Sažetak sa skupa

NEUROPLASTICITY AND THE DEVELOPING BRAIN

Ingeborg Krageloh-Mann ; University Children‘s Hospital, Department of Developmental Neurology, Tübingen, Germany

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Sažetak

The compensatory potential of the young nervous system following brain injury is considered to be superior to that of the adult brain (Kennard principle). The healthy hemisphere plays an important role after unilateral lesions. Its role will be discussed for the sensorimotor and language system. In the motor system, when a unilateral lesion disrupts the motor tracts, abnormal fast conducting corticospinal projections from the healthy hemisphere exert the primary motor control. Such ipsilateral projections are physiological in the neonate; they do not mature and can no longer be elicited in later normal development. They can apparently be maintained under pathological conditions, e.g., when the contralateral projections are severed. However, their functional role seems to decrease already during late gestation. In contrast to the possibility for interhemispheric reorganization in the motor system, there is no clear evidence up to now that this can also occur in the sensory system. Rather is there evidence for dissociation between primary motor and primary sensory representation in larger unilateral lesions where the healthy hemisphere has taken over primary motor control of the paretic hand, whereas the sensory representation is still remaining in the lesioned hemisphere with some evidence for axonal deviations but not substantial intrahemispheric reorganization of the cortical representation. The restricted compensatory potential in the sensorimotor system is in contrast to the possibilities for compensation in the language system after early left hemispheric lesions. The entire language network can be reorganized to the right hemisphere, to the expense of the originally right hemispheric functions. Only when examined with the eye of a linguist, the right hemispheric language is not equivalent to the normal situation of language organization. In conclusion, early plasticity after unilateral lesions relies on the non-lesioned hemisphere. Reorganization is interhemispheric and homotopic in the motor and language system. There is no clear evidence for substantial reorganization in the sensory system.

Ključne riječi

Hrčak ID:

105052

URI

https://hrcak.srce.hr/105052

Datum izdavanja:

25.6.2013.

Posjeta: 548 *