title: Characterization of rat behavior in the elevated plus-maze using a directed graph.
abstract: The elevated plus-maze is a device widely used to assess rodent anxiety under the effect of several treatments, including pharmacological agents. The animal is placed at the center of the apparatus, which consists of two open arms and two arms enclosed by walls, and the number of entries and duration of stay in each arm are measured for a 5-min exposure period. The effect of an anxiolytic drug is to increase the percentage of time spent and number of entries into the open arms. In this work, we propose a new measure of anxiety levels in the rat submitted to the elevated plus-maze. We represented the spatial structure of the elevated plus-maze in terms of a directed graph and studied the statistics of the rat's transitions between the nodes of the graph. By counting the number of times each transition is made and ordering them in descending frequency we represented the rat's behavior in a rank-frequency plot. Our results suggest that the curves obtained under different pharmacological conditions can be well fitted by a power law with an exponent sensitive to both the drug type and the dose used.
authors.affiliation: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av.Bandeirantes, 3900, Monte Alegre, 14040-901 Ribeirão Preto, SP, Brazil. jtejada@usp.br
authors.forename: Julián
authors.initials: J
authors.lastname: Tejada
authors.forename: Geraldine G
authors.initials: GG
authors.lastname: Bosco
authors.forename: Sílvio
authors.initials: S
authors.lastname: Morato
authors.forename: Antonio C
authors.initials: AC
authors.lastname: Roque
mesh_terms: D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D001007:Anxiety / Q000188:drug therapy / Q000523:psychology; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D003627:Data Interpretation, Statistical; D005010:Ethology / Q000295:instrumentation / Q000379:methods*; D005106:Exploratory Behavior / Q000187:drug effects / Q000502:physiology; D006799:Housing, Animal; D008433:Mathematics; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology*; D023421:Models, Animal; D008962:Models, Theoretical; D009480:Neuropharmacology / Q000295:instrumentation / Q000379:methods*; D009484:Neuropsychology / Q000295:instrumentation / Q000379:methods*; D051381:Rats
chemical_list: D014151:Anti-Anxiety Agents