title: Population rate dynamics and multineuron firing patterns in sensory cortex.
abstract: Cortical circuits encode sensory stimuli through the firing of neuronal ensembles, and also produce spontaneous population patterns in the absence of sensory drive. This population activity is often characterized experimentally by the distribution of multineuron "words" (binary firing vectors), and a match between spontaneous and evoked word distributions has been suggested to reflect learning of a probabilistic model of the sensory world. We analyzed multineuron word distributions in sensory cortex of anesthetized rats and cats, and found that they are dominated by fluctuations in population firing rate rather than precise interactions between individual units. Furthermore, cortical word distributions change when brain state shifts, and similar behavior is seen in simulated networks with fixed, random connectivity. Our results suggest that similarity or dissimilarity in multineuron word distributions could primarily reflect similarity or dissimilarity in population firing rate dynamics, and not necessarily the precise interactions between neurons that would indicate learning of sensory features.
authors.affiliation: Department of Bioengineering, Imperial College, London SW7 2AZ, United Kingdom.
authors.forename: Michael
authors.initials: M
authors.lastname: Okun
authors.forename: Pierre
authors.initials: P
authors.lastname: Yger
authors.forename: Stephan L
authors.initials: SL
authors.lastname: Marguet
authors.forename: Florian
authors.initials: F
authors.lastname: Gerard-Mercier
authors.forename: Andrea
authors.initials: A
authors.lastname: Benucci
authors.forename: Steffen
authors.initials: S
authors.lastname: Katzner
authors.forename: Laura
authors.initials: L
authors.lastname: Busse
authors.forename: Matteo
authors.initials: M
authors.lastname: Carandini
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Harris
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D002415:Cats; D008297:Male; D008959:Models, Neurological; D009415:Nerve Net / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013003:Somatosensory Cortex / Q000502:physiology*