Mechanisms of Working Memory Dysfunction After Mild and Moderate TBI: Evidence from Functional MRI and Neurogenetics
Thomas W. McAllister, Laura A. Flashman, Brenna C. McDonald, and Andrew J. Saykin.
Journal of Neurotrauma. October 2006, 23(10): 1450-1467.
PMID: 17020482 [PubMed – indexed for MEDLINE]
Cognitive complaints are a frequent source of distress and disability after mild and moderate traumatic brain injury (TBI). While there are deficits in several cognitive domains, many aspects of these complaints and deficits suggest that problems in working memory (WM) play an important role. Functional imaging studies in healthy individuals have outlined the neural substrate of WM and have shown that regions important in working memory circuitry overlap with regions commonly vulnerable to damage in traumatic brain injury.
Use of functional MRI (fMRI) in individuals with mild and moderate traumatic brain injury suggests that they can have problems in the activation and allocation of working memory, and several lines of evidence suggest that subtle alterations in central catecholaminergic sensitivity may underlie these problems. We review the evidence from MRI and neurogenetic studies that support the role of catecholaminergic dysregulation in the etiology of working memory complaints and deficits after mild and moderate traumatic brain injury.