title: Dopamine D2L Receptor Is Required for Visual Discrimination and Reversal Learning.
abstract: The corticostriatothalamic circuit regulates learning behaviors via dopamine neurotransmission. D2 long (D2L) receptors are an isoform of dopamine D2 receptors (D2Rs) and may act mainly at postsynaptic sites. It is well known that D2Rs influence high brain functions, but the roles of individual D2R isoforms are still unclear. To assess the influence of D2L receptors in visual discrimination learning, we performed visual discrimination and reversal tasks with D2L knockout mice using a touchscreen operant system. There were no significant differences in an operant conditioning task between genotypes. However, D2L knockout mice were impaired in both visual discrimination and reversal learning tasks. D2L knockout mice were also significantly slower than wild-type mice in collecting the reward in the visual discrimination task. These results indicate that D2L receptors play an important role in visual discrimination and reversal learning.
authors.affiliation: Medical Innovation Center, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Makiko
authors.initials: M
authors.lastname: Morita
authors.affiliation: Department of Pharmacology and Beckman Institute, University of Illinois, Urbana-Champaign, Ill., USA.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Brain Research Institute, Niigata University, Niigata, Japan.
authors.forename: Toshikuni
authors.initials: T
authors.lastname: Sasaoka
authors.affiliation: Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, Md., USA.
authors.forename: Kinya
authors.initials: K
authors.lastname: Okada
authors.affiliation: Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, Md., USA.
authors.forename: Minae
authors.initials: M
authors.lastname: Niwa
authors.affiliation: Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, Md., USA.
authors.forename: Akira
authors.initials: A
authors.lastname: Sawa
authors.affiliation: Medical Innovation Center, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Hikida
keywords: Dopamine receptor; Flexibility; Touchscreen