Proportions of model instances, depicted as Venn diagrams, falling within target ranges of fitness metrics.

<p>Out of a total of 734,205 model instances which were simulated, 490,023 were at least quasi-functional. The left hand column of Venn diagrams shows the model instances which were capable of producing not only basic fitness metrics (average spike frequency, spike height, slow-wave height) but also the proper phase for the peristaltic or synchronous mode in the indicated heart motor neuron. For example, there were 54,361 models which produced a phase and duty cycle within an acceptable deviation from the target for the HE(8) motor neuron with the peristaltic input pattern, but only 4,471 of these also produced the correct activity with the synchronous input pattern. 431 instances produced output which was within the target range for all metrics, i.e. they produced the target output with all four input patterns: HE(8)p, HE(8)s, HE(12)p and HE(12)s. Three sets were used in subsequent analyses based on the targets they achieved in addition to the basic metrics: set A (blue), the instances which achieved output within the target range for the HE(12) metrics; set B (green), HE(8) metrics; and set C (red), the intersection of sets A and B.