Melly Oitzl in Journal of Cognitive Neuroscience - Corticosteroids operate as a switch between memory systems

foto Melly.JPG

Norman White, McGill University, Canada, July 15, 2010 commented: This study and its follow-up show that stress tends to impair spatial or cognitive memory but probably has no effect on stimulus-response (S-R) or habit memory. The apparent facilitation of S-R behavior may be due to reduced competition from spatial behavior.

This study used a task in which mice learned to respond both to an individual cue and to the spatial cues in the test room, and were then tested with the two types of cues arranged so that they elicited conflicting responses. Under control conditions all mice responded to the spatial cues.

However, if the mice were stressed -- with an injection of vehicle or corticosterone, or with restraint -- immediately prior to training and testing almost half of them switched their response to the individual cue. This finding is taken to suggest that stress interferes with the acquisition and/or expression of spatial or cognitive information and facilitates acquisition and/or expression of S-R or habit information. In a subsequent study, the spatial and S-R responses were learned by different groups of mice {1}. Stress impaired acquisition and/or expression of the spatial response. Although only about a third of the mice trained on the S-R task learned it, there was no evidence of an effect of stress on the performance of this task in these mice. The findings suggest that stress impairs spatial or cognitive memory and that it is the consequent reduction in the tendency to make these responses that allows the S-R responses to occur more frequently.

Faculty of 1000 Biology rating: Recommended reading of special interest, regarding new findings and hypotheses in Pharmacology & Drug Discovery (Stress and Cognition)

"Corticosteroids operate as a switch between memory systems."
Schwabe L, Sch├Ąchinger H, de Kloet ER, and Oitzl MS
J Cogn Neurosci 2010 Jul 22(7):1362-72

Other References: {1} Schwabe et al. Behav Brain Res 2010, 213:50-5 [ PMID:20420857].