Fig. 4: Globus pallidus opto-inhibition suppresses parkinsonian abnormal β-synchronization in cortico-BG loop.

a Epifluorescence images showing the eArch3-EYFP labeling in GP of 6-OHDA rats (top, scale: 200 µm, arrowhead indicates the optic fiber track) and dense axonal labeling in STN (middle, scale: 200 µm) and SNr (bottom, scale: 500 µm). b Electrophysiological activity of prototypic and arkypallidal neurons during SWA (top) and global activation (bottom). ECoG scale: 0.2 mV; spike unit: 0.5 mV. c Proportion of GP neurons inhibited (black), excited (blue), or not modulated (white) by laser stimulation. d Effect of opto-inhibition on prototypic and arkypallidal firing. Population PSTH of opto-inhibition on prototypic (e) and arkypallidal neurons (f) (bin: 50 ms). g Experimental paradigm (top left) and representative recordings of ECoG (scales: 250 µV), β-filtered ECoG (12–30 Hz, scale: 250 µV), and one STN unit (scale: 1 mV) during GP opto-inhibition. Example of juxtacellularly labeled STN neuron (bottom left, scale: 20 µm). h Scatter plot of GP opto-inhibition on STN firing. i STN firing rate changes during OFF versus ON GP opto-inhibition. j Mean PSTH of STN during laser stimulations (bin: 50 ms). k Peri-event spectrogram of mCx ECoG illustrating the impact of GP opto-inhibition during β-oscillations. l Mean normalized power spectrum of mCx ECoG OFF versus ON GP opto-inhibition (analysis on the best β epochs). m Cumulative distribution function of the β-AUCs differences calculated for AUC_(Pre–OFF) versus AUC_(OFF–ON) for all ECoG β epochs during GP opto-inhibition. n Mean phase histograms of STN neurons during β-oscillations OFF versus ON laser epochs. Group data represents mean ± SEM, box-and-whisker plots indicate median, first and third quartile, min and max values. See also Supplementary Table 4 for statistical information.