Supplementary Figure 3: Identification of high-firing-rate neurons using optogenetic ID of LC noradrenaline neurons in a TH-Cre rat.

(a-d) Representative waveform (a), cluster (b), interspike interval (c), and autocorrelogram (d) of high frequency firing cell. (e) Example of perievent time histogram of optogenetic inhibition in high frequency firing cell. Bin size = 100 ms. (f) Distribution of spontaneous firing rate of all optogenetically identified units in overtraining experiment. 6/24 (data from 5 rats: rat 1=6 cells, rat 2=8 cells, rat 3=7 cells, rat 4=2 cells, rat 5=1 cell) cells are defined as high firing rate based on baseline firing rates of >10 Hz. Optogenetically identified, high firing rate cells were also apparent before any behavioral manipulation (2/10 optogenetically identified cells, data from 4 rats: rat 1=1 cell, rat 2=3 cells, rat 3=4 cells, rat 4=1 cell). (g) Perievent time histograms showing shock US evoked firing rate (y-axis) responses in example LC cell. Time is on x-axis with 0=CS or US onset time (US period denoted by bar). Bin size=200 ms. (h) Pie chart showing proportion of high-frequency firing rate cells (n=6) which were identified as auditory responsive (red, 50.0%), shock responsive (yellow inside, 83.3%) or non-responsive to shocks or auditory stimuli (black). 33.3% of cells responded to both CS and US, 16.6% responded to CS alone and 50.0% responded to US alone.