The Hyperarousal Continuum: ‘Fight or Flight’ Responses

Hippocampus: Another key system linked with the RAS and playing a central role in the fear response is the hippocampus, located at the interface between the cortex and the lower diencephalic areas. It plays a major role in memory and learning. In addition it plays a key role in various activities of the autonomic nervous and neuroendocrine systems. Stress hormones and stress related neurotransmitter systems (i.e., those from the locus coeruleus and other key brainstem nuclei) have the hippocampus as a target. In animal models, various hormones (e.g., cortisol) appear to alter hippocampus synapse formation and dendritic structure, thereby causing actual changes in gross structure and hippocampal volume as defined using various brain imaging techniques (see McEwen, 1999 for review). Repeated stress appears to inhibit the development of
neurons in the dentate gyrus (part of the hippocampus) and atrophy of dendrites in the CA3 region of the hippocampus (Sapolsky & Plotsky, 1990; Sapolsky et al., 1990). These neurobiological changes are likely related to some of the observed functional problems with memory and learning that accompany stress-related neuropsychiatric syndromes, including post-traumatic stress disorder (PTSD: see Perry & Azad, 1999)

Leave a Reply, All comments will be moderated - Many thanks for your contribution

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: