Imaging stress effects on memory: a review of neuroimaging studies.
OBJECTIVE
To review and give an overview of neuroimaging studies that look at the role of stress (hormones) on memory.


METHODS
An overview will be given of imaging studies that looked at the role of stress (hormones) on memory. Stress is here defined as the acute provocation of the sympathetic adrenal medullar system and the hypothalamic-pituitary-adrenal axis in experimental designs. Stress hormone levels can be raised endogenously in response to stimulus material (for example, pictures and films) or social evaluative threat situations (stress tasks). Other studies use the exogenous application of drugs to enhance or decrease stress hormone levels. Finally, we review studies on chronic stress and memory.


RESULTS
Stress or emotional arousal, leading to increased noradrenaline or cortisol levels, led to better memory performance when it is applied during perception or encoding. Brain regions involved in this process were medial temporal lobe regions such as amygdala and hippocampus, and several parts of the prefrontal cortex (PFC). High stress levels accompanied by high cortisol levels during retrieval led to impaired memory performance. Sex effects on memory as well as lateralization effects on brain activation were found.


CONCLUSIONS
High stress levels during encoding and consolidation of emotional material involve increased amygdala and hippocampus activation. The role of the anterior cingulate cortex and other parts of the PFC during perception and encoding of arousing material appears to be a modulating one. However, additional research is needed to shed more light on the nature of the brain changes during stress, especially during retrieval.
van Stegeren
Anda H
AH
Researcher and Assistant Professor, University of Amsterdam, Department of Clinical Psychology and Cognitive Science Centre, Amsterdam, the Netherlands.
D000679:Amygdala / Q000503:physiopathology*; D006624:Hippocampus / Q000503:physiopathology*; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D008279:Magnetic Resonance Imaging; D008569:Memory Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000378:metabolism*; D049268:Positron-Emission Tomography; D017397:Prefrontal Cortex / Q000503:physiopathology*; D013315:Stress, Psychological / Q000378:metabolism*; D013702:Temporal Lobe / Q000503:physiopathology*
D006854:Hydrocortisone