Skeptical About Brain Scans?
Brain Scanning--Just the Tip of the Iceberg? Neuroimaging studies may be giving us a misleading picture of the brain, according to two big papers just out. March 21, 2012 blog by Neuroskeptic provides an overview and discussion of two new scientific papers that raise questions about the research technique that assigns significance to scans that show areas of the brain 'lighting up' during thought or activities. The human brain is much more globally active than is acknowledged by much scan research related to behaviors and other psychiatric and psychological brain scan studies.
"Very large fMRI study using the IMAGEN database: Sensitivity-specificity and population effect modeling in relation to the underlying anatomy" Neuroimage, 2012 Mar 10, Thyreau B, et al see the full study here.
"Whole-brain, time-locked activation with simple tasks revealed using massive averaging and model-free analysis" PNAS, Feb. 21, 2012, Gonzalez-Castillo J., et al
"The brain is the body's largest energy consumer, even in the absence of demanding tasks. Electrophysiologists report on-going neuronal firing during stimulation or task in regions beyond those of primary relationship to the perturbation. Although the biological origin of consciousness remains elusive, it is argued that it emerges from complex, continuous whole-brain neuronal collaboration. Despite converging evidence suggesting the whole brain is continuously working and adapting to anticipate and actuate in response to the environment, over the last 20 y, task-based functional MRI (fMRI) have emphasized a localizationist view of brain function, with fMRI showing only a handful of activated regions in response to task/stimulation. Here, we challenge that view with evidence that under optimal noise conditions, fMRI activations extend well beyond areas of primary relationship to the task; and blood-oxygen level-dependent signal changes correlated with task-timing appear in over 95% of the brain for a simple visual stimulation plus attention control task. Moreover, we show that response shape varies substantially across regions, and that whole-brain parcellations based on those differences produce distributed clusters that are anatomically and functionally meaningful, symmetrical across hemispheres, and reproducible across subjects. These findings highlight the exquisite detail lying in fMRI signals beyond what is normally examined, and emphasize both the pervasiveness of false negatives, and how the sparseness of fMRI maps is not a result of localized brain function, but a consequence of high noise and overly strict predictive response models."
"The Voodoo Science of Brain Imaging" Newsweek-The Daily Beast, Sharon Begley Jan. 9, 2009.
"The neuroscience blogosphere is crackling with–so far—glee over the upcoming paper, which rips apart an entire field: the use of brain imaging in social neuroscience, which studies how the brain processes/produces/handles the social and emotional aspects of human behavior such as jealousy, grief and altruism. This field includes stuff like the above, and has exploded in the last 10 years as psychiatrists and social psychologists became enamored of fMRI and other brain imaging toys. (My guess: like so many researchers in the social sciences, they have physics envy, and think that the illusory precision and solidity of neuroimaging can give their field some rigor.)" Read more here.
"Puzzlingly High Correlations in fMRI Studies of Emotion, Personality, and Social Cognition" Edward Vul, et al, Perspectives on Psychological Science, Vol 4, No. 3.
ABSTRACT—Functional magnetic resonance imaging (fMRI) studies of emotion, personality, and social cognition have drawn much attention in recent years, with high-proﬁle studies frequently reporting extremely high (e.g.,>.8) correlations between brain activation and personality measures. We show that these correlations are higher than should be expected given the evidently limited) reliability of both fMRI and personality measures. The high correlations are all the more puzzling because method sections rarely contain much detail about how the correlations were obtained. We surveyed authors of 55 articles that reported ﬁndings of this kind to determine a few details on how these correlations were computed. More than half acknowledged using a strategy
that computes separate correlations for individual voxels and reports means of only those voxels exceeding chosen thresholds.
We show how this nonindependent analysis inﬂates correlations while yielding reassuring-looking scattergrams. This analysis technique was used to obtain the vast majority of the implausibly high correlations in our survey sample. In addition, we argue that, in some cases, other analysis problems likely created entirely spurious correlations. We outline how the data from these studies could be reanalyzed with unbiased methods to provide accurate estimates of the correlations in question and urge authors to perform such reanalyses. The underlying problems described here appear to be common in fMRI research of many kinds—not just in
studies of emotion, personality, and social cognition.
"Immune cells gobble up healthy but idle brain cells" by Andy Coghlan, New Scientist June 1, 2012
USE it or lose it: a class of immune cell demolishes idle circuits and connections in the brain, even a healthy one. Understanding more about the process could help prevent the onset of degenerative brain diseases. Until now, microglia have been dismissed as simple immune cells that do little more than protect brain cells from damage and tidy up in the aftermath of disease. "The idea they can clean up brain debris has been well established in studies of brain disease," says Beth Stevens of Boston Children's Hospital. "But now, even without damage, we've found them to respond to subtle changes in synaptic function." Read more here.
Inferring Mental States from Neuroimaging Data: From Reverse Inference to Large-Scale Decoding, by Russell A. Poldrack, Neuron, Dec. 8, 2011
Can we share the joy of others? Empathic neural responses to distress vs joy, Daniella Perry, Social Cotgnitive and Affective Neuroscience, Dec. 2011
Amyvid, Alzheimer's Brain Plaque Imaging Test, OKed By FDA, Reuters, April 7, 2012 The Huffington Post
U.S. regulators gave the nod to an imaging test from Eli Lilly and Co. that can for the first time help doctors detect brain plaque tied to Alzheimer's disease, the company said. The U.S. Food and Drug Administration approved the radioactive dye, called Amyvid, to help doctors rule out whether patients have Alzheimer's, the most common form of dementia, Lilly announced.
Neuroscience wants to be the answer to everything. It isn’t. by Roger Scruton, Spectator.co.uk, 17 March 2012.
"In 1986 Patricia Churchland published Neurophilosophy, arguing that the questions that had been discussed to no effect by philosophers over many centuries would be solved once they were rephrased as questions of neuroscience. This was the first major outbreak of a new academic disease, which one might call ‘neuroenvy’. If philosophy could be replaced by neuroscience, why not the rest of the humanities, which had been wallowing in a methodless swamp for far too long? Old disciplines that relied on critical judgment and cultural immersion could be given a scientific gloss when rebranded as ‘neuroethics’, ‘neuroaesthetics’, ‘neuromusicology’, ‘neurotheology’, or ‘neuroarthistory’ (subject of a book by John Onians). Michael Gazzaniga’s influential study, The Ethical Brain, of 2005, has given rise to ‘Law and
Neuroscience’ as an academic discipline, combining legal reasoning and brain imagining, largely to the detriment of our old ideas of responsibility. One by one, real but non-scientific disciplines are being rebranded as infant sciences, even though the only science involved has as yet little or nothing to say about them.
"2 UC Davis neurosurgeons accused of experimental surgery are banned from human research," By Marjie Lundstrom, The Sacramento Bee, Jul. 22, 2012, Page 1A
A prominent UC Davis neurosurgeon was banned from performing medical research on humans after he and an underling were accused of experimenting on dying brain cancer patients without university permission, The Bee has learned.
Dr. J. Paul Muizelaar, who earns more than $800,000 a year as chairman of the department of neurological surgery, was ordered last fall to "immediately cease and desist" from any research involving human subjects, according to documents obtained by The Bee.
Also banned was the colleague, Dr. Rudolph J. Schrot, an assistant professor and neurosurgeon who has worked under Muizelaar the past 13 years.
The university has admitted to the federal government that the surgeons' actions amounted to "serious and continuing noncompliance" with federal regulations. Read more here.