Functional dissection of circuitry in a neural integrator

Nat Neurosci. 2007 Apr;10(4):494-504. doi: 10.1038/nn1877. Epub 2007 Mar 18.


In neural integrators, transient inputs are accumulated into persistent firing rates that are a neural correlate of short-term memory. Integrators often contain two opposing cell populations that increase and decrease sustained firing as a stored parameter value rises. A leading hypothesis for the mechanism of persistence is positive feedback through mutual inhibition between these opposing populations. We tested predictions of this hypothesis in the goldfish oculomotor velocity-to-position integrator by measuring the eye position and firing rates of one population, while pharmacologically silencing the opposing one. In complementary experiments, we measured responses in a partially silenced single population. Contrary to predictions, induced drifts in neural firing were limited to half of the oculomotor range. We built network models with synaptic-input thresholds to demonstrate a new hypothesis suggested by these data: mutual inhibition between the populations does not provide positive feedback in support of integration, but rather coordinates persistent activity intrinsic to each population.

Publication types

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

MeSH terms

  • Action Potentials / physiology*
  • Anesthetics, Local / pharmacology
  • Animals
  • Behavior, Animal
  • Brain / cytology
  • Computer Simulation
  • Dominance, Ocular
  • Eye Movements / physiology
  • Feedback
  • Goldfish
  • Lidocaine / pharmacology
  • Models, Neurological*
  • Nerve Block / methods
  • Nerve Net / drug effects
  • Nerve Net / physiology*
  • Neurons / classification
  • Neurons / physiology*
  • Ocular Physiological Phenomena*


  • Anesthetics, Local
  • Lidocaine