Fig. 4: Correlation between neuronal firing and loss tangent.

Neurons were treated with isoflurane (iso, red/yellow asterisk), or flowing air (air, blue/cyan points) as a control. Linear regression (pink dashed lines) was performed on the mean number of times neurons fired vs. mean neuronal loss tangent (\(\tan \delta\)) measured at: 0.5, 1, 2.5, 5, 7.5 or 10 Hz, shown in a–f, respectively. Linear regression (metrics shown in each panel and in Supplementary Table S14) was performed on measurements collected at five experimental time points: 15, 30 and 45 min during gas exposure, and 30 and 45 min after gas exposure (indicated by point shading). Measurements before gas exposure were excluded because the sample was at a higher temperature during Before measurements than during subsequent measurements. Similarly, control measurements of no gas flow were excluded from the regression in order to avoid convoluting the effects of isoflurane with those of the flow itself. Significant correlations are indicated by: *p < 0.05 and **p < 0.005.