The spontaneous emission in the human brain at the time of sleeping or without any input stimulus or sensory input indicates the presence of noise in it. Many researches show, the adding of noise enhances biological signals such as ECG and EEG to detect on a device. However, in simulation-based recognition, quality assessment, or perception of sensory signals system, the performance starts to decrease with an increase of noise level. Now, the question is, how the human brain is so robust to various conditions for the above mentioned tasks? Does noise really enhance the brain works? If yes, how?