Figure 1.
Serotonin concentration prediction from dual transmitter model. (a) An illustration of voltammograms acquired for varying levels of serotonin concentration (left) and dopamine concentration (right) in the flow cell. We see that low to high concentration levels produce changes in current magnitude around the oxidation potentials (insets). Concentration is denoted by []. (b) The flow cell predictions are illustrated for serotonin under varying concentrations of dopamine in the mixture. Serotonin was sampled at each level of concentration from 0.1 to 8 μM in 0.1 μM increments. For each of these 80 concentrations we computed the serotonin prediction over different levels of dopamine. Not all concentration mixtures for dopamine and serotonin were acquired and acquired mixtures are denoted by the asterisk. Over this test grid we interpolated (using linear triangulation) across the acquired tests samples to produce a three-dimensional heat map of serotonin predictions. This plot show that serotonin predictions do not vary systematically with increasing dopamine levels. We illustrate one outlying serotonin prediction, which was observed but not included in the interpolated plot for visualization purposes. (c) Flow cell predictions for dopamine in the mixture, plotted as a function of increasing dopamine and increasing serotonin as per b. Again, dopamine predictions using our model do not appear to be systematically affected by the level of serotonin in the sample. (d) We tested 200 out-of-sample voltammograms for each concentration level to quantify the error in generalizability. Illustrated in gray are predictions for different concentration ranges and their 99.99% confidence intervals. Red crosses denote the mean of the (correct) test range. For each range we randomly selected 20 predictions from the full test set.