Multisensory stimulation in stroke rehabilitation.

The brain has a large capacity for automatic simultaneous processing and integration of sensory information. Combining information from different sensory modalities facilitates our ability to detect, discriminate, and recognize sensory stimuli, and learning is often optimal in a multisensory environment. Currently used multisensory stimulation methods in stroke rehabilitation include motor imagery, action observation, training with a mirror or in a virtual environment, and various kinds of music therapy.

The sigma-1 receptor enhances brain plasticity and functional recovery after experimental stroke.

Stroke leads to brain damage with subsequent slow and incomplete recovery of lost brain functions. Enriched housing of stroke-injured rats provides multi-modal sensorimotor stimulation, which improves recovery, although the specific mechanisms involved have not been identified. In rats housed in an enriched environment for two weeks after permanent middle cerebral artery occlusion, we found increased sigma-1 receptor expression in peri-infarct areas.

Cultural and linguistic influence on brain organization for language and possible consequences for dyslexia: a review.

Current neuroimaging and neurophysiologic techniques have substantially increased our possibilities to study processes related to various language functions in the intact human brain. Learning to read and write influences the functional organization of the brain. What is universal and what is specific in the languages of the world are important issues.

Regeneration and plasticity in the brain and spinal cord.

The concept of brain plasticity covers all the mechanisms involved in the capacity of the brain to adjust and remodel itself in response to environmental requirements, experience, skill acquisition, and new challenges including brain lesions. Advances in neuroimaging and neurophysiologic techniques have increased our knowledge of task-related changes in cortical representation areas in the intact and injured human brain. The recognition that neuronal progenitor cells proliferate and differentiate in the subventricular zone and dentate gyrus in the adult mammalian brain has raised the hope that regeneration may be possible after brain lesions.

On neural plasticity, new neurons and the postischemic milieu: an integrated view on experimental rehabilitation.

This review discusses actual and potential contributors to functional improvement after stroke injuries. Topics that will be covered are neuronal re-organization and sprouting, neural stem/progenitor cell activation and neuronal replacement, as well as the neuronal milieu defined by glia, inflammatory cells and blood vessel supply. It is well established that different types of neuronal plasticity ultimately lead to post-stroke recovery.

Enriched environment after focal cortical ischemia enhances the generation of astroglia and NG2 positive polydendrocytes in adult rat neocortex.

Environmental enrichment (EE) alleviates sensorimotor deficits after brain infarcts but the cellular correlates are not well-known. This study aimed to test the effects of postischemic EE on neocortical cell genesis. A neocortical infarct was caused by distal ligation of the middle cerebral artery in adult spontaneously hypertensive rats, subsequently housed in standard environment or EE.

Postischemic exercise attenuates whereas enriched environment has certain enhancing effects on lesion-induced subventricular zone activation in the adult rat.

Experimental stroke increases cell proliferation and neurogenesis in the subventricular zone (SVZ) and in the dentate gyrus subgranular zone (SGZ) in the adult mammalian brain. This study examined the effects of postischemic voluntary exercise (running wheel) and environmental enrichment on the SVZ and SGZ 1 week after focal cortical ischemia in adult spontaneously hypertensive rats. Immunohistochemical labeling was performed for incorporation of specific cell markers such as Ki67 and 5-bromodeoxyuridine (proliferating and newborn cells), terminal deoxynucleotidyl transferase-mediated dUTP in situ nick-end labeling (apoptotic cells), Sox-2 and glial fibrillary acidic protein (neural stem and progenitor cells), polysialylated neural cell adhesion molecule and doublecortin (neuroblasts).

Enriched environment increases neural stem/progenitor cell proliferation and neurogenesis in the subventricular zone of stroke-lesioned adult rats.

Background And Purpose: The subventricular zone in the adult brain is identified as an endogenous resource of neuronal precursors that can be recruited to adjacent lesioned areas. The hypothesis was tested that postischemic environmental enrichment might enhance subventricular zone cell genesis.

Methods: A cortical infarct was induced in adult spontaneously hypertensive rats by ligating the middle cerebral artery distal to the striatal branches, after which animals were housed in either standard or enriched environment and allowed to survive for 5 weeks.

Brain plasticity in health and disease.

Research during the last decades has greatly increased our understanding of brain plasticity, i.e. how neuronal circuits can be modified by experience, learning and in response to brain lesions.

Functional and cellular effects of environmental enrichment after experimental brain infarcts.

Our genes interact with environmental stimuli throughout our lives. The attitude and reaction to an acute cerebral trauma or stroke, as well as the pre-lesion life event and activities, can influence functional outcome. Although difficult to separate in adult human beings, genetic and environmental factors can be selectively evaluated in animal studies.

Enriched environment influences adrenocortical response to immune challenge and glutamate receptor gene expression in rat hippocampus.

Housing of animals in an enriched environment (EE) has many positive effects on brain structure and function and can facilitate recovery from various brain injuries. The purpose of this study was to evaluate whether enriched rearing could alter the stress response induced by repeated immune challenge and to investigate the influence of EE and immune challenge on glutamate receptor gene expression in the hippocampus. Male 2-mo-old Wistar rats were kept under standard conditions (SC) or in an EE for 5 weeks.

Environmental influence on recovery after brain lesions--experimental and clinical data.

One aim of rehabilitation after brain lesions should be to optimise the function of the remaining intact brain. Experimental studies on focal cerebral infarcts in the rat have demonstrated that postischemic environmental enrichment significantly improves functional outcome, increases dendrite branching and number of dendritic spines in the contralateral cortex, influences expression of many genes and modifies lesion-induced stem cell differentiation in the hippocampus. Furthermore, environmental factors can interact with specific interventions such as necrotic grafting and drug treatment, which underlines the importance of general stimulation and activation in rehabilitation after brain damage.

Effects of cortical ischemia and postischemic environmental enrichment on hippocampal cell genesis and differentiation in the adult rat.

The study aimed to elucidate the effects of cortical ischemia and postischemic environmental enrichment on hippocampal cell genesis. A cortical infarct was induced by a permanent ligation of the middle cerebral artery distal to the striatal branches in 6-month-old spontaneously hypertensive rats. Bromodeoxyuridine (BrdU) was administered as 7 consecutive daily injections starting 24 hours after surgery and animals were housed in standard or enriched environment.

Environmental influences on functional outcome after a cortical infarct in the rat.

The effect of postoperative housing conditions on functional outcome and brain-derived neurotrophic factor (BDNF) gene expression was evaluated 1 month after a distal ligation of the right middle cerebral artery (MCA) in spontaneously hypertensive rats. Two days postoperatively the rats were randomized into four groups; individually housed with no equipment (deprived group), individually housed with free access to a connected running wheel (running group), housed together in a large cage with no equipment (social group) or in the same size of cage furnished with bars, chains and various things to manipulate (enriched group). The enriched rats had significantly higher scores when crossing a rotating horizontal rod than deprived and running rats.

Neuronal plasticity and dendritic spines: effect of environmental enrichment on intact and postischemic rat brain.

The authors compared the influence of environmental enrichment on intact and lesioned brain, and tested the hypothesis that postischemic exposure to an enriched environment can alter dendritic spine density in pyramidal neurons contralateral to a cortical infarct. The middle cerebral artery was occluded distal to the striatal branches in spontaneously hypertensive rats postoperatively housed either in a standard or in an enriched environment. Intact rats were housed in the same environment.