  By combining high-density super-resolution imaging with a novel stochastic
analysis, we report here a peculiar nano-structure organization revealed by the
density function of individual AMPA receptors moving on the surface of cultured
hippocampal dendrites. High density regions of hundreds of nanometers for the
trajectories are associated with local molecular assembly generated by direct
molecular interactions due to physical potential wells. We found here that for
some of these regions, the potential wells are organized in ring structures. We
could find up to 3 wells in a single ring. Inside a ring receptors move in a
small band the width of which is of hundreds of nanometers. In addition, rings
are transient structures and can be observed for tens of minutes. Potential
wells located in a ring are also transient and the position of their peaks can
shift with time. We conclude that these rings can trap receptors in a unique
geometrical structure contributing to shape receptor trafficking, a process
that sustains synaptic transmission and plasticity.
