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Last November, the op-ed page of theNew
York Times, which typically airs political
controversies, managed to create one of its
own. It published a column describing astudy in which 20
undecided voters had their
brain activity scanned by functional mag-
netic resonance imaging (fMRI) while view-
ing photographs and videos of the major
candidates in the upcoming U.S. presidential
election. The findings revealed some voter
impressions on which this election may well
turn, according to the authors, who
included a political scientist, a neuroscien-
tist, and several people affiliated with FKF
Applied Research, a company based in
Washington, D.C., that sells fMRI-based
marketing studies.
The column infuriated some neuroscien-
tists and ignited an animated discussion in theimaging field. It
was really closer to astrol-
ogy than it was to real science, says Russell
Poldrack of the University of California, Los
Angeles (UCLA), who drafted a letter to the
newspaper that was signed by 16 other cogni-
tive neuroscientists and published 3 days later.
It epitomized everything that a lot of us feel is
wrong about where certain parts of the field
are going, which is throw someone in a scan-
ner and tell a story about it.
Since its introduction in the early 1990s,
fMRI has transformed neur
science. Now in its teenage year
the fMRI field is still experiencin
growing pains. Some cognitiv
neuroscientists say theyre fru
trated that many studiesinclu
ing some of those that garner th
most attention in the popul
pressreveal little about the neu
ral mechanisms of human cogn
tion. The problem right now wi
imaging is that doing experimen
right is really, really hard, but ge
ting pictures out is really, real
easy, says Steven Petersen, a ve
eran brain-imaging researcher
Washington University in S
Louis, Missouri.
At the same time, there a
signs that the field is maturing,
researchers confront the limit
tions of fMRI. Such effor
include painstaking experimenthat match human fMRI data wi
analogous fMRI data and electr
physiological recordings of neur
activity in monkeys, as well a
new analytical methods capable
revealing information processin
in the brain that would be imposs
ble to detect with standard meth
ods. I think [these methods] a
really going to revolutionize ho
we think about our data, says Po
drack. They also have the potenti
to introduce more rigor into fMRresearchsomething thats bad
needed, Poldrack says, otherwise, peop
will start to see fMRI as neophrenology, ju
telling stories and not giving explanations.
Neuroimagers gone wildWhat irked Poldrack and others most
abo
the Timess op-ed was the way the autho
inferred particular mental states from th
activation of particular brain regions: Acti
ity in the anterior cingulate cortex indicate
mixed feelings about Hillary Clinton, f
example, whereas amygdala activation ind
cated voter anxiety about Republican candidate Mitt Romney.
The basic problem, the objectors wrote
their letter, is that its not possible to infer
particular mental state (such as anxiety) fro
the activation of a particular brain region (suc
as the amygdala). Although its true that anx
ety engages the amygdala, says co-signer Eli
abeth Phelps, a cognitive neuroscientist
New York University, so do intense smell
sexually arousing images, and many oth
things. To conclude that Romney makes vote
13 JUNE 2008 VOL 320 SCIENCE www.sciencemag.org12
NEWSFOCUS
As the use of functional magnetic resonance imaging has
exploded,
some researchers say the field could use a dose of rigor. Will
new
experimental approaches come to the rescue?
Growing Pains for fMRI
Published by AAAS
8/14/2019 Growing Pains for fMRI
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anxious based on amygdala activation alone is
unjustified, Phelps says.
The neuroscientist co-author on the op-ed
piece, Marco Iacoboni of UCLA, stands by the
columns conclusions as reasonable and says
hes been surprised and stung by what he views
as an overly harsh and hypocritical rebuke.
After all, he points out, most of his critics use
similar reverse inferences themselves.
Thats true, says Poldrack, and its a prob-
lem the field needs to confront. He and oth-
ers argue that reverse inferences are particu-
larly common in newer fields such as social
cognitive neuroscience and neuroeconomics
(not to mention neuropolitics), fields in
which researchers are still trying to identify
the cognitive processes underlying the
behaviors they study. As an example, Pol-
drack points to a widely cited paper that used
fMRI to investigate brain activity in subjects
pondering moral dilemmas (Science, 14
Sept embe r 20 01, p. 2105); some of the
brain regions that lit up had been linked inprevious studies to
emotional and rational
cognitive processes, and the authors con-
cluded that these two types of processes are
active, to different degrees, in different types
of moral judgments. But the strength of such
arguments hinges on how specifically a
given brain area is linked to a given mental
process. Poldrack points out, for example,
that some of the emotional brain regions in
the morality study have also been connected
to memory and languagea caveat that is
rarely mentioned in medi a cove rage of
the work (Science, 9 May, p. 734).
Monkeying aroundThe general public may be easily seduced by
pretty images generated by fMRI (see sidebar,below), but even
neuroscientists sometimes
seem to fall under the spell and overlook the
methods limitations. One constraint is the nar-
row sliver of the human experience that can be
captured when a person has to keep his or her
head still for long periods inside an fMRI scan-
ner. Another is the resolution. Using fMRI to
spy on neurons is something like using Cold
Warera satellites to spy on people: Only
large-scale activity is visible. With standard
fMRI equipment, the smallest cube of brain
tissue that can be imaged is generally a fe
millimeters on a side. Each such voxel
mashup of volume and pixel) contains millio
of neurons. And although neurons can fi
hundreds of impulses per second, the fMR
signalwhich indicates an increase oxygenated blood bringing
energy to activ
neuronsdevelops sluggishly, over sever
seconds. This makes fMRI a crude tool f
investigating how circuits of intricately con
nected neurons do the computational work
cognition and behavior, says Roger Tootell,
neuroscientist at Harvard University. fMRI
really good for telling you where to look, h
says, but I dont think you can ever real
come up with mechanisms.
Tootell is one of a handful of researche
trying to circumvent such obstacles by com
bining human fMRI with monkey experments. The general idea, he
explains, is to fo
low up on the human findings by using fMR
to identify analogous regions of the monke
brain and then record the activity of individu
neurons there with microelectrodes.
In some cases, single neuron recordin
have confirmed fMRI findings. In 200
Tootell and colleagues reported micro
electrode data showing that 97% of neurons
the monkey equivalent of the fusiform fac
areaa region of the temporal cortex th
appears in human fMRI studies to respon
selectively to images of facesdo indee
respond preferentially to faces (Scienc3 February 2006, p. 670).
But Tootell says th
more recent human fMRI experiments h
group has done suggest that neurons in a
adjacent place region in the temporal corte
respond preferentially to edges, not places p
se. The researchers are planning monke
experiments to investigate the preferences
neurons in this region in greater detail.
Such studies, he says, can also begin
reveal mechanisms of visual object processin
in the brain, such as how face or place ne
www.sciencemag.org SCIENCE VOL 320 13 JUNE 2008
NEWSFO
Few advances in neuroscience have generated as much public
interestas the ability to see the human brain in action. The
enthusiasm isnthard to understand. Methods such as functional
magnetic resonanceimaging (fMRI) have enabled researchers to bring
distinctly humanattributeslove, faith, moralityunder scientific
scrutiny.
But the images generated by such methods may have a power to
cap-tivate that reaches beyond their power to explain.
Psychologists David McCabe of Colorado StateUniversity in Fort
Collins and Alan Castel of the University of California, Los
Angeles, recently asked156 undergraduate students to evaluate
several mock news articles describing brain-imaging stud-ies. But
the research each described was bogus. One study, for instance,
reached the dubious con-clusion that because watching television
and doing arithmetic problems both activate the temporallobes of
the brain, watching television improves arithmetic abilities.
Students saw one of three versions of each article: the text
alone, the text plus an fMRI imagedepicting activity in part of the
brain, or the text plus a bar chart summarizing the fMRI
result.Those who saw the brain image rated the scientific reasoning
in the article as more compellingthan did the others even though
the images themselves added no relevant information, McCabeand
Castel reported in the April issue of Cognition.
People seem to believe that images of brain activity make a
behavioral observation morereal, says bioethicist ric Racine of the
Institut de Recherches Cliniques de Montral in Canada.Racine calls
this effect neurorealism and says its often amplified by media
coverage that over-simplifies research findings and glosses over
caveats. In other words, dont let the pretty colorsfool you. You
dont need an fMRI scan to know that candy tastes good, pain feels
bad, and tele-vision wont turn you into a genius at math. G.M.
CREDITS(TOPTOB
OTTOM):JENNIFERDANIEL;DAN
LOPEZ-PANIAGUA
Political blunder? The New York Times used this graphic, showing
that U.S. presidential candidates BaraObama and John McCain
stimulated relatively little activity in the brains of undecided
voters, to illustraonline a brain-imaging study published as an
op-ed column last November.
DONT BE SEDUCED BY THE BRAIN
Published by AAAS
