Breathlessness-related Brain Activation: Electroencephalogram Dipole Modeling Analysis

Dyspnea is the feeling of shortness of breath and is a primary symptom of cardiopulmonary disease. Dyspneic symptoms include sensations such as labored respiration, chest tightness, air hunger, and uncomfortable or unpleasant urges to breathe. In this study, we investigated the brain areas associated with dyspnea using electroencephalogram dipole (EEG/DT) modeling. We hypothesize that good temporal resolution of EEG/DT recordings will enable determination of the neuroanatomical substrates of dyspnea in time course measures of inspiration. We measured EEG and respiration simultaneously during CO2 rebreathing, which induced dyspnea in the subjects and allowed us to find inspiration-related potentials during dyspnea. The waveform of the potentials was composed of a negative peak at 100ms and a positive peak at 250ms. Our EEG/DT modeling estimated their source generators in the left superior frontal and left orbitofrontal cortex (OFC) at 100ms after inspiration onset. In the next 100ms, the anterior cingulate cortex was activated, followed by the superior frontal and OFC. At 200ms to 300ms, dipoles finally converged in the left insula and amygdala. The first component of inspiration-related potentials thus involved frontal areas that play a role in the intention to inspire and emotional guidance, while the late component incorporated areas related to emotional reaction. We suggest that dyspnea with increasing ventilation could involve intentions or efforts to continue inspiration activities, and consequently, the perception of dyspnea could be associated with unpleasant emotions