Tony Ye1, Hilda Pozos1, Tamara J Phillips2, Alicia Izquierdo3. 1. University of California, Los Angeles, Department of Psychology, Los Angeles, CA, USA. 2. Oregon Health & Science University, Veterans Affairs Medical Center and Methamphetamine Abuse Research Center, Portland, OR, USA. 3. University of California, Los Angeles, Department of Psychology, Los Angeles, CA, USA. Electronic address: aizquie@psych.ucla.edu.
Abstract
BACKGROUND: Flexible cognition is a set of processes mediated by the prefrontal cortex (PFC), an area of the brain that continues to develop during adolescence and into adulthood. Adult rodents exhibit impairments specific to reversal learning across various dosing regimens of methamphetamine (mAMPH). For adolescent rodents, ongoing PFC development can be assessed by discrimination reversal learning, a task dependent on frontostriatal integrity. The task may also index an increased vulnerability for mAMPH sampling in adulthood. METHODS: The purpose of the present study was to investigate the long-term effects of escalating, adolescent mAMPH exposure on reversal learning, a PFC-dependent task (Experiment 1) and the likelihood of later sampling of mAMPH in adulthood (Experiment 2). RESULTS: Unlike previous research in adult-treated rats, our results show more generalized learning impairments after adolescent mAMPH exposure to include both attenuated visual discrimination as well as reversal learning. Additionally, we found that rats pre-exposed to mAMPH during adolescence consumed significantly more drug in adulthood. Intake of mAMPH was positively correlated with this learning. Taken together, these findings show that even modest exposure to mAMPH during adolescence may induce general learning impairments in adulthood, and an enduring sensitivity to the effects of mAMPH.
BACKGROUND: Flexible cognition is a set of processes mediated by the prefrontal cortex (PFC), an area of the brain that continues to develop during adolescence and into adulthood. Adult rodents exhibit impairments specific to reversal learning across various dosing regimens of methamphetamine (mAMPH). For adolescent rodents, ongoing PFC development can be assessed by discrimination reversal learning, a task dependent on frontostriatal integrity. The task may also index an increased vulnerability for mAMPH sampling in adulthood. METHODS: The purpose of the present study was to investigate the long-term effects of escalating, adolescent mAMPH exposure on reversal learning, a PFC-dependent task (Experiment 1) and the likelihood of later sampling of mAMPH in adulthood (Experiment 2). RESULTS: Unlike previous research in adult-treated rats, our results show more generalized learning impairments after adolescent mAMPH exposure to include both attenuated visual discrimination as well as reversal learning. Additionally, we found that rats pre-exposed to mAMPH during adolescence consumed significantly more drug in adulthood. Intake of mAMPH was positively correlated with this learning. Taken together, these findings show that even modest exposure to mAMPH during adolescence may induce general learning impairments in adulthood, and an enduring sensitivity to the effects of mAMPH.
Authors: J M Wheeler; C Reed; S Burkhart-Kasch; N Li; C L Cunningham; A Janowsky; F H Franken; K M Wiren; J G Hashimoto; A C Scibelli; T J Phillips Journal: Genes Brain Behav Date: 2009-07-21 Impact factor: 3.449
Authors: Alicia Izquierdo; Annabelle M Belcher; Lori Scott; Victor A Cazares; Jack Chen; Steven J O'Dell; Melissa Malvaez; Tiffany Wu; John F Marshall Journal: Neuropsychopharmacology Date: 2010-01 Impact factor: 7.853
Authors: Nicole L Schramm-Sapyta; Q David Walker; Joseph M Caster; Edward D Levin; Cynthia M Kuhn Journal: Psychopharmacology (Berl) Date: 2009-06-23 Impact factor: 4.530
Authors: Alicia Izquierdo; Hilda Pozos; Adrianna De La Torre; Simone DeShields; James Cevallos; Jonathan Rodriguez; Alexandra Stolyarova Journal: Behav Brain Res Date: 2016-04-26 Impact factor: 3.332
Authors: Emily R Hankosky; Sara R Westbrook; Rachel M Haake; Jari Willing; Lori T Raetzman; Janice M Juraska; Joshua M Gulley Journal: Behav Brain Res Date: 2018-04-30 Impact factor: 3.332