ABSTRACT
Early central information processing, measured in humans by the gating of the middle latency auditory evoked potential (AEP) P50 and the effect of attention on AEP N100, is affected in schizophrenia. Exploring the possibility of using miniature pigs in longitudinal studies of chronic neuropsychiatric disorders, we present a method for recording seven channel surface middle latency AEP in the awake animal. The AEP and the AEP gating measured in a paired stimulus paradigm similar to the P50 gating paradigm used in humans, were recorded in six adult male minipigs in two sessions. The AEP had a stable N40/P60/N120/P200 configuration and in the gating paradigm the difference between stimulus one (S1) and two (S2) P60 and N120 amplitudes were significant. Mean AEP P60 gating ratio (S2/S1) at the posterior central electrode was 0.66 (std 0.29) range 0.21-1.08 and corresponding N120 was 0.60 (std 0.19) range 0.28-0.76. The method presented is feasible for scalp recordings of middle latency evoked potentials in the awake animal, but further studies of interval sensitivity and the effect of arousal manipulation are needed to assess the equivalence of the pig components to those of the human at similar latencies.
