PT  - JOURNAL ARTICLE
AU  - Michael R. DeWeese
AU  - Michael Wehr
AU  - Anthony M. Zador
TI  - Binary Spiking in Auditory Cortex
AID  - 10.1523/JNEUROSCI.23-21-07940.2003
DP  - 2003 Aug 27
TA  - The Journal of Neuroscience
PG  - 7940--7949
VI  - 23
IP  - 21
4099  - http://www.jneurosci.org/content/23/21/7940.short
4100  - http://www.jneurosci.org/content/23/21/7940.full
SO  - J. Neurosci.2003 Aug 27; 23
AB  - Neurons are often assumed to operate in a highly unreliable manner: a neuron can signal the same stimulus with a variable number of action potentials. However, much of the experimental evidence supporting this view was obtained in the visual cortex. We have, therefore, assessed trial-to-trial variability in the auditory cortex of the rat. To ensure single-unit isolation, we used cell-attached recording. Tone-evoked responses were usually transient, often consisting of, on average, only a single spike per stimulus. Surprisingly, the majority of responses were not just transient, but were also binary, consisting of 0 or 1 action potentials, but not more, in response to each stimulus; several dramatic examples consisted of exactly one spike on 100% of trials, with no trial-to-trial variability in spike count. The variability of such binary responses differs from comparably transient responses recorded in visual cortical areas such as area MT, and represent the lowest trial-to-trial variability mathematically possible for responses of a given firing rate. Our study thus establishes for the first time that transient responses in auditory cortex can be described as a binary process, rather than as a highly variable Poisson process. These results demonstrate that cortical architecture can support a more precise control of spike number than was previously recognized, and they suggest a re-evaluation of models of cortical processing that assume noisiness to be an inevitable feature of cortical codes.