A theory of working memory without consciousness or sustained activity
Abstract
Working memory and conscious perception are thought to share similar brain mechanisms, yet recent reports of non-conscious working memory challenge this view. Combining visual masking with magnetoencephalography, we investigate the reality of non-conscious working memory and dissect its neural mechanisms. In a spatial delayed-response task, participants reported the location of a subjectively unseen target above chance-level after several seconds. Conscious perception and conscious working memory were characterized by similar signatures: a sustained desynchronization in the alpha/beta band over frontal cortex, and a decodable representation of target location in posterior sensors. During non-conscious working memory, such activity vanished. Our findings contradict models that identify working memory with sustained neural firing, but are compatible with recent proposals of ‘activity-silent’ working memory. We present a theoretical framework and simulations showing how slowly decaying synaptic changes allow cell assemblies to go dormant during the delay, yet be retrieved above chance-level after several seconds.
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Author details
Funding
Ecole des Neurosciences de Paris (PhD Fellowship)
- Darinka Trübutschek
Fondation Schneider Electric (PhD Fellowship)
- Darinka Trübutschek
CEA
- Stanislas Dehaene
INSERM
- Stanislas Dehaene
Collège de France
- Stanislas Dehaene
European Research Council (Senior Grant,NeuroConsc)
- Stanislas Dehaene
Fondation Roger de Spoelberch
- Stanislas Dehaene
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Human subjects: The study was approved by the by CPP IDF under the reference CPP 08 021. All subjects gave written informed consent and consent to publish before participating in the study.
Copyright
© 2017, Trübutschek et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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