Slowly adapting pulmonary stretch receptor spike patterns carry lung distension information.

Slowly adapting pulmonary stretch receptors (SARs) provide the respiratory and cardiovascular control systems with information regarding the rate and depth of breathing. Previous information theoretical analysis demonstrated that SAR spike count provides a reliable representation of lung distension. This study examines whether SAR spike patterns may also provide information about lung distension. To investigate this, artificial spike trains were generated with the same number of spikes (but randomized intervals) as those recorded from SARs in response to three different lung inflation volumes in urethane-anesthetized rabbits. Three different spike train classification methods were applied to estimate which stimulus evoked them, and the accuracy with which artificial spike trains were classified was compared to that of real SAR spike trains using the same methods. Because real SAR spike trains were classified with higher accuracies than artificial ones containing the same number of spikes, we conclude that SAR spike patterns, in addition to spike counts, contain information concerning the amplitude of lung distension.