Subcellular topography of visually driven dendritic activity in the vertebrate visual system

Neuron. 2009 Mar 26;61(6):895-905. doi: 10.1016/j.neuron.2009.01.018.

Abstract

Neural pathways projecting from sensory organs to higher brain centers form topographic maps in which neighbor relationships are preserved from a sending to a receiving neural population. Sensory input can generate compartmentalized electrical and biochemical activity in the dendrites of a receiving neuron. Here, we show that in the developing retinotectal projection of young Xenopus tadpoles, visually driven Ca2+ signals are topographically organized at the subcellular, dendritic scale. Functional in vivo two-photon Ca2+ imaging revealed that the sensitivity of dendritic Ca2+ signals to stimulus location in visual space is correlated with their anatomical position within the dendritic tree of individual neurons. This topographic distribution was dependent on NMDAR activation, whereas global Ca2+ signals were mediated by Ca2+ influx through dendritic, voltage-dependent Ca2+ channels. These findings suggest a framework for plasticity models that invoke local dendritic Ca2+ signaling in the elaboration of neural connectivity and dendrite-specific information storage.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials / physiology
  • Animals
  • Brain Mapping*
  • Calcium / metabolism
  • Calcium Signaling / physiology
  • Dendrites / physiology*
  • Excitatory Amino Acid Antagonists / pharmacology
  • GABA Antagonists / pharmacology
  • Imaging, Three-Dimensional / methods
  • Larva
  • Light
  • Microscopy, Confocal / methods
  • Neurons / cytology*
  • Photic Stimulation / methods
  • Presynaptic Terminals / physiology
  • Pyridazines / pharmacology
  • Receptors, N-Methyl-D-Aspartate / physiology
  • Subcellular Fractions / physiology
  • Valine / analogs & derivatives
  • Valine / pharmacology
  • Visual Pathways / cytology*
  • Xenopus

Substances

  • Excitatory Amino Acid Antagonists
  • GABA Antagonists
  • Pyridazines
  • Receptors, N-Methyl-D-Aspartate
  • 2-amino-5-phosphopentanoic acid
  • gabazine
  • Valine
  • Calcium