[Effect of central coordination in the sense of v. Holst on the control of breathing and limb movements in humans].

We found modulations in the time-course of breathing during rhythmic abduction-adduction movements in shoulder and hip joints which can be interpreted as phenomena of central coordination in the sense of v. Holst. They occurred in more than 75% of the recorded breaths. The strength of this coordination depends on number and kind of limbs moving rhythmically and on the use of an acoustic trigger signal ("Zeitgeber") for the limb rhythm as well. Our findings indicate that reactions of the respiratory apparatus cannot be regarded only in connection with its homeostatic function and with mechanical influences. Breathing control appears integrated in the whole organism's "motor control system". Therefore, an influence of breathing movements on other motor processes is possible as well. Coordination leads to a stable temporal order between breathing and additional movements. Its possible advantage could be an energetic economization as may be concluded from analogous phenomena in coupled non-linear oscillators.