RESUMEN
There are several studies in the literature showing that male and female rats explore novel environments and exhibit different exploration patterns when submitted to different apparatuses. In general, female rats spend more time moving and exploring the apparatuses than males do. A previous study showed that male woodlice (Armadillidium vulgare) explore novel environments in a very similar way to male rats (Rattus norvegicus) when tested in apparatuses analogous to the open-field test and light/dark box. Since that study was conducted only with male rats and woodlice, and since they exhibited very similar patterns of behavior, the present experiment aimed at investigating whether male and female woodlice explore novel environments with different behavioral patterns. Female and male woodlice were tested in the open-field and in the dry/moist box. Results obtained in the open-field test showed that both males and females remained longer in the corners than along the walls and avoided staying in the center. However, females remained longer along the walls and less in the corners. In the dry/moist box, there were no significant differences between the sexes: both females and males remained significantly longer in the moist compartment.
Asunto(s)
Conducta Animal , Conducta Exploratoria , Animales , Masculino , Femenino , RatasRESUMEN
There are several studies in the literature showing that male and female rats explore novel environments and exhibit different exploration patterns when submitted to different apparatuses. In general, female rats spend more time moving and exploring the apparatuses than males do. A previous study showed that male woodlice (Armadillidium vulgare) explore novel environments in a very similar way to male rats (Rattus norvegicus) when tested in apparatuses analogous to the open-field test and light/dark box. Since that study was conducted only with male rats and woodlice, and since they exhibited very similar patterns of behavior, the present experiment aimed at investigating whether male and female woodlice explore novel environments with different behavioral patterns. Female and male woodlice were tested in the open-field and in the dry/moist box. Results obtained in the open-field test showed that both males and females remained longer in the corners than along the walls and avoided staying in the center. However, females remained longer along the walls and less in the corners. In the dry/moist box, there were no significant differences between the sexes: both females and males remained significantly longer in the moist compartment.
RESUMEN
Bidirectional selection is a procedure in which an arbitrary characteristic is chosen as a selection criterion and animals exhibiting more of this characteristic are bred in one group and animals exhibiting less are bred in another group. The procedure is repeated along generations until the selected characteristic becomes stable, resulting in two strains that are opposite in relation to the chosen characteristic. The present study aimed at selectively breeding rats exhibiting either a high or a low tendency to socialize by using the proximity test. We tested male and female Wistar rats in a square open field with a communicating birdcage, separated by a grid, containing a co-specific rat and coupled on the outside. Subjects that remained more time in front of the birdcage, interacting with the co-specific rat were bred in a group considered of high sociability (SOC+). Likewise, subjects that remained little time in front of the birdcage, with little interaction with the co-specific rat, were bred in a second group considered of low sociability (SOC-). By the 10th generation, the bidirectional selection resulted in SOC+ rats that spent a large amount of time in front of the cage sniffing and rearing in interaction with the co-specific rat and spent less time in the corners, exploring and grooming. It also resulted in SOC- rats that spent a small amount of time in front of the cage sniffing and rearing in interaction with the co-specific rat and spent more time in the corners and used most of their time grooming.
Asunto(s)
Conducta Social , Interacción Social , Animales , Femenino , Humanos , Masculino , Ratas , Ratas Wistar , Selección GenéticaRESUMEN
The elevated gradient of aversion (EGA) is an apparatus for investigating the exploratory behavior of rats in 3-min sessions, consisting of three different sections of the same size: tunnel, closed arm, and open arm. Factorial analyses have defined three factors: exploration, impulsivity, and self-protection. In general, male rats are placed in the tunnel end and tend to hesitate leaving this starting point. Then, they hesitate leaving the tunnel and entering the closed arm, which they explore and tend to avoid entering the open arm or even just stick their head in and not enter it at all. Since females were not used for this test and are reported to be more explorative than male rats, the present work aimed to compare the behavior of male and female rats in the EGA. Thirty male and 34 female Wistar rats were submitted to 3-min sessions in the EGA. In general, results indicated that females were different from males: they explored more (Factor 1 - Exploration), are more impulsive (Factor 2 - Impulsivity), and are less anxious/fearful (Factor 3 - Self-protection). These results confirmed the results of other studies obtained with other apparatuses and show that females exhibit higher locomotion than males and are less anxious/fearful.
Asunto(s)
Ansiedad , Conducta Exploratoria , Animales , Conducta Animal , Femenino , Conducta Impulsiva , Locomoción , Masculino , Aprendizaje por Laberinto , Ratas , Ratas WistarRESUMEN
Bidirectional selection is a procedure in which an arbitrary characteristic is chosen as a selection criterion and animals exhibiting more of this characteristic are bred in one group and animals exhibiting less are bred in another group. The procedure is repeated along generations until the selected characteristic becomes stable, resulting in two strains that are opposite in relation to the chosen characteristic. The present study aimed at selectively breeding rats exhibiting either a high or a low tendency to socialize by using the proximity test. We tested male and female Wistar rats in a square open field with a communicating birdcage, separated by a grid, containing a co-specific rat and coupled on the outside. Subjects that remained more time in front of the birdcage, interacting with the co-specific rat were bred in a group considered of high sociability (SOC+). Likewise, subjects that remained little time in front of the birdcage, with little interaction with the co-specific rat, were bred in a second group considered of low sociability (SOC-). By the 10th generation, the bidirectional selection resulted in SOC+ rats that spent a large amount of time in front of the cage sniffing and rearing in interaction with the co-specific rat and spent less time in the corners, exploring and grooming. It also resulted in SOC- rats that spent a small amount of time in front of the cage sniffing and rearing in interaction with the co-specific rat and spent more time in the corners and used most of their time grooming.
RESUMEN
The elevated gradient of aversion (EGA) is an apparatus for investigating the exploratory behavior of rats in 3-min sessions, consisting of three different sections of the same size: tunnel, closed arm, and open arm. Factorial analyses have defined three factors: exploration, impulsivity, and self-protection. In general, male rats are placed in the tunnel end and tend to hesitate leaving this starting point. Then, they hesitate leaving the tunnel and entering the closed arm, which they explore and tend to avoid entering the open arm or even just stick their head in and not enter it at all. Since females were not used for this test and are reported to be more explorative than male rats, the present work aimed to compare the behavior of male and female rats in the EGA. Thirty male and 34 female Wistar rats were submitted to 3-min sessions in the EGA. In general, results indicated that females were different from males: they explored more (Factor 1 - Exploration), are more impulsive (Factor 2 - Impulsivity), and are less anxious/fearful (Factor 3 - Self-protection). These results confirmed the results of other studies obtained with other apparatuses and show that females exhibit higher locomotion than males and are less anxious/fearful.
RESUMEN
Few behavioral tests allow measuring several characteristics and most require training, complex analyses, and/or are time-consuming. We present an apparatus based on rat exploratory behavior. Composed of three different environments, it allows the assessment of more than one behavioral characteristic in a short 3-min session. Factorial analyses have defined three behavioral dimensions, which we named Exploration, Impulsivity, and Self-protection. Behaviors composing the Exploration factor were increased by chlordiazepoxide and apomorphine and decreased by pentylenetetrazole. Behaviors composing the Impulsivity factor were increased by chlordiazepoxide, apomorphine, and both acute and chronic imipramine treatments. Behaviors composing the Self-protection factor were decreased by apomorphine. We submitted Wistar rats to the open-field test, the elevated-plus maze, and to the apparatus we are proposing. Measures related to exploratory behavior in all three tests were correlated. Measures composing the factors Impulsivity and Self-protection did not correlate with any measures from the two standard tests. Also, compared with existing impulsivity tests, the one we proposed did not require previous learning, training, or sophisticated analysis. Exploration measures from our test are as easy to obtain as the ones from other standard tests. Thus, we have proposed an apparatus that measured three different behavioral characteristics, was simple and fast, did not require subjects to be submitted to previous learning or training, was sensitive to drug treatments, and did not require sophisticated data analyses.
Asunto(s)
Ansiedad/psicología , Conducta Animal/fisiología , Investigación Conductal/instrumentación , Conducta Exploratoria/fisiología , Miedo/fisiología , Conducta Impulsiva/fisiología , Animales , Ansiolíticos/farmacología , Antidepresivos Tricíclicos/farmacología , Apomorfina/farmacología , Conducta Animal/efectos de los fármacos , Clordiazepóxido/farmacología , Agonistas de Dopamina/farmacología , Conducta Exploratoria/efectos de los fármacos , Miedo/efectos de los fármacos , Antagonistas del GABA/farmacología , Conducta Impulsiva/efectos de los fármacos , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Aprendizaje por Laberinto/fisiología , Modelos Animales , Pentilenotetrazol/farmacología , Ratas Wistar , Factores de TiempoRESUMEN
Few behavioral tests allow measuring several characteristics and most require training, complex analyses, and/or are time-consuming. We present an apparatus based on rat exploratory behavior. Composed of three different environments, it allows the assessment of more than one behavioral characteristic in a short 3-min session. Factorial analyses have defined three behavioral dimensions, which we named Exploration, Impulsivity, and Self-protection. Behaviors composing the Exploration factor were increased by chlordiazepoxide and apomorphine and decreased by pentylenetetrazole. Behaviors composing the Impulsivity factor were increased by chlordiazepoxide, apomorphine, and both acute and chronic imipramine treatments. Behaviors composing the Self-protection factor were decreased by apomorphine. We submitted Wistar rats to the open-field test, the elevated-plus maze, and to the apparatus we are proposing. Measures related to exploratory behavior in all three tests were correlated. Measures composing the factors Impulsivity and Self-protection did not correlate with any measures from the two standard tests. Also, compared with existing impulsivity tests, the one we proposed did not require previous learning, training, or sophisticated analysis. Exploration measures from our test are as easy to obtain as the ones from other standard tests. Thus, we have proposed an apparatus that measured three different behavioral characteristics, was simple and fast, did not require subjects to be submitted to previous learning or training, was sensitive to drug treatments, and did not require sophisticated data analyses.