Do some neurological conditions induce brain plasticity processes?

Paillard [Paillard J. Réflexions sur l’usage du concept de plasticité en Neurobiologie. J Psychol Norm Pathol 1976;1:33–47] defined adaptive plasticity as the capacity of the system to change its own structure and expand its behavioural repertoire. We review the literature on brain damage patients, in whom, adaptive plasticity was observed via neuropsychological and functional neuroimaging examinations. Attentional and memory system alterations and some resulting changes considered as compensatory mechanisms are commented. We have selected a single case presenting with developmental amnesia [Vargha-Khadem F, Gadian DG, Watkins KE, Connelly A, Van Paesschen W, Mishkin M. Differential effects of early hippocampal pathology on episodic and semantic memory. Science 1997;277(5324):376–80; Maguire EA, Vargha-Khadem F, Mishkin M. The effects of bilateral hippocampal damage on fMRI regional activations and interactions during memory retrieval. Brain 2001;124(Pt 6):1156–70] and several groups of multiple sclerosis patients studied recently [e.g. Mainero C, Pantano P, Caramia F, Pozzilli C. Brain reorganization during attention and memory tasks in multiple sclerosis: insights from functional MRI studies. J Neurol Sci 2006;245(1/2):93–8; Morgen K, Sammer G, Courtney SM, Wolters T, Melchior H, Blecker CR, et al. Distinct mechanisms of altered brain activation in patients with multiple sclerosis. Neuroimage 2007;37(3):937–46; Nebel K, Wiese H, Seyfarth J, Gizewski ER, Stude P, Diener HC, et al. Activity of attention related structures in multiple sclerosis patients. Brain Res 2007;1151:150–60]. Convergence evidence via the two approaches – neuropsychological and functional fMRI – was shown as functional and structural brain plasticity was demonstrated in the selected works. Some common characteristics of brain plasticity emerge from this review independently of the neurological conditions we reviewed.