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Updated: May 23, 2026
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Whole-Brain 3D Activation and Functional Connectivity Mapping in Mice using Transcranial Functional Ultrasound Imaging
Published on: February 24, 2021
Whole-brain, time-locked activation with simple tasks revealed using massive averaging and model-free analysis
Javier Gonzalez-Castillo1, Ziad S Saad, Daniel A Handwerker
1Section on Functional Imaging Methods, Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA. javier.gonzalez-castillo@nih.gov
Summary
Functional MRI (fMRI) reveals widespread brain activity, challenging the view of localized brain function. Optimized conditions show over 95% of the brain is active during simple tasks, highlighting extensive neural collaboration.
Area of Science:
- Neuroscience
- Cognitive Science
- Neuroimaging
Background:
- The brain is the largest energy consumer, with ongoing neuronal activity observed even without demanding tasks.
- Current task-based functional MRI (fMRI) studies often emphasize a localizationist view of brain function.
- Evidence suggests the brain continuously collaborates to anticipate and respond to environmental stimuli.
Purpose of the Study:
- To challenge the prevailing localizationist view of brain function derived from fMRI.
- To demonstrate that fMRI activations extend beyond task-specific regions under optimal conditions.
- To investigate the extent of brain-wide neuronal collaboration during cognitive tasks.
Main Methods:
- Utilized fMRI with optimized noise conditions for enhanced signal detection.
- Employed a simple visual stimulation plus attention control task.
- Analyzed blood-oxygen-level-dependent (BOLD) signal changes across the entire brain.
- Developed whole-brain parcellations based on regional response shape variations.
Main Results:
- fMRI activations were observed in over 95% of the brain during a simple visual task.
- Signal changes correlated with task timing across widespread brain regions.
- Regional response shapes varied, enabling meaningful, reproducible, and symmetrical whole-brain parcellations.
- Findings suggest widespread brain activity is often missed due to high noise and strict models.
Conclusions:
- The sparseness of typical fMRI maps is a consequence of technical limitations, not localized brain function.
- The brain functions as a continuously collaborating network, with activity far more pervasive than commonly depicted.
- Optimized fMRI analysis reveals intricate details of whole-brain function, emphasizing the need to reconsider current models.
