Complex cognitive operations such as memory formation and decision-making are thought to be mediated not by single, isolated brain structures but by multiple, connected brain areas. To facilitate studies on the neural communication between connected brain structures, we developed a multi-electrode microdrive for chronically recording ensembles of neurons in two different brain areas simultaneou...

The striatum integrates excitatory inputs from the cortex and the thalamus to control diverse functions. Although the striatum is thought to consist of sensorimotor, associative and limbic domains, their precise demarcations and whether additional functional subdivisions exist remain unclear. How striatal inputs are differentially segregated into each domain is also poorly understood. This stud...

Learning and memory and navigation literatures emphasize interactions between multiple memory systems: a flexible, planning-based system and a rigid, cached-value system. This has profound implications for decision-making. Recent conceptualizations of flexible decision-making employ prospection and projection arising from a network involving the hippocampus. Recent recordings from rodent hippoc...

Patients with Parkinson's disease (PD) have been shown to be impaired on some nondeclarative memory tasks that require cognitive skill learning (perceptual-motor sequence learning, probabilistic classification). To determine what other skill-based tasks are impaired, 13 patients with PD were tested on artificial grammar learning, artificial grammar learning with transfer to novel lettersets, an...

Emotional reactivity following lesions in structures corresponding to the main components of dorsal prefrontal system of the monkey was evaluated in a total of 165 rats by a six-categorial rating scale. Frontomedial cortical damage (FM) and lesions in anterodorsal (DH) or posteroventral (VH) hippocampal regions elicited marked increases in emotional reactivity, relative to sham operated control...

Hungry rats were trained to report the occurrence and location of brief, unpredictable visual stimuli presented to the left of their heads in 1 of 2 response locations. After training, they received unilateral infusions of 6-hydroxydopamine, depleting dopamine throughout the head of the caudate putamen, either on the left or the right side, that is, either ipsilateral or contralateral to the si...

Dopamine, norepinephrine and DOPAC were measured in two cortical areas (the medial prefrontal and the posterolateral, Te2) and in the anterior and posterior neostriatum in rats which were exposed to three different experiences for three different lengths of time. One group learned delayed alternation and the two others served as controls. Throughout the training period all animals were housed i...

The postnatal development of the electrophysiological properties and morphology of rat neostriatum was studied using in vivo and in vitro intracellular recording and biocytin staining and light and electron microscopy. The principal neurons, the medium spiny neurons, were found to undergo a protracted postnatal development of their electrophysiological and morphological characteristics. Most of...

Memory can strongly influence how attention is deployed in future encounters. Though memory dependent on the medial temporal lobes has been shown to drive attention, how other memory systems could concurrently and comparably enhance attention is less clear. Here, we demonstrate that both reinforcement learning and context memory facilitate attention in a visual search task. Using functional mag...

Decision-making studies across different domains suggest that decisions can arise from multiple, parallel systems in the brain: a flexible system utilizing action-outcome expectancies and a more rigid system based on situation-action associations. The hippocampus, ventral striatum, and dorsal striatum make unique contributions to each system, but how information processing in each of these stru...