FROST: A Distributed Neurocomputational Model of Working Memory Maintenance

Ashby, F. Gregory; Ell, Shawn W.; Valentin, Vivian V.; Casale, Michael

doi:10.1162/089892905774589271

Cited by 120 publications

(129 citation statements)

References 49 publications

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“…Previous studies have shown a load--related increase in activation in the left thalamus during WM tasks (Altamura et al, 2007;Choo et al, 2005;Nyberg et al, 2009). Furthermore, a specific role for the thalamus during WM maintenance has been proposed by Ashby et al (2005), in which activation during the delay interval is sustained by an excitatory prefrontal cortico--thalamic loop (in conjunction to the fronto--parietal excitatory loop). As such, the thalamus may be differentially activated in an effort to support the maintenance of information in the absence of input from external stimuli.…”

Section: Discussionmentioning

confidence: 99%

The effect of caffeine on working memory load-related brain activation in middle-aged males

et al. 2013

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Section: Discussionmentioning

confidence: 99%

The effect of caffeine on working memory load-related brain activation in middle-aged males

et al. 2013

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“…At the cognitive level, the winning node represents the selected motor response (for similar ideas, see Guthrie et al, 2009;Suri & Schultz, 1999). Unlike most existing basal ganglia models (Ashby, Ell, Valentin, & Casale, 2005;Frank, 2005;Suri & Schultz, 1999;Houk, 1995), the basal ganglia, in our model, learns to map representations of attended-to stimuli to motor responses. These mechanisms, as discussed below, can explain performance in various multiple-cue category learning tasks.…”

Section: Model Architecturementioning

confidence: 99%

A Neurocomputational Model of Dopamine and Prefrontal–Striatal Interactions during Multicue Category Learning by Parkinson Patients

Moustafa¹,

Gluck²

2011

Journal of Cognitive Neuroscience

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Abstract■ Most existing models of dopamine and learning in Parkinson disease (PD) focus on simulating the role of basal ganglia dopamine in reinforcement learning. Much data argue, however, for a critical role for prefrontal cortex (PFC) dopamine in stimulus selection in attentional learning. Here, we present a new computational model that simulates performance in multicue category learning, such as the "weather prediction" task. The model addresses how PD and dopamine medications affect stimulus selection processes, which mediate reinforcement learning. In this model, PFC dopamine is key for attentional learning, whereas basal ganglia dopamine, consistent with other models, is key for reinforcement and motor learning. The model assumes that competitive dynamics among PFC neurons is the neural mechanism underlying stimulus selection with limited attentional resources, whereas competitive dynamics among striatal neurons is the neural mechanism underlying action selection. According to our model, PD is associated with decreased phasic and tonic dopamine levels in both PFC and basal ganglia. We assume that dopamine medications increase dopamine levels in both the basal ganglia and PFC, which, in turn, increase tonic dopamine levels but decrease the magnitude of phasic dopamine signaling in these brain structures. Increase of tonic dopamine levels in the simulated PFC enhances attentional shifting performance. The model provides a mechanistic account for several phenomena, including (a) medicated PD patients are more impaired at multicue probabilistic category learning than unmedicated patients and (b) medicated PD patients opt out of reversal when there are alternative and redundant cue dimensions. ■

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“…Most computational models of VWM rely upon intercommunication between the PFC and the striatum such that memories are maintained via recurrent activation in fronto-striatal loops (14)(15)(16). In vivo, working memory maintenance is associated with sustained delay-period activity in the PFC (5,17) and BG (18), although the BG are thought to play a role in gating information into the PFC to allow it to update representations where necessary (19).…”

mentioning

confidence: 99%

Prefrontal cortex and basal ganglia contributions to visual working memory

Voytek

Knight

2010

Proc. Natl. Acad. Sci. U.S.A.

163

116

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Visual working memory (VWM) is a remarkable skill dependent on the brain's ability to construct and hold an internal representation of the world for later comparison with an external stimulus. The prefrontal cortex (PFC) and basal ganglia (BG) interact within a cortical and subcortical network supporting VWM. We used scalp electroencephalography in groups of patients with unilateral PFC or BG lesions to provide evidence that these regions play complementary but dissociable roles in VWM. PFC patients show behavioral and electrophysiological deficits manifested by attenuation of extrastriate attention and VWM-related neural activity only for stimuli presented to the contralesional visual field. In contrast, patients with BG lesions show behavioral and electrophysiological VWM deficits independent of the hemifield of stimulus presentation but have intact extrastriate attention activity. The results support a model wherein the PFC is critical for top-down intrahemispheric modulation of attention and VWM with the BG involved in global support of VWM processes.attention | electroencephalography | lesion | stroke E ven a seemingly simple action such as determining which of two bananas is riper requires us to compare real world visual information, such as the color of the banana you are currently looking at in the store, with your memory of the yellowness of the other banana you just put down. This relies in part on visual working memory (VWM), a remarkable ability wherein we construct and hold an internal model of a real-world visual stimulus that we then later compare against another stimulus. In essence, we construct and hold a model of the visual world and compare that model against subsequent inputs from the external world. VWM relies upon an intact and functioning prefrontal cortex (PFC), and damage to this region, such as from stroke, causes VWM impairments (1-3). However, cognitive processes do not localize to specific brain regions per se and a behavior as complex as VWM recruits a distributed network of cortical and subcortical structures (4-8), including the basal ganglia (BG) (9, 10) and visual extrastriate regions (11)(12)(13).Most computational models of VWM rely upon intercommunication between the PFC and the striatum such that memories are maintained via recurrent activation in fronto-striatal loops (14-16). In vivo, working memory maintenance is associated with sustained delay-period activity in the PFC (5, 17) and BG (18), although the BG are thought to play a role in gating information into the PFC to allow it to update representations where necessary (19). Although neurons in both visual extrastriate and the PFC maintain VWM representations during delay periods, PFC neurons encode more information about the stimuli and are more resistant to distractors than visual extrastriate neurons (20). Animal research shows that the BG rapidly learn task-relevant rules and may send relevant, preprocessed information to the PFC for subsequent selection and further processing (21). Anatomically, the BG are situate...

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FROST: A Distributed Neurocomputational Model of Working Memory Maintenance

Cited by 120 publications

References 49 publications

The effect of caffeine on working memory load-related brain activation in middle-aged males

The effect of caffeine on working memory load-related brain activation in middle-aged males

A Neurocomputational Model of Dopamine and Prefrontal–Striatal Interactions during Multicue Category Learning by Parkinson Patients

Prefrontal cortex and basal ganglia contributions to visual working memory

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