Elicitation of mismatch negativity and its influence from stimuli deviant in the healthy youth

Abstract

To work out the elicitation plan, obtain the mismatch negativity (MMN) and get out the laboratory normal value as well as to study the influence to MMN from the deviation of auditory stimuli. Hearing test of the tone burst stimulation was performed on 21 healthy young volunteers according to oddball stimulation sequence. Each subject was performed two kinds of auditory stimuli including frequency deviant stimuli and intensity deviant stimuli, and of each one included three series of stimulation. MMN was gained by subtracting the ERP of deviant stimuli from the ERP of standard stimuli. The latency and amplitude of each MMN were recorded, and then the effect of the deviant extent for MMN was analyzed. By this setup the MMN of normal young people was recorded and normal value of latency and amplitude of MMN were got. In the group of frequency deviant stimuli, the MMN latency [(155.81 +/- 29.08) ms], if the frequency was up to 2000 Hz, was shorter than that when the frequency deviance was 1000 Hz [(182.89 +/- 45.85) ms, (183.32 +/- 43.33) ms] (P = 0.033, 0.030); when the deviant extent were the same, the latency had no obvious difference if changing the frequency of the standard and deviant stimuli (P = 0.973); the MMN amplitude of three groups [(3.85 +/- 2.22) microV, (2.90 +/- 2.05) microV, (2.66 +/- 2.12) microV] had no obvious difference among them (P > 0.05). In the group of intensity deviant stimuli, the MMN latency [(157.04 +/- 34.87) ms], if the frequency was up to 20 dB, was shorter (P = 0.025, 0.017) than that when the intensity deviance was 10 dB [(184.46 +/- 38.05) ms, (186.24 +/- 42.36) ms]. When the deviant extent were the same, the latency had no obvious difference (P = 0.882) if changing the intensity of the standard and deviant stimuli but only group 4 and group 6 [(3.41 +/- 1.64) microV, (2.37 +/- 1.47) microV] were different in evidence (P = 0.031) while the others had no obvious difference (P = 0.524, 0.122). MMN was only related to the difference between standard stimuli and deviant stimuli, but there was no relationship between MMN and the notice, which indicate that MMN could objectively reflect the capability of brain to detect the change of stimuli. MMN is the representation of brain high-level sensory function.