Experimental application of an additional inspiratory load in awake healthy subjects causes a compensatory increase in respiratory work to maintain effective ventilation, and the subject does not develop hypoventilation. This respiratory drive to breathe has been demonstrated by quantified electroencephalography in inspiratory load tests in the form of pre-inspiratory negative deflections of low amplitude similar to the potential described during the preparation of the voluntary movement of a limb. These inspiratory pre-motor potentials begin about 2.5 seconds before the start of a movement in the additional motor area.