Trauma can occur in two ways that affect the brain: traumatic brain injury and traumatic stress. The National Institute of Neurological Disorders and Stroke (NINDS) defines traumatic brain injury as an impact to the head, such as one caused by blunt force. Even if the skull is not fractured, the brain can be damaged from the force. With a traumatic experience, the stress negatively affects the amygdala, hippocampus and prefrontal cortex in the brain, according to Dr. JD Bremner, author of the article "Traumatic Stress: Effects on the Brain." Both types of trauma can result in long-term effects.
Decreased Memory Function
Both types of stress can negatively impact a person's memory. In traumatic brain injury, damage to the brain can disrupt cognition; however, that symptom depends on where in the head the injury occurs. The NINDS notes that thinking, memory and reasoning can be affected after the injury. As a result, neuropsychological rehabilitation is recommended, which helps the patient adapt to learning after the brain damage.
During traumatic stress, the brain releases increased levels of cortisol, which Bremner notes has an adverse effect on the hippocampus. The hippocampus is found in the medial temporal lobe of the brain, and is responsible for converting short-term memories to long-term memories. In his article, Bremner mentions that in animal studies, those who underwent traumatic stress have smaller hippocampi.
Personality Changes
Personality changes can also occur from traumatic stress and traumatic brain injury. One of the areas affected from traumatic stress is the amygdala, which is part of the limbic system in the brain. During heightened traumatic stress, the amygdala has an increased function. As a result, the patient develops "conditioned fear."
In traumatic brain injury, changes in personality is another long-term effect if damage occurs in the frontal lobe. The frontal lobe is one of the areas of the brain responsible for personality. The traumatic brain injury patients can exhibit aggression, acting out and social inappropriateness after the injury.
Sensory Processing
The NINDS notes that permanent sensory damage can occur with traumatic brain injury, such as deficits with smell, sight, taste, touch and hearing. The damage to the brain from the injury is irreversible. While traumatic stress does not result in damage to the senses, it can cause an adverse reaction to certain stimuli. Activation of the amygdala during a specific stimulus can result in an emotional response when exposed to that stimulus again.
