Spatial memory deficits, increased phosphorylation of the transcription factor CREB, and induction of the AP-1 complex following experimental brain injury.

Traumatic brain injury causes both short- and long-term neurological impairments. A cascade of biochemical changes triggered by the injury may increase the expression of several genes, which has been hypothesized to contribute to the observed cognitive deficits. The mechanism(s) of induction for these genes is not yet known. We present evidence that lateral cortical impact injury in rats that produces spatial memory deficits also increases phosphorylation of the transcription factor CREB (cAMP response element binding). Subsequent to the phosphorylation of CREB, c-Fos expression and the AP-1 complex are enhanced. The temporal and spatial activation of c-Fos is consistent with it being induced by phosphorylated CREB proteins. Thus, CREB-mediated gene activation may contribute to the observed behavioral deficits. Further elucidation of the biochemical and pathophysiological changes will be of importance for clinical therapy.