Stimulus preceding slow potential shifts (SPS), EEG and visual evoked potentials (VEP) in rabbits.

In experiments of a modified "amplitude trigger" design on rabbits with chronically implanted cortical electrodes we looked for correlations between the partial activation state and EEG, DC-shifts and amplitudes of visual evoked potentials. The activation states are characterized by power spectra of EEG frequencies, actual heart and respiration rates and were in strong correlation with N1 amplitude of VEP as well as polarity and amplitude of stimulus preceding slow potential shifts. Three different activation states could be separated: low vs. "optimum" vs. high activation state. The "optimum" activation state is characterized by large amplitude VEP, positive directed stimulus preceding slow potential shifts as well as a desynchronized preflash EEG.