I won't pretend I can write like Paul Muldoon. But I might be
able to make more interesting pictures.
Many of the spectacular achievements of 20th-century science followed
a simple paradigm. As new directions in basic atomic or molecular
physics matured, they were adopted by chemists and applied physicists.
This work in turn enabled applications in biological, clinical,
and environmental science. The centers I direct at Princeton (including
POEM, the center for Photonics and Optoelectronic Materials) support
this process by bridging the gaps between innovation, technology,
Imaging technologies provide many of the best-known illustrations
of this evolution. Fifty years ago, measurements of the magnetism
created when atomic nuclei "spin" were at the forefront
of esoteric physics research, with no conceivable application. Gradually
the applications became clear, and by the 1960s, every modern chemistry
department had "nuclear magnetic resonance" spectrometers.
By the 1980s, most hospitals had "magnetic resonance imagers"
("nuclear" was dropped to avoid scaring patients) which
give beautifully detailed images of soft tissue.
Imaging function, not just structure, is the modern research frontier,
and new methods are unraveling the workings of the brain. The black
and white images below come from a conventional MRI of a volunteer,
similar to what you would get in a hospital. The slice at right
(located at the position of the yellow line at left) shows colored
dots at points that differed when the volunterr read Muldoon's poem
verses a non-emotive text. This activation in the prefrontal cortex
is no surprise: It is the most evolved part of the brain, and a
center of both critical and emotional response.
More extensive studies (with multiple subjects and multiple tasks)
can give better spatial resolution. In recent papers, scientists
have imaged differences in the brain activation between viewing
a lover and viewing an opposite-sex friend; between male and female
perceptions; and between moral reasoning and simple decision-making.
Some would say that the mind-imaging revolution threatens to convert
the field of psychology into a quantitative science over the next
few decades. For this to happen, new technological advances must
improve both spatial and temporal resolution. One promising advance
involves lasers. Starting with a very short lump of light (in time),
we can sculpt pulses that quickly change amplitude and color in
complex patterns. The figure at right shows the "gremlin pulse,"
a very simple pulse used in my laboratories to test shaping capabilities
(we can actually program hundreds of features simultaneously). One
application of shaped pulses is "making molecules dance,"
or producing just the right color and time distribution to excite
specific compounds. A related application is imaging. The human
body is almost transparent at specific near-infrared wavelengths,
just slightly outside of the visible region (but easily detected
by modern instruments), and subtle brain changes can change the
amount of transmitted light. Unfortunately, light scattering currently
makes high-resolution pictures impossible. Pulse shaping may provide
an attractive solution, allowing low power lasers to see through
scattering and find hidden chemical signals.
We are not yet able to probe truly deep questions (brain sensors
will not replace literary critics for some time). Still, the evolving
ability to image the mind has enormous consequences that range far
beyond neuroscience. The world needs more poets who follow science,
and more scientists who learn to appreciate beauty in words.