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. 2019 Aug 27;116(37):18664–18672. doi: 10.1073/pnas.1907810116

Fig. 4.

Fig. 4.

SPNs predominantly show stable responses to DA in control animals infused with rAAV-eGFP. (A and B) Examples of SPN stable activity changes in response to s.c. l-Dopa injection in animals infused with rAAV-eGFP. Short (12 s) raster plots and spectrograms for the whole segment duration (180 s) are shown for each segment (OFF, ON, and DYS). Firing rates of SPNs were increased (A) or decreased (B) from the OFF to the ON state. In DYS state, SPNs with increase or decrease in ON continued to change their firing rates in the same direction, ie, increase (A) or decrease (B). (C–F) Changes of SPN firing frequency (in Hertz) across units grouped by the type of response: stable and unstable increase in ON-LID transition (C and E, respectively) or stable and unstable decrease in ON-LID transition (D and F, respectively). In each of the 4 types of response, units recorded weekly in each month are presented in separate graphs. In each graph, each curve represents an individual SPN. Responses were classified as increase or decrease depending on significant firing frequency change from OFF to ON and as stable or unstable by significant firing frequency change in the same or opposite direction in the transition from ON to LID, all taken at P < 0.01. No significant change from ON to LID was also taken as stable. SPN firing rasters in A and B are derived from SPNs shown as a thick green curve in month 1 of C and D, respectively. (G and H) The proportion of SPNs with stable (blue bars) or unstable (red bars) responses through the recordings of each month. In the group of SPNs with increased activity in the ON state (G), a progression to reduced stable responses in the transition to LID was found from month 1 to month 2 and to month 3 (75%, 62.5%, and 50% of SPNs in each month). In the group of SPNs with decreased activity in the ON state (H), more rapid reduction of stable responses in the transition to LID developed after month 1 (87.5%, 47%, and 57% of SPNs in each month; *P < 0.05 versus SPNs with unstable changes in the same month).