Non-Gaussian membrane potential dynamics imply sparse, synchronous activity in auditory cortex

DeWeese, M. R., Zador, A. M. (2006) Non-Gaussian membrane potential dynamics imply sparse, synchronous activity in auditory cortex. J Neurosci, 26 (47). pp. 12206-18. ISSN 1529-2401 (Electronic)

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URL: http://www.ncbi.nlm.nih.gov/pubmed/17122045
DOI: 10.1523/jneurosci.2813-06.2006

Abstract

Many models of cortical dynamics have focused on the high-firing regime, in which neurons are driven near their maximal rate. Here we consider the responses of neurons in auditory cortex under typical low-firing rate conditions, when stimuli have not been optimized to drive neurons maximally. We used whole-cell patch-clamp recording in vivo to measure subthreshold membrane potential fluctuations in rat primary auditory cortex in both the anesthetized and awake preparations. By analyzing the subthreshold membrane potential dynamics on single trials, we made inferences about the underlying population activity. We found that, during both spontaneous and evoked responses, membrane potential was highly non-Gaussian, with dynamics consisting of occasional large excursions (sometimes tens of millivolts), much larger than the small fluctuations predicted by most random walk models that predict a Gaussian distribution of membrane potential. Thus, presynaptic inputs under these conditions are organized into quiescent periods punctuated by brief highly synchronous volleys, or "bumps." These bumps were typically so brief that they could not be well characterized as "up states" or "down states." We estimate that hundreds, perhaps thousands, of presynaptic neurons participate in the largest volleys. These dynamics suggest a computational scheme in which spike timing is controlled by concerted firing among input neurons rather than by small fluctuations in a sea of background activity.

Item Type: Paper
Uncontrolled Keywords: Acoustic Stimulation methods Anesthetics Local pharmacology Animals Animals Newborn Auditory Cortex cytology Cortical Synchronization Electric Stimulation methods Lidocaine analogs derivatives pharmacology Membrane Potentials drug effects physiology radiation effects Models Neurological Neural Inhibition physiology Neurons physiology Nonlinear Dynamics Patch-Clamp Techniques Rats Rats Sprague-Dawley Tetrodotoxin pharmacology Time Factors Wakefulness
Subjects: Investigative techniques and equipment > electrophysiology
organs, tissues, organelles, cell types and functions > cell types and functions > cell types > neurons
organs, tissues, organelles, cell types and functions > cell types and functions > cell types > neurons
organs, tissues, organelles, cell types and functions > cell types and functions > cell types > neurons

Investigative techniques and equipment > patch-clamp recording
Investigative techniques and equipment > recording devices > patch-clamp recording

organism description > animal > mammal > rodent > rat
organism description > animal > mammal > rodent > rat
CSHL Authors:
Communities: CSHL labs > Zador lab
Depositing User: CSHL Librarian
Date Deposited: 20 Dec 2011 16:50
Last Modified: 01 Mar 2013 14:49
Related URLs:
URI: http://repository.cshl.edu/id/eprint/22781

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