Bimodality of PII of ABR in Rats

Abstract

This study was performed to clarify the origin of PII wave of the rat's ABR. The PII was characterized by the bimodality of PII a and PIIb, and usually this bimodality was clearly recognized using non-cephalic reference electrode.
In this study, the reference electrode was set at the base of the tail as a non-cephalic reference point, and special attention was paid to avoid the ECG interference.
The development of PII was studied in a series of rats over a postnatal period ranging immediate after birth to 60 days. PII a was appeared at 14 days after birth, while PIIb was recognized at 18 days.
PIIa had a large amplitude at the recoding sites of contralateral to the stimuli, whereas PIIb was larger than PIIa at the ipsilateral sites to the stimuli.
These results indicate that PII is a complex wave having at least two generators.