Cognitive effort drives workspace configuration of human brain functional networks

• Published in: The Journal of neuroscience 2011-06, Vol.31 (22), p.8259-8270
• Main Authors: Kitzbichler, Manfred G, Henson, Richard N A, Smith, Marie L, Nathan, Pradeep J, Bullmore, Edward T
• Format: Article
• Language: English
• Subjects: Adult; Brain Waves - physiology; Cognition - physiology; Female; Humans; Magnetoencephalography - methods; Memory, Short-Term - physiology; Nerve Net - physiology; Psychological Theory; Psychomotor Performance - physiology
• ISSN: 0270-6474; 1529-2401
• DOI: 10.1523/JNEUROSCI.0440-11.2011

Effortful cognitive performance is theoretically expected to depend on the formation of a global neuronal workspace. We tested specific predictions of workspace theory, using graph theoretical measures of network topology and physical distance of synchronization, in magnetoencephalographic data recorded from healthy adult volunteers (N = 13) during performance of a working memory task at several levels of difficulty. We found that greater cognitive effort caused emergence of a more globally efficient, less clustered, and less modular network configuration, with more long-distance synchronization between brain regions. This pattern of task-related workspace configuration was more salient in the β-band (16-32 Hz) and γ-band (32-63 Hz) networks, compared with both lower (α-band; 8-16 Hz) and higher (high γ-band; 63-125 Hz) frequency intervals. Workspace configuration of β-band networks was also greater in faster performing participants (with correct response latency less than the sample median) compared with slower performing participants. Processes of workspace formation and relaxation in relation to time-varying demands for cognitive effort could be visualized occurring in the course of task trials lasting