Abstract
A convergence between molecular biological technique and the technology of miniaturization has produced the "gene chip" or microhybridization array. This device multiplies by several thousand fold the power of the northern blot for studying gene expression. Now, it is possible to survey simultaneously a large fraction of all genes in an experimental organism, and within a few years all of the approximately 140,000 human genes will be within reach of the technique. This capability is not only accelerating the rate of research into gene expression and function, it is changing the perspective of inquiry from single genes in isolation to networks of genes operating as a system. Many neurological diseases, from hydrocephalus to schizophrenia, have a genetic component, and individual responses to therapeutic drugs can vary with the genetic background of patients. In neurology and neurobiology, the ability to obtain "gene expression profiles" from nervous tissue promises to illuminate interactions between neuronal genes and the environment, development, disease, aging, and response to drugs and injury.