Thalamic–Cortical–Striatal Circuitry Subserves Working Memory during Delayed Responding on a Radial Arm Maze

Abstract

The medial dorsal nuclei of the thalamus (MDNt), the prefrontal cortex, and the ventral striatum form an interconnected neural circuit that may subserve certain types of working memory. The present series of experiments investigated functional interactions between these brain regions in rats during the performance of delayed and nondelayed spatially cued radial-arm maze tasks. In Experiment 1, transient inactivation of the MDNt by a bilateral injection of lidocaine selectively disrupted performance on a delayed task but not on a nondelayed random foraging version of the radial arm maze task. In Experiment 2, asymmetrical lidocaine injections into the MDNt on one side of the brain and the prefrontal cortex on the other transiently disconnected these two brain regions and significantly impaired foraging during the delayed task. Similarly, disconnections between the prefrontal cortex and the nucleus accumbens also disrupted foraging on this task, whereas disconnections between the MDNt and the nucleus accumbens had no effect. These data suggest that serial transmission of information among the MDNt, the prefrontal cortex, and the nucleus accumbens is required when trial-unique, short-term spatial memory is used to guide prospective search behavior. The results are discussed with respect to a distributed neural network linking limbic, thalamic, cortical, and striatal regions, which mediates executive functions of working memory.

Neonatal Damage of the Ventral Hippocampus Impairs Working Memory in the Rat

“…Taken together, the present findings indicate that an insult to the ventral hippocampus during development disturbs the associative functions of PFC (a brain region that matures late and shows an array of molecular and physiological anomalies in the neonatally lesioned animals) and/or functions of the remaining hippocampus or other critical regions (Floresco et al 1997(Floresco et al , 1999, more profoundly than if it had occurred during adulthood. These findings are consistent with previous reports that temporolimbic development affects the ontogeny of working memory Stanton 1991, 1992;Green and Stanton 1989), and that the neonatal hippocampal lesions may have widespread and lasting adverse effects in the interconnected areas implicated in certain cognitive processes (Van Praag et al 1998;Khaing et al 2000;Chambers et al 1996;Le Pen et al 2000).…”

Dopamine D1 receptors involved in locomotor activity and accumbens neural responses to prediction of reward associated with place

“…Action of dopamine expressed via the D1R and D2R in the NAc and its afferent sources may interact with glutamatergic action through NMDA receptors (11,(20)(21)(22)31), which then affect learning (5,32) or other conditions such as drug sensitization (33). Depletion of dopamine, and lesions of the NAc or its afferent pathways, such as damage to the HF, cause changes in spatial performance (2,5,34,35). A blockade of D1-like receptors caused a decrease in stability of hippocampal place fields (36), which in turn could influence spatial task performance.…”

Neurocircuitry Underlying the Preferential Sensitivity of Prefrontal Catecholamines to Low-Dose Psychostimulants

“…The NAc is implicated in the regulation of impulsivity (Cardinal et al, 2001;Christakou et al, 2001) and working memory (Floresco et al, 1999), as well as the pathophysiology of ADHD (for review, Castellanos and Tannock, 2002). Functional imaging studies indicate that MPH-induced improvement in certain cognitive/behavioral tasks is associated with alterations in NAc activity (Dodds et al, 2008;Seidman et al, 2005).…”