anthony
27-04-2006, 12:29 AM
When the instinctual part of brain (limbic system) perceives danger, it sends messages to your Autonomic Nervous System (ANS). The ANS has two parts, being:
SNS (sympathetic) is activated with effort & stress, gets the body primed for action; and
PNS (parasympathetic) is activated in states of rest & relaxationSNS & PNS function inbalance, generally when one is activated, the other is suppressed, and this does not go through the logical part of your brain (neocortex).
The following images provide a few different ways off looking at the system, with more discussion below these.
http://www.ptsdforum.org/images/autonomic-system.gif
http://www.ptsdforum.org/images/autonomic_system.jpg
http://www.ptsdforum.org/images/autonomicsystem.jpg
Fight or Flight
During traumatic events the SNS kicks in and produces a huge adrenalin rush, ie. survival strategy to mobilise body for fight or flight. The reaction:
Increased breathing & heart rate, more oxygen, blood into big muscles for quick movement,
No oxygen to stomach (nausea) or brain (lightheadedness), and
Fast acting systemAfter the danger or enough time, the feedback loop to the brain says enough adrenalin, PNS then kicks in and relaxation occurs. The chain reaction:
Halts alarm reaction & adrenalin production, restoring restful state, and
Is the slow acting system.Freeze
If fight or flight is not possible, or trauma is prolonged, ANS & PNS can be simultaneously activated, causing a state of freezing/tonic immobility (eg. mouse going dead with cat, rabbit freezing in headlights). The process contains:
System shuts down and trauma victim enters an altered reality,
Heart rate slows down, skin goes pale, as if dead,
Time slows down, no / less intense fear and pain (eg. people falling from heights or mauled by animals), and
Freezing increases chances of survival & can save life.An attacker loses interest if the victim appears dead (cat gives up on lifeless mouse, hijacker leaves woman for dead).
Fight, Flight or Freeze?
Fight, flight & freeze are automatic, instinctive survival responses, not thoughtful or considered responses. Which one occurs depends on the limbic system's perception of the strength & time available. For example:
If time & strength to run away - flee
If no time but strength - fight
If no time or strength & death imminent - freeze"If I have a chance to flee I will, if I have a chance to fight I will, if I have to freeze I will"
How this relates to survivor's guilt or shame for freezing & not protecting themselves, fighting back or running away.What Goes Wrong?
The ANS continues to be chronically aroused even though the threat has passed & is survived. Usual fight / flight response is truncated & the trauma gets "stuck" in the body. Animals don't get PTSD for their instinctual "shiver down the spine" allows trauma to be sequenced through their body (wish we had this ability). Survivors physiological housekeeping systems are messed up by the trauma. Therapy needs to pay attention to the trauma in the body, ie. body therapies, mindfulness and grounding.
SNS (sympathetic) is activated with effort & stress, gets the body primed for action; and
PNS (parasympathetic) is activated in states of rest & relaxationSNS & PNS function inbalance, generally when one is activated, the other is suppressed, and this does not go through the logical part of your brain (neocortex).
The following images provide a few different ways off looking at the system, with more discussion below these.
http://www.ptsdforum.org/images/autonomic-system.gif
http://www.ptsdforum.org/images/autonomic_system.jpg
http://www.ptsdforum.org/images/autonomicsystem.jpg
Fight or Flight
During traumatic events the SNS kicks in and produces a huge adrenalin rush, ie. survival strategy to mobilise body for fight or flight. The reaction:
Increased breathing & heart rate, more oxygen, blood into big muscles for quick movement,
No oxygen to stomach (nausea) or brain (lightheadedness), and
Fast acting systemAfter the danger or enough time, the feedback loop to the brain says enough adrenalin, PNS then kicks in and relaxation occurs. The chain reaction:
Halts alarm reaction & adrenalin production, restoring restful state, and
Is the slow acting system.Freeze
If fight or flight is not possible, or trauma is prolonged, ANS & PNS can be simultaneously activated, causing a state of freezing/tonic immobility (eg. mouse going dead with cat, rabbit freezing in headlights). The process contains:
System shuts down and trauma victim enters an altered reality,
Heart rate slows down, skin goes pale, as if dead,
Time slows down, no / less intense fear and pain (eg. people falling from heights or mauled by animals), and
Freezing increases chances of survival & can save life.An attacker loses interest if the victim appears dead (cat gives up on lifeless mouse, hijacker leaves woman for dead).
Fight, Flight or Freeze?
Fight, flight & freeze are automatic, instinctive survival responses, not thoughtful or considered responses. Which one occurs depends on the limbic system's perception of the strength & time available. For example:
If time & strength to run away - flee
If no time but strength - fight
If no time or strength & death imminent - freeze"If I have a chance to flee I will, if I have a chance to fight I will, if I have to freeze I will"
How this relates to survivor's guilt or shame for freezing & not protecting themselves, fighting back or running away.What Goes Wrong?
The ANS continues to be chronically aroused even though the threat has passed & is survived. Usual fight / flight response is truncated & the trauma gets "stuck" in the body. Animals don't get PTSD for their instinctual "shiver down the spine" allows trauma to be sequenced through their body (wish we had this ability). Survivors physiological housekeeping systems are messed up by the trauma. Therapy needs to pay attention to the trauma in the body, ie. body therapies, mindfulness and grounding.