Complex sectioning (transverse) at mid pons level along with vagi results in
→ Section A: Cut at upper part of pons: (Decerebration): Normal rhythmic breathing continues. Loss of voluntary breath holding. If vagi are cut, increase in depth and slow breathing.
→ Section B: Cut at mid-pons: Apneustic center (Ap) intact but pneumotaxic centre separated. Ap stimulates Inspiratory (I) neurons, which increase depth of breathing.

Vagi intact: Regular respiration with deep and slow breathing (increase in TV and a slight decrease in RR).
Vagi cut: Arrest of respiration in maximum inspiratory phase (apneusis) interrupted by brief expiration.

→ Section C: Cut at inferior portion of pons: All the pontine tissue is separated

Vagi intact: Irregular and gasping but it is rhythmic (because pacemaker tissue is intact).
Vagi cut: Same effect as above, because vagi are connected to Ap center.

→ Section D: Cut below medulla: Complete transection of brainstem:

Stops all respiration (apnoea and death).

Bilateral vagotomy only: Regular respiration with deep and slow breathing (increase in TV and a slight decrease in RR).
Asphyxia
Hyperventilation
Rapid and shallow breathing
Apneusis