lecture 21: Post-Traumatic Stress Disorder (PTSD)

These flashcards cover key concepts, definitions, and mechanisms related to Post-Traumatic Stress Disorder (PTSD) as discussed in the lecture notes.

Post-Traumatic Stress Disorder (PTSD)

A stress and learning disorder characterized by symptoms that develop after experiencing or witnessing a traumatic event.

Requires a traumatic event - symptoms affect memory 

Acute Stress Response

The body's initial response to stress, activated by the sympathetic adrenal-medullary system (SAM) (faster) and the hypothalamic-pituitary-adrenal (HPA) axis. (Slower)

1. In response to stress the hypothalamus activates the sympathetic nervous system to stimulate many physiological systems 

2. Including the adrenal medulla (the core of the adrenal gland) to release the hormones epinephrine and norepinephrine 

3. The hypothalamus also stimulates the anterior pituitary to release hormones that drive the outer part of the adrenal gland, the adrenal cortex, to release steroids such as cortisol

4. All these hormones prepare the body for action

Sympathetic Adrenal-Medullary System (SAM)

The faster system. A system activated during stress that releases adrenaline and noradrenaline, preparing the body for the 'fight or flight' response.

Nodes

• hypothalamus (PVN activates sympathetic nervous system)

• Sympathetic nervous system

• Adrenal medulla

Hormones released

• epinephrine (adrenaline)

• Norepinephrine

Main functions

• fight or flight

• Increase heart rate

• Increase blood pressure

• Increase respiration

• Increase glucose availability 

• Heightened arousal and vigilance

Hypothalamic-Pituitary-Adrenal (HPA) Axis

The slower system. A system involving the hypothalamus, pituitary gland, and adrenal glands that regulates stress responses and body homeostasis.

Important for keeping stress response in check 

Disrupted negative feedback associated with neuropsychiatric disease 

Nodes

• hypothalamus (PVN) → releases CRH (corticotropin releasing hormone) 

• Anterior pituitary→ releases ACTH (adrenocorticotropic hormone)

• Adrenal cortex → releases cortisol

Amygdala

A brain structure involved in the processing of emotions, threat detection, and activation of the stress response.

Receiver of consequence of fear system, receive the glucocorticoids and epinephrine, which enhance memory. 

Stress can enhance the consolidation of emotional memories. 

Functions

1. Mobilizing defensive systems (stress system activation)

2. Learning about threats (fear learning) 

Chronic Stress

A prolonged and constant feeling of stress that can lead to negative health effects and alterations in brain structure.

Amygdala neurons increase in size after prolonged stress

Prefrontal & hippocampus neurons shrink after prolonged stress 

Fear Learning

The process of acquiring and retaining fears through conditioning, where certain cues become associated with aversive experiences.

Fear Extinction

The process by which conditioned responses to fear cues diminish when the cues are repeatedly presented without the associated aversive event.

The process of reducing behavioral responses that threat-associated cues and situations 

Extinction is NOT forgetting, but new learning.

Three R's of Extinction Memory

Spontaneous recovery, renewal, and reinstatement—principles indicating how extinguished fear responses can return under different circumstances.

Spontaneous Recovery - return of fear after passage of time 

Renewal of Fear - Return of fear in any other context except the extinction context

Reinstatement - return of fear after reminder of aversive experience

DSM-5

The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, which provides standardized criteria for diagnosing mental health conditions, including PTSD.

Trauma and Stressor-related Disorders

A category in the DSM-5 that includes PTSD and is distinguished from anxiety disorders.

Chronic Activation of Stress System

Continued and excessive activation of the stress response leading to health issues, including changes in brain structure related to emotional regulation.

Hypervigilance

An enhanced state of sensory sensitivity and increased anxiety, often associated with PTSD, characterized by an exaggerated awareness of potential threats.

Cognitive Behavioral Therapy (CBT)

A type of psychotherapy that helps patients challenge and change unhelpful cognitive distortions and behaviors, often used to treat PTSD.

Reinstatement

The return of a previously extinguished fear response following a reminder of the aversive experience.

Neurobiological Changes in PTSD

Alterations in brain structures such as the amygdala, prefrontal cortex, and hippocampus that affect emotion regulation and memory in PTSD patients.

Vulnerability vs. Resilience

The balance between factors that increase the likelihood of developing PTSD versus factors that promote recovery and mental health.

Women are twice as likely to develop PTSD

Neural basis of fear extinction

Prefrontal cortex - extinction learning (related to top-down suppression of emotional responding)

Hippocampus - fear renewal (related to contextual/relational learning)

Amygdala- fear and extinction learning (related to emotional learning and threat-responding)

Extinction Learning

Extinction learning is not specific to fear

A CS-UCS association can be extinguished with CS-no UCS training

The three R’s apply to other Types of associations as well. 

Neural basis of fear extinction

Refers to the brain structures and processes involved in the learning and unlearning of fear responses, primarily involving the prefrontal cortex, hippocampus, and amygdala.

Prefrontal cortex - extinction learning (Related to top-down suppression of emotional responding)

Hippocampus - fear renewal (Related to contextual/relational learning)

Amygdala - fear and extinction learning (related to emotional learning and threat-responding)

cognitive behavioral therapy

A type of psychotherapy that helps individuals understand and change their thought patterns and behaviors related to anxiety, depression, and PTSD. It often involves techniques like exposure therapy and cognitive restructuring.