title: Adolescent exposure to methylphenidate impairs serial pattern learning in the serial multiple choice (SMC) task in adult rats.
abstract: The long-term effects of adolescent exposure to methylphenidate (MPD) on adult cognitive capacity are largely unknown. We utilized a serial multiple choice (SMC) task, which is a sequential learning paradigm for studying complex learning, to observe the effects of methylphenidate exposure during adolescence on later serial pattern acquisition during adulthood. Following 20.0mg/kg/day MPD or saline exposure for 5 days/week for 5 weeks during adolescence, male rats were trained to produce a highly structured serial response pattern in an octagonal operant chamber for water reinforcement as adults. During a transfer phase, a violation to the previously-learned pattern structure was introduced as the last element of the sequential pattern. Results indicated that while rats in both groups were able to learn the training and transfer patterns, adolescent exposure to MPD impaired learning for some aspects of pattern learning in the training phase which are learned using discrimination learning or serial position learning. In contrast adolescent exposure to MPD had no effect on other aspects of pattern learning which have been shown to tap into rule learning mechanisms. Additionally, adolescent MPD exposure impaired learning for the violation element in the transfer phase. This indicates a deficit in multi-item learning previously shown to be responsible for violation element learning. Thus, these results clearly show that adolescent MPD produced multiple cognitive impairments in male rats that persisted into adulthood long after MPD exposure ended.
authors.affiliation: Department of Psychology, Wesleyan College, Macon, GA 31210-4462, USA. Electronic address: jrowan@wesleyancollege.edu.
authors.forename: James D
authors.initials: JD
authors.lastname: Rowan
authors.affiliation: Department of Psychology, Wesleyan College, Macon, GA 31210-4462, USA. Electronic address: mkmccarty@wesleyancollege.edu.
authors.forename: Madison K
authors.initials: MK
authors.lastname: McCarty
authors.affiliation: Department of Psychology, Hood College, Frederick, MD 21701, USA. Electronic address: kundey@hood.edu.
authors.forename: Shannon M A
authors.initials: SM
authors.lastname: Kundey
authors.affiliation: Department of Psychology, Wesleyan College, Macon, GA 31210-4462, USA. Electronic address: cdosburn@wesleyancollege.edu.
authors.forename: Crystal D
authors.initials: CD
authors.lastname: Osburn
authors.affiliation: Department of Psychological Sciences, Kent State University, Kent, OH 44242-0001, USA. Electronic address: srenaud@kent.edu.
authors.forename: Samantha M
authors.initials: SM
authors.lastname: Renaud
authors.affiliation: Department of Psychology, Bridgewater College, Bridgewater, VA 22812, USA. Electronic address: bkelleyphd@gmail.com.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Kelley
authors.affiliation: Department of Social Science, Bluefield State College, Bluefield, WV 24701, USA. Electronic address: awilley@bluefieldstate.edu.
authors.forename: Amanda Willey
authors.initials: AW
authors.lastname: Matoushek
authors.affiliation: Department of Psychological Sciences, Kent State University, Kent, OH 44242-0001, USA. Electronic address: sfountai@kent.edu.
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Fountain
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D000697:Central Nervous System Stimulants / Q000633:toxicity*; D002755:Choice Behavior / Q000187:drug effects*; D007859:Learning Disabilities / Q000139:chemically induced*; D008297:Male; D008774:Methylphenidate / Q000633:toxicity*; D051381:Rats; D020318:Rats, Long-Evans; D012691:Serial Learning / Q000187:drug effects*; D014163:Transfer, Psychology / Q000187:drug effects
chemical_list: D000697:Central Nervous System Stimulants; D008774:Methylphenidate
keywords: Adolescent Exposure; Chunking; Methylphenidate; Phrasing; Rats; Ritalin; Sequential Behavior; Serial Multiple Choice Task; Serial Pattern Learning