Developmental Neurorehabilitation, October 2009; 12(5): 298–312 CASE REPORT Cerebral plasticity and recovery of function after childhood prefrontal cortex damage KYLE THOMPSON 1 , KATHLEEN R. BIDDLE 2 , MELISSA ROBINSON-LONG 3 , JENNIFER POGER 1 , JIANLI WANG 4 , QING X. YANG 4,5 , & PAUL J. ESLINGER 1,3,4,6 1 Department of Neurology, Penn State College of Medicine and Hershey Medical Center, Hershey, Pennsylvania, 2 Department of Education, Juniata College, Huntingdon, Pennsylvania, 3 Department of Neural and Behavioral Sciences, 4 Department of Radiology (Center for NMR Research), 5 Department of Neurosurgery, and 6 Department of Pediatrics, Penn State College of Medicine and Hershey Medical Center, Hershey, Pennsylvania (Received 12 July 2009; revised 3 August 2009; accepted 5 August 2009) 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. Keywords: Neural plasticity, recovery of function, prefrontal cortex, fMRI, brain development, executive functions Introduction The right dorsolateral prefrontal cortex is a highly integrative region of the brain that is part of several neural networks that mediate specific cognitive functions such as spatial working memory, emo- tional face recognition, calculations, reasoning and moral judgements [1–5]. Its functional capacities mature gradually throughout development and are thought to be linked to both neurobiological pro- cesses of cortical and white matter pruning and sculpting and also to experiential factors [6–8]. Early injuries to prefrontal regions, as opposed to similar injuries later in life, have been shown to be advan- tageous and disadvantageous. That is, the earlier the injury, the greater the possibility that other brain areas can compensate for functional deficits due to the plasticity of the younger brain (i.e. the ‘Kennard effect’) [9–14]. However, as some case reports, group studies and animal model studies have shown, early frontal lobe injuries may also signifi- cantly interfere with later maturational events that are necessary for typical, adaptive development, causing late-emerging deficits [6, 11, 14–16]. Some of these differences in developmental outcomes may Correspondence: Paul J. Eslinger, PhD, Penn State Hershey Medical Center, Department of Neurology EC037, 30 Hope Drive, PO Box 859, Hershey, PA 17033-0859, USA. Tel: 717-531-1804. Fax: 717-531-4694. E-mail: peslinger@hmc.psu.edu ISSN 1751–8423 print/ISSN 1751–8431 online/09/050298–15 ß 2009 Informa UK Ltd. DOI: 10.1080/17518420903236262