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. Author manuscript; available in PMC: 2021 Sep 7.
Published in final edited form as: Neurobiol Dis. 2021 May 15;155:105393. doi: 10.1016/j.nbd.2021.105393

Figure 1: Alterations in MCx and SNpr high beta/low gamma LFP activity, spike-LFP relationships, LFP spectral peaks, and motor performance in the week following unilateral 6-OHDA induced dopamine cell lesion.

Figure 1:

A-C: Representative time-frequency wavelet scalograms of spectral power in LFP recordings from MCx and SNpr, and FFT-based time-frequency MCx-SNpr coherence during treadmill walking. Recordings were obtained before injection of 6-OHDA into the median forebrain bundle (Control/Ctrl), and, starting 24 hours (Day 1) after injection, on days 1, 3, 5 and 7. Power is plotted on a logarithmic scale and coherence spectrograms are plotted on a linear scale with greater values represented by red. D-F: Averaged MCx and SNpr LFP power spectra and MCx-SNpr coherence spectra with bar graphs (inset) depicting mean total LFP power around dominant peaks (peak +/− 3 Hz) in the high beta/low gamma (HB/LG) 29–40 Hz frequency range in the MCx (D, red bars), SNpr (E, blue bars) and MCx-SNpr coherence (F, black bars), and in the mid-gamma 40–55 Hz range (D-F grey bars). Bar graphs show linear increases in MCx and SNpr HB/LG LFP power (R2 = 0.94) and MCx-SNpr coherence (R2 = 0.99) over days 1, 3, 5 and 7 following the 6-OHDA injection. Data are reported as mean ± SEM. * p < 0.05, relative to control (Ctrl). G: Distribution of the frequencies of dominant spectral peaks in MCx and SNpr LFP power and MCx-SNpr coherence spectra in recordings from before lesion (Control) and on days 1, 3, 5 and 7 after unilateral dopamine cell lesion during treadmill walking. Box plots depict 25th to 75th percentile values and black dots show individual peak frequencies. * p < 0.05, relative to control, n = 9 rats, max 8 peaks per rat, see methods). H-I: Spike-LFP phase-locking of spikes from SNpr multiunit spike-trains with SNpr and MCx LFP activity in the HB/LG range from control rats and on 1, 2, and 7 days post-lesion. Box plots (H) show ratios of unshuffled:shuffled peak-to-trough amplitude in STWAs (see Methods) and (I) the proportion of multi-unit SNpr spike trains with spikes significantly correlated to SNpr LFPs (blue bars) and MCx LFP (red bars). * p < 0.05, relative to control, n = 64 multiunit spike trains, 2 epochs/train, 4–8 trains per rat, 5 rats). J-L: Motor function in control rats and following unilateral DA cell lesion. J: Bar graph shows the number of steps made by the right paw and the left paw in the forelimb step test in control and over days 1–7 post-lesion. K: Bar graph displays inner:outer hind limb step count ratios during ipsilateral (purple bars) and contralateral (gray bars) walking in a circular treadmill. L: Bar graph indicates the % completed trials (black bars) vs incidences of failure (white bars) to initiate and maintain steady treadmill walking for at least 30 seconds when oriented in the direction contralateral to the lesion. * p < 0.05, relative to control.