Figure 6.

Isocitrate reconfigures the respiratory network by changing firing frequency of respiratory elements and connectivity strength between them. (A) Left: Histogram of the number of links in the respiratory network, indicating that the functional connectivity between elements did not change significantly in the presence of isocitrate and further application of hypoxia. Right: Histogram of the change in correlated firing among elements between normoxic and hypoxic conditions (multiunits and units were grouped together), showing a significant increase in correlation in the presence of isocitrate and a further increase upon hypoxia application (^*p < 0.05). (B) Graphic representation of respiratory network configurations in normoxia before and after isocitrate application and in hypoxic conditions in the presence of isocitrate. Each respiratory element is represented as a circle and each significant correlation between two elements is represented as a connecting line (functional link). The diameter of the circles is proportional to the number of functional links that each element has with other elements in the network. The width of the lines is proportional to the correlation value of any given link. Note that isocitrate increases the strength of the functional links but does not significantly change their number. When hypoxia is applied in the presence of isocitrate, the strength of the functional links increases even further, but again, their number remains constant.