Hauptautor*innen: Christoph T. Block

Co-Autor*innen: Yousef Arzhanginia, Christian Puller, Malte T. Ahlers, Martin Greschner

Abstract:

The retina encodes visual stimuli as patterns of spikes with millisecond precision. Classically, this is studied at the level of the ganglion cell somata as it is easy to record from there. This is done with the implicit assumption that the spike pattern at the soma is transmitted through the axon unaltered. However, it was shown that the spike conduction velocity decreases if neurons were stimulated at high frequencies over extended periods. It is unknown whether this effect occurs under physiological conditions.

Here, we examined axonal spike propagation in a cell type with a naturally high firing rate. The conduction velocity of individual spikes was strongly linked to the interspike interval (ISI) between the current and the preceding spike. But surprisingly, the slowest spikes were associated with average ISIs, while both large and even small ISIs were associated with faster spikes.

In total, the spike pattern was modified during axonal conduction, however, preserving a systematic mapping of the visual input. However, some spike patterns became more and others less easily distinguishable as they were transmitted. In particular, the coding capacity of small ISIs decreased, as these tended to reduce even further and thereby became more similar to the refractory period.