Research1

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	Research

1. Plasticity and functional reorganization in children and adults with focal brain lesion.
This project on functional reorganization following brain damage focuses on differences in plasticity patterns between patients with brain damage occurring at or soon after birth and those with lesion acquired in adulthood. The project is based on a series of previous studies using positron emission tomography (PET) that examined functional reorganization after brain injury in infancy and childhood (see Figures below). Data from project 1 on healthy subjects provide reference data for the study of pediatric and adult patients with left hemisphere damage. Projects 1 is performed in close cooperation with studies of the Center for Research on Language at UCSD. Our main hypothesis is that compensatory reorganization after brain lesion may involve partial suspension of regressive events (e.g., synaptic pruning).


Developmental plasticity of motor organization. PET study, showing activation (regional cerebral blood flow increase) associated with finger movement in a 6-year old hemispherectomy patient. The patient had been diagnosed with Rasmussen's encephalitis and underwent right-sided hemispherectomy at age 3. The absence of resting perfusion in loci of the resected right hemisphere can be seen in the grayscale image. The color overlay (>13% rCBF increase) shows normal activation in primary motor cortex during movement of the intact right hand. The hand contralateral to the hemispherectomy is weakened and movement is associated with unusual activity in medial frontal cortex (arrows). For complete case description, see Müller et al. Journal of Child Neurology 13 (1998): 16-22.		Developmental plasticity of language organization. The example is from the study of an 8-year old patient with Sturge-Weber syndrome of congenital onset. Progressive atrophy, associated with calcification in the left hemisphere can be seen on the grayscale T1-weighted structural MRI. Activation (rCBF increase), overlaid in color, shows atypical participation of the right frontal and parietal cortex during sentence generation (arrows). The case is included in Müller et al. Prog Neuro-Psychopharmacol & Biol Psychiat 23 (1999): 657-68.

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