Sensorimotor systems are not rigidly wired predetermined networks but rather highly plastic structures that learn and modify their entire performance in response to changes in external or internal conditions. Lesions or distortions of the system's input, which initially cause a functional disorganization, induce an active reorganization which often leads to a recovery of function. Examples of lesion-induced neural plasticity have been known for some hundred years; however, an awareness of their value as research tools is relatively new. This current interest is a consequence of rapid ly changing ideas concerning the nature of CNS organization. Out of these, concepts are emerging which describe neural nets as modifiable, highly dynamic, self-organizing structures. This trend is clearly reflected in this volume, which contains the proceedings of a symposium held in Bremen in July 1980 as a satellite meeting of the XXVIIIth International Congress of Physiological Sciences. The first part of this conference was devoted to some gen eral aspects of plasticity, discussing the current theories of functional recovery as well as morphological, neurochemical, physiological, molecular, and ontogenetic aspects. The second part dealt with lesion induced plasticity in specific sensorimotor systems of the spinal cord, brain stem, and cerebral cortex.
Neural networks are not rigidly wired but rather highly plastic structures, the functional architecture of which can be actively reorganized in response to external or internal events. Lesions of such networks induce plastic processes which in time may lead to a recovery of the initially disrupted function. This type of neural plasticity is the main focus of the book, which presents a broad spectrum of experimental paradigms for lesion-induced plasticity as in the spinal cord, the vestibular, oculomotor, visual and olfactory system, the cerebellum and the cerebral cortex, including recent methodological developments. Concepts and perspectives in understanding neural plasticity are reported in reviews and original research reports and are thoroughly discussed.
Neural networks are not rigidly wired but rather highly plastic structures, the functional architecture of which can be actively reorganized in response to external or internal events. Lesions of such networks induce plastic processes which in time may lead to a recovery of the initially disrupted function. This type of neural plasticity is the main focus of the book, which presents a broad spectrum of experimental paradigms for lesion-induced plasticity as in the spinal cord, the vestibular, oculomotor, visual and olfactory system, the cerebellum and the cerebral cortex, including recent methodological developments. Concepts and perspectives in understanding neural plasticity are reported in reviews and original research reports and are thoroughly discussed.
Traumatic brain injury (TBI) remains a significant source of death and permanent disability, contributing to nearly one-third of all injury related deaths in the United States and exacting a profound personal and economic toll. Despite the increased resources that have recently been brought to bear to improve our understanding of TBI, the developme
Synthesizing current information about sensory-motor plasticity, Neural Plasticity in Adult Somatic Sensory-Motor Systems provides an up-to-date description of the dynamic processes that occur in somatic sensory-motor cortical circuits or somatic sensory pathways to the cortex due to experience, learning, or damage to the nervous system. The book e
Over the last twenty years there has been an explosive growth in our understanding of the molecular, cellular, and anatomical changes that occur in the days and weeks following brain injury. It is now clear that training and exposure to certain environments can modify and shape neuronal plasticity in lower animals and humans. In humans, in particular, there are new ways of charting neuronal plasticity at the ensemble or regional level using functional neuroimaging techniques such as positron emission tomography and functional magnetic resonance imaging. Thus, the time seems right for transporting the laboratory results to the clinic so that experimental findings can be tested in the "field". This volume provides some impetus to moving the field of cognitive neuroscience a little further in its efforts to improve the lives of patients who have suffered a debilitating brain injury.
It is now well known that the functional organisation of the cerebral cortex is plastic and that changes in organisation occur throughout life in response to normal and abnormal experience. Transcranial magnetic stimulation (TMS) is a non-invasive and painless technique that has opened up completely new and fascinating avenues to study neural plasticity. First, TMS can be used to detect changes in excitability or connectivity of the stimulated cortex which may have occurred through processes such as learning or recovery from a lesion. Second, repeated TMS by itself can induce changes in excitability and connectivity of the stimulated cortex which may be used therapeutically in neurological and psychiatric disease. Third, TMS can induce short-lasting 'virtual lesions', which may directly test the functional relevance of brain plasticity. Current knowledge of all these exciting possibilities is brought together in this book, written by the world's leading experts in the field. The book is an essential compendium on plasticity of the human brain for clinical neurophysiologists, neurologists, psychiatrists and neuroscientists.
"Research on plasticity in motor systems has for the most part developed separately from work on sensory plasticity, as if training-induced changes to the brain affected each of these systems in isolation. The aim of this thesis is to explore the association between the sensory and motor systems when a new skill is acquired. The experiments reported in this dissertation systematically examine two hypotheses about neuroplasticity: (i) that motor learning changes perceptual function and the function of somatosensory areas of the brain, and (ii) that somatosensory training changes both motor function and motor areas of the brain. The first study aimed at providing a unified approach to test the first hypothesis. We combined both psychophysical and neuroimaging procedures to examine the connection between changes in the behavior and brain as a result of motor learning. We used a dynamics adaptation task as a model of motor learning in conjunction with somatosensory discrimination of the limb's movement direction which permits quantification of perceptual changes that occurs in conjunction with motor learning. We used functional magnetic resonance imaging (fMRI) to calculate measures of functional connectivity during resting-state periods following learning. This technique allowed us to study longer lasting plasticity in the sensorimotor system, during the period in which the motor memory is being consolidated. We developed a new hypothesis-driven technique which enables us to incorporate psychophysical measures in functional connectivity analysis to identify behaviorally-related neuroplasticity as a result of learning. Using this technique, we identified a new network in motor learning involving second somatosensory cortex, ventral premotor cortex and supplementary motor area whose activation is specifically related to perceptual changes that occur in conjunction with motor learning. Subjects who showed greater change in functional connectivity within this network, also showed a greater change in perceptual function. In study two, we proposed and implemented a new analytic data-driven method based on independent component analysis (ICA), which enabled us to systematically extract and classify shared and condition-specific networks corresponding to the pre-learning and post-learning conditions. The proposed algorithm was specifically designed to solve the problems of the regular ICA approach in conducting between-condition comparisons. Using this method we identified a specific network corresponding to the post-learning condition comprising clusters in contralateral superior parietal lobule, second somatosensory cortex, premotor cortex, and supplementary motor area. The third study was aimed at testing the second hypothesis described above. Using similar procedures and techniques to those used in the first study, we found that somatosensory discrimination training combined with periods of passive movement as short as 45 minutes increased functional connectivity between sensory and motor areas of the brain and, importantly, in motor areas alone. In behavioral terms, somatosensory training facilitates motor learning. Improvements were seen in both the rate and extent of learning and they persisted for at least one day. Sensory repetition without perceptual learning was less able to induce plasticity in the motor system. This suggests that somatosensory training can induce reorganization in the motor system and benefits from cognitive involvement and skill acquisition in the sensory domain. Overall, our studies point to a unified model of sensorimotor plasticity in which the effects of learning are not local to either sensory or motor systems, but rather each has effects that spread into functionally related areas of the brain beyond the base modality." --
Brain plasticity is the focus of a growing body of research with significant implications for neurorehabilitation. This state-of-the-art volume explores ways in which brain-injured individuals may be helped not only to compensate for their loss of cognitive abilities, but also possibly to restore those abilities. Expert contributors examine the extent to which damaged cortical regions can actually recover and resume previous functions, as well as how intact regions are recruited to take on tasks once mediated by the damaged region. Evidence-based rehabilitation approaches are reviewed for a range of impairments and clinical populations, including both children and adults.
Rarely have the many mechanisms that might underlie neural plasticity been examined as explicitly as they are in this broad, lavishly illustrated treatment of plasticity in the somatosensory system. The reader is provided with state-of-the-art knowledge of connections at all levels of the somatosensory system. The authors examine the propensity for changes of connectivity in both the mature and developing mammal and make clear proposals regarding the mechanisms underlying these changes. Their functional significance to relevant psychophysical and neurological observations is also discussed.
