Modern neuroimaging consistently shows we use virtually all of our brain, not just 10%.
The provided neuroimaging studies demonstrate extensive brain activation across multiple regions during various tasks and conditions. These studies show widespread neural activity in frontal, temporal, parietal, limbic, and subcortical areas, contradicting the 10% myth. Advanced brain imaging techniques like fMRI reveal that even during rest, large portions of the brain remain metabolically active.
Caveats
While we use most of our brain, different regions are more or less active depending on the task, and not all neurons fire simultaneously.