Comparison of the effects of 2,5-dimethoxy-4-iodoamphetamine and D-amphetamine on the ability of rats to discriminate the durations and intensities of light stimuli.
Behav Pharmacol
; 21(1): 11-20, 2010 Feb.
Article
em En
| MEDLINE
| ID: mdl-19949322
ABSTRACT
Rats' ability to discriminate durations is disrupted by the monoamine-releasing agent D-amphetamine and the 5-HT2 receptor agonist 2,5-dimethoxy-4-iodoamphetamine (DOI). It is unknown whether this effect is specific for temporal discrimination or reflects general disruption of stimulus control. This experiment addressed this question by comparing the effects of D-amphetamine and DOI on temporal discrimination and discrimination along a nontemporal dimension, light intensity. Twelve rats responded on a schedule in which a light (intensity 22 cd/m) was presented for t seconds (2.5-47.5 s), after which levers A and B were presented. Responses on A were reinforced when t was less than 25 s, and responses on B were reinforced when t was greater than 25 s. Twelve rats responded on a similar schedule in which a light of intensity i (3.6-128.5 cd/m) was presented for 25 s. Responses on A were reinforced when i was less than 22 cd/m, and responses on B were reinforced when i was greater than 22 cd/m. Logistic functions were fitted and psychophysical parameters estimated [T50, I50 (central tendency of temporal or light-intensity discrimination); Weber fraction (relative discriminative precision)]. D-Amphetamine (0.2-0.8 mg/kg) increased the Weber fraction for temporal and light-intensity discrimination; DOI (0.625-0.25 mg/kg) increased it for temporal discrimination only. Both drugs increased T50; neither altered I50. D-Amphetamine and DOI have similar effects on temporal discrimination but different effects on light-intensity discrimination. The increase in T50 may reflect the impairment of sustained attention during prolonged stimulus presentation.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Percepção Visual
/
Agonistas do Receptor de Serotonina
/
Dextroanfetamina
/
Aprendizagem por Discriminação
/
Anfetaminas
/
Estimulantes do Sistema Nervoso Central
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2010
Tipo de documento:
Article