(A) Examples of 1 s traces of multi-unit activity recorded in the vicinity of an isolated neuron (striatal MSN, striatal TAN, STN, GPe and SNr neurons) in the normal (before MPTP, left) and parkinsonian (after MPTP, right) state and PSDs of the respective multi-unit activity. Multi-unit activity was online filtered between 250 and 6000 Hz. PSD was calculated over the complete recording span of the multi-unit activity constrained by the period of stable discharge rate and satisfactory isolation quality of the isolated neuron. Abscissas of the PSDs are in log scale. (B) Average PSDs of activity of MSN, STN (BG input stage, top panels), GPe and SNr (BG downstream stages, bottom panels) recordings, before and after MPTP intoxication (left and right, respectively). Average PSD of activity of striatal TANs is in the inset of the top panels. Abscissas are in log scale. The shaded areas mark SEMs. N is the number of recording sites averaged.