Biological psychiatry
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Biological psychiatry · Feb 2012
Concussive brain injury enhances fear learning and excitatory processes in the amygdala.
Mild traumatic brain injury (cerebral concussion) results in cognitive and emotional dysfunction. These injuries are a significant risk factor for the development of anxiety disorders, including posttraumatic stress disorder. However, because physically traumatic events typically occur in a highly emotional context, it is unknown whether traumatic brain injury itself is a cause of augmented fear and anxiety. ⋯ These results suggest that mild traumatic brain injury predisposes the brain toward heightened fear learning during stressful postinjury events and provides a potential molecular mechanism by which this occurs. Furthermore, these data represent a novel rodent model that can help advance the neurobiological and therapeutic understanding of the comorbidity of posttraumatic stress disorder and traumatic brain injury.
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Biological psychiatry · Feb 2012
Catecholamines in the bed nucleus of the stria terminalis reciprocally respond to reward and aversion.
Traditionally, norepinephrine has been associated with stress responses, whereas dopamine has been associated with reward. Both of these catecholamines are found within the bed nucleus of the stria terminalis (BNST), a brain relay nucleus in the extended amygdala between cortical/limbic centers, and the hypothalamic-pituitary-adrenal axis. Despite this colocalization, little is known about subsecond catecholamine signaling in subregions of the BNST in response to salient stimuli. ⋯ This reciprocal relationship, coupled with their different time courses, can provide integration of opposing hedonic states to influence response outputs appropriate for survival.