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 ambiguus.^[1][2]

Function

The Bötzinger complex plays an important role in controlling breathing^[3][4] and responding to hypoxia.^[5][6] The Bötzinger complex consists primarily of glycinergic neurons^[7] which inhibit respiratory activity. Of the respiratory cycle phases BötC generates post-inspiratory (Post-I) activity and augmenting expiratory (aug-e) activity.^[8][9][10]

Name

The Bötzinger complex was named by UCLA Professor Jack Feldman in 1978, after a bottle of white wine named Botzinger present at his table during a scientific meeting in Hirschhorn, Germany, that year.^[11]

Connections

The Bötzinger Complex has projections to

• Phrenic pre-motor neurons in the medulla^[12]
• Phrenic motor neurons in the cervical spinal cord^[13][14]
• The dorsal respiratory group (DRG) ^[13][15]
• Ventral respiratory group (VRG)^[12][13][16]
• Pre-Bötzinger complex^[17]
• Bötzinger complex ^{[2][13][18][19]}
• Parabrachial Kolliker-Fuse nucleus^[20]

Only augmenting expiratory neurons of BötC, which are exclusively glycinergic, project to the phrenic nucleus.^[21][14]

Projections to the Bötzinger complex include the nucleus tractus solitarii (NTS)^[22][23] the DRG and the VRG.^[24]

Physiology

These neurons are intrinsic pacemakers.^[25] 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.^[19][26]