Cross-compartmental Modulation of Dendritic Signals for Retinal Direction Selectivity

Neuron. 2017 Aug 16;95(4):914-927.e4. doi: 10.1016/j.neuron.2017.07.020. Epub 2017 Aug 3.


Compartmentalized signaling in dendritic subdomains is critical for the function of many central neurons. In the retina, individual dendritic sectors of a starburst amacrine cell (SAC) are preferentially activated by different directions of linear motion, indicating limited signal propagation between the sectors. However, the mechanism that regulates this propagation is poorly understood. Here, we find that metabotropic glutamate receptor 2 (mGluR2) signaling, which acts on voltage-gated calcium channels in SACs, selectively restricts cross-sector signal propagation in SACs, but does not affect local dendritic computation within individual sectors. mGluR2 signaling ensures sufficient electrotonic isolation of dendritic sectors to prevent their depolarization during non-preferred motion, yet enables controlled multicompartmental signal integration that enhances responses to preferred motion. Furthermore, mGluR2-mediated dendritic compartmentalization in SACs is important for the functional output of direction-selective ganglion cells (DSGCs). Therefore, our results directly link modulation of dendritic compartmentalization to circuit-level encoding of motion direction in the retina.

Keywords: Direction selectivity; electrotonic isolation; mGluR2; motion computation; retina; starburst amacrine.

MeSH terms

  • Action Potentials / drug effects
  • Action Potentials / physiology
  • Amacrine Cells / cytology*
  • Amacrine Cells / physiology*
  • Amino Acids / pharmacology
  • Animals
  • Animals, Newborn
  • Cadmium Chloride / pharmacology
  • Calcium Channel Blockers / pharmacology
  • Dendrites / drug effects
  • Dendrites / physiology*
  • Excitatory Amino Acid Antagonists / pharmacology
  • Female
  • Inhibitory Postsynaptic Potentials / physiology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Motion Perception / physiology*
  • Photic Stimulation
  • Receptors, AMPA / genetics
  • Receptors, AMPA / metabolism
  • Retina / cytology*
  • Retina / physiology
  • Signal Transduction / drug effects
  • Signal Transduction / genetics
  • Signal Transduction / physiology*
  • Synapses / drug effects
  • Synapses / physiology
  • Xanthenes / pharmacology
  • omega-Conotoxin GVIA / pharmacology


  • Amino Acids
  • Calcium Channel Blockers
  • Excitatory Amino Acid Antagonists
  • LY 341495
  • Receptors, AMPA
  • Xanthenes
  • omega-Conotoxin GVIA
  • Cadmium Chloride
  • glutamate receptor ionotropic, AMPA 2