Continuous Dynamic Photostimulation - inducing in-vivo-like fluctuating conductances with Channelrhodopsins

TL;DR

This paper introduces CoDyPs, a novel continuous photostimulation method that mimics in-vivo-like fluctuating conductances in neurons, enabling more natural activity patterns and larger data collection in neural studies.

Contribution

The study presents a new noninvasive photostimulation technique, CoDyPs, that reproduces in-vivo-like conductance fluctuations in neurons transfected with ChIEF, improving natural activity modeling.

Findings

CoDyPs induces reproducible, in-vivo-like spike patterns.

It precisely predicts current waveforms from light-conductance transfer functions.

Allows larger data sets for studying neuronal dynamics.

Abstract

Central neurons operate in a regime of constantly fluctuating conductances, induced by thousands of presynaptic cells. Channelrhodopsins have been almost exclusively used to imprint a fixed spike pattern by sequences of brief depolarizations. Here we introduce continuous dynamic photostimulation (CoDyPs), a novel approach to mimic in-vivo like input fluctuations noninvasively in cells transfected with the weakly inactivating channelrhodopsin variant ChIEF. Even during long-term experiments, cultured neurons subjected to CoDyPs generate seemingly random, but reproducible spike patterns. In voltage clamped cells CoDyPs induced highly reproducible current waveforms that could be precisely predicted from the light-conductance transfer function of ChIEF. CoDyPs can replace the conventional, flash-evoked imprinting of spike patterns in in-vivo and in-vitro studies, preserving natural activity. When combined with non-invasive spike-detection, CoDyPs allows the acquisition of order of magnitudes larger data sets than previously possible, for studies of dynamical response properties of many individual neurons.