[The 40 Hertz auditory event-related potential in chick: optimized recording conditions and threshold value]

In order to seek optimized recording parameters for 40 Hz AERP in chick, the present study was carried out with a statistical model of orthogonal test. The following measuring parameters to be selected includ the rise/decay time of tone pip (1, 2 and 3 cycle), platform time (1, 2 and 3 cycle), high-pass filters (5, 20 and 30 Hz), low-pass filter (70, 100 and 250 Hz). The results showed that 1. the filter setting is a high significant factor, the most optimum basswidth is 20-70 Hz; 2. the ideal time of rise/decay and platform of tone pip are 2-1-2 cycle. The adult animals showed the greatest sensitivity nearby 1.5-2 kHz frequency. In sixday-old chicks, the threshold at every frequency has reached the same values as adult, indicating that their auditory function is essentially mature.