Remarkable and continued growth in the
field of brainaging
research has been fueled by a confluence of fac-tors.
Developments in molecular biology, imaging, andgenetics
coupled with the imperative caused by theaging
of the population has created fertile ground forimproved
understanding of the interaction betweenbrain
function and behavior. Aging changes in neuro-chemical
systems may account for the spectrum of cog-nitive
and behavioral states of successfully aged per-sons,
but may also contribute to enhanced vulnerabilityto
depressive or dementing illness. In particular, therefinement
of in vivo imaging approaches to investi-gating
the structure and function of the aging brainhas
provided the opportunity to strengthen our knowl-edge
of the biological substrate of the aging brain andneuropsychiatric
disorders, and translate these intotherapeutics.Man
(and woman) has long been fascinated withthe
workings of the human mind. Yet it is only recentlythat we have developed the tools to
explore its biologi-cal
underpinnings in the living state. The 1990 to 2000interval was hailed as the Decade of
the Brain.Advancesin
imaging, genetics, molecular biology, and pharmacol-ogy continue to advance our horizons
in neuroscienceresearch, but
the scientific yield from these highly pro-ductive
past 10 years will surely both usher in the devel-opments
of the future and guide the research achieve-ments
to important clinical applications. The gapbetween bench and bedside is narrower
than ever and,importantly, there
is increasing focus on not only length-ening
the life span, but also improving the quality ofmental
and physical health in aging.Anatomical
and neurochemical systemsaffected
by brain agingImaging
structural brain changes in agingStructural
brain changes accompanying normal agingand
neurodegenerative and psychiatric disorders mayparallel
and provide insight into the etiology of changesin
cognition, mood, and motor function in the elderly.However, postmortem studies of
brain morphology areplagued
by artifacts caused by changes in hydrationstates
just prior to death and tissue fixation.These stud-ies
are biased toward end-stage disease states and per-mit
only retrospective correlations with measures ofbrain
function and behavior. Magnetic resonance imag-ing
(MRI) offers a means of assessing structural brainchanges
in vivo and provides the opportunity to evalu-ate
the relationship of morphologic parameters tomood, neuropsychological dysfunction, and
treatmentresponse.It is well known from both imaging
and autopsy seriesthat
cerebrospinal fluid (CSF) increases and cerebralvolume
reductions accompany normal human aging.1-8Brain
aging research at the close of the 20thcentury: from
bench to bedsideCarolyn
Cidis Meltzer, MD; Paul T. Francis, PhDKeywords:
Alzheimer’s disease; brain aging; depression; neurotransmitter; magnetic
resonance imaging (MRI); positron emission tomography (PET)
Author affiliations: Departments of Radiology and Psychiatry,
University of Pitts-burgh, Pittsburgh, Pa, USA (Carolyn Cidis
Meltzer); Centre for Neuroscience Research, GKT School of Biomedical
Science, King’s College, London, UK (Paul T. Francis)
Address for correspondence: Carolyn Cidis Meltzer, MD, University
of Pitts-burgh Medical Center, PET Facility, B-938, 200 Lothrop
Street, Pittsburgh, PA 15213-2582, USA
(e-mail: meltzercc@msx.arad.upmc.edu)
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