This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Introduction to Central Nervous System, Subject name: Physiology
[{'content': 'Noradrenergic neurons are chiefly present in: \nSelect and explain. \nA. Locus ceruleus, B. Nucleus accumbens, C. Nucleus raphe magnus, D. Nigrostriatal pathway', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Cells in the locus ceruleus have noradrenergic neurons that are projected to all pas of the cerebral coex and limbic system. It is involved in the regulation of attention, arousal, sleep-wake cycles, mood and affect. Raphe nucleicontain serotonergic neurons. These neurons fire most rapidly during wakefulness Nucleus accumbens and nigro-striatal pathway contain dopaminergic neurons.', 'role': 'assistant'}]