In men and women with PTSD, there is a cluster of abnormal brain signals in an area of the brain involved in memory. Exactly why is still a mystery, but this cluster may interfere with the ability to suppress bad memories, one of the hallmarks of post-traumatic stress.
While usually associated with combat, PTSD has been linked to many psychologically traumatic events. It generates severe anxiety along with flashbacks, nightmares and anger, and is generally treated with therapy and medication.
When an experience alters behavior and therefore the brain, the alteration may not be drastic or even noticeable but it exists. Post Traumatic Stress Disorder, (PTSD) is an example of memories that are so intense that the person has flashbacks and which creates a noticeable difference in behavior. Typical symptoms are flashbacks or dreams where the experience is relived where the victim has a sense of numbness, detachment from others, unresponsiveness to surroundings, and avoidance of situations similar to that of the trauma. There can also be instances of "shell shock" where a stimuli triggers a re-enactment of the trauma. The magnitude of how an experience is remembered is effected by the emotional state of the individual.
There are obviously different kinds of memories. There are memories concerning facts and figures, learned skills, emotions, faces, survival skills, long term, short term, vacations, etc. All of these types of memories are different for all people, and are different from experience to experience. This is due to the fact that the brain is always changing, and no two situations are identical. Once a person has an experience, their brain is permanently altered, and two people can have the same exact experience but remember the event completely differently.
There are two kinds of memory: normal and trauma.
Near our forehead is the part of the brain is called the frontal lobes. These handle conscious functions, like language, speech, and normal memory.
Normal memory is where normal events are stored in the front part of the brain and are recalled in story format. Over time the memory changes to fit into our story telling. Thus, normal memory is not pure memory.
Trauma memory is stored in the back part of the brain that handles emotions and sensations, as well as our hearing, sight, and smell. Trauma memory is not part of ordinary consciousness. Nor can it be called up at will or be changed over time. Trauma memory is a raw, pure-form of memory.
Whether an ordinary or traumatic experience becomes normal or trauma memory depends on a “safety value” built into our human brain. Within the center of our brain is an area that regulates survival behaviors—such as eating, sexual reproduction, and the instinctive defenses of fight or flight. This area also handles emotional expression and memory processing.
The Limbic System, is the central area that includes the hippocampus and amygdala. These two parts determine where our memories are stored—either in the frontal lobes or in the back part of the brain.
Why? How does the brain change? What changes occur within the brain? New neurons are being synthesized and new synapses are forming continuously. The connections are influenced by past, present and suspected future experiences. Various neurochemicals have different effects on neurons. It was found that the storage of information in the brain is modulated by endogenous hormone systems or that the surrounding chemicals influence the new connections being made. Fear, an emotion that evolved to deal with danger, causes an automatic, rapid protective response that occurs without the need for conscious thought. It has been found that the body's fear response is coordinated by a small structure deep inside the brain, called the amygdala. Traumatic experiences are high stress situations and particular chemicals are released to cause the fear and the anxiety that the victim experiences. In fact, people with PTSD tend to have abnormal levels of key hormones involved in stress response, in particular, cortisol present at lower levels and both norepinephrine and epinephrine are present at higher levels.
So what part of the brain signals for the release of these stress hormones? Evidence suggests that the control point for this is the amygdala, more specifically the region of the basolateral nucleus.
The amygdala influences memory recollection. The hippocampus is influenced by the amygdala. Sustained stress can damage the hippocampus because stress glucocortoids (over time) accelerate the death of hippocampus neurons. The hippocampus is particularly sensitive to cortisol which after a stressful experience, can continue to circulate for extended periods of time. The experience caused a chemical change within the brain which altered the structure of the hippocampus. Because portions of the hippocampus are under the influence of the stress chemicals, the storage of the experience happening at the time is effected.
The stress hormone cortisol LITERALLY shrinks the hippocampus – the part of the brain that’s essential to memory and thinking. Doing so ages the brain much sooner than it wants to age!
Experts say that the one thing that seems to work for everyone is meditation. All this means is taking a few minutes each day to quiet your mind, calm your nervous system, lower your heart rate and oxygenate your brain with deep breathing. As important as we all know that eating right is, and as much respect as we have for exercise and daily activity – we should realize that this period of time is just as important. Maybe even more so.
Symptoms of PTSD.
There are three basic sets of symptoms associated with PTSD. They may begin immediately after the event or can develop up to a year afterward:
* Re-experiencing. In such cases, patients persistently re-experience the trauma in at least one of the following ways: in recurrent images, thoughts, flashbacks, dreams, or feelings of distress at situations that remind them of the traumatic event. Children may engage in play, in which traumatic events are enacted repeatedly.
* Avoidance. Patients may avoid reminders of the event, such as thoughts, people, or any other factors that trigger recollection. They tend to have an emotional numbness, a sense of being in a daze or of losing contact with their own identity or even external reality. They may be unable to remember important aspects of the event.
* Increased Arousal. This includes symptoms of anxiety or heightened awareness of danger (sleeplessness, irritability, being easily startled, or becoming overly vigilant to unknown dangers).
To further qualify for a diagnosis of PTSD, patients must have at least one symptom in the re-experiencing category, three avoidance symptoms, and two arousal symptoms. Symptoms are chronic (3 months or more). Symptoms should also not be associated with alcohol, medications, or drugs and should not be intensifications of a pre-existing psychological disorder.
Your amygdalae are essential to your ability to feel certain emotions and to perceive them in other people. This includes fear and the many changes that it causes in the body. If you are being followed at night by a suspect-looking individual and your heart is pounding, chances are that your amygdalae are very active!
Source: University of Washington Digital Anatomist Program
In certain studies, researchers have directly stimulated the amygdalae of patients who were undergoing brain surgery, and asked them to report their impressions. The subjective experience that these patients reported most often was one of imminent danger and fear. In studies of the very small number of patients who have had had only their amygdala destroyed (as the result of a stroke, for example), they recognized the facial expressions of every emotion except fear.
In fact, the amygdala seems to modulate all of our reactions to events that are very important for our survival. Events that warn us of imminent danger are therefore very important stimuli for the amygdala, but so are events that signal the presence of food, sexual partners, rivals, children in distress, and so on.
Functions
Emotion, danger, disgust, fear (conditioning); Operant conditioning S (closely connected to the pOFC)
Processing of emotional and social information
Emotion recognition in others, emotional assessment of (amongst others negative) facial expressions (are they threatening or not?), empathy
Modulation of memory-related processes (both enhancement and suppression of impulses) in other brain regions, such as the Hippocampus ; recognition of negative items
Important part of the reward system
Impact on the Autonomic Nervous System, homeostasis (OFC -> Amygdala,)
Motivation
"The OFC, which is thought to be involved in the extinction of fear conditioning and the retrieval of emotional memory, might play an important role in the pathophysiology of PTSD."
"In the subgroup (of BPD patients) with additional PTSD, we observed right more than left activation of anterior temporal lobes, mesiotemporal areas, amygdala, posterior cingulate gyrus, occipital areas, and cerebellum (during the recall of traumatic memories)."
Dentate Gyrus
Functions: Memory formation; regulation of stress responses, neurogenesis even in adults
Geometry of the environment,
spatial pattern separation during learning
Hippocampus
Encoding, retention and retrieval of spatial and episodic experiences;
memory,
above all episodic and autobiographic, but not procedural, and only in part semantic learning,
recognition
Encoding and retrieval of relational information in visual short-term memory
Spatial (CA3 subregion) and contextual learning and memory, continuous encoding of ongoing experience, categorization, pattern separation and pattern completion
Behavioral regulation and inhibition (e.g. of food intake for body weight regulation)
Speech comprehension through mnemonic encoding of narrative information
http://www.anxietypanicattack.com/ptsdquestionnaire.html- PTSD Questionaire
Research Brings Hope for Veterans....who Suffer from Post Traumatic Stress Disorder. Press Release National Institute of Mental Health.
Hidden Scars: Sexual and other abuse may alter a brain region. Mukerjee, Madhusree. Scientific American. Reprinted from Oct1995.
Dissociation, A Normal Response To Trauma-Marsha Laura English Initially written for a Special Research & Technical Writing Project,
Spring Quarter, 2002,
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