Axon Guidance by Gradients of a Target-Derived Component

TLDR

Spatial gradients of axon guiding molecules have long been suspected to provide positional and directional cues for retinal ganglion cell axons growing within the optic tectum. The study aims to investigate the physiological significance of molecular gradients for retinal growth cone behavior in vitro. It uses a guiding activity identified from tectal cell membranes to examine retinal growth cone responses to these gradients. Temporal retinal growth cones were highly sensitive to small concentration changes of the guiding component, with response magnitude correlating with gradient strength, demonstrating that growth cones can read surface‑associated gradients.

Abstract

Spatial gradients of axon guiding molecules have long been suspected to provide positional and directional cues for retinal ganglion cell axons growing within the optic tectum. With the identification of a guiding activity from tectal cell membranes, it has become possible to investigate the potential physiological significance of molecular gradients for retinal growth cone behavior in vitro. A subset of retinal growth cones, those from the temporal half, were highly sensitive to small concentration changes of the guiding component. The degree of response was correlated with the strength of the gradient. These findings demonstrate that the neural growth cone can read gradients of surface-associated information.