Which brain structure plays a central role in initiating the fear response associated with anxiety disorders?
Prefrontal cortex
Hippocampus
Amygdala
Thalamus
The Correct Answer is C
Choice A reason: The prefrontal cortex is responsible for executive function, impulse control, and the cognitive appraisal of threats. In anxiety, it usually acts as an inhibitory mechanism to "down-regulate" the fear response. It does not initiate the rapid, subconscious fear reaction but rather attempts to modulate or extinguish it.
Choice B reason: The hippocampus is primarily involved in memory formation and spatial navigation. In the context of anxiety, it provides contextual information to the fear response (e.g., remembering a scary location), but it is not the primary generator of the physiological "fight or flight" activation seen in acute panic.
Choice C reason: The amygdala is an almond-shaped cluster in the temporal lobe that serves as the brain's "alarm system." It processes sensory input to detect threats and coordinates the immediate emotional and physiological response by activating the hypothalamus and autonomic nervous system, making it central to the pathology of anxiety.
Choice D reason: The thalamus acts as a relay station for sensory information, directing signals to the appropriate areas of the cortex for processing. While it passes data to the amygdala, it does not possess the intrinsic emotional processing capabilities required to initiate the specific neurobiological fear response itself.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
Choice A reason: Risperidone long-acting injection utilizes microsphere technology that requires a significant lag time for the polymer to degrade and release the active medication. Consequently, therapeutic plasma levels are typically not reached for 3 to 4 weeks, necessitating oral supplementation during the initial induction phase to maintain clinical stability.
Choice B reason: Immediate therapeutic effects are physiologically impossible with depot risperidone formulations due to the slow-release matrix design. Unlike immediate-release aqueous injections used for acute agitation, the depot form is engineered for sustained maintenance therapy and lacks the rapid bioavailability required to produce an instantaneous reduction in psychotic symptoms.
Choice C reason: Full clinical effects are not observed after a single dose because the steady-state concentration of the drug is only achieved after multiple sequential injections. The titration of the medication within the systemic circulation occurs gradually, and clinical improvement is usually assessed over a period of several months.
Choice D reason: The pharmacokinetics of depot risperidone are specifically designed to provide a duration of action far exceeding 24 hours, usually lasting 2 weeks per injection. If the effects dissipated within 1 day, the medication would fail its primary purpose of improving adherence and providing stable neuroleptic coverage.
Correct Answer is D
Explanation
Choice A reason: While tardive dyskinesia is a serious concern with many antipsychotics, clozapine is actually associated with a very low risk of this condition. In fact, clozapine is often used as a treatment strategy for patients who have already developed severe tardive dyskinesia from other neuroleptic medications.
Choice B reason: Clozapine has a unique pharmacological profile with low D2 receptor occupancy in the striatum, making extrapyramidal symptoms like tremors or rigidity highly unlikely. It is specifically chosen for patients who are treatment-resistant or highly sensitive to the motor side effects caused by other typical or atypical antipsychotics.
Choice C reason: Serotonin syndrome is a toxic state caused by excessive serotonergic activity, usually resulting from interactions between SSRIs, SNRIs, or MAOIs. While clozapine affects various neurotransmitter systems, it is not primarily associated with the development of serotonin syndrome, which presents with hyperreflexia, clonus, and autonomic instability.
Choice D reason: Agranulocytosis is a life-threatening reduction in the white blood cell count (specifically neutrophils) that can occur in patients taking clozapine. This requires strict mandatory blood monitoring of the Absolute Neutrophil Count (ANC) to prevent severe sepsis or death, making it the most critical safety priority for the nurse.
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