Optogenetic tools, providing non‐invasive control over selected cells, have the potential to revolutionize sensory prostheses for humans. Optogenetic stimulation of spiral ganglion neurons (SGNs) in the ear provides a future alternative to electrical stimulation used in cochlear implants. However, most channelrhodopsins do not support the high temporal fidelity pertinent to auditory coding because they require milliseconds to close after light‐off. Here, we biophysically characterized the fast channelrhodopsin Chronos and revealed a deactivation time constant of less than a millisecond at body temperature. In order to enhance neural expression, we improved its trafficking to the plasma membrane (Chronos‐ES/TS). Following efficient transduction of SGNs using early postnatal injection of the adeno‐associated virus AAV‐PHP.B into the mouse cochlea, fiber‐based optical stimulation elicited optical auditory brainstem responses (oABR) with minimal latencies of 1 ms, thresholds of 5 μJ and 100 μs per pulse, and sizable amplitudes even at 1,000 Hz of stimulation. Recordings from single SGNs demonstrated good temporal precision of light‐evoked spiking. In conclusion, efficient virus‐mediated expression of targeting‐optimized Chronos‐ES/TS achieves ultrafast optogenetic control of neurons.

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BackgroundCurriculum design and specific topic selection for on-site practical courses in clinical disciplines with limited teaching time is challenging. An electronic learning supported curriculum based on the flipped classroom principle has a high potential to effectively gain knowledge and education along with improving practical experience. Here, we demonstrate the introduction of a flipped classroom curriculum for practical courses in Otorhinolaryngology (ORL) in real world practice to improve the on-site time management and students’ experience.MethodsEducational aims of our practical curriculum were analysed and rearranged into a flipped classroom (FC) framework. Core knowledge was taught preliminary based on a moodle platform in predominantly interactive formats. Two quasi-randomized groups were formed with 212 participants either receiving or not receiving access to the e-learning program to reduce a potential allocation bias to the e-learning group. All students completed a questionnaire with learning related items. Focusing the study on the intervention group, we investigated if students using the flipped classroom more often felt better prepared for the practical course.ResultsThe online learning platform was highly accepted and frequently used by 66% of participating students in the e-learning group. Students with frequent use of our e-learning platform significantly felt better prepared for the practical course (p = 0.001). The far majority of all students supports the idea of further development of e-learning. More than 70% were generally interested in ORL. Handouts were the overall most important learning resource and more than 50% relied solely on them.ConclusionsFlipped classroom curricula can save time and help improving the on-site experience in practical courses especially in smaller surgical disciplines. The acceptance of digital learning is high, and most students rely on handouts for learning ORL, emphasizing the need for guidance by the teacher e.g. through electronic learning. Our results underline the high potential of FC to address teaching challenges for smaller medical disciplines with limited teaching time like ORL.Electronic supplementary materialThe online version of this article (10.1186/s12909-018-1398-5) contains supplementary material, which is available to authorized users.