The performance of all regression models at the voltage prediction task, on test data, is shown in Fig. . The left and right columns of the figure stand in contrast, where the former represents models trained and tested on data from 'all cells', and the latter represents models trained and tested on folds of 'held out cells'. The results, as a whole, indicate that no model was able to identify patterns which would correlate acoustic signals to the voltage in a way that generalises to the cell population. Models trained on 'all cells' can be successful; however, this must be due to the learning of cell-specific patterns. Specific aspects of the results are discussed next, which reinforce this argument.