Figure 4.

Preliminary model for the neurogenesis of swallow-breathing coordination (adapted from (21)). Second order swallow behavioral control assembly (Swallow BCA) is postulated to receive swallow related afferent input (red lines). When the swallow BCA is activated, these neurons project to specific neural elements of the respiratory neural network (red lines). Results from swallow induced stimulation of the Swallow BCA suggest neurons with shared afferent input and reciprocal inhibition relay to the swallow (green lines) and respiratory motor neurons. Also represented are the Cough BCA’s for laryngeal and tracheobronchial induced cough. Definitions: NTS – nucleus of the tractus solitaries, DSG – dorsal swallow group, I-DRIVER - Inspiratory neuron also active during the expiratory-inspiratory phase transition, I-Dec - Inspiratory neuron with decrementing firing rate during the phase, I-Aug - Inspiratory neuron with augmenting firing rate during the phase, I-Aug (premotor) - Inspiratory neuron with augmenting firing rate during the phase axon projects down spinal cord, E/EI - Phase spanning-starts in E ends in I, E-Dec - Expiratory neuron with decrementing firing rate most active during the early-expiratory (post-inspiratory) interval, E-Aug (early) - Rostral VRC/Böt expiratory neuron with augmenting or symmetrical discharge pattern begins activity early in phase and active throughout, E-Aug (late) - Rostral VRC/ Böt expiratory neuron with augmenting discharge pattern activity limited primarily to late part of expiratory interval (stage 2 expiration), E-Aug - Caudal expiratory neuron with augmenting discharge pattern propriobulbar axon confined to brainstem, E-Aug (premotor) - Expiratory neuron with augmenting discharge pattern premotor excitatory bulbospinal.