Final answer:
Increased amygdala activity in people with PTSD leads to exaggerated fear and emotional responses, as the amygdala is key in emotional processing and fear learning.
Step-by-step explanation:
Increased amygdala activity in people with PTSD is responsible for exaggerated fear and emotional responses(D). The amygdala, a component of the brain's limbic system, is involved in emotional processing especially fear and aggression. When the amygdala becomes hyperactive, as is often the case in individuals with posttraumatic stress disorder (PTSD), it can lead to heightened emotional responses and fear learning. The activation of the amygdala is part of the process by which strong emotions enhance the consolidation of memories, making the recollection of emotionally charged events more vivid and durable, a premise supported by the arousal theory.
PTSD is also associated with changes in the hippocampus, which not only affects memory and emotional regulation but can also be observed as reduced volume in this brain region. The interconnected nature of the amygdala and hippocampus contributes to the emotional and memory-related symptoms experienced by those with PTSD. Therefore, the correct answer for the effects of increased amygdala activity in people with PTSD is an exaggerated fear and emotional responses.