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
The peak of fast EPSP or, fast IPSP is seen at what time after stimulus application: 
Select and explain. 
A. 0.5 ms, B. 0.5 to 1.5 ms, C. 11.5 ms, D. 100-500 ms
B: 0.5 to 1.5 ms
Answer: B: 0.5 to 1.5 ms 
Explanation: Fast EPSP and fast IPSP begins 0.5 ms after the stimulus (known as latency). They peak 1-1.5 ms after the stimulus then decreases exponentially. Fast EPSP is due to influx of Na+ and or Ca++ in post synaptic neuron. Fast IPSP is due to influx of Cl- in post synaptic neuron.