Local origin of field potentials in visual cortex

Neuron. 2009 Jan 15;61(1):35-41. doi: 10.1016/j.neuron.2008.11.016.


The local field potential (LFP) is increasingly used to measure the combined activity of neurons within a region of tissue. Yet, available estimates of the size of this region are highly disparate, ranging from several hundred microns to a few millimeters. To measure the size of this region directly, we used a combination of multielectrode recordings and optical imaging. We determined the orientation selectivity of stimulus-evoked LFP signals in primary visual cortex and were able to predict it on the basis of the surrounding map of orientation preference. The results show that > 95% of the LFP signal originates within 250 microm of the recording electrode. This quantitative estimate indicates that LFPs are more local than often recognized and provides a guide to the interpretation of the increasing number of studies that rest on LFP recordings.

Publication types

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

MeSH terms

  • Animals
  • Cats
  • Electrodes
  • Electrophysiology / methods
  • Evoked Potentials, Visual / physiology*
  • Neurons / physiology*
  • Visual Cortex / cytology
  • Visual Cortex / physiology*
  • Visual Perception / physiology