An easy method to record slow potential shifts (SPS) in rabbits using the "oddball" paradigm

Rabbits with chronically implanted Ag-AgCl electrodes over somatosensory and visual cortex were trained to a modified 'oddball' paradigm with visual stimulation. Event related potentials (ERP) and slow potential shifts (SPS) were recorded. By means of a computer controlled stimulator 'frequent' and 'rare' LED flashes were administered to the eyes of the rabbit. If 'rare' stimuli were reinforced by a weak electrical footshock, negative SPS rose steeper and reached significantly higher amplitudes than in 'frequent' conditions without reinforcement. Different kinds of the follow-up of 'frequent' and 'rare' series were tested. Best effects were obtained, if a session was divided into 3 blocks (3 srs. 'frequent'--5 srs. 'rare' reinforced--2 srs. 'frequent' and probability of 'rare' flashes was 20%. Our present data formed a basis for investigations on the neuronal and glial sources of SPS in rabbits.