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The behavioral and motivational changes that result from use of abused substances depend upon activation of neuronal populations in the reward centers of the brain, located primarily in the corpus striatum in primates. To gain insight into the cellular mechanisms through which abused drugs reinforce behavior in the primate brain, changes in firing of(More)
OBJECTIVE Maintenance of cognitive control is a major concern for many human disease conditions; therefore, a major goal of human neuroprosthetics is to facilitate and/or recover the cognitive function when such circumstances impair appropriate decision making. APPROACH Minicolumnar activity from the prefrontal cortex (PFC) was recorded from nonhuman(More)
To investigate the mechanisms of fixation disengagement and saccade initiation, we electrically stimulated the macaque frontal eye fields (FEF) while monkeys performed a visual fixation task. We tested the effect of introducing a temporal gap between fixation target offset and the onset of the electrical stimulus. We found that the duration of the gap had a(More)
The mammalian frontal cortex (FCx) is at the top of the brain's sensorimotor hierarchy and includes cells in the supragranular Layer 2/3, which integrate convergent sensory information for transmission to infragranular Layer 5 cells to formulate motor system outputs that control behavioral responses. Functional interaction between these two layers of FCx(More)
Tracing the neural circuitry of decision formation is a critical step in the understanding of higher cognitive function. To make a decision, the primate brain coordinates dynamic interactions between several cortical and subcortical areas that process sensory, cognitive, and reward information. In selecting the optimal behavioral response, decision(More)
The prefrontal cortex of the primate brain has a modular architecture based on the aggregation of neurons in minicolumnar arrangements having afferent and efferent connections distributed across many brain regions to represent, select and/or maintain behavioural goals and executive commands. Prefrontal cortical microcircuits are assumed to play a key role(More)
OBJECTIVE Memory accuracy is a major problem in human disease and is the primary factor that defines Alzheimer's, ageing and dementia resulting from impaired hippocampal function in the medial temporal lobe. Development of a hippocampal memory neuroprosthesis that facilitates normal memory encoding in nonhuman primates (NHPs) could provide the basis for(More)
A long-standing issue concerning the executive function of the primate dorsolateral prefrontal cortex is how the activity of prefrontal neurons is linked to behavioral response selection. To establish a functional relationship between prefrontal memory fields and saccade target selection, we trained three macaque monkeys to make saccades to the remembered(More)
RATIONALE Investigations of the neural consequences of the effects of cocaine on cognition have centered on specific brain circuits including prefrontal cortex, medial temporal lobe and striatum and their roles in controlling drug dependent behavior and addiction. These regions are critical to many aspects of drug abuse; however recent investigations in(More)
The critical role of the mammalian hippocampus in the formation, translation and retrieval of memory has been documented over many decades. There are many theories of how the hippocampus operates to encode events and a precise mechanism was recently identified in rats performing a short-term memory task which demonstrated that successful information(More)