This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Psychiatry
Sleep waves in the hippocampal area are - 
Select and explain. 
A. Delta, B. Theta, C. Beta, D. Alpha
B: Theta
Answer: B: Theta 
Explanation: Alpha rhythm → Parietal and occipital lobe.
Beta rhythm→ Frontal lobe
Theta rhythm  → Hippocampus (in non-human mammals), cortex (in human).