatment plans and goals. This article discusses a clinical neurological paradigm, using rigorous clinical assessment of neuropathological and clinical diagnosis, along with prognostication of natural history and recovery. In the context of the role of neuroplasticity in recovery, this paradigm can add significant value to rehabilitation team management and planning. It contributes to enhanced understanding of neurological impairments and syndromes as they relate to functional disability, aiding in targeting deficits and setting treatment goals. Rehabilitation strategies and goals should be informed by natural history and prognosis, and viewed in the framework of the stage of recovery. Prognostic formulations should suggest an emphasis on restorative versus compensatory strategies for functional problems. Treatment planning should be informed by evidence on how interventions modulate brain reorganization in promoting recovery. Strategies that promote adaptive neuroplasticity should be favored, especially with restorative efforts, and evidence supporting optimal techniques, timing, and dosing of rehabilitation should be considered in treatment planning.

Seven Solutions for Neuroprotection in Parkinson's Disease

Parkinson's disease (PD) is a neurodegenerative disorder characterized by loss of dopaminergic neurons in the substantia nigra and accumulation of iron and alpha-synuclein; it follows a characteristic pattern throughout the nervous system. Despite decades of successful preclinical neuroprotective studies, no drug has then shown efficacy in clinical trials. Considering this dilemma, we have reviewed and organized solutions of varying importance that can be exclusive or additive, and we outline approaches to help generate successful development of neuroprotective drugs for PD: (1) select patients in which the targeted mechanism is involved in the pathological process associated with the monitoring of target engagement, (2) combine treatments that target multiple pathways, (3) establish earliest interventions and develop better prodromal biomarkers, (4) adopt rigorous methodology and specific disease-relevant designs for disease-modifying clinical trials, (5) customize drug with better brain biodistribution, (6) prioritize repurposed drugs as a first line approach, and (7) adapt preclinical models to the targeted mechanisms with translational biomarkers to increase their predictive value. © 2020 International Parkinson and Movement Disorder Society.

Feasibility of single and combined with other treatments using transcranial direct current stimulation for chronic stroke: A pilot study

Objectives

This pilot study aimed to investigate the safety and efficacy of transcranial direct current stimulation (tDCS) for chronic stroke in adult and pediatric patients. We also aimed to verify the efficacy of botulinum toxin A and peripheral neuromuscular electrical stimulation combined therapy involving bilateral tDCS in adult patients with chronic stroke.

Methods

We conducted a pilot study applying an unblinded, non-randomized design. Eleven patients were recruited, and classified into three groups. Group I-a involved bilateral transcranial direct current stimulation and intensive occupational therapy for chronic stroke in adult patients. Group I-b involved bilateral tDCS and intensive occupational therapy for chronic stroke in pediatric patients. Group II involved bilateral tDCS, peripheral neuromuscular electrical stimulation, and intensive occupational therapy after botulinum toxin A injection for chronic stroke in adult patients. Clinical evaluations to assess motor function and spasticity were performed at baseline as well as in 2-week and 4-month follow-up visits. The questionnaire included questions regarding the presence of tDCS side effects, such as headache, redness, pain, itching, and fever.

Results

There were clinically meaningful changes in total Fugl-Meyer Assessment Upper Extremity (FMA-UE) scores at the 2-week follow-up and in the Action Research Arm Test (ARAT) scores at 4-month follow-up in Group I-b. In addition, Group II showed significant improvement in total FMA-UE scores in the 2-week follow-up (p < 0.05) but not on the ARAT scores (p > 0.05). However, Group II showed improvements in total Motor Activity Log scores at both follow-up visits (p < 0.05). No serious adverse events were reported.

Conclusion

The results of this study indicate that tDCS therapy is a potential treatment in pediatric patients with chronic stroke. Furthermore, our data indicate that botulinum toxin A and peripheral neuromuscular electrical stimulation combined therapy may enhance the efficacy of tDCS on motor function.

A perspective on the development of hemispheric specialization, infant handedness, and cerebral palsy

Cerebral Palsy (CP), a common form of neurological pediatric disability, results from pre- or perinatal brain injury. Although there is growing evidence of the efficacy of motor learning-based therapies, several factors interact to produce variability in impairment and limit the effectiveness of these therapies. The variability of hand function present in children with CP indicates that a range of developmental pathways must contribute to the manifestation of individually unique characteristics of impairment. Despite two decades of progress using therapies derived from understanding the mechanisms controlling hand function, very little is known about the sensorimotor experiences occurring during development that likely shape later functional problems for children with CP. In this "perspective" paper, we propose that the study of the development of motor skills in typically developing infants may reveal experiential factors potentially important for creating remedial therapies for children with CP. Specifically, we use the development of infant handedness, a model of hemispheric specialization of function, as an example of how self-generated experiences and sensorimotor feedback can shape the development of limb control and hemispheric specialization. We illustrate how early sensorimotor asymmetries concatenate into pronounced differences in skill between the two hands. We suggest that this model of infant handedness provides a framework for studying the individual differences manifested in children with CP. These differences likely arise from aberrant sensorimotor experiences created by sensorimotor circuits disrupted by the early brain injury. We conclude that knowledge of the developmental events, including subtle motor behaviors, that shape sensorimotor pathways, can improve treatment options for children with CP.

Hypothermia: Impact on plasticity following brain injury

Therapeutic hypothermia (TH) is a potent neuroprotectant against multiple forms of brain injury, but in some cases, prolonged cooling is needed. Such cooling protocols raise the risk that TH will directly or indirectly impact neuroplasticity, such as after global and focal cerebral ischemia or traumatic brain injury. TH, depending on the depth and duration, has the potential to broadly affect brain plasticity, especially given the spatial, temporal, and mechanistic overlap with the injury processes that cooling is used to treat. Here, we review the current experimental and clinical evidence to evaluate whether application of TH has any adverse or positive effects on postinjury plasticity. The limited available data suggest that mild TH does not appear to have any deleterious effect on neuroplasticity; however, we emphasize the need for additional high-quality preclinical and clinical work in this area.

Sex differences in central nervous system plasticity and pain in experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) is a neurodegenerative autoimmune disease with many known structural and functional changes in the central nervous system. A well-recognized, but poorly understood, complication of MS is chronic pain. Little is known regarding the influence of sex on the development and maintenance of MS-related pain. This is important to consider, as MS is a predominantly female disease. Using the experimental autoimmune encephalomyelitis (EAE) mouse model of MS, we demonstrate sex differences in measures of spinal cord inflammation and plasticity that accompany tactile hypersensitivity. Although we observed substantial inflammatory activity in both sexes, only male EAE mice exhibit robust staining of axonal injury markers and increased dendritic arborisation in morphology of deep dorsal horn neurons. We propose that tactile hypersensitivity in female EAE mice may be more immune-driven, whereas pain in male mice with EAE may rely more heavily on neurodegenerative and plasticity-related mechanisms. Morphological and inflammatory differences in the spinal cord associated with pain early in EAE progression supports the idea of differentially regulated pain pathways between the sexes. Results from this study may indicate future sex-specific targets that are worth investigating for their functional role in pain circuitry.

Unmet Needs in Children With Attention Deficit Hyperactivity Disorder-Can Transcranial Direct Current Stimulation Fill the Gap? Promises and Ethical Challenges

Attention deficit hyperactivity disorder (ADHD) is a disorder most frequently diagnosed in children and adolescents. Although ADHD can be effectively treated with psychostimulants, a significant proportion of patients discontinue treatment because of adverse events or insufficient improvement of symptoms. In addition, cognitive abilities that are frequently impaired in ADHD are not directly targeted by medication. Therefore, additional treatment options, especially to improve cognitive abilities, are needed. Because of its relatively easy application, well-established safety, and low cost, transcranial direct current stimulation (tDCS) is a promising additional treatment option. Further research is needed to establish efficacy and to integrate this treatment into the clinical routine. In particular, limited evidence regarding the use of tDCS in children, lack of clear translational guidelines, and general challenges in conducting research with vulnerable populations pose a number of practical and ethical challenges to tDCS intervention studies. In this paper, we identify and discuss ethical issues related to research on tDCS and its potential therapeutic use for ADHD in children and adolescents. Relevant ethical issues in the tDCS research for pediatric ADHD center on safety, risk/benefit ratio, information and consent, labeling problems, and nonmedical use. Following an analysis of these issues, we developed a list of recommendations that can guide clinicians and researchers in conducting ethically sound research on tDCS in pediatric ADHD.

BDNF expression increases without changes in play behavior following concussion in juvenile rats (Rattus Norvegicus)

PURPOSE

Young children have a high risk of concussion or mild traumatic brain injury (mTBI). Children often appear healthy soon after mTBI, but some have pervasive cognitive and/or motor impairments. Understanding underlying mechanisms recruited after concussion may help for return to play protocols and mitigating what might be lifelong impairments.

METHODS

We investigated molecular and behavioral changes in a rat model of childhood concussion. Rats received an injury or sham procedure at an age approximately equivalent to the human period of early childhood. Social play was analyzed for behavioral differences. Tissue from the right motor cortex (impacted), left motor cortex, and medial prefrontal cortex were analyzed for brain derived neurotrophic factor (BDNF) protein.

RESULTS

Play behavior was not significantly different between conditions. BDNF levels were much higher in both the right and left motor cortices of the mTBI group compared to medial prefrontal cortex, which is relatively remote from the impact site, within the mTBI group and all tissue collected from the sham group.

CONCLUSIONS

There is ongoing plastic change at the cellular level in both the impacted area and the well-connected contralateral area after a concussion, suggesting compensatory mechanisms after injury are still at play.

Advanced biomarkers of pediatric mild traumatic brain injury: Progress and perils

There is growing public concern about neurodegenerative changes (e.g., Chronic Traumatic Encephalopathy) that may occur chronically following clinically apparent and clinically silent (i.e., sub-concussive blows) pediatric mild traumatic brain injury (pmTBI). However, there are currently no biomarkers that clinicians can use to objectively diagnose patients or predict those who may struggle to recover. Non-invasive neuroimaging, electrophysiological and neuromodulation biomarkers have promise for providing evidence of the so-called "invisible wounds" of pmTBI. Our systematic review, however, belies that notion, identifying a relative paucity of high-quality, clinically impactful, diagnostic or prognostic biomarker studies in the sub-acute injury phase (36 studies on unique samples in 28 years), with the majority focusing on adolescent pmTBI. Ultimately, well-powered longitudinal studies with appropriate control groups, as well as standardized and clearly-defined inclusion criteria (time post-injury, injury severity and past history) are needed to truly understand the complex pathophysiology that is hypothesized (i.e., still needs to be determined) to exist during the acute and sub-acute stages of pmTBI and may underlie post-concussive symptoms.

Neural Reorganization Due to Neonatal Amygdala Lesions in the Rhesus Monkey: Changes in Morphology and Network Structure

It is generally believed that neural damage that occurs early in development is associated with greater adaptive capacity relative to similar damage in an older individual. However, few studies have surveyed whole brain changes following early focal damage. In this report, we employed multimodal magnetic resonance imaging analyses of adult rhesus macaque monkeys who had previously undergone bilateral, neurotoxic lesions of the amygdala at about 2 weeks of age. A deformation-based morphometric approach demonstrated reduction of the volumes of the anterior temporal lobe, anterior commissure, basal ganglia, and pulvinar in animals with early amygdala lesions compared to controls. In contrast, animals with early amygdala lesions had an enlarged cingulate cortex, medial superior frontal gyrus, and medial parietal cortex. Diffusion-weighted imaging tractography and network analysis were also used to compare connectivity patterns and higher-level measures of communication across the brain. Using the communicability metric, which integrates direct and indirect paths between regions, lesioned animals showed extensive degradation of network integrity in the temporal and orbitofrontal cortices. This work demonstrates both degenerative as well as progressive large-scale neural changes following long-term recovery from neonatal focal brain damage.

The Neuroprotective Effects of Experience on Cognitive Functions: Evidence from Animal Studies on the Neurobiological Bases of Brain Reserve

Brain plasticity is the ability of the nervous system to change structurally and functionally in response to experience. By shaping brain structure and function, experience leads to the creation of a protective reserve that accounts for differences among individuals in susceptibility to age-related brain modifications and pathology. This review is aimed to address the biological bases of the experience-dependent "brain reserve" by describing the results of animal studies that focused on the neuroanatomical and molecular effects of environmental enrichment. More specifically, the effects at the cellular level are considered in terms of changes in neurogenesis, gliogenesis, angiogenesis, and synaptogenesis. Moreover, the effects at the molecular level are described, highlighting gene- and protein-level changes in neurotransmitter and neurotrophin expression. The experimental evidence for the basic biological consequences of environmental enrichment is described for healthy animals. Subsequently, by discussing the findings for animal models that mimic age-related diseases, the involvement of such plastic changes in supporting an organism as it copes with normal and pathological age-related cognitive decline is considered. On the whole, studies of the structural and molecular effects of environmental enrichment strongly support the neuroprotective action of a particularly stimulating lifestyle on cognitive functions. Our current level of understanding of these effects and mechanisms is such that additional and novel studies, systematic reviews, and meta-analyses are necessary to investigate the specific effects of the different components of environmental enrichment in both healthy and pathological models. Only in this way can comprehensive recommendations for proper life habits be developed.

Perinatal 192 IgG-Saporin as Neuroteratogen

The immunotoxin 192 IgG-saporin selectively destroys basal forebrain cholinergic neurons that provide cholinergic input to the hippocampus, entire cortical mantle, amygdala, and olfactory bulb. Perinatal immunotoxic lesions by 192 IgG-saporin induce long-lasting cholinergic depletion mimicking a number of developmental disorders reported in humans. The perinatal injection of 192 IgG-saporin induces several brain modifications, which are observed in neocortex and hippocampus at short and long term. These plastic changes involve both structural (alterations in brain volume, neuronal morphology, and neurogenesis) and molecular (modulations of the levels of neurotransmitters and other proteins related to neurodegeneration) levels. Moreover, the perinatal injection of 192 IgG-saporin may interact with the brain plastic capacity to react to other injuries. Perinatal 192 IgG-saporin lesions allowed investigating the role of the basal forebrain cholinergic system in modulating behavioral functions in developing as well as adult rats. After perinatal cholinergic depletion, rats display reduced ultrasonic vocalizations as neonates, learning and exploratory deficits as juveniles, altered discriminative abilities, impulsive and perseverative behaviors, and memory deficits as adults. Overall, these findings underline the importance of cholinergic system integrity for the development of specific structural and functional features.

Transcranial Direct Current Stimulation: Considerations for Research in Adolescent Depression

Adolescent depression is a prevalent disorder with substantial morbidity and mortality. Current treatment interventions do not target relevant pathophysiology and are frequently ineffective, thereby leading to a substantial burden for individuals, families, and society. During adolescence, the prefrontal cortex undergoes extensive structural and functional changes. Recent work suggests that frontolimbic development in depressed adolescents is delayed or aberrant. The judicious application of non-invasive brain stimulation techniques to the prefrontal cortex may present a promising opportunity for durable interventions in adolescent depression. Transcranial direct current stimulation (tDCS) applies a low-intensity, continuous current that alters cortical excitability. While this modality does not elicit action potentials, it is thought to manipulate neuronal activity and neuroplasticity. Specifically, tDCS may modulate N-methyl-d-aspartate receptors and L-type voltage-gated calcium channels and effect changes through long-term potentiation or long-term depression-like mechanisms. This mini-review considers the neurobiological rationale for developing tDCS protocols in adolescent depression, reviews existing work in adult mood disorders, surveys the existing tDCS literature in adolescent populations, reviews safety studies, and discusses distinct ethical considerations in work with adolescents.

Neurorehabilitation: applied neuroplasticity

The prevalence of disability due to neurological conditions is escalating worldwide. Neurological disorders have significant disability-burden with long-term functional and psychosocial issues, requiring specialized rehabilitation services for comprehensive management, especially treatments tapping into brain recovery 'neuroplastic' processes. Neurorehabilitation is interdisciplinary and cross-sectorial, requiring coordinated effort of diverse sectors, professions, patients and community to manage complex condition-related disability. This review provides evidence for a range of neurorehabilitation interventions for four common neurological conditions: multiple sclerosis (MS), stroke, traumatic brain injury and Parkinson's disease using the Grade of Recommendation, Assessment, Development and Evaluation tool for quality of evidence. Although, existing best-evidence for many interventions is still sparse, the overall findings suggest 'strong' evidence for physical therapy and psychological intervention for improved patient outcomes; and. 'moderate' evidence for multidisciplinary rehabilitation for longer term gains at the levels of activity (disability) and participation in MS and stroke population. The effect of other rehabilitation interventions is inconclusive, due to a paucity of methodologically robust studies. More research is needed to improve evidence-base for many promising rehabilitation interventions.

Predictors of Post-concussive Symptoms in Young Children: Injury versus Non-injury Related Factors

OBJECTIVES

A notable minority of children will experience persistent post-concussive symptoms (PCS) following mild traumatic brain injury (mTBI), likely maintained by a combination of injury and non-injury related factors. Adopting a prospective longitudinal design, this study aimed to investigate the relative influence of child, family, and injury factors on both acute and persistent PCS in young children.

METHODS

Participants were 101 children aged 2-12 who presented to an Emergency Department, with either mTBI or minor bodily trauma (control). PCS were assessed at time of injury, 1 week, and 1, 2, and 3 months post-injury. Predictors included injury and demographic variables, premorbid child behavior, sleep hygiene, and parental stress. Random effects ordinal logistic regression models were used to analyze the relative influence of these predictors on PCS at early (acute - 1 week) and late (1-3 month) post-injury phases.

RESULTS

Presence of mTBI was a stronger predictor of PCS in the early [odds ratio (OR)=18.2] compared with late (OR=7.3) post-injury phase. Older age at injury and pre-existing learning difficulties were significant predictors of PCS beyond 1 month post-injury. Family factors, including higher levels of parental stress, higher socio-economic status, and being of Anglo-Saxon descent, consistently predicted greater PCS.

CONCLUSIONS

Injury characteristics were significantly associated with PCS for 3 months following mTBI but the association weakened over time. On the other hand, pre-existing child and family factors displayed an increasingly strong association with PCS over time. Follow-up for these "at-risk" children which also addresses family stress may minimize longer-term complications. (JINS, 2016, 22, 793-803).

The Risk of Sleep Disorder Among Persons with Mild Traumatic Brain Injury

Sleep disorders and mild traumatic brain injury (mTBI) are among the most commonly occurring neurological problems clinicians encounter simultaneously. Each can cause the other, and both share common predisposing factors. An important question that remains to be addressed is whether high-risk groups can be defined. We observed an accumulation of considerable knowledge on sleep dysfunction in mTBI in recently published works. The results highlight sleep disturbances in mTBI as the product of diverse internal and external influences, acting on a genetically determined substrate. This may partially explain the clinical heterogeneity of mTBI, pointing to the importance of establishing an accurate history on the onset and course of a specific sleep disorder in the early stages post-mTBI in the individual patient. Such an approach will aid not only diagnosis and treatment but may also lead to identification of disorders whose symptoms mimic those of TBI and thereby direct the most suitable treatment and management.

The effects of amphetamine exposure on juvenile rats on the neuronal morphology of the limbic system at prepubertal, pubertal and postpubertal ages

Amphetamines (AMPH) are psychostimulants widely used for therapy as well as for recreational purposes. Previous results of our group showed that AMPH exposure in pregnant rats induces physiological and behavioral changes in the offspring at prepubertal and postpubertal ages. In addition, several reports have shown that AMPH are capable of modifying the morphology of neurons in some regions of the limbic system. These modifications can cause some psychiatric conditions. However, it is still unclear if there are changes to behavioral and morphological levels when low doses of AMPH are administered at a juvenile age. The aim of this study was to assess the effect of AMPH administration (1mg/kg) in Sprague-Dawley rats (postnatal day, PD21-PD35) on locomotor activity in a novel environment and compare the neuronal morphology of limbic system areas at three different ages: prepubertal (PD 36), pubertal (PD50) and postpubertal (PD 62). We found that AMPH altered locomotor activity in the prepubertal group, but did not have an effect on the other two age groups. The Golgi-Cox staining method was used to describe the neural morphology of five limbic regions: (Layers 3 and 5) the medial prefrontal cortex (mPFC), the dorsal and ventral hippocampus, the nucleus accumbens and the amygdala, showing that AMPH induced changes at pubertal ages in arborization and spine density of these neurons, but interestingly these changes did not persist at postpubertal ages. Our findings suggest that even early-life AMPH exposure does not induce long-term behavioral and morphological changes, however it causes alterations at pubertal ages in the limbic system networks, a stage of life strongly associated with the development of substance abuse behaviors.

Transcranial direct current stimulation in children and adolescents: a comprehensive review

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation method that has shown promising results in various neuropsychiatric disorders in adults. This review addresses the therapeutic use of tDCS in children and adolescents including safety, ethical, and legal considerations. There are several studies addressing the dosage of tDCS in children and adolescents by computational modeling of electric fields in the pediatric brain. Results suggest halving the amperage used in adults to obtain the same peak electric fields, however, there are some studies reporting on the safe application of tDCS with standard adult parameters in children (2 mA; 20-30 min). There are several randomized placebo controlled trials suggesting beneficial effects of tDCS for the treatment of cerebral palsy. For dystonia there are mixed data. Some studies suggest efficacy of tDCS for the treatment of refractory epilepsy, and for the improvement of attention deficit/hyperactivity disorder and autism. Interestingly, there is a lack of data for the treatment of childhood and adolescent psychiatric disorders, i.e., childhood onset schizophrenia and affective disorders. Overall, tDCS seems to be safe in pediatric population. More studies are needed to confirm the preliminary encouraging results; however, ethical deliberation has to be weighed carefully for every single case.

Plasticity and Reorganization in the Rehabilitation of Stroke

Abstract. This paper outlines some actual developments in the behavioral treatment and rehabilitation of stroke and other brain injuries in post-acute and chronic conditions of brain lesion. It points to a number of processes that demonstrate the enormous plasticity and reorganization capacity of the human brain following brain lesion. It also highlights a series of behavioral and neuroscientific studies that indicate that successful behavioral rehabilitation is paralleled by plastic changes of brain structures and by cortical reorganization and that the amount of such plastic changes is obviously significantly determining the overall outcome of rehabilitation.

Musical training as an alternative and effective method for neuro-education and neuro-rehabilitation

In the last decade, important advances in the field of cognitive science, psychology, and neuroscience have largely contributed to improve our knowledge on brain functioning. More recently, a line of research has been developed that aims at using musical training and practice as alternative tools for boosting specific perceptual, motor, cognitive, and emotional skills both in healthy population and in neurologic patients. These findings are of great hope for a better treatment of language-based learning disorders or motor impairment in chronic non-communicative diseases. In the first part of this review, we highlight several studies showing that learning to play a musical instrument can induce substantial neuroplastic changes in cortical and subcortical regions of motor, auditory and speech processing networks in healthy population. In a second part, we provide an overview of the evidence showing that musical training can be an alternative, low-cost and effective method for the treatment of language-based learning impaired populations. We then report results of the few studies showing that training with musical instruments can have positive effects on motor, emotional, and cognitive deficits observed in patients with non-communicable diseases such as stroke or Parkinson Disease. Despite inherent differences between musical training in educational and rehabilitation contexts, these results favor the idea that the structural, multimodal, and emotional properties of musical training can play an important role in developing new, creative and cost-effective intervention programs for education and rehabilitation in the next future.

The connectomics of brain disorders

Pathological perturbations of the brain are rarely confined to a single locus; instead, they often spread via axonal pathways to influence other regions. Patterns of such disease propagation are constrained by the extraordinarily complex, yet highly organized, topology of the underlying neural architecture; the so-called connectome. Thus, network organization fundamentally influences brain disease, and a connectomic approach grounded in network science is integral to understanding neuropathology. Here, we consider how brain-network topology shapes neural responses to damage, highlighting key maladaptive processes (such as diaschisis, transneuronal degeneration and dedifferentiation), and the resources (including degeneracy and reserve) and processes (such as compensation) that enable adaptation. We then show how knowledge of network topology allows us not only to describe pathological processes but also to generate predictive models of the spread and functional consequences of brain disease.

Feasibility of transcranial direct current stimulation use in children aged 5 to 12 years

Transcranial direct current stimulation is a noninvasive brain stimulation technique that has been studied for the treatment of neuropsychiatric disorders in adults, with minimal side effects. The objective of this study is to report the feasibility, tolerability, and the short-term adverse effects of transcranial direct current stimulation in children from 5 to 12 years of age. It is a naturalistic study of 14 children who underwent 10 sessions of transcranial direct current stimulation as an alternative, off-label, and open-label treatment for various languages disorders. Frequency, intensity, adverse effects, and perception of improvement reported by parents were collected. The main side effects detected were tingling (28.6%) and itching (28.6%), acute mood changes (42.9%), and irritability (35.7%). Transcranial direct current stimulation is a feasible and tolerable technique in children, although studies regarding plastic and cognitive changes in children are needed to confirm its safety. In conclusion, this is a naturalistic report in which we considered transcranial direct current stimulation as feasible in children.

Clinical Outcome after Intra-Arterial Stroke Therapy in the Very Elderly: Why is it so Heterogeneous?

Very elderly patients (i.e., ≥80 years) are disproportionally affected by acute ischemic stroke. They account for a third of hospital stroke admissions, but two-thirds of overall stroke-related morbidity and mortality. There is some evidence of clinical benefit in treating selected very elderly patients with intravenous thrombolysis (IVT). For very elderly patients ineligible or non-responsive to IVT, intra-arterial therapy (IAT) may have promise in improving clinical outcome. However, its unequivocal efficacy in the general population remains to be proven in randomized trials. Small cohort studies reveal that the rate of good clinical outcome for very elderly patients after IAT is highly variable, ranging from 0 to 28%. In addition, they experience higher rates of futile reperfusion than younger patients. Thus, it is imperative to understand the factors that impact on clinical outcome in very elderly patients after IAT. The aim of this review is to examine the factors that may be responsible for the heterogeneous clinical response of the very elderly to IAT. This will allow the reader to integrate the current available evidence to individualize intra-arterial stroke therapy in very elderly patients. Placing emphasis on pre-stroke independent living, smaller infarct core size, short procedure times, and avoiding general anesthesia where feasible, will help improve rates of good clinical outcome.

Environmental enrichment alters structural plasticity of the adolescent brain but does not remediate the effects of prenatal nicotine exposure

Exposure to both drugs of abuse and environmental enrichment (EE) are widely studied experiences that induce large changes in dendritic morphology and synaptic connectivity. As there is an abundance of literature using EE as a treatment strategy for drug addiction, we sought to determine whether EE could remediate the effects of prenatal nicotine (PN) exposure. Using Golgi-Cox staining, we examined eighteen neuroanatomical parameters in four brain regions [medial prefrontal cortex (mPFC), orbital frontal cortex (OFC), nucleus accumben, and Par1] of Long-Evans rats. EE in adolescence dramatically altered structural plasticity in the male and female brain, modifying 60% of parameters investigated. EE normalized three parameters (OFC spine density and dendritic branching and mPFC dendritic branching) in male offspring exposed to nicotine prenatally but did not remediate any measures in female offspring. PN exposure interfered with adolescent EE-induced changes in five neuroanatomical measurements (Par1 spine density and dendritic branching in both male and female offspring, and mPFC spine density in male offspring). And in four neuroanatomical parameters examined, PN exposure and EE combined to produce additive effects [OFC spine density in females and mPFC dendritic length (apical and basilar) and branching in males]. Despite demonstrated efficacy in reversing drug addiction, EE was not able to reverse many of the PN-induced changes in neuronal morphology, indicating that modifications in neural circuitry generated in the prenatal period may be more resistant to change than those generated in the adult brain.

Beta oscillations reflect changes in motor cortex inhibition in healthy ageing

Beta oscillations are involved in movement and have previously been linked to levels of the inhibitory neurotransmitter GABA. We examined changes in beta oscillations during rest and movement in primary motor cortex (M1). Amplitude and frequency of beta power at rest and movement-related beta desynchronization (MRBD) were measured during a simple unimanual grip task and their relationship with age was explored in a group of healthy participants. We were able to show that at rest, increasing age was associated with greater baseline beta power in M1 contralateral to the active hand, with a similar (non-significant) trend in ipsilateral M1. During movement, increasing age was associated with increased MRBD amplitude in ipsilateral M1 and reduced frequency (in contralateral and ipsilateral M1). These findings would be consistent with greater GABAergic inhibitory activity within motor cortices of older subjects. These oscillatory parameters have the potential to reveal changes in the excitatory–inhibitory balance in M1 which in turn may be a useful marker of plasticity in the brain, both in healthy ageing and disease.

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Changes in motor cortex beta oscillations are linked with changes in GABA.

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Changes in GABA-related cortical inhibition are linked with plasticity.

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Older subjects had higher resting beta power and greater beta decrease during grip.

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Beta oscillations are useful markers of cortical inhibition and plasticity.

Mean girls: sex differences in the effects of mild traumatic brain injury on the social dynamics of juvenile rat play behaviour

Clinical studies indicate that children who experience a traumatic brain injury (TBI) are often the victim of peer rejection, have very few mutual friends, and are at risk for long-term behavioural and social impairments. Owing to the fact that peer play is critical for healthy development, it is possible that the long-term impairments are associated not only with the TBI, but also altered play during this critical period of brain development. This study was designed to determine if social dynamics and juvenile play are altered in rats that experience a mild TBI (mTBI) early in life. Play-fighting behaviours were recorded and analyzed for young male and female Sprague Dawley rats that were given either an mTBI or a sham injury. The study found that the presence of an mTBI altered the play fighting relationship, and the nature of the alterations were dependent upon the sex of the pairing and the injury status of their peers. Sham rats were significantly less likely to initiate play with an mTBI rat, and were more likely to respond to a play initiation from an mTBI rat with an avoidant strategy. This effect was significantly more pronounced in female rats, whereby it appeared that female rats with an mTBI were particularly rejected and most often excluded from play experiences. Male rats with an mTBI learned normal play strategies from their sham peers (when housed in mixed cages), whereas female rats with an mTBI show heightened impairment in these conditions. Play therapy may need to be incorporated into treatment strategies for children with TBI.

Elderly patients and intra-arterial stroke therapy

Ischemic stroke disproportionately affects the elderly, particularly those over the age of 80 years. Rates of stroke are expected to increase over the next several decades due to increasing numbers of elderly individuals, making understanding stroke treatment in this population an imperative. The only proven acute stroke therapy is early reperfusion, accomplished through intravenous or intra-arterial means. Intra-arterial stroke therapy (IAT) offers higher recanalization rates than intravenous tissue plasminogen activator, but has yet to show clear superiority over intravenous tissue plasminogen activator alone. Existing data suggest that elderly stroke patients suffer worse outcomes following IAT, despite similar rates of recanalization and symptomatic intracranial hemorrhage. This article reviews the application of IAT in the elderly population and summarizes the available studies that investigate the response of elderly patients to IAT.

Alterations of dendritic protrusions over the first postnatal year of a mouse: an analysis in layer VI of the barrel cortex

Dendritic spines are small protrusions that serve as the principal recipients of excitatory inputs onto cortical pyramidal cells. Alterations in spine and filopodia density and morphology correlate with both developmental maturity and changes in synaptic strength. In order to better understand the developmental profile of dendritic protrusion (dendritic spines + filopodia) morphology and density over the animal's first postnatal year, we used the Golgi staining technique to label neurons and their dendritic protrusions in mice. We focused on quantifying the density per length of dendrite and categorizing the morphology of dendritic protrusions of layer VI pyramidal neurons residing in barrel cortex using the computer assisted reconstruction program Neurolucida. We classified dendritic protrusion densities at seven developmental time points: postnatal day (PND) 15, 30, 60, 90, 180, 270, and 360. Our findings suggest that the dendritic protrusions in layer VI barrel cortex pyramidal neurons are not static, and their density as well as relative morphological distribution change over time. We observed a significant increase in mushroom spines and a decrease in filopodia as the animals matured. Further analyses show that as the animal mature there was a reduction in pyramidal cell dendritic lengths overall, as well as a decrease in overall protrusion densities. The ratio of apical to basilar density decreased as well. Characterizing the profile of cortical layer VI dendritic protrusions within the first postnatal year will enable us to better understand the relationship between the overall developmental maturation profile and dendritic spine functioning.

MicroRNA-132 may play a role in coexistence of depression and cardiovascular disease: a hypothesis

Different individuals have different degrees of neuroplasticity due to their different experiences. Neuroplasticity may play a role in individual differences among neuropsychiatric disease treatment efficacy. Since the nervous system monitors and coordinates internal organ function, neuroplasticity may be associated with other diseases. Cardiovascular disease (CVD) is associated with depression, which is a disorder of disrupted neuroplasticity. MicroRNA-132 (miR-132) has a roles in neuroplasticity and cardiovascular function. Thus, we hypothesize that miR-132 may play a role in coexistence of depression and CVD.

Displacement of sensory maps and disorganization of motor cortex after targeted stroke in mice

BACKGROUND AND PURPOSE

Recovery from stroke is hypothesized to involve the reorganization of surviving cortical areas. To study the functional organization of sensorimotor cortex at multiple time points before and after stroke, we performed longitudinal light-based motor mapping of transgenic mice expressing light-sensitive channelrhodopsin-2 in layer 5 cortical neurons.

METHODS

Pulses of light stimulation were targeted to an array of cortical points, whereas evoked forelimb motor activity was recorded using noninvasive motion sensors. Intrinsic optical signal imaging produced maps of the forelimb somatosensory cortex. The resulting motor and sensory maps were repeatedly generated for weeks before and after small (0.2 mm3) photothrombotic infarcts were targeted to forelimb motor or sensory cortex.

RESULTS

Infarcts targeted to forelimb sensory or motor areas caused decreased motor output in the infarct area and spatial displacement of sensory and motor maps. Strokes in sensory cortex caused the sensory map to move into motor cortex, which adopted a more diffuse structure. Stroke in motor cortex caused a compensatory increase in peri-infarct motor output, but did not affect the position or excitability of sensory maps.

CONCLUSIONS

After stroke in motor cortex, decreased motor output from the infarcted area was offset by peri-infarct excitability. Sensory stroke caused a new sensory map to form in motor cortex, which maintained its center position, despite becoming more diffuse. These data suggest that surviving regions of cortex are able to assume functions from stroke-damaged areas, although this may come at the cost of alterations in map structure.