[Mechanism of hyperventilation in exertion (an uncommon factor)].

Electrical stimulation of the corticospinal tract increases the excitability of the phrenic motoneurons directly. As a result the responses of these motoneurons to the impulses from the respiratory centre are facilitated. Until now there were attempts to explain exercise hyperpnea by increasing the activity of the respiratory centre. The experiments permit to suppose that the hyperpnea may be produced by facilitatory action of the corticospinal tract on the respiratory motoneurons, i.e. independently from the respiratory centre.