Evidence accumulator or decision threshold - which cortical mechanism are we observing?

Title:
Evidence accumulator or decision threshold - which cortical mechanism are we observing?
Authors:
Simen, Patrick
Abstract:
Most psychological models of perceptual decision making are of the accumulation-to- threshold variety. The neural basis of accumulation in parietal and prefrontal cortex is therefore a topic of great interest in neuroscience. In contrast, threshold mechanisms have received less attention, and their neural basis has usually been sought in subcortical structures. Here I analyze a model of a decision threshold that can be implemented in the same cortical areas as evidence accumulators, and whose behavior bears on two open questions in decision neuroscience: (1) When ramping activity is observed in a brain region during decision making, does it reflect evidence accumulation? (2) Are changes in speed-accuracy tradeoffs and response biases more likely to be achieved by changes in thresholds, or in accumulation rates and starting points? The analysis suggests that task-modulated ramping activity, by itself, is weak evidence that a brain area mediates evidence accumulation as opposed to threshold readout; and that signs of modulated accumulation are as likely to indicate threshold adaptation as adaptation of starting points and accumulation rates. These conclusions imply that how thresholds are modeled can dramatically impact accumulator-based interpretations of this data.
Citation:
Simen P. 2012. "Evidence accumulator or decision threshold – which cortical mechanism are we observing?" Frontiers in Psychology 3(183). June 21, 2012, doi: 10.3389/fpsyg.2012.00183.
Publisher:
Frontiers Research Foundation
DATE ISSUED:
2012-06-21
Department:
Neuroscience
Type:
article
PUBLISHED VERSION:
10.3389/fpsyg.2012.00183
PERMANENT LINK:
http://hdl.handle.net/11282/309653

Full metadata record

DC FieldValue Language
dc.contributor.authorSimen, Patricken_US
dc.date.accessioned2013-12-23T16:14:12Zen
dc.date.available2013-12-23T16:14:12Zen
dc.date.issued2012-06-21en
dc.identifier.citationSimen P. 2012. "Evidence accumulator or decision threshold – which cortical mechanism are we observing?" Frontiers in Psychology 3(183). June 21, 2012, doi: 10.3389/fpsyg.2012.00183.en_US
dc.identifier.issn1664-1078en_US
dc.identifier.urihttp://hdl.handle.net/11282/309653en
dc.description.abstractMost psychological models of perceptual decision making are of the accumulation-to- threshold variety. The neural basis of accumulation in parietal and prefrontal cortex is therefore a topic of great interest in neuroscience. In contrast, threshold mechanisms have received less attention, and their neural basis has usually been sought in subcortical structures. Here I analyze a model of a decision threshold that can be implemented in the same cortical areas as evidence accumulators, and whose behavior bears on two open questions in decision neuroscience: (1) When ramping activity is observed in a brain region during decision making, does it reflect evidence accumulation? (2) Are changes in speed-accuracy tradeoffs and response biases more likely to be achieved by changes in thresholds, or in accumulation rates and starting points? The analysis suggests that task-modulated ramping activity, by itself, is weak evidence that a brain area mediates evidence accumulation as opposed to threshold readout; and that signs of modulated accumulation are as likely to indicate threshold adaptation as adaptation of starting points and accumulation rates. These conclusions imply that how thresholds are modeled can dramatically impact accumulator-based interpretations of this data.en_US
dc.language.isoen_USen_US
dc.publisherFrontiers Research Foundationen_US
dc.identifier.doi10.3389/fpsyg.2012.00183en
dc.subject.departmentNeuroscienceen_US
dc.titleEvidence accumulator or decision threshold - which cortical mechanism are we observing?en_US
dc.typearticleen_US
dc.identifier.journalFrontiers in Psychologyen_US
dc.subject.keywordDecisionen_US
dc.subject.keywordThresholden_US
dc.subject.keywordAccumulatoren_US
dc.subject.keywordIntegrationen_US
dc.subject.keywordSwitchen_US
dc.subject.keywordRewarden_US
dc.subject.keywordSequenceen_US
dc.rightsThis document is protected by copyright and was first published by Frontiers. All rights reserved. It is reproduced with permission.en_US
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