Cognition and Neurosciences Post-traumatic functional recovery and reorganization in animal models: A theoretical and methodological challenge

The Unit for Cognitive Neuroscience, Department of Psychology, University of Copenhagen, DenmarkMogensen, J. & Mala´, H. (2009). Post-traumatic functional recovery and reorganization in animal models: A theoretical and methodological challenge.Scandinavian Journal of Psychology, 50, 561–573.Studies addressing cerebral functional localization face methodological and theoretical problems. Lesion experiments expect that when a functionallyspecialized structure is missing, its function can be deduced from the resulting impairments. Mostly, however, initial impairments are partially or fullyeliminated through functional recovery. Apparently, such a recovery contradicts the notion of functional localization. In order to understand the mecha-nisms of recovery, improved methodology and a new theoretical framework are required. Insights into the mechanisms of recovery can be achieved byusing ‘‘challenge’’ techniques, where functionally recovered individuals are exposed to organic and behavioral challenges, e.g. pharmacological manip-ulations or additional lesions, as well as modified test situations. Using such methods, a number of principles of functional recovery have emerged. Weevaluate some of the available theories of post-traumatic recovery against these principles and find that none of them can account for the principles.Finally, we present a new conceptual framework – the Reorganization of Elementary Functions (REF) model. This model reconceptualizes the term‘‘function’’, suggests mechanisms of post-traumatic reorganizations, and resolves the contradiction between localization and functional recovery.Key words: Functional recovery, functional localization, brain injury, post-traumatic reorganization, animal models, neural plasticity, cognitive plas-ticity, experimental methodology, challenges.Jesper Mogensen, The Unit for Cognitive Neuroscience, Department of Psychology, University of Copenhagen, Oester Farimagsgade 2 A,DK-1353 Copenhagen K, Denmark. Tel: (45) 35324873; fax: (45) 35324802; e-mail: jesper.mogensen@psy.ku.dk