'Specific' and 'non-specific' stimuli in the drive of respiration

In decerebrate and awake cats it was shown that central chemosensitivity can be blocked by cooling or coagulating bilaterally a formerly described area on the ventral medullary surface of cats, called area S. Such a procedure is followed by apnoea under the condition that vagi and sinus nerves are cut. With either vagi, sinus nerves, or central chemosensitivity intact respiration can be influenced by noise, touch, and electrical stimulation of dorsal roots, femoral nerves, and pontine reticular formation. With vagi, sinus nerves, and central chemosensitivity blocked, these "non-specific" stimuli are not able to influence respiration. In the described experiments vagi, sinus nerves, and central chemosensitivity were essential for the activity of the respiratory centres and were therefore called "specific".