Can Synchronization Explain Representational Content?

A Reply to Caspar M. Schwiedrzik

Author

John-Dylan Haynes

haynes @ bccn-berlin.de

Charité – Universitätsmedizin Berlin

Berlin, Germany

Commentator

Caspar M. Schwiedrzik

cschwiedrz @ rockefeller.edu

The Rockefeller University

New York, NY, U.S.A.

Editors

Thomas Metzinger

metzinger @ uni-mainz.de

Johannes Gutenberg-Universität

Mainz, Germany

Jennifer M. Windt

jennifer.windt @ monash.edu

Monash University

Melbourne, Australia

Multivariate decoding provides an important tool for studying the representation and transformation of mental contents in the human brain. Specifically, decoding can be used to identify the neural correlates of contents of consciousness (NCCCs). Decoding of functional magnetic resonance imaging (fMRI) signals has so far mostly revealed content-selectivity in sensory brain regions, but not in prefrontal cortex. The limitations of fMRI-decoding only permit cautious conclusions because fMRI signals are only indirectly related to neural coding. However, the role of prefrontal cortex in visual awareness is also questioned by other findings, reviewed in Schwiedrzik (this collection). Neural synchronization might offer an alternative to solving the binding problem by providing a computational means of integrating information encoded in distributed brain regions. However, it is unclear whether synchronization in itself serves as a coding dimension for visual features. Furthermore, other alternatives to synchronization, especially the role of spatial codes, need to be considered as potential solutions to the feature binding problem.

Keywords

Bias | Binding problem | Contents of consciousness | Dynamically changing coding space | fMRI-decoding | Functional magnetic resonance imaging | Global workspace theory | Multivariate decoding | Prefrontal cortex | Spatial code | Synchronization | Tolerance | Visual awareness