Botzinger complex

In mammals, the Bötzinger complex (BötC) is a group of neurons located in the rostral ventrolateral medulla, and ventral respiratory column. In the medulla, this group is located caudally to the facial nucleus and ventral to nucleus ambiguous.

Function

The Bötzinger complex plays an important role in controlling breathing and responding to hypoxia. The BötC consists primarily of glycinergic neurons which inhibit respiratory activity. Of the respiratory cycle phases BötC generates post-inspiratory (Post-I) activity and augments expiratory (aug-e) activity.

Name

The Bötzinger Complex was named by UCLA Professor Jack Feldman in 1978. Feldman named this area after a bottle of white wine named Botzinger present at his table during a scientific meeting in Hirschhorn, Germany, that year.

Connections

The Bötzinger Complex has projections to

• Phrenic pre-motor neurons in the medulla
• Phrenic motor neurons in the cervical spinal cord
• The dorsal respiratory group (DRG)
• Ventral respiratory group (VRG)
• Pre-Bötzinger complex
• Bötzinger complex
• Parabrachial Kolliker-Fuse nucleus

Only augmenting expiratory neurons of BötC, which are exclusively glycinergic, project to the phrenic nucleus.

Projections to the Bötzinger complex include the nucleus tractus solitarii (NTS) the DRG and the VRG.

Physiology

These neurons are intrinsic pacemakers. Post-I neurons display an initial burst of activity followed by decrease in activity at the end of inspiration. Aug-E neurons begin firing during the E2 phase and end before the phrenic nerve burst.