TTC Neurobiological Effects of Trauma 3 — Questions and Answers
Question 1: Hippocampal volume reduction in trauma survivors is primarily linked to which mechanism?
- Increased neurogenesis from stress hormones
- Glucocorticoid-mediated neurotoxicity and reduced neurogenesis (Correct answer)
- Elevated oxytocin suppressing synaptic growth
- Dopamine depletion in the dentate gyrus
Correct answer: Glucocorticoid-mediated neurotoxicity and reduced neurogenesis
Chronic glucocorticoid exposure causes dendritic atrophy and inhibits neurogenesis in the hippocampus, reducing its volume.
Question 2: What role does the prefrontal cortex (PFC) play in the trauma response?
- Amplifies amygdala fear signals
- Exerts top-down inhibitory control over the amygdala (Correct answer)
- Stores traumatic memories permanently
- Activates the HPA axis directly
Correct answer: Exerts top-down inhibitory control over the amygdala
The medial prefrontal cortex provides top-down inhibitory regulation of amygdala activity, a function impaired in PTSD.
Question 3: The 'fear extinction' process is primarily mediated by which brain circuit?
- Amygdala-hippocampus inhibitory loop
- Ventromedial PFC projections to the amygdala (Correct answer)
- Dorsolateral PFC projections to the thalamus
- Hypothalamus-cingulate feedback loop
Correct answer: Ventromedial PFC projections to the amygdala
Ventromedial prefrontal cortex projections to the amygdala mediate extinction learning by inhibiting conditioned fear responses.
Question 4: Which finding best explains why trauma survivors struggle to contextualize traumatic memories as past events?
- Overactive PFC suppresses hippocampal time-stamping
- Hippocampal dysfunction impairs contextual and temporal encoding (Correct answer)
- Excessive dopamine erases temporal markers
- Amygdala hyperactivation prevents thalamic relay
Correct answer: Hippocampal dysfunction impairs contextual and temporal encoding
Hippocampal dysfunction during and after trauma impairs the contextual and temporal tagging of memories, leaving them feeling present-tense.
Question 5: Broca's area deactivation during trauma recall, observed in neuroimaging studies, is associated with which symptom?
- Flashback-triggered motor paralysis
- Difficulty verbalizing traumatic experiences (Correct answer)
- Selective mutism in all contexts
- Auditory hallucinations
Correct answer: Difficulty verbalizing traumatic experiences
Deactivation of Broca's area during trauma recall helps explain why survivors often struggle to articulate traumatic experiences in words.
Question 6: The 'speechless terror' phenomenon in trauma is neurobiologically linked to decreased activity in which area?
- Right amygdala
- Left hemisphere language areas (Correct answer)
- Anterior cingulate cortex
- Thalamic relay nuclei
Correct answer: Left hemisphere language areas
Left hemisphere language areas, including Broca's area, show decreased activation during trauma recall, contributing to speechless terror.
Question 7: Which neuroimaging finding is most consistently associated with PTSD compared to trauma-exposed non-PTSD individuals?
- Enlarged hippocampal volume
- Reduced medial PFC activation during fear processing (Correct answer)
- Increased Broca's area activity
- Enlarged corpus callosum
Correct answer: Reduced medial PFC activation during fear processing
Reduced medial PFC activation during fear processing reflects impaired top-down regulation and distinguishes PTSD from resilient trauma exposure.
TTC Neurobiological Effects of Trauma 3
Hippocampal volume reduction in trauma survivors is primarily linked to which mechanism?