AI Insight
Researchers used advanced diffusion MRI techniques to observe structural changes in living human brains during motor skill learning. They discovered two distinct cellular responses: a temporary expansion of neuronal cell bodies across all task-engaged brain regions, and a lasting increase in neural process density specifically in key motor areas. This study represents the first direct observation of cellular-level plasticity mechanisms in living humans, previously only observable in animal models.
Why it matters
This breakthrough enables scientists to study how the human brain physically changes during learning without relying solely on animal research. The ability to distinguish between temporary cellular responses and lasting structural changes could improve understanding of brain disorders and potentially inform treatments for conditions involving impaired neuroplasticity.
by Guillermina Griffa, Marco Palombo, Abraham Yeffal, Hong-Hsi Lee, Agustin Solano, Susie Y. Huang, Valeria Della-Maggiore
Structural neuroplasticity supports learning, development, and shapes vulnerability to brain disorders, making it a central priority in neuroscience research. However, progress in humans has remained limited by the inability to probe cellular processes in vivo, leaving mechanistic insight largely dependent on animal models. To address this gap, here we combined the sub-voxel sensitivity of ultra–high-gradient diffusion MRI with the cell-compartment specificity of the Soma and Neurite Density Imaging (SANDI) model to probe structural plasticity directly in the living human brain. By tracking how learning modulates the temporal dynamics of cell bodies and cell processes, we aimed to distinguish plastic from nonplastic biological processes driving changes in microstructure. We found that learning a motor skill triggered two distinct temporal responses: a transient expansion of cell bodies across all brain regions engaged by the task, consistent with a short-lived homeostatic mechanism, and a sustained increase in cell-process density restricted to key motor regions, consistent with structural plasticity. Our approach provides a mechanistic window into human neuroplasticity and marks a significant step toward bridging the gap between animal and human neuroscience.
Source: Learning engages transient and sustained cellular mechanisms in the human brain