Neurobiology During Trauma

Amygdala: Brain region responsible for emotional processing, integrating memory and emotion, and the automatic responses associated with fear.

Hippocampus: Brain region responsible for processing sensory information into memories. This region is very sensitive to hormone fluctuations.

Hypothalamic-Pituitary-Adrenal (HPA)Axis: Controls the body’s stress response. Releases hormones and chemicals, including cortisol, to respond to external stress.

The HPA axis also rebalances the body after experiencing stress.

Hypothalamus: Brain region that regulates hormones, initiates the stress response of the HPA axis, and maintains homeostasis.

During trauma, the amygdala first detects a threat from the external environment.

Then the amygdala activates the hypothalamus, the first structure of the HPA axis, which in turn floods the body with hormones and chemicals designed to enhance survival.

The hormones and chemicals released by The HPA axis can impede rational thought, cause a flat affect, reduce energy available, increase hyperactivity, cause a complete shutdown of the body, and critically impair memory processing and consolidation.

Since the hippocampus is very sensitive to hormone fluctuations, the flood of hormones accounts for traumatic memories frequently being fragmented, complete, or out of sequence.

Encoding in the context of trauma is impaired, so details such as time, place, and sequence of events may be further fragmented or not encoded at all. However, the hippocampus can often still in code sensory details such as sight sound smell touch taste etc..

Since the hippocampus is very sensitive to hormone fluctuations, the flood of hormones accounts for traumatic memories frequently being fragmented, complete, or out of sequence.

Encoding in the context of trauma is impaired, so details such as time, place, and sequence of events may be further fragmented or not encoded at all. However, the hippocampus still encodes sensory details such as sight sound smell touch taste etc..