Suppose $x$ is a position in the brain, and $n_i(x)$ is the density of neuro recepter $i$ around that point. Any given human will have some distribution of neruo recepters $n_i(x)$ through out there brain.
I am wondering what do we know about the statistics of these densities, or how they vary from person to person?
For example, is there a variance in the amount of serotonin receptors in the brain between healthy or unhealthy people?
How does one go about measuring this?