- Di Lorenzo Alho, Ana Tereza;
- Suemoto, Claudia Kimie;
- Polichiso, Lívia;
- Tampellini, Edilaine;
- de Oliveira, Kátia Cristina;
- Molina, Mariana;
- Santos, Glaucia Aparecida Bento;
- Nascimento, Camila;
- Leite, Renata Elaine Paraizo;
- de Lucena Ferreti-Rebustini, Renata Eloah;
- da Silva, Alexandre Valotta;
- Nitrini, Ricardo;
- Pasqualucci, Carlos Augusto;
- Jacob-Filho, Wilson;
- Heinsen, Helmut;
- Grinberg, Lea Tenenholz
The human brain undergoes non-uniform changes during aging. The substantia nigra (SN), the source of major dopaminergic pathways in the brain, is particularly vulnerable to changes in the progression of several age-related neurodegenerative diseases. To establish normative data for high-resolution imaging, and to further clinical and anatomical studies we analyzed SNs from 15 subjects aged 50-91 cognitively normal human subjects without signs of parkinsonism. Complete brains or brainstems with substantia nigra were formalin-fixed, celloidin-mounted, serially cut and Nissl-stained. The shapes of all SNs investigated were reconstructed using fast, high-resolution computer-assisted 3D reconstruction software. We found a negative correlation between age and SN volume (p = 0.04, rho = -0.53), with great variability in neuronal numbers and density across participants. The 3D reconstructions revealed SN inter- and intra-individual variability. Furthermore, we observed that human SN is a neuronal reticulum, rather than a group of isolated neuronal islands. Caution is required when using SN volume as a surrogate for SN status in individual subjects. The use of multimodal sequences including those for fiber tracts may enhance the value of imaging as a diagnostic tool to assess SN in vivo. Further studies with a larger sample size are needed for understanding the structure-function interaction of human SN.