Ultrafast optogenetic stimulation of the auditory pathway by targeting-optimized Chronos

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-PHPB 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

Modernization, Risk, and Conservation of the World\u27s Largest Carnivores

Large carnivores are threatened worldwide by a variety of human-driven factors, including persecution, which regularly results when they come into conflict with people. Although human activities are almost universally viewed as negatively affecting carnivore conservation, we contend that conservation outcomes for carnivores are improved when social and economic forces reduce the risks associated with these species and facilitate the acquisition of values favorable to their conservation. We make three specific propositions: (1) Societal tolerance for carnivores is affected by the distribution of risks and benefits associated with these species, (2) modernization and its associated social changes reduce the risks associated with large carnivores and their conservation, and (3) modernization induces lasting effects on conservation by changing societal values. We review existing evidence and present cross-sectional data showing that variation among nations in large carnivore conservation outcomes are related to three facets of modernization believed to reduce the risks associated with large carnivores

Modernization, Risk, and Conservation of the World's Largest Carnivores

© 2017 The Author(s). Large carnivores are threatened worldwide by a variety of human-driven factors, including persecution, which regularly results when they come into conflict with people. Although human activities are almost universally viewed as negatively affecting carnivore conservation, we contend that conservation outcomes for carnivores are improved when social and economic forces reduce the risks associated with these species and facilitate the acquisition of values favorable to their conservation. We make three specific propositions: (1) Societal tolerance for carnivores is affected by the distribution of risks and benefits associated with these species, (2) modernization and its associated social changes reduce the risks associated with large carnivores and their conservation, and (3) modernization induces lasting effects on conservation by changing societal values. We review existing evidence and present cross-sectional data showing that variation among nations in large carnivore conservation outcomes are related to three facets of modernization believed to reduce the risks associated with large carnivores