As these examples illustrate, new combination techniques are already advancing the threshold of applying imaging innovations to further understanding brain functions and the effects of experiences, diseases and therapies in altering these.
A decade ago, we would not envisioned that PET imaging with probes that attach only to the protein amyloid could help diagnose Alzheimer’s disease and assess effects of therapies to reduce amyloid or prevent its further deposition in the brain. We would not have foreseen that PET (which has relatively poorer spatial resolution) combined with optical imaging in laboratory animals could visualize fluorescently marked neurons in the brain to reveal how one neuron hooks up with another to form neural circuits and to monitor this process over time during development to see changes in response to disease or experience.
Since biochemical changes in cells precede changes that occur in response to disease, identifying these cellular changes could provide the means to diagnose diseases in their earliest stages, when they are most likely to be responsive to effective therapies. Imaging biochemical changes in molecules, rather than physical differences between normal and diseased tissues, has the potential not only to improve early identification and diagnosis of diseases, but also to quickly assess the efficacy of various treatments.
Combining molecular imaging with anatomical and physiological imaging technologies, as these examples illustrate, is fundamentally advancing scientific understanding of how the brain functions and the translation of that understanding to improve human health.