Fig. 4.

PreBötC inhibitory neuron populations have distinct effects on inspiratory burst frequency. a Diagram of Vgat-ChR2 brainstem slice configuration used to identify inhibitory preBötC neuron activity relative to preBötC burst phase. b Representative activity of a Vgat− inspiratory neuron showing post-inhibitory rebound following light stimulation (left) and a Vgat+ neuron with inspiratory activity (right). 14/37 (37%) recorded inspiratory neurons were inhibitory. c Example Vgat+ expiratory neuron at baseline and during blockade of synaptic inhibition with strychnine (1 µM) and gabazine (1 µM) (n = 3). Note that expiratory activity transitions to inspiratory activity following blockade of synaptic inhibition. 10/10 (100%) recorded expiratory neurons were inhibitory. d Example recording of preBötC population activity from a Vgat-ChR2 slice during phase-specific light stimulation. Average data shown in Fig. 5c