title: Millisecond Coupling of Local Field Potentials to Synaptic Currents in the Awake Visual Cortex.
abstract: The cortical local field potential (LFP) is a common measure of population activity, but its relationship to synaptic activity in individual neurons is not fully established. This relationship has been typically studied during anesthesia and is obscured by shared slow fluctuations. Here, we used patch-clamp recordings in visual cortex of anesthetized and awake mice to measure intracellular activity; we then applied a simple method to reveal its coupling to the simultaneously recorded LFP. LFP predicted membrane potential as accurately as synaptic currents, indicating a major role for synaptic currents in the relationship between cortical LFP and intracellular activity. During anesthesia, cortical LFP predicted excitation far better than inhibition; during wakefulness, it predicted them equally well, and visual stimulation further enhanced predictions of inhibition. These findings reveal a central role for synaptic currents, and especially inhibition, in the relationship between the subthreshold activity of individual neurons and the cortical LFP during wakefulness.
authors.affiliation: UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK. Electronic address: bilal.haider@bme.gatech.edu.
authors.forename: Bilal
authors.initials: B
authors.lastname: Haider
authors.affiliation: UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK.
authors.forename: David P A
authors.initials: DP
authors.lastname: Schulz
authors.affiliation: Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Häusser
authors.affiliation: UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK.
authors.forename: Matteo
authors.initials: M
authors.lastname: Carandini
mesh_terms: D000818:Animals; D008564:Membrane Potentials / Q000502:physiology*; D051379:Mice; D009474:Neurons / Q000502:physiology*; D018408:Patch-Clamp Techniques; D010775:Photic Stimulation; D009435:Synaptic Transmission; D014793:Visual Cortex / Q000502:physiology*; D014851:Wakefulness