PT  - JOURNAL ARTICLE
AU  - Northall, Alicia
AU  - Doehler, Juliane
AU  - Weber, Miriam
AU  - Vielhaber, Stefan
AU  - Schreiber, Stefanie
AU  - Kuehn, Esther
TI  - Topographic Stability and Layer-Specific Flexibility are Mechanisms of Human Cortical Plasticity
AID  - 10.1101/2022.05.29.493865
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2022.05.29.493865
4099  - http://biorxiv.org/content/early/2022/05/30/2022.05.29.493865.short
4100  - http://biorxiv.org/content/early/2022/05/30/2022.05.29.493865.full
AB  - Age-related cortical plasticity reveals insights into the mechanisms underlying the stability and flexibility of neuronal circuits. Classical parcellation has long demonstrated the importance of microstructural features yet 3D approaches have rarely been applied to human brain organization in-vivo. We acquired functional and structural 7T-MRI and behavioral data of living younger and older adults to investigate human primary motor cortex (M1) aging, employing 3D parcellation techniques. We identify distinct cortical fields in M1 based on quantitative tissue contrast, which are, along with the myelin-poor borders between them, stable with age. We also show age-related iron accumulation, particularly in the output layer 5b and the lower limb field. Our data offers a new model of human M1 with distinct cortical fields, a mechanistic explanation for the stability of topographic organization in the context of aging and plasticity, and highlights the specific vulnerability of output signal flows to cortical plasticity.Competing Interest StatementThe authors have declared no competing interest.