The cellular basis for parallel neural transmission of a high-frequency stimulus and its low-frequency envelope

doi:10.1073/pnas.0604103103

The cellular basis for parallel neural transmission of a high-frequency stimulus and its low-frequency envelope

*Department of Physics, University of Ottawa, 150 Louis Pasteur Avenue, Ottawa, ON, Canada K1N 6N5;
^†Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, Canada K1H 8M5; and
^§Institute for Theoretical Biology, Humboldt University, Invalidenstrasse 43, D-10115 Berlin, Germany

Edited by Masakazu Konishi, California Institute of Technology, Pasadena, CA, and approved August 4, 2006 (received for review May 18, 2006)

Abstract

Sensory stimuli often have rich temporal and spatial structure. One class of stimuli that are common to visual and auditory systems and, as we show, the electrosensory system are signals that contain power in a narrow range of temporal (or spatial) frequencies. Characteristic of this class of signals is a slower variation in their amplitude, otherwise known as an envelope. There is evidence suggesting that, in the visual cortex, both narrowband stimuli and their envelopes are coded for in separate and parallel streams. The implementation of this parallel transmission is not well understood at the cellular level. We have identified the cellular basis for the parallel transmission of signal and envelope in the electrosensory system: a two-cell network consisting of an interneuron connected to a pyramidal cell by means of a slow synapse. This circuit could, in principle, be implemented in the auditory or visual cortex by the previously identified biophysics of cortical interneurons.

Footnotes

^‡To whom correspondence should be addressed. E-mail: jmidd046{at}uottawa.ca
Author contributions: J.W.M. and L.M. designed research; J.W.M. performed research; J.W.M., A.L., and J.B. contributed new reagents/analytic tools; J.W.M. and L.M. analyzed data; and J.W.M., L.M., and A.L. wrote the paper.
The authors declare no conflict of interest.
This paper was submitted directly (Track II) to the PNAS office.
Abbreviations:

AM,

amplitude modulation;

EOD,

electric organ discharge;

ELL,

electrosensory lateral line lobe;

DBP,

deep basilar pyramidal;

nP,

nucleus praeminentialis.