Light-evoked dendritic spikes in sustained but not transient rabbit retinal ganglion cells.

Dendritic computations have a central role in neuronal function, but it is unknown how cell-class heterogeneity of dendritic electrical excitability shapes physiologically engaged neuronal and circuit computations. To address this, we examined dendritic integration in closely related classes of retinal ganglion cells (GCs) using simultaneous somato-dendritic electrical recording techniques in a functionally intact circuit. Simultaneous recordings revealed sustained OFF-GCs generated powerful dendritic spikes in response to visual input that drove action potential firing.

Activity-dependent modulation of layer 1 inhibitory neocortical circuits by acetylcholine.

Layer 1 neocortical GABAergic interneurons control the excitability of pyramidal neurons through cell-class-specific direct inhibitory and disynaptic disinhibitory circuitry. The engagement of layer 1 inhibitory circuits during behavior is powerfully controlled by the cholinergic neuromodulatory system. Here we report that acetylcholine (ACh) influences the excitability of layer 1 interneurons in a cell-class and activity-dependent manner.

HCN1 channels significantly shape retinal photoresponses.

In this chapter, the impact of HCN1 channels on the retinal functional properties was presented. HCN1 channel loss led to an intensity-dependent prolongation of the rod system response, in agreement with the threshold mechanism of activation of the channel. Rod outer segment functionality was not altered, supporting the main site of action in the inner segment.

Modulation of rod photoreceptor output by HCN1 channels is essential for regular mesopic cone vision.

Retinal photoreceptors permit visual perception over a wide range of lighting conditions. Rods work best in dim, and cones in bright environments, with considerable functional overlap at intermediate (mesopic) light levels. At many sites in the outer and inner retina where rod and cone signals interact, gap junctions, particularly those containing Connexin36, have been identified.