ERPs were elicited by auditory stimuli that were presented through a small speaker centered approximately 70 cm above the rat's head. Electrophysiological recordings were made in the periadolescent rats at PD33-39, the adult rats were recorded on PD100-106. ERPs were elicited by an acoustic “oddball” plus noise paradigm identical to the “passive” paradigm described above for the periadolescent human participants. Signals were transferred to a PC and digitized at a rate of 256 Hz. The EEG amplifier input range corresponding to the full range of the 12-bit analog-to-digital converter was about ± 250 microvolts. Periodic calibration results were used to scale the digitized EEG to microvolts.
