Dissociations between glucose metabolism and blood oxygenation in the human default mode network revealed by simultaneous PET-fMRI
Lars Stiernman, F. Grill, A. Hahn, L. Rischka, Rupert Lanzenberger, Vania Panes Lundmark, K. Riklund, J. Axelsson, Anna Rieckmann
Proceedings of the National Academy of Sciences June 30, 2021 DOI: 10.1073/pnas.2021913118 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Experimental study using hybrid PET-MRI Peer reviewed |
|---|---|
| Population | Human participants |
| Topics | Default mode network |
| Key findings | Task-negative BOLD responses in the default mode network during cognitive control are not accompanied by decreases in glucose metabolism, indicating that these signals do not reflect relative metabolic increases during rest. |
Abstract
Significance A consistent finding from functional MRI (fMRI) of externally focused cognitive control is negative signal change in the brain’s default mode network (DMN), but it is unknown whether this reflects an increase of synaptic activity during rest periods or active suppression during task. Using hybrid PET-MRI, we show that task-positive fMRI responses align with increasing glucose metabolism during cognitive control, but task-negative fMRI responses in DMN are not accompanied by corresponding decreases in metabolism. The results are incompatible with an interpretation of task-negative fMRI signal in DMN as a relative metabolic increase during a resting baseline condition. The present results open up avenues for understanding abnormal fMRI activity patterns in DMN in aging and psychiatric disease. The finding of reduced functional MRI (fMRI) activity in the default mode network (DMN) during externally focused cognitive control has been highly influential to our understanding of human brain function. However, these negative fMRI responses, measured as relative decreases in the blood-oxygenation-level–dependent (BOLD) response between rest and task, have also prompted major questions of interpretation. Using hybrid functional positron emission tomography (PET)-MRI, this study shows that task-positive and -negative BOLD responses do not reflect antagonistic patterns of synaptic metabolism. Task-positive BOLD responses in attention and control networks were accompanied by concomitant increases in glucose metabolism during cognitive control, but metabolism in widespread DMN remained high during rest and task despite negative BOLD responses. Dissociations between glucose metabolism and the BOLD response specific to the DMN reveal functional heterogeneity in this network and demonstrate that negative BOLD responses during cognitive control should not be interpreted to reflect relative increases in metabolic activity during rest. Rather, neurovascular coupling underlying BOLD response patterns during rest and task in DMN appears fundamentally different from BOLD responses in other association networks during cognitive control.
Comparable studies
Other experimental studies on default mode network, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Functional connectivity of default mode network components: Correlation, anticorrelation, and causality Healthy subjects | 2008 | Observational study using resting-state fMRI and seed correlation analysis | |
| Patterns of Brain Activity Supporting Autobiographical Memory, Prospection, and Theory of Mind, and Their Relationship to the Default Mode Network Healthy subjects | 2009 | Experimental study using fMRI | |
| Dynamic reconfiguration of the default mode network during narrative comprehension Human subjects | 2016 | Experimental study | |
| Broadband Cortical Desynchronization Underlies the Human Psychedelic State Healthy human participants | 2013 | Experimental study | |
| The brain on art: intense aesthetic experience activates the default mode network Human observers | 2012 | Observational study with fMRI and behavioral analysis |
Citations in the library
Cited by 4
- Distinctive and Complementary Roles of Default Mode Network Subsystems in Semantic Cognition Journal of Neuroscience April 8, 2024
- Extending metabolic considerations to the default mode network. Behavioral and Brain Sciences October 2, 2026
- Task-evoked metabolic demands of the posteromedial default mode network are shaped by dorsal attention and frontoparietal control networks. Elife May 25, 2023
- Cognition is entangled with metabolism: relevance for resting-state EEG-fMRI. Frontiers in Human Neuroscience April 11, 2023
Cites 4
- A default mode of brain function Proceedings of the National Academy of Sciences January 16, 2001
- Recruitment of the default mode network during a demanding act of executive control Elife April 13, 2015
- Role of the Default Mode Network in Cognitive Transitions Cerebral Cortex June 21, 2018
- Attention Shifts Recruit the Monkey Default Mode Network Journal of Neuroscience January 31, 2018