This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Sleep Disorders, Subject name: Psychiatry
In which stage of the sleep we can see spindle complexes and sleep spindles in EEG? 
Select and explain. 
A. Stage N1, B. Stage N2, C. Stage N3, D. REM
B: Stage N2
Answer: B: Stage N2 
Explanation: Ans. B. Stage N2Sleep is scored in epochs of 30 seconds, with stages of sleep defined by visual scoring of 3 parameters: electroencephalogram (EEG), electrooculogram (EOG) & electromyogram (EMG) recorded beneath chin.1. NREM:* Stage 1: 1st stage, light sleep, loss of alpha waves (eyes closed but awake) and predominant theta waves* Stage 2: Maximum time spent. Findings in EEG include- Sleep spindles: bursts of waves of frequency of 11-16Hz- K-complexes: high voltage spikes, negative sharp waves followed by positive waves* Stage 3: Deepening of sleep, appearance of delta waves.* Stage 4: Deep sleep characterized by delta waves- New NREM stages: N1 (stage 1), N2 (stage 2), N3 (stage 3+4)2. REM sleep: (aka paradoxical sleep)* EEG: beta wave (similar to awake state), alpha wave