Dendritic coincidence detection in Purkinje neurons of awake mice

<p><span>Dendritic coincidence detection is thought fundamental to neuronal processing yet remains largely unexplored in awake animals. Specifically, the underlying dendritic voltage-calcium relationship has not been directly addressed. Here, using simultaneous voltage and calcium two-photon imaging of Purkinje neuron spiny dendrites, we show how coincident synaptic inputs and resulting dendritic spikes modulate dendritic calcium signaling during sensory stimulation in awake mice.<span> </span></span><span>Sensory stimulation increase</span><span>d</span><span><span> </span>the rate of post</span><span>-</span><span>synaptic potentials and dendritic calcium spikes evoked by climbing<span> </span></span><span>fiber<span> </span></span><span>and parallel fiber</span><span><span> </span>synaptic input. These inputs are integrated in a time-dependent and non-linear fashion to enhance the sensory evoked dendritic calcium signal. Intrinsic supralinear dendritic mechanisms, including voltage-gated calcium channels and metabotropic glutamate receptors, are recruited cooperatively to expand the dynamic range of sensory evoked dendritic calcium signals. This establishes how dendrites can use multiple interplaying mechanisms to perform coincidence detection, as a fundamental and ongoing feature of dendritic integration in behaving animals.</span></p>