Cerebral plasticity and recovery of function after childhood prefrontal cortex damage

Abstract

Objective: Recovery of function after early brain injury depends upon both reparative and compensatory processes that are minimally understood. Using functional magnetic resonance imaging (fMRI), this study investigated the reorganization of hemispheric brain activity of a 24 year old male who suffered right prefrontal cortex damage at 7 years of age related to ruptured arteriovenous malformation. His pattern of recovery has been examined and tracked over the past 17 years and evolved from initial significant impairments in executive, spatial and attentional abilities from the brain lesion to remarkable recovery of function.Methods: High field fMRI studies were completed with experimental cognitive tasks sensitive to right prefrontal functions, including visuospatial relational reasoning, spatial working memory, go no-go, emotional face recognition, and coin calculation. Results were compared to a matched control group for total hemispheric activity patterns.Results: Analyses revealed that on fMRI activation tasks where the patient scored similar to controls, he activated a broader network of bilateral cortical regions than controls. On tasks where he scored lower than controls, there was under-activation of prefrontal cortical regions in comparison to controls.Conclusion: Recovery of function after prefrontal cortex damage in childhood can occur and be associated with significant functional reorganization of hemispheric activity patterns (i.e. developmental cerebral plasticity). Although not all tasks showed recovery to the same extent in this case, those tasks with the most robust recovery entailed compensatory activation of additional cortical regions on fMRI. Further studies are needed to confirm and extend these findings.