Article abstract
Nature Neuroscience 10, 494 - 504 (2007)
Published online: 18 March 2007 | Corrected online: 2 May 2007 | doi:10.1038/nn1877
There is an Erratum (June 2007) associated with this Article.
Functional dissection of circuitry in a neural integrator
Emre Aksay1,2, Itsaso Olasagasti3, Brett D Mensh4, Robert Baker5, Mark S Goldman3 & David W Tank2
Abstract
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.
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, 1300 York Avenue, Box 75, New York, New York 10021, USA.
- Departments of Physics and Molecular Biology, Princeton University, Washington Road, Princeton, New Jersey 08544, USA.
- Department of Physics and Program in Neuroscience, Wellesley College, 106 Central Street, Wellesley, Massachusetts 02481, USA.
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, 125 Nashua Street, Boston, Massachusetts 02139, USA.
- Department of Physiology and Neuroscience, New York University Medical Center, 550 First Avenue, New York, New York 10016, USA.
Correspondence to: Emre Aksay1,2 e-mail: ema2004@med.cornell.edu
Correspondence to: Mark S Goldman3 e-mail: mgoldma2@wellesley.edu
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