Prefrontal cortical unit activity and delayed alternation performance in monkeys.

Kubota, Kisou; Niki, Hiroaki

doi:10.1152/jn.1971.34.3.337

Cited by 613 publications

(305 citation statements)

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“…This is exactly what has been reported now several times in unit recordings in the PFC of monkeys [5][6][7]28,33,39]. A few event-related fMRI studies have varied the length of the retention delay up to 24 s and have reported that the DLPFC activity does indeed span the entire delay [34 -37].…”

Section: Memory Load Effectssupporting

confidence: 76%

Persistent activity in the prefrontal cortex during working memory

Curtis

D’Esposito

2003

Trends in Cognitive Sciences

1,762

101

1,184

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The dorsolateral prefrontal cortex (DLPFC) plays a crucial role in working memory. Notably, persistent activity in the DLPFC is often observed during the retention interval of delayed response tasks. The code carried by the persistent activity remains unclear, however. We critically evaluate how well recent findings from functional magnetic resonance imaging studies are compatible with current models of the role of the DLFPC in working memory. These new findings suggest that the DLPFC aids in the maintenance of information by directing attention to internal representations of sensory stimuli and motor plans that are stored in more posterior regions.Working memory refers to the temporary representation of information that was just experienced or just retrieved from long-term memory. These active representations are short-lived, but can be maintained for longer periods of time through active rehearsal strategies, and can be subjected to various operations that manipulate the information in such a way that makes it useful for goaldirected behavior. Most definitions of working memory include both storage and (executive) control components [1]. Cognitive neuroscientists are searching for ways to disassociate the separate components of working memory in attempts to localize and clearly characterize their neural implementation. The prefrontal cortex (PFC) is thought to be the most important substrate for working memory (Fig. 1). Two key findings from studies of monkeys performing delayed response tasks suggest a crucial role for the PFC in working memory. First, experimental lesions of the principal sulcus in the dorsolateral prefrontal cortex (DLPFC) cause delay-dependent impairments [2][3][4]. That is, forgetting increases not only when a delay is imposed but increases with the length of the delay. Second, neurophysiological unit recordings from the DLPFC often show persistent, sustained levels of neuronal firing during the retention interval of delayed response Fig. 1. Lateral surface of (a) macaque and (b) human brain. The PFC is composed of lateral, medial, and orbital sectors that are believed to be functionally distinct given the selective effects of damage and distribution of afferent and efferent projections. The tinted areas correspond to those defined by Petrides and Pandya [71] based on cytoarchitecture and connectivity. Notably, the mid-DLPFC comprises areas 46 and 9/46 and the mid-VLPFC comprises areas 45 and 47/12. Note that much of area 46 lies in the depths of the principle sulcus of the monkey and the intermediate frontal sulcus of the human. Frontal premotor regions are also highlighted. The frontal eye field (F) in the macaque lies in the anterior bank of the arcuate sulcus in area 8A. In the human, F is found in the vicinity of the precentral sulcus and superior frontal sulcus junction (area 6 and maybe the caudal-most portion of 8A). The frontal eye field is a premotor region involved in the control of eye movements. Broca's area (B, area 44) is also a premotor area that is involved in the product...

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Section: Memory Load Effectssupporting

confidence: 76%

Persistent activity in the prefrontal cortex during working memory

Curtis

D’Esposito

2003

Trends in Cognitive Sciences

1,762

101

1,184

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“…This task requires a relatively simple form of working memory, where the prior stimulus must be maintained over a delay until the next stimulus appears, so that the subject can discriminate the target from non-target sequences. This is the kind of activationbased working memory that has often been observed for example in electrophysiological studies of working memory in monkeys (e.g., Fuster & Alexander, 1971;Kubota & Niki, 1971;Miyashita & Chang, 1988;Funahashi, Bruce, & Goldman-Rakic, 1989;Miller, Erickson, & Desimone, 1996).…”

Section: The Pbwm Model Of Working Memorymentioning

confidence: 83%

Banishing the homunculus: Making working memory work

2006

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Abstract:The prefrontal cortex (PFC) has long been thought to subserve both working memory and "executive" function, but the mechanistic basis of their integrated function has remained poorly understood, often amounting to a homunculus. This paper reviews the progress in our lab and others pursuing a long-term research agenda to deconstruct this homunculus by elucidating the precise computational and neural mechanisms underlying these phenomena. We outline six key functional demands underlying working memory, and then describe the current state of our computational model of the PFC and associated systems in the basal ganglia (BG). The model, called PBWM (prefrontal-cortex, basal-ganglia working memory model), relies on actively maintained representations in the PFC, which are dynamically updated/gated by the BG. It is capable of developing human-like performance largely on its own by taking advantage of powerful reinforcement learning mechanisms, based on the midbrain dopaminergic system and its activation via the BG and amygdala. These learning mechanisms enable the model to learn to control both itself and other brain areas in a strategic, task-appropriate manner. The model can learn challenging working memory tasks, and has been corroborated by several important empirical studies.

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“…Indeed a distinct class of neurons in the caudalhalf of the principalis fires in association with the motor aspect of a task. 31 ' 37 ' 38 It is of interest that the part of the principalis cortex which is most essential for delayed-response tasks is also the part which preferentially receives visuomotor, premotor and somatosensory projections.…”

Section: Discussionmentioning

confidence: 99%

Cortical afferent input to the principals region of the rhesus monkey

1985

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Abstract-The sources of ipsilateral cortical afferent projections to regions along both banks of the principalis sulcus in the prefrontal cortex were studied with horseradish peroxidase in macaque monkeys. The principalis cortex receives a substantial proportion of its projections from neighboring prefrontal regions. However, differences were noted in the distribution of labeled cells projecting to the various principalis regions. These differences were most marked with respect to the relative proportion of cells originating in visual, auditory, somatosensory, premotor and limbic cortical areas. The findings indicate that the caudal ventral principalis region receives projections from both visual and visuomotor regions, whereas the anterior tip of the principalis appears to be the major target of projections from auditory association regions. The ventral bank at the middle extent of the principalis was the only case with a significant proportion of labeled cells in somatosensory association and premotor regions. There was a consistent increase in the proportion of labeled cells in limbic cortical areas projecting to more rostral principalis sites, irrespective of whether the injection was placed in the dorsal or ventral bank.These findings suggest that the caudal principalis region has a visual-visuomotor and the rostral, an auditorylimbic bias with respect to the long projections they receive.

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Prefrontal cortical unit activity and delayed alternation performance in monkeys.

Cited by 613 publications

References 0 publications

Persistent activity in the prefrontal cortex during working memory

Persistent activity in the prefrontal cortex during working memory

Banishing the homunculus: Making working memory work

Cortical afferent input to the principals region of the rhesus monkey

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