Extended Data Fig. 9. Schematic model of the vIRt_PV circuit that generates rhythmic whisking in normal and experimental conditions.

a, In Resting state, vIRt_PV neurons show unsynchronized tonic activity. b, In Normal whisking condition, tonic excitatory inputs to vFMN protractor motoneurons protract vibrissae. Concurrently, tonic excitatory inputs to vIRt_PV neurons induce recurrent inhibition within vIRt_PV and which in turn switches vIRt_PV from tonic firing to synchronized rhythmic bursting mode. The rhythmic signal from vIRt_PV periodically silences vFMN protractor motoneurons and leads to rhythmic whisking. The rhythmic inhibitory signal from the inspiratory rhythm generator preBötC resets the activity of vIRt_PV. The expiratory oscillator activates vFMN retractor motoneurons. c, In vIRt_PV-TeLC condition, outputs from vIRt_PV are abolished. Lack of inhibition from vIRt_PV results in strong continuous activation of vFMN protractor motoneurons and strong protraction of vibrissae. Because of the strong tonic activity of protractor intrinsic muscles, extrinsic retractor muscles play a minor role in vibrissa movement. d, In vIRt_PV-GFE3 condition, tonic excitation induces strong unsynchronized tonic inhibitory outputs from vIRt_PV to vFMN protractor motoneurons, which results in a less protracted midpoint compared with vIRt_PV-TeLC’s. Under this condition, the contribution of expiratory oscillator-extrinsic retractor muscles becomes pronounced. A group of inhibitory neurons in the left top corner of vIRt indicates PV⁻/vGat⁺ vIRt neurons. Dotted lines denote putative connections.