Medial Prefrontal Cortex and Dorsomedial Striatum Are Necessary for the Trial-Unique, Delayed Nonmatching-to-Location (TUNL) Task in Rats: Role of NMDA Receptors

• Published in: Learning & memory (Cold Spring Harbor, N.Y.) Vol. 24; no. 6; pp. 262 - 266
• Main Authors: Davies, Don A, Hurtubise, Jessica L, Greba, Quentin, Howland, John G
• Format: Journal Article
• Language: English
• Published: United States Cold Spring Harbor Laboratory Press 01.06.2017
• Subjects: Accuracy; Animals; Brain; Brain Hemisphere Functions; Brief Communication; Cephalosporins - pharmacology; Choice Behavior; Ciprofloxacin - analogs & derivatives; Ciprofloxacin - pharmacology; Conditioning, Operant - physiology; Corpus Striatum - drug effects; Corpus Striatum - physiology; Dose-Response Relationship, Drug; Experiments; Male; Neurological Organization; Operant Conditioning; Piperazines - pharmacology; Prefrontal Cortex - drug effects; Prefrontal Cortex - physiology; Rats; Rats, Long-Evans; Receptors, N-Methyl-D-Aspartate - antagonists & inhibitors; Receptors, N-Methyl-D-Aspartate - metabolism; Short Term Memory; Space Perception - drug effects; Space Perception - physiology; Spatial Ability; Task Analysis; Touch - physiology; Valine - analogs & derivatives; Valine - pharmacology
• ISSN: 1072-0502; 1549-5485; 1549-5485
• DOI: 10.1101/lm.044750.116

The trial-unique, delayed nonmatching-to-location (TUNL) task is a recently developed behavioral task that measures spatial working memory and a form of pattern separation in touchscreen-equipped operant conditioning chambers. Limited information exists regarding the neurotransmitters and neural substrates involved in the task. The present experiments tested the effects of systemic and intracranial injections of NMDA receptor antagonists on the TUNL task. After training, male Long Evans rats systemically injected with the competitive NMDA receptor antagonist CPP (10 mg/kg) had impaired accuracy regardless of the degree of stimuli separation or length of delay between the sample and test phases. Injections of Ro 25-6981 (6 or 10 mg/kg), an antagonist selective for GluN2B subunit-containing NMDA receptors, did not affect accuracy on the task. Direct infusion of the competitive NMDA receptor antagonist AP5 into mPFC or dmSTR reduced overall accuracy on the TUNL task. These results demonstrate that TUNL task performance depends on NMDA receptors within the mPFC and dmSTR.