Optogenetic stimulation of PiCo specific ChATcre:Vglut2FlpO:ChR2 neurons triggers variable swallow motor patterns in mice exposed to chronic intermittent hypoxia (CIH). (A) Representative trace of water triggered swallow. (B) Representative traces of PiCo triggered swallows: (Bi) “classic” swallow with the preserved rostrocaudal sequence shown in the red arrows. (Bii) “non-classic” swallow with similar onset, offset and loss of sequence in submental and laryngeal complexes. (Biii) “Tonic” pre-swallow activity with preserved rostrocaudal sequence and low tonic submental and laryngeal activity during the laser pulse, converging into a swallow. (Biv) “Laryngeal Adductor Reflex” (LAR) (purple arrow) followed by a swallow.
There is a period of quiescent activity between the LAR and swallow (red arrow). (Bv) “Non-LAR” followed by a swallow. There is an absence of quiescent activity between the laryngeal activity and the swallow (red arrow). (C) Percentage of all PiCo triggered swallows (816 total swallows) in ChATcre:Vglut2FlpO:ChR2 mice. Black is classic, pink is non-classic, blue is tonic, purple is LAR, and green is non-LAR. (D) representative traces of submental complex (SC) and laryngeal complex (LC) from the swallows in panel B with color coding the same as panel C. (E) Scatter plot of behavior duration versus laser pulse duration for swallow in ChATcre:Vglut2FlpO:ChR2 mice. Each dot represents the average duration per mouse. The gold dots represent mice exposed to CIH and the black dots are in control mice exposed to room air taken from Figure 3A in (A. D. Huff et al., 2023).