Doctor Brian Bacskai explaine that senile plaques lead to an increase in resting calcium in astrocytes in the entire brain.
What we have observed is that senile plaques lead to a global increase in resting calcium in astrocytes throughout the brain, not just a focal increase in calcium which is what we observe in neuronal networks. The exact mechanism whereby the presence of plaques leads to the increase in calcium level in astrocytes is still unknown. So when I say global increase that means astrocytes that are both very close to senile plaques physically, and far away. So in terms of the whole brain, the only parts of the brain we image are the superficial cortex, which is the predominant area of plaque deposition. So we don’t image the entire brain, so we can’t say that it’s the entire brain but because of the density of plaque formation in the brain, there are cells that can be far from a plaque or very close to a plaque and it doesn’t matter how close they are to a plaque; the intracellular calcium is elevated in those cells.