Lifespan leisure physical activity profile,brain plasticity and cognitive function in old age

Objectives: Despite the evidence suggesting physical activity (PA) as a major factor for the prevention of age-related cognitive decline, only a few studies have systematically investigated the impact of leisure PA during the lifespan (LLPA). This study investigates the effects of LLPA on cognitive function (CF) and brain plasticity (BP) in old age.

Method: Participants’ (n = 50, 72 ± 5 yrs, 27 females) LLPA energy expenditure and volume was assessed via a validated questionnaire investigating five epochs (14–80 yrs). Using current WHO PA recommendations as reference, participants were stratified into energy expenditure and volume groups. CF outcomes were attention, executive functions, working memory and memory. BP was assessed using magnetic resonance spectroscopy (MRSI) and brain derived neurotropic factor (BDNF).

Results: Correlation analysis revealed associations of mean LLPA energy expenditure with attention (CF) and N-acetylaspartate to choline ratios (NAA/Cho) (MRSI). ANOVA revealed higher interference control performance (CF) and NAA/Cho in participants complying with current PA recommendations (2-3 h per week) compared to non-compliers. Further CF and BP outcomes including BDNF were not associated with LLPA.

Conclusion: Lifelong adherence to minimum recommended PA seems to be associated with markers of cognitive function and neuronal integrity in old age.     

Imaging brain plasticity after trauma

The brain is highly plastic after stroke or epilepsy; however, there is a paucity of brain plasticity investigation after traumatic brain injury （TBI）. This mini review summarizes the most recent evidence of brain plasticity in human TBI patients from the perspective of advanced magnetic resonance imaging. Similar to other forms of acquired brain injury, TBI patients also demonstrat- ed both structural reorganization as well as functional compensation by the recruitment of other brain regions. However, the large scale brain network alterations after TBI are still unknown, and the field is still short of proper means on how to guide the choice of TBI rehabilitation or treat- ment plan to promote brain plasticity. The authors also point out the new direction of brain plas- ticity investigation.     

A role for sleep in brain plasticity

The idea that sleep might be involved in brain plasticity has been investigated for many years through a large number of animal and human studies, but evidence remains fragmentary. Large amounts of sleep in early life suggest that sleep may play a role in brain maturation. In particular, the influence of sleep in developing the visual system has been highlighted. The current data suggest that both Rapid Eye Movement (REM) and non-REM sleep states would be important for brain development. Such findings stress the need for optimal paediatric sleep management. In the adult brain, the role of sleep in learning and memory is emphasized by studies at behavioural, systems, cellular and molecular levels. First, sleep amounts are reported to increase following a learning task and sleep deprivation impairs task acquisition and consolidation. At the systems level, neurophysiological studies suggest possible mechanisms for the consolidation of memory traces. These imply both thalamocortical and hippocampo-neocortical networks. Similarly, neuroimaging techniques demonstrated the experience-dependent changes in cerebral activity during sleep. Finally, recent works show the modulation during sleep of cerebral protein synthesis and expression of genes involved in neuronal plasticity.     

Seasonal female brain plasticity in processing social vs. sexual vocal signals

While cerebral plasticity has been extensively studied and demonstrated – during ontogenetic development, few studies have considered adult plasticity in different social contexts using relevant social communication signals. Communication requires adaptability throughout the life of an individual, especially in species for which breeding periods (when intersexual signaling prevails) are interspersed with more ‘social’ (non‐sexual) periods when intrasexual bonding prevails. In songbirds, structure or frequency of songs or song elements may convey different information depending on the season. This is the case in the European starling, where some song structures characterize social bonds between females while other song structures are more characteristic of male courtship. We hypothesized that the female perceptual system may have adapted to these changes in song structure and function according to season, and we tested for potential seasonal brain plasticity. Electrophysiological recordings from adult female starlings during playback of song elements with different functions showed clear seasonal (breeding/non‐breeding) changes in neuronal responses in the primary auditory area. The proportion of responsive sites was higher in response to social (non‐sexual) songs during the non‐reproductive season, and higher in response to sexual songs during the reproductive season.     

Altered protein markers related to neural plasticity and motor function following electro-acupuncture treatment in a rat model of ischemic-hypoxic brain injury *☆

BACKGROUND：Previous studies have demonstrated that acupuncture treatment could ameliorate impaired motor function,and these positive effects might be due to neural plasticity.OBJECTIVE：Myelin basic protein（MBP）,microtubule-associated protein 2（MAP2）,growth-associated protein-43（GAP-43）,and synaptophysin（SYN） were selected as markers of neural remodeling,and expression of these markers was evaluated with regard to altered motor function following brain injury and acupuncture treatment.DESIGN,TIME AND SETTING：A completely randomized experiment was performed at the Central Laboratory of Peking University First Hospital from November 2006 to May 2007.MATERIALS：Twenty-four Sprague Dawley rat pups,aged 7 days,were selected for the present experiment.The left common carotid artery was ligated to establish a rat model of ischemic-hypoxic brain injury.METHODS：All animals were randomly divided into three groups：sham operation,model,and electro-acupuncture treatment,with 8 rats in each group.Rats in the model and electro-acupuncture treatment group underwent establishment of ischemic-hypoxic brain injury.Upon model established,rats underwent hypobaric oxygen intervention for 24 hours.Only the left common carotid artery was exposed in rats of the sham operation group,without model establishment or oxygen intervention.The rats in the electro-acupuncture treatment group were treated with electro-acupuncture.One acupuncture needle electrode was inserted into the subcutaneous layer at the Baihui and Dazhui acupoint.The stimulation condition of the electro-acupuncture simulator was set to an amplitude-modulated wave of 0-100% and alternative frequency of 100 cycles/second,as well as frequency-modulated wave of 2-100 Hz and an alternative frequency of 3 cycles/second.Maximal current through the two electrodes was limited to 3-5 mA.The stimulation lasted for 30 minutes per day for 2 weeks.Rats in the sham operation and model groups were not treated with electro-acupuncture,but only fixed to the table for     

Altered protein markers related to neural plasticity and motor function following electro-acupuncture treatment in a rat model of ischemic-hypoxic brain injury

BACKGROUND:Previous studies have demonstrated that acupuncture treatment could ameliorate impaired motor function,and these positive effects might be due to neural plasticity.OBJECTIVE:Myelin basic protein(MBP),microtubule-associated protein 2(MAP2),growth-associated protein-43(GAP-43),and synaptophysin(SYN) were selected as markers of neural remodeling,and expression of these markers was evaluated with regard to altered motor function following brain injury and acupuncture treatment.DESIGN,TIME AND SETTING...     

Models of brain injury and alterations in synaptic plasticity

Animal models are crucial for understanding human pathophysiological processes and for understanding how connections are injured, lost, or even regenerated and/or repaired. When animal models are used in conjunction with theoretical computational models, an ideal combination is achieved that potentially yields insight and encourages the formation of new theories concerning connectionism, cognitive functioning, and synaptic mechanisms. Mechanisms regulating glutamate receptor activation and intracellular calcium levels are important for normal synaptic transmission. These mechanisms (and others) are also critical during and after brain injury when the potential exists for these mechanisms to function pathologically. Interestingly enough, the regulation of glutamate receptor activation and intracellular calcium levels is also involved in normal processes of neuronal and synaptic plasticity. In addition, studies have shown that neurotrophins and cytokines, which are released after brain injury, can be neuroprotective and may also be important in synaptic plasticity. Furthermore, synaptic plasticity is a phenomenon thought by many to be necessary for memory encoding. If this is the case, then research described in this review has significant scientific merit concerning plasticity and memory and clinical benefit for understanding pathophysiologic processes associated with brain injury and memory impairment. This paper reviews the application of experimental animal models of brain injury for simulating conditions of stroke, trauma, and epilepsy (and/or seizure generation) and the associated cellular mechanisms of brain injury. The paper also briefly addresses the advantage of using computational models in combination with experimental models for hypothesis building and for aiding in the interpretation of empirical data. Finally, it reviews studies concerning brain injury and synaptic plasticity.     

Early exercise promotes positive hippocampal plasticity and improves spatial memory in the adult life of rats

There is a great deal of evidence showing the capacity of physical exercise to enhance cognitive function, reduce anxiety and depression, and protect the brain against neurodegenerative disorders. Although the effects of exercise are well documented in the mature brain, the influence of exercise in the developing brain has been poorly explored. Therefore, we investigated the morphological and functional hippocampal changes in adult rats submitted to daily treadmill exercise during the adolescent period. Male Wistar rats aged 21 postnatal days old (P21) were divided into two groups: exercise and control. Animals in the exercise group were submitted to daily exercise on the treadmill between P21 and P60. Running time and speed gradually increased over this period, reaching a maximum of 18 m/min for 60 min. After the aerobic exercise program (P60), histological and behavioral (water maze) analyses were performed. The results show that early-life exercise increased mossy fibers density and hippocampal expression of brain-derived neurotrophic factor and its receptor tropomyosin-related kinase B, improved spatial learning and memory, and enhanced capacity to evoke spatial memories in later stages (when measured at P96). It is important to point out that while physical exercise induces hippocampal plasticity, degenerative effects could appear in undue conditions of physical or psychological stress. In this regard, we also showed that the exercise protocol used here did not induce inflammatory response and degenerating neurons in the hippocampal formation of developing rats. Our findings demonstrate that physical exercise during postnatal development results in positive changes for the hippocampal formation, both in structure and function.     

Deep brain stimulation in the treatment of depression

Blomstedt P, Sjöberg RL, Hansson M, Bodlund O, Hariz MI. Deep brain stimulation in the treatment of depression. Objective: To present the technique of deep brain stimulation (DBS) and to evaluate the studies conducted on DBS in the treatment of therapy‐refractory major depressive disorder (MDD). Method: A review of the literature on DBS in the treatment of MDD was conducted. Results: The results of DBS in MDD have been presented in 2 case reports and 3 studies of 47 patients operated upon in 5 different target areas. Positive effects have been presented in all studies and side effects have been minor. DBS in the nucleus accumbens resulted in a mean reduction of Hamilton depression rating scale (HDRS) of 36% after 1 year and 30% of the 10 patients achieved remission. DBS in the internal capsule/ventral striatum resulted in a reduction of 44% after 1 year, and at the last evaluation after in mean 2 years, 40% of the 15 patients were in remission. The 20 patients with subcallosal cingulated gyrus DBS had a reduction of HDRS of 52% after 1 year, and 35% were within 1 point from remission or in remission. Conclusion: DBS is a promising treatment for therapy‐refractory MDD. The published experience is, however, limited, and the method is at present an experimental therapy.     

Representational cortical plasticity associated with brain tumours: evidence from laser-induced interstitial thermotherapy

OBJECTIVES: To test the hypothesis that cortical plasticity related to destructive tumour growth is functionally relevant. This hypothesis predicts that function is dependent on the intactness of tissue surrounding the tumour. MATERIAL AND METHODS: Eight patients underwent laser-induced interstitial thermotherapy (LITT) for minimally invasive palliative treatment of brain tumours located in eloquent frontal motor regions including the primary motor cortex. A multimodal approach was used to assess the functional outcome of patients after LITT in detail. RESULTS: Following LITT, motor function deteriorated in four patients. In three of these four patients the LITT-induced lesion involved minimal parts of adjacent non-tumorous tissue. By contrast, the other four patients whose LITT-induced signal changes were confined to the tumour, showed no functional deficits. CONCLUSION: These findings support the idea that peri-tumorous neuronal circuitry in motor competent areas may permanently take over those functions that were formerly represented in the neuronal tissue destroyed by the tumour.     

8-hydroxy-dipropylaminotetralin promotes neural plasticity in epileptic rats with depression

Rats with chronic pilocarpine-induced temporal lobe epilepsy complicated with depression were studied. Anti-5-bromodeoxyuridine immunofluorescence staining and Timms staining showed that neurogenesis within the hippocampal dentate gyrus and mossy fiber sprouting were increased in model rats. Neurogenesis within the hippocampal dentate gyrus was further enhanced, while mossy fiber sprouting was decreased in model rats administered carbamazepine alone or in combination with the 5-hydroxytryptamine 1A receptor agonist, 8-hydroxy-dipropylaminotetralin (0.1 and 1 mg/kg). Among the groups, the effect was the most significant in rats receiving carbamazepine in conjunction with 1 mg/kg 8-hydroxy-dipropylaminotetralin. Thus, high dose 8-hydroxy-dipropylaminotetralin can improve neural plasticity in epileptic rats with depression.     

Exercise improves recognition memory and synaptic plasticity in the prefrontal cortex for rats modelling vascular dementia

Objectives: Functional electrical stimulation (FES) may induce involuntary exercise and make beneficial effects on vascular dementia (VD) by strengthening the BDNF-pCREB-mediated pathway and hippocampal plasticity. Whether FES improves recognition memory and synaptic plasticity in the prefrontal cortex (PFC) was investigated by establishing a VD model.

Methods: The VD rats were administered with two weeks of voluntary exercise, forced exercise, or involuntary exercise induced with FES. Sham-operated and control groups were also included. The behavioral changes were assessed with the novel object recognition test and novel object location test. The expression levels of key proteins related to synaptic plasticity in the PFC were also detected.

Results: All types of exercise improved the rats’ novel object recognition index, but only voluntary exercise and involuntary exercise induced with FES improved the novel object location index. Any sort of exercise enhanced the expression of key proteins in the PFC.

Conclusion: Involuntary exercise induced with FES can improve recognition memory in VD better than forced exercise. The mechanism is associated with increased synaptic plasticity in the PFC. FES may be a useful alternative tool for cognitive rehabilitation.     

Altered protein markers related to neural plasticity and motor function following electro-acupuncture treatment in rat model of ischemic-hypoxic brain injury

BACKGROUND: Previous studies have demonstrated that acupuncture treatment could ameliorate impaired motor function, and these positive effects might be due to neural plasticity. OBJECTIVE: Myelin basic protein (MBP), microtubule-associated protein 2 (MAP2), growth-associated protein-43 (GAP-43), and synaptophysin (SYN) were selected as markers of neural remodeling, and expression of these markers was evaluated with regard to altered motor function following brain injury and acupuncture treatment. DESIGN, TIME AND SETTING: A completely randomized experiment was performed at the Central Laboratory of Peking University First Hospital from November 2006 to May 2007. MATERIALS: Twenty-four Sprague Dawley rat pups, aged 7 days, were selected for the present experiment. The left common carotid artery was ligated to establish a rat model of ischemic-hypoxic brain injury.METHODS: All animals were randomly divided into three groups: sham operation, model, and electro-acupuncture treatment, with 8 rats in each group. Rats in the model and electro-acupuncture treatment group underwent establishment of ischemic-hypoxic brain injury. Upon model established, rats underwent hypobaric oxygen intervention for 24 hours. Only the left common carotid artery was exposed in rats of the sham operation group, without model establishment or oxygen intervention. The rats in the electro-acupuncture treatment group were treated with electro-acupuncture. One acupuncture needle electrode was inserted into the subcutaneous layer at the Baihui and Dazhui acupoint. The stimulation condition of the electro-acupuncture simulator was set to an amplitude-modulated wave of 0-100% and alternative frequency of 100 cycles/second, as well as frequency-modulated wave of 2-100 Hz and an alternative frequency of 3 cycles/second. Maximal current through the two dectrodes was limited to 3-5 mA. The stimulation lasted for 30 minutes per day for 2 weeks. Rats in the sham operation and model groups were not treated with electro-acupuncture, but only fixed to the table for the same time period. MAIN OUTCOME MEASURES: After 2 weeks stimulation, expression of MBP, MAP2, GAP-43, and SYN were detected in the brain by immunohistochemistry. Motor function was evaluated in the three groups. RESULTS: In the sham operation group, MBP was abundant in the myelinated nerve fibers. In the electro-acupuncture treatment group, however, the corpus callosum exhibited more MBP staining than the model group. MAP2 expression was increased in the model group, and increased further in the electro-acupuncture treatment group compared with the sham operation group. GAP-43 expression in the cerebral cortex was less in model group than in sham operation, but present in abundance in the electro-acupuncture treatment group. SYN expression in the cerebral cortex was less in the model and electro-acupuncture treatment group compared with the sham operation group. There was no significant difference in SYN expression and distribution between the model and electro-acupuncture treatment groups. Motor function of rats in the electro-aeapuncture treatment group was significantly better than the model group (P < 0.05), although function remained lower than the sham operation group (P < 0.05). CONCLUSION: Two weeks of electro-acupuncture treatment improved motor function in rats, and protein markers related to neural plasticity also changed, which may be a mechanism for improved motor function in rats with ischemic-hypoxic brain injury.     

抑郁症与脑肿瘤患者认知状况比较分析

目的 探讨抑郁症及不同脑叶肿瘤患者在认知损伤方面的异同,推测抑郁症患者脑功能缺陷与各脑叶损伤间的关系。方法 运用威斯康星卡片分类测验(WCST)、词汇流畅性测验(VFT)、Stroop测验(CWT),对抑郁症40例,脑肿瘤88例(包括额叶48、颞叶20、顶枕叶20)患者和正常对照组30人,进行测查,并对不同组别的各测查指标进行比较分析。结果 与正常对照组相比,抑郁症、各脑叶肿瘤患者均存在不同程度、不同特征的认知损伤,其中抑郁症组与额叶肿瘤组损伤类似,两者的WCST及VFT操作的各个指标间无显著差异(P>0.05)。结论 抑郁症患者大脑额叶功能受损明显。     

Abnormal cortical and brain stem plasticity in Gilles de la Tourette syndrome

We investigated primary motor cortex and brain stem plasticity in patients with Gilles de la Tourette syndrome. The study group comprised 12 patients with Gilles de la Tourette syndrome and 24 healthy subjects. Patients were clinically evaluated using the Yale Global Tic Severity Scale. We tested cortical plasticity by conditioning left primary motor cortex with intermittent or continuous theta‐burst stimulation in 2 separate sessions. Test stimulation consisted of 20 motor‐evoked potentials recorded from right first interosseous muscle before and after theta‐burst stimulation. We also tested brain stem plasticity by conditioning the right supraorbital nerve with facilitatory electric high‐frequency stimulation delivered at the same time as the late response of the blink reflex or inhibitory high‐frequency stimulation delivered before the late response on 2 separate sessions. Test stimulation consisted of 10 blink reflexes from the right orbicularis oculi muscle before and after high‐frequency stimulation. After intermittent theta‐burst stimulation, motor‐evoked potential amplitudes in healthy subjects increased significantly but remained unchanged in patients. Similarly, after continuous theta‐burst stimulation, motor‐evoked potential amplitudes decreased significantly in healthy subjects but did not in patients. After facilitatory high‐frequency stimulation, the blink reflex late response area in healthy subjects increased, whereas after inhibitory high‐frequency stimulation, it decreased. Conversely, in patients, both interventions left the blink reflex late response area unchanged. The lack of the expected inhibitory and facilitatory changes in motor‐evoked potential amplitudes and blink reflex late response area suggests that abnormal plasticity in the primary motor cortex and brain stem play a role in the pathophysiology of Gilles de la Tourette syndrome. © 2011 Movement Disorder Society     

Rapid-onset antidepressant efficacy of glutamatergic system modulators:The neural plasticity hypothesis of depression

Depression is a devastating psychiatric disorder widely attributed to defi cient monoaminergic signaling in the central nervous system. However,most clinical antidepressants enhance monoaminergic neurotransmission with little delay but require 4-8 weeks to reach therapeutic efficacy,a paradox suggesting that the monoaminergic hypothesis of depression is an oversimplifi cation. In contrast to the antidepressants targeting the monoaminergic system,a single dose of the N-methyl-D-aspartate receptor(NMDAR) antagonist ketamine produces rapid(within 2 h) and sustained(over 7 days) antidepressant effi cacy in treatment-resistant patients. Glutamatergic transmission mediated by NMDARs is critical for experience-dependent synaptic plasticity and learning,processes that can be modifi ed indirectly by the monoaminergic system. To better understand the mechanisms of action of the new antidepressants like ketamine,we review and compare the monoaminergic and glutamatergic antidepressants,with emphasis on neural plasticity. The pathogenesis of depression may involve maladaptive neural plasticity in glutamatergic circuits that may serve as a new class of targets to produce rapid antidepressant effects.     

卒中后抑郁与脑卒中患者载脂蛋白E水平对照研究

目的:探讨卒中后抑郁(PSD)患者载脂蛋白E(ApoE)水平特点,为PSD的诊断提供新的客观依据。方法:采用实时荧光定量PCR技术和酶联免疫吸附法(ELISA)检测PSD患者及卒中后非抑郁患者ApoE水平。结果:PSD组ApoE基因mRNA表达量低于卒中组,差异具有统计学意义(P<0.01);PSD组血清ApoE水平高于卒中组,差异具有统计学意义(P<0.05)。结论:PSD患者外周血ApoE基因mRNA表达和血清ApoE水平与卒中非抑郁患者不同。     

The selective noradrenergic reuptake inhibitor reboxetine restores spatial learning deficits,biochemical changes,and hippocampal synaptic plasticity in an animal model of depression

Depression is a major psychiatric illness that is associated with cognitive dysfunctions. The underlying mechanism of depression‐associated memory impairment is unclear. Previously, we showed altered hippocampal synaptic plasticity in an animal model of depression. Although several antidepressants are beneficial in the treatment of depression, very little is known about the effects of these drugs on depression‐associated learning and memory deficits. Prolonged antidepressant treatment might contribute to neuroplastic changes required for clinical outcomes. Accordingly, we evaluated the effect of chronic reboxetine (a selective noradrenergic reuptake inhibitor) treatment on depression‐induced reduced hippocampal synaptic plasticity, neurotransmitter levels, and spatial learning and memory impairments. Depression was induced in male Wistar rats by the administration of clomipramine from postnatal days 8 to 21, and these rats were treated with reboxetine in adulthood. The neonatal clomipramine administration resulted in impaired hippocampal long‐term potentiation (LTP), decreased hippocampal cholinergic activity and monoamine levels, and poor performance in a partially baited eight‐arm radial maze task. Chronic reboxetine treatment restored the hippocampal LTP, acetylcholinesterase activity, and levels of biogenic amines and ameliorated spatial learning and memory deficits in the depressed state. Thus, restoration of hippocampal synaptic plasticity might be a cellular mechanism underlying the beneficial effect of reboxetine in depression‐associated cognitive deficits. This study furthers the existing understanding of the effects of antidepressants on learning, memory, and synaptic plasticity and could ultimately assist in the development of better therapeutic strategies to treat depression and associated cognitive impairments. © 2014 Wiley Periodicals, Inc.     

Exercise normalizes levels of MAG and Nogo-A growth inhibitors after brain trauma

Myelin is a major obstacle for axonal growth after CNS injury, to the extent that it is crucial to develop interventions to counteract postinjury growth inhibition and foster neural repair. We have studied the effects of the fluid percussion injury (FPI) model of traumatic brain injury (TBI) on protein levels of two myelin-associated molecules, myelin-associated glycoprotein (MAG) and Nogo-A, in the adult rat. We found that FPI elevated hippocampal levels of MAG and Nogo-A. Given the beneficial effects of exercise on CNS function, we evaluated the capacity of exercise to reduce these myelin-derived proteins after FPI. One week of voluntary running wheel exercise overcame the injury-related increase in MAG and Nogo-A. The action of brain-derived neurotrophic factor (BDNF) has been associated with exercise as well as with the modulation of growth inhibition in vitro . We found that the selective blockade of BDNF using the immunoadhesive chimera TrkB-IgG abolished the effects of exercise on MAG and Nogo-A. FPI reduced levels of growth-associated protein 43 (GAP-43), a marker of axonal growth, and synaptophysin (SYP), an indicator of synaptic growth. Exercise counteracted the effects of FPI on GAP-43 and SYP, while BDNF blockade abolished these effects of exercise. Protein kinase A (PKA) has been related to the ability of BDNF to overcome growth inhibition. In agreement, we found that exercise increased PKA levels and this effect was prevented by BDNF blockade. These results indicate that exercise promotes a permissive cellular environment for repair after TBI, in a process in which BDNF plays a central role.