Investigating cognitive neuroplasticity in single cases: lessons learned from applying functional neuroimaging techniques to the traditional neuropsychological case study framework.

We summarize two case studies as a context for discussing the use of neuroimaging as a convergent methodology in the study of neuroplasticity in single subjects. Throughout this paper we argue for a different approach for including neuroimaging in these types of study. Previous case studies of neuroplasticity in patients (ours as well as others reported elsewhere) have added neuroimaging to the traditional neuropsychological framework of comparing patient results with matched control groups, and synthesized results through descriptions of anatomical and behavioral dissociations. This type of approach is referred to as the comparison approach. We advocate a different approach that builds on findings from previous behavioral skill learning research. Specifically, we propose adding neuroimaging throughout learning or recovery of the ability of interest and making inferences from systematic changes in activation topography and intensity that occur within the context of predicted behavioral changes. We dub this approach the online approach. This approach should allow future investigators to circumvent many of the interpretation pitfalls that are common in comparison studies.