Restorative Neurology and Neuroscience - Volume 22, issue 3-5

Authors: Platz, T.

Article Type: Other

Citation: Restorative Neurology and Neuroscience, vol. 22, no. 3-5, pp. 137-142, 2004

Authors: Kaas, Jon H. | Qi, Hui-Xin

Article Type: Research Article

Abstract: As a result of an extensive search, we were able to obtain a limited number of macaque monkeys, New World squirrel monkeys, and prosimian galagos years after they had received a therapeutic amputation of a forelimb or hindlimb as a treatment for injury. Forelimb or hindlimb regions of primary motor cortex, M1, were stimulated in these primates with microelectrodes using amounts of current just sufficient to evoke a movement. Results were compared to those obtained from …normal primates or from M1 contralateral to the intact limb in the same primates. In all cases, more sites in M1 contralateral to the amputated limb evoked movements of the limb stump and muscle in the adjoining shoulder or hip. In two of the macaque monkeys, injections in M1 reveal more widespread intrinsic connections than in normal M1, and in several monkeys and galagos, injections of tracers in muscles of the stump, shoulder, or hip labeled spinal cord motor neurons that normally project to the distal limb. These anatomical results suggest that the functional changes in M1 following amputation are mediated in part by the formation of new connections. Show more

Citation: Restorative Neurology and Neuroscience, vol. 22, no. 3-5, pp. 145-152, 2004

Authors: Woodlee, Martin T. | Schallert, Timothy

Article Type: Research Article

Abstract: The effects of extreme disuse or overuse of the limbs in rat models of Parkinson's disease and stroke are discussed. In unilaterally lesioned rats, immobilizing one forelimb in a cast forces complete disuse of this limb and extreme overuse of the uncasted limb. This procedure has diverse effects on histological and behavioral outcomes in these models, depending upon how and when it is applied relative to the lesion. Effects on behavioral outcome, post-lesion plasticity events, and …expression of trophic factors are discussed. The effects of forced disuse or overuse vary among lesion types and can include neuroprotection, changes in synaptogenesis, or even exaggeration of tissue loss. The diversity of behavior-driven structural changes in the brain underscores the potential importance of carefully tailoring physical restorative therapy to specific neurological problems in order to optimize outcomes. In addition, we stress the need to recognize the reciprocal influence that behavior and the brain can have upon each other. Show more

Keywords: Parkinson's disease, stroke, constraint therapy, trophic factors, rehabilitation, casting, use-dependency, plasticity

Citation: Restorative Neurology and Neuroscience, vol. 22, no. 3-5, pp. 153-161, 2004

Authors: Johansson, Barbro B.

Article Type: Research Article

Abstract: 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. Post- ischemic housing in an enriched environment, i.e. larger cages which allow both social interaction and various activities improves functional outcome, modifies gene …activation, and increases dendrite branching and number of dendritic spines in pyramidal neurons in layers II-III in the contra-lateral cortex. Furthermore, it alters lesion-induced progenitor cell differentiation and interacts with neocortical transplantation, drug treatment and training. It is proposed that the interaction between environment and specific treatment needs more clinical attention, and that a general stimulating and positive environment is the optimal base for specific interventions in neurological rehabilitation. Show more

Keywords: brain infarcts, dendritic spines, gene activation, progenitor cell differentiation, neocortical transplantation, plasticity, spontaneously hypertensive rats, stroke

Citation: Restorative Neurology and Neuroscience, vol. 22, no. 3-5, pp. 163-174, 2004

Authors: Feeney, Dennis M. | De Smet, Ayshea M. | Rai, Seema

Article Type: Research Article

Abstract: This review presents data from laboratory studies and clinical trials indicating the efficacy of the "Noradrenergic Strategy" for enhancing recovery after cortical injury. Short-term acute treatment combining Physical Therapy (PT) with drugs increasing noradrenaline (NA) levels enhances recovery of hemiplegia in both laboratory studies and clinical trials which also report improved aphasia recovery. Importantly these effects endure even when treatment is initiated months after stroke onset. The hypothesized mechanisms included modulation of …neuronal processes underlying "spontaneous" recovery since drugs reducing NA levels slow spontaneous recovery. The effect of some drugs change with time after sensorimotor cortex (SMCx) injury. Drugs reducing NA levels, including clonidine and prazosin, and GABA receptor agonists at doses having little effect early after injury, when administered to animals or stroke patients after "complete recovery" transiently reinstate the original symptoms. Reinstatement by prazosin remains unchanged after repeated testing for over six months in rat, and the deficits can be as severe as the first days after injury. This suggests "completed" recovery is an inaccurate label for an enduring "fragile" state. This transient reinstatement of symptoms may be useful for distinguishing causal from corollary relationships between symptoms and physiological processes proposed as mechanisms for recovery of function. Show more

Keywords: noradrenaline, norepinephrine, recovery of function, rehabilitation, brain injury, diaschisis

Citation: Restorative Neurology and Neuroscience, vol. 22, no. 3-5, pp. 175-190, 2004

Authors: Rossini, Paolo M. | Forno, Gloria Dal

Article Type: Research Article

Abstract: Contrary to what previously believed, recent research advances have demonstrated that the adult brain has a certain capacity for plastic reorganization and self-repair after a lesion such as cerebrovascular accidents. The mechanisms subtending post-stroke recovery are probably complex and operating at different levels, from molecular to synaptic to anatomical reorganization. The integrated use of functional neuroimaging techniques, by overcoming the limitations of each specific methodology is likely to shed much light on …plasticity mechanisms. In this review we discuss the neuroanatomy and neurophysiology possibly underlying reorganization of the central nervous system, as well as the experimental evidence of "in vivo" post-stroke plasticity. Better understanding of these mechanisms can provide neurorehabilitation with powerful tools in designing and implementing new therapeutic approaches to stroke patients both in the acute and the chronic stages after a brain tissue lesion has occurred and stabilized. Show more

Keywords: plasticity, post-stroke recovery, integrated functional neuroimaging, TMS, MEG

Citation: Restorative Neurology and Neuroscience, vol. 22, no. 3-5, pp. 193-206, 2004

Authors: Seitz, Rüdiger J. | Bütefisch, Cathrin M. | Kleiser, Raimund | Hömberg, Volker

Article Type: Research Article

Abstract: Animal experiments suggest that reorganisation of cerebral representations is the neurobiological basis of post-lesional recovery. In human ischemic brain disease recovery is a dynamic and sustained process beginning after stroke manifestation. The mechanisms underlying recovery can be investigated non-invasively in the human brain using functional neuroimaging and transcranial magnetic stimulation (TMS). In the acute stage, the mismatch area of the perfusion deficit and the impaired water diffusion as assessed by magnetic resonance imaging (MRI) …shows the brain tissue that potentially can be rescued by thrombolysis or emergency carotid endarteriectomy. Since spontaneous motor recovery is a function of the corticospinal tract integrity, early reperfusion of ischemic tissue is critical. In the subacute and chronic stage after stroke, recovery of motor function was shown to take place irrespective of a concomitant affection of the somatosensory system. Functional MRI with simultaneous recordings of the electromyogram provides evidence that the abnormal activation of motor and premotor cortical areas in both hemispheres related to finger movements has a large interindividual variability. As evident from TMS, recovery results from regression of perilesional inhibition and from remote intracortical disinhibition. Repetitive training, constraint induced training and motor imagery can augment recovery promoting a re-emerging activation in the affected hemisphere. Evolution of altered local perilesional and large-scale bihemispheric circuits appears to allow for post-lesional deficit compensation. Show more

Keywords: stroke, plasticity, recovery, motor system, functional neuroimaging, lesion morphometry, transcranial magnetic stimulation, perfusion weighted imaging, diffusion weighted imaging

Citation: Restorative Neurology and Neuroscience, vol. 22, no. 3-5, pp. 207-229, 2004

Authors: Cramer, Steven C.

Article Type: Research Article

Abstract: Motor system impairments are common after stroke and are a major contributor to disability after stroke. Most patients show improvement in the weeks-months following a stroke. Understanding the neurobiological underpinnings of these behavioral gains may be useful for refining treatments that aim to improve outcome and reduce disability. A number of brain mapping studies have examined how stroke affects motor system function. Numerous changes have been identified in this setting and are reviewed herein, including …reduced laterality, widespread changes across a distributed sensorimotor network, and a change in the site and size of key activation foci. Some of these changes have been found to correlate with features of injury, behavior, or treatment-induced behavioral gains. A current challenge is to extend these findings to improve clinical decision making. Show more

Keywords: functional MRI, stroke, recovery, motor, plasticity

Citation: Restorative Neurology and Neuroscience, vol. 22, no. 3-5, pp. 231-238, 2004

Authors: Nelles, Gereon

Article Type: Research Article

Abstract: Recovery from hemiparesis after stroke largely depends on widespread functional and structural neuronal plasticity. Based on animal studies of rehabilitative and pharmacological interventions on recovery, recent neuroscientific findings suggest that new rehabilitative interventions may also have benefits by modulating neuroplastic mechanisms in stroke patients. Neurofunctional imaging methods such as Positron Emission Tomography (PET) and functional Magnetic Resonance Imaging (fMRI) as well as transcranial magnetic stimulation (TMS) now permit direct studies of training-induced …plasticity in stroke patients. Prospectively conducted studies using these techniques have investigated how plasticity relates to recovery of motor function and how intensive training modulates cortical reorganization. Despite technical and methodological differences, consistent neuroanatomic findings on training-induced reorganization of the motor system have been reported. These discoveries have important implications for the future development of neurorehabilitative training methods. With continuously improving methods to study cortical reorganization and over 100 randomized clinical trials on stroke rehabilitation published during the past five years, this promises to be an exciting time in stroke rehabilitation research. Show more

Keywords: cortical reorganization, plasticity, neurorehabilitation, stroke, PET, fMRI

Citation: Restorative Neurology and Neuroscience, vol. 22, no. 3-5, pp. 239-244, 2004

Authors: Matthews, P.M. | Johansen-Berg, H. | Reddy, H.

Article Type: Research Article

Abstract: Modern cognitive neuroscience provides a powerful framework in which biological models of recovery and neurorehabilitation can be constructed and tested. The widespread availability, relatively low cost and informativeness of functional magnetic resonance imaging (fMRI) has made it the most popular of the techniques available to help with this task. Here, on the basis of functional imaging studies of stroke, diffuse microvascular disease and multiple sclerosis, we argue that processes of motor control and learning in …the healthy brain share common mechanisms with those for adaptive functional reorganisation during spontaneous recovery after brain injury or with neurorehabilitation. Relatively stringent criteria can be met to confirm that adaptive functional reorganisation limits disability even in the adult brain: functional brain changes are related to disease burden, can be found in patients with demonstrable pathology but no clinical deficits and can be defined (in motor cortex) even in the absence of volitional recruitment. Initial studies of neurorehabilitation responses using fMRI and transcranial magnetic stimulation demonstrate that adaptive reorganisation can be manipulated directly with both pharmacological and behavioural interventions. The combination of strategies based on a strong biological rational with monitoring their effects using highly informative functional brain imaging methods heralds a new era of scientifically-founded neurorehabilitation. Show more

Keywords: FMRI, neurorehabilitation, learning, transcranial magnetic stimulation, motor control

Citation: Restorative Neurology and Neuroscience, vol. 22, no. 3-5, pp. 245-260, 2004