Figure 3. Light-evoked EPSCs produced by ascending cochlear nucleus inputs were due to inwardly rectifying AMPARs.
(A) Sagittal micrograph of a ChR2-Venus-positive ventral cochlear nucleus (* marks the presumed injection site). (B) Micrograph from the same mouse as in (A), where ChR2-positive fibers are present in the VNTB and RPO near MOC neuron somata. (C) Two MOC neurons in the VNTB that were recorded from a coronal brain section and filled with biocytin after post-hoc histochemistry. (D) Example of loose-patch cell-attached recording of a ChR2-Venus-positive neuron in the VCN. Neurons positive for ChR2-Venus can reliably fire action potentials in response to light stimuli. (E) An example of EPSCs evoked during voltage clamp, with holding potentials ranging from −62.8 mV to +57.2 mV in 20 mV steps. Each sweep was baselined to 0 pA and low-pass Bessel filtered at 3000 Hz. (F) I-V relation of normalized cumulative data (N = 3–9 per mean). Error bars are ± SEM. Abbreviations: VCN, ventral cochlear nucleus; aVCN, anteroventral cochlear nucleus; pVCN, posteroventral cochlear nucleus; DCN, dorsal cochlear nucleus; grC, granule cell layer; 7N, facial motor nucleus; RPO, rostral periolivary region; MOC, medial olivocochlear; VNTB, ventral nucleus of the trapezoid body.
Figure 3—figure supplement 1. AAV injection schemes to target ascending or descending inputs to MOC neurons.
