Cluster analysis - a mainstay technique of molecular biology - offers an alternative to the simpler change model. It interprets data (control and experimental) and change as mathematical patterns that can be displayed as trees (dendrograms).

In the hippocampus of a Parkinson's patient, what is the mathematical phenotype of neurons?

How does this Parkinson's tree compare to that of the normal? The answer gives us a global view of neurons in health and disease.