Proximity as a predictor of social behavior in rats.

Background: In studies that measure social behavior of a freely interacting pair rats social behavior of one rat is strongly influenced by the behavior of the other. This prevents evaluating social behavior of one single rat.

New Method: We assessed the motivation to interact socially in a modified open-field, by measuring the time a rat attempted to interact with a co-specific separated by a grid in a birdcage outside of the apparatus.

A computational model for exploratory activity of rats with different anxiety levels in elevated plus-maze.

The elevated plus-maze is an apparatus widely used to study the level of anxiety in rodents. The maze is plus-shaped, with two enclosed arms and two open arms, and elevated 50cm from the floor. During a test, which usually lasts for 5min, the animal is initially put at the center and is free to move and explore the entire maze.

Mathematical methods to model rodent behavior in the elevated plus-maze.

The elevated plus maze is a widely used experimental test to study anxiety-like rodent behavior. It is made of four arms, two open and two closed, connected at a central area forming a plus shaped maze. The whole apparatus is elevated 50 cm from the floor.

The effects of pentylenetetrazol, chlordiazepoxide and caffeine in rats tested in the elevated plus-maze depend on the experimental illumination.

The so-called anxiolytic and anxiogenic drugs are considered to cause, respectively, increases and decreases in plus-maze open arm exploration, without modifying locomotor activity occurring in the closed arms in an elevated plus-maze when the animals are tested in an illuminated environment. Simply testing animals in the dark also increases open arm exploration, which may be interpreted as an anxiolytic effect. We investigated the effects of two GABAergic drugs, pentylenetetrazol (10 and 20 mg/kg) and chlordiazepoxide (1.

Characterization of the rat exploratory behavior in the elevated plus-maze with Markov chains.

The elevated plus-maze is an animal model of anxiety used to study the effect of different drugs on the behavior of the animal. It consists of a plus-shaped maze with two open and two closed arms elevated 50cm from the floor. The standard measures used to characterize exploratory behavior in the elevated plus-maze are the time spent and the number of entries in the open arms.

Neonatal exposure to LPS leads to heightened exploratory activity in adolescent rats.

Although several reports have demonstrated physiological and behavioral changes in adult rats due to neonatal immune challenges, little is known about their effects in adolescence. Since neonatal exposure to lipopolysaccharide (LPS) alters the neural substrates involved in cognitive disorders, we tested the hypothesis that it may also alter the response to novel environments in adolescent rats. At 3 and 5 days of age, male Wistar rats received intraperitoneal injections of either vehicle solution or E.

Measuring anxiety in zebrafish: a critical review.

Zebrafish are increasingly being used in behavioral neuroscience, neuropsychopharmacology and neurotoxicology. Recently, behavioral screens used to model anxiety in rodents were adapted to this species, and novel models which tap on zebrafish behavioral ecology have emerged. However, model building is an arduous task in experimental psychopathology, and a continuous effort to assess the validity of these measurements is being chased among some researchers.

Effects of reversible inactivation of the medial septum on rat exploratory behavior in the elevated plus-maze using a test-retest paradigm.

The effect of intraseptal injections of lidocaine before a first or a second session in the elevated plus-maze, in a test-retest paradigm, was investigated. In addition to gross session analyses, a minute-by-minute analysis of the sessions was used to evaluate both anxiety and memory. Lidocaine injections before the test session produced increases in the frequency of entries, time spent and distance run in the open arms without affecting activity occurring in the closed arms.

Scototaxis as anxiety-like behavior in fish.

The scototaxis (dark/light preference) protocol is a behavioral model for fish that is being validated to assess the antianxiety effects of pharmacological agents and the behavioral effects of toxic substances, and to investigate the (epi)genetic bases of anxiety-related behavior. Briefly, a fish is placed in a central compartment of a half-black, half-white tank; following habituation, the fish is allowed to explore the tank for 15 min; the number and duration of entries in each compartment (white or black) are recorded by the observer for the whole session. Zebrafish, goldfish, guppies and tilapias (all species that are important in behavioral neurosciences and neuroethology) have been shown to demonstrate a marked preference for the dark compartment.

Parametric analyses of anxiety in zebrafish scototaxis.

Scototaxis, the preference for dark environments in detriment of bright ones, is an index of anxiety in zebrafish. In this work, we analyzed avoidance of the white compartment by analysis of the spatiotemporal pattern of exploratory behavior (time spent in the white compartment of the apparatus and shuttle frequency between compartments) and swimming ethogram (thigmotaxis, freezing and burst swimming in the white compartment) in four experiments. In Experiment 1, we demonstrate that spatiotemporal measures of white avoidance and locomotion do not habituate during a single 15-min session.

Characterization of rat behavior in the elevated plus-maze using a directed graph.

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.

Behavior ontogeny in the elevated plus-maze: prenatal stress effects.

Prenatal stress is a putative model for studying some psychopathological disorders. Indeed, submitting pregnant animals to stress leads to enhanced anxiety in the adult offspring. However, little is known about how prenatal stress effects interacts with anxiety throughout development.

Effects of apomorphine on rat behavior in the elevated plus-maze.

It has been reported that novelty may evoke both an exploratory and a fear drive, thus generating behavior responding to an approach/avoidance conflict. However, not much is known about the approach component. Whereas there exists abundant evidence referring to the avoidance component as the main target for the anxiolytic action of benzodiazepines, the involvement of dopaminergic mechanisms in fear and anxiety is controversial.

Prenatal stress produces more behavioral alterations than maternal separation in the elevated plus-maze and in the elevated T-maze.

Prenatal stress and maternal separation are used in a large number of studies on early adversity consequences and present some similarities in their effects. The present work investigates the behavioral effects of these two procedures on two models of anxiety: the elevated plus-maze and the elevated T-maze. During pregnancy, female rats were submitted to uncontrollable electric foot shock sessions every other day or kept undisturbed.

Effect of different illumination levels on rat behavior in the elevated plus-maze.

The present study addressed the role of environmental light intensity on the exploratory behavior of rats in the elevated plus-maze, with the specific goal of determining the light intensity threshold for triggering the aversion to the open arms. Male Wistar-derived rats were tested in the elevated plus-maze under different illumination levels: 0, 1, 3, 10, 30, 100 and 300 lx. Exploratory behavior occurring in the open arms (e.

Influence of the estrous cycle on the behavior of rats in the elevated T-maze.

The elevated T-maze is an animal anxiety model which can discriminate between anxiety-like and fear-like behaviors. The estrous cycle is an important variable of the response in animal anxiety tests and is known to affect other models. The aim of the present study was to investigate the influence of the estrous cycle on behavior displayed in the elevated T-maze test.

Conflict as a determinant of rat behavior in three types of elevated plus-maze.

Three groups of rats were tested in different types of elevated plus-mazes, a normal one (two closed and two open arms), a totally closed one (four closed arms) and a totally open (four open arms). Closed arms were surrounded by 40-cm high wooden walls and open arms were surrounded by 0.5-cm high transparent Plexiglas ledges.

The role of vision and proprioception in the aversion of rats to the open arms of an elevated plus-maze.

The elevated plus-maze test is usually run with a short edge surrounding the open arms in order to prevent the rats from falling. The present experiment investigated the role of transparent edges differing in heights: 1 (used as control), 5, 10, 20 and 40 cm, the latter the same height as the closed arm walls. Additionally, this 40-cm high transparent edge was also studied covered by white translucent or black opaque paper.