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Abstract #26010 Published in IGR 12-2
Recovery of function and plasticity after lesions of the central visual pathway
Gall C; Prilloff S; Sabel BAJournal fur Neurologie, Neurochirurgie und Psychiatrie 2010; 11: 18-30
Even beyond the critical developmental period, the visual system is not rigidly fixed. Rather, the brain shows plasticity at all levels of information processing (retina, lateral geniculate nucleus and primary visual cortex), even in old age, and this is observed especially well after lesions. Reorganisation of receptive fields and changes of cortical activation patterns have been shown after retinal as well as pre- and postchiasmatic lesions of the central visual pathway. Evidence for neuronal plasticity has been found in animal models as well as in patients with damage of the retina (macular degeneration, glaucoma), the optic nerve (e. g., after trauma) and postchiasmatic areas including the primary visual cortex (producing hemianopia). The brain can adapt itself within certain limits to the resulting visual field defects caused by the damage. Signs for postlesional plasticity are (1) development of eccentric fixation in foveal lesions, (2) recovery of function during the first weeks after the damage (spontaneous remissions), (3) pseudo-hallucinative perceptions of phosphenes and complex objects which are attributed to cortical hyperactivity as well as (4) blindsight and residual vision in impaired visual field areas. Even after spontaneous recovery has plateaued, plasticity can be initiated again by repetitive stimulation of residual visual field areas using vision training or, as recently shown, by transorbital electric stimulation. Therefore, the visual system has a plasticity potential, i.e. an ability for spontaneous and induced adaptive processes that is comparable to that known of other functional systems. It is now essential to make better use of this plasticity and repair potential in clinical practice. LA: German
C. Gall. Institut fur Medizinische Psychologie, Medizinische Fakultat, Otto-von-Guericke-Universitat Magdeburg, Leipziger Strasse 44, D-39120 Magdeburg, Germany. carolin.gall@med.ovgu.de
Classification:
2.16 Chiasma and retrochiasmal central nervous system (Part of: 2 Anatomical structures in glaucoma)
11.8 Neuroprotection (Part of: 11 Medical treatment)
