Fig. 4From: Synchronization of inspiratory burst onset along the ventral respiratory column in the neonate mouse is mediated by electrotonic couplingVariability of neuronal activity is correlated with motor output expiratory and inspiratory duration. A.i Definition of system-level variables correlated with lag and inspiratory burst duration of individual neurons. A.ii Heat map of burst durations from one optical recording. Over successive breaths, inspiratory duration of neuron 6 is positively correlated with motor output inspiratory duration (T(I)); similarly, the lag of neuron 78 is negatively correlated with the preceding expiratory duration (T(E-))(E-1) A.iii Top: time-series of neuron 7 burst duration (orange) and motor output (blue) inspiratory duration; when these variables are plotted against each other, strong positive correlation (0.75) is apparent (right). Bottom: time-series of neuron 78 lags (orange) and preceding expiratory duration (blue); when these variables are plotted against each other a weak negative correlation (0.44) is apparent (right). B Plot of the relative number of neurons with significant positive (red) and negative (blue) correlations between lag (left) and neuronal burst duration (right) and system-level variables shown in A.i. Dashed light-blue line indicates threshold below which correlations are expected by chance. Roughly 20% of neurons have lags that are significantly correlated with preceding expiratory duration (T(E-); positive), inspiratory duration (T(I); positive), and subsequent expiratory duration (T(E); positive and negative). More than 50% of neurons had burst durations that showed significant positive correlations with motor output T(I) duration and T(E). C Anatomical distribution of most robust correlations between neuronal lag (left) and neuronal burst duration (right) and system-level variables with positive (red) or negative (blue) correlations between lag and T(E-), T(I), and T(E). Gray shading represents the spatial average of the relative number of neurons positively or negatively correlated with each system-level variable. D Venn diagrams of neurons with significant positive and negative correlations between lag and system-level variables (T(E-), T(I), T(E))Back to article page