title: Behavioral sequence analysis reveals a novel role for beta2* nicotinic receptors in exploration.
abstract: Nicotinic acetylcholine receptors (nAChRs) are widely expressed throughout the central nervous system and modulate neuronal function in most mammalian brain structures. The contribution of defined nAChR subunits to a specific behavior is thus difficult to assess. Mice deleted for beta2-containing nAChRs (beta2-/-) have been shown to be hyperactive in an open-field paradigm, without determining the origin of this hyperactivity. We here develop a quantitative description of mouse behavior in the open field based upon first order Markov and variable length Markov chain analysis focusing on the time-organized sequence that behaviors are composed of. This description reveals that this hyperactivity is the consequence of the absence of specific inactive states or "stops". These stops are associated with a scanning of the environment in wild-type mice (WT), and they affect the way that animals organize their sequence of behaviors when compared with stops without scanning. They characterize a specific "decision moment" that is reduced in beta2-/- mutant mice, suggesting an important role of beta2-nAChRs in the strategy used by animals to explore an environment and collect information in order to organize their behavior. This integrated analysis of the displacement of an animal in a simple environment offers new insights, specifically into the contribution of nAChRs to higher brain functions and more generally into the principles that organize sequences of behaviors in animals.
authors.affiliation: Unité Neurobiologie Intégrative des Systèmes Cholinergiques, Institut Pasteur, Paris, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Maubourguet
authors.forename: Annick
authors.initials: A
authors.lastname: Lesne
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Changeux
authors.forename: Uwe
authors.initials: U
authors.lastname: Maskos
authors.forename: Philippe
authors.initials: P
authors.lastname: Faure
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D005106:Exploratory Behavior / Q000502:physiology*; D006948:Hyperkinesis / Q000235:genetics / Q000503:physiopathology; D008390:Markov Chains; D051379:Mice; D018345:Mice, Knockout; D011978:Receptors, Nicotinic / Q000235:genetics* / Q000502:physiology*; D018709:Statistics, Nonparametric
chemical_list: D011978:Receptors, Nicotinic