The Distributed Nature of Working Memory. Issue 2 (February 2017)

• Record Type: Journal Article
• Authors: Christophel, Thomas B.; Klink, P. Christiaan; Spitzer, Bernhard; Roelfsema, Pieter R.; Haynes, John-Dylan
• Is Part Of: Trends in cognitive sciences. Volume 21:Issue 2(2017)
• Page Start: 111
• Page End: 124
• Publication Date: 2017-02
• Subjects: Cognitive science -- Periodicals; Cognitive neuroscience -- Periodicals; 153.05
• DOI: 10.1016/j.tics.2016.12.007
• Languages: English
• ISSNs: 1364-6613

Abstract

Abstract : Studies in humans and non-human primates have provided evidence for storage of working memory contents in multiple regions ranging from sensory to parietal and prefrontal cortex. We discuss potential explanations for these distributed representations: (i) features in sensory regions versus prefrontal cortex differ in the level of abstractness and generalizability; and (ii) features in prefrontal cortex reflect representations that are transformed for guidance of upcoming behavioral actions. We propose that the propensity to produce persistent activity is a general feature of cortical networks. Future studies may have to shift focus from asking where working memory can be observed in the brain to how a range of specialized brain areas together transform sensory information into a delayed behavioral response. Trends: There is no evidence for a single site of working memory storage. Rather, persistent neuronal activity that is informative about a currently memorized stimulus can be found in sensory, parietal, and prefrontal brain regions. Working memory entails a gradient of abstraction from sensory areas reflecting low-level sensory features to prefrontal regions encoding more abstract, semantic, and response-related aspects of stimuli. We hypothesize that all regions of neocortex have the capability to briefly retain their specialized representations in the service of upcoming task demands. Persistent activity in most, if not all, cortical regions can exert control over future behavior. The contributions of individual brain regions to working memory are best understood as different representational stages with various levels of transformation and abstraction.