Figure 2.

The result of feature selection during the development of the EEG maturational age. The number of times a feature was selected during cross-validation is overlaid with the correlation of each feature with the PMA (cross-validation iterations = 39, feature number = 46); feature numbers align with feature labels given in Fig. 3A. Note that, the features selected most often are not always the features with the highest individual correlation between EMA and PMA. The legend refers to the segment of EEG each feature was estimated on: full denotes full 1 h EEG epoch and low SAT% refers to a segment of EEG with low SAT activity. Similarly, feature correlations are denoted by ‘ + ’ when estimated on the full 1 h epoch and ‘x’ when estimated on the low SAT% segment of the epoch.