PTSD PTSD Neurobiology & Physiological Responses 1 — Questions and Answers
Question 1: Which brain structure is primarily responsible for the fear response dysregulation seen in PTSD?
- Hippocampus
- Amygdala (Correct answer)
- Prefrontal cortex
- Cerebellum
Correct answer: Amygdala
The amygdala is hyperactivated in PTSD, driving exaggerated fear responses and emotional reactivity.
Question 2: What physiological change in the hippocampus is commonly observed in individuals with chronic PTSD?
- Increased hippocampal volume
- Reduced hippocampal volume (Correct answer)
- Hippocampal calcification
- Hippocampal hyperplasia
Correct answer: Reduced hippocampal volume
Chronic stress hormones such as cortisol can cause hippocampal atrophy, impairing memory consolidation and contextualization of fear.
Question 3: Which neurotransmitter system is most implicated in the hyperarousal symptoms of PTSD?
- Serotonergic system
- GABAergic system
- Noradrenergic system (Correct answer)
- Dopaminergic system
Correct answer: Noradrenergic system
Norepinephrine dysregulation drives the hyperarousal, hypervigilance, and exaggerated startle response characteristic of PTSD.
Question 4: What is the role of cortisol in PTSD pathophysiology?
- Cortisol levels are uniformly elevated in PTSD
- Cortisol levels are typically low or dysregulated in PTSD (Correct answer)
- Cortisol has no measurable role in PTSD
- Cortisol exclusively causes flashbacks
Correct answer: Cortisol levels are typically low or dysregulated in PTSD
Many PTSD patients show low baseline cortisol with exaggerated feedback sensitivity, reflecting HPA axis dysregulation rather than simple elevation.
Question 5: Which autonomic nervous system state is most associated with PTSD hyperarousal symptoms?
- Parasympathetic dominance
- Sympathetic dominance (Correct answer)
- Balanced autonomic tone
- Dorsal vagal shutdown only
Correct answer: Sympathetic dominance
Sympathetic nervous system dominance underlies the hyperarousal cluster, including elevated heart rate, sweating, and increased startle response.
Question 6: What does the term 'fear extinction deficit' mean in the context of PTSD neurobiology?
- The inability to form new fear memories
- Impaired ability to learn that previously feared stimuli are no longer dangerous (Correct answer)
- Complete loss of all fear responses
- Overactive fear extinction leading to emotional numbness
Correct answer: Impaired ability to learn that previously feared stimuli are no longer dangerous
PTSD involves impaired prefrontal cortex-mediated extinction learning, so conditioned fear responses persist even when the threat is no longer present.
PTSD PTSD Neurobiology & Physiological Responses 1
Which brain structure is primarily responsible for the fear response dysregulation seen in PTSD?