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Poor Phineas Gage. In 1848, the supervisor for the Rutland andBurlington Railroad in Vermont was using a 13-pound, 3-foot-7-inchrod to pack blasting powder into a rock when he triggered anexplosion that drove the rod through his left cheek and out of thetop of his head. As reported at the time, the rod was later found,"smeared with blood and brains." Miraculously, Gage lived, becoming the most famous case in thehistory of neuroscience - not only because he survived a horrificaccident that led to the destruction of much of his left frontallobe but also because of the injury's reported effects on hispersonality and behavior, which were said to be profound. Gage wentfrom being an affable 25-year-old to one that was fitful,irreverent and profane. His friends and acquaintances said he was"no longer Gage." Over the years, various scientists have studied and argued aboutthe exact location and degree of damage to Gage's cerebral cortexand the impact it had on his personality. Now, for the first time,researchers at UCLA, using brain-imaging data that was lost toscience for a decade, have broadened the examination of Gage tolook at the damage to the white matter "pathways" that connectvarious regions of the brain. Reporting in the journal PLoS ONE, Jack Van Horn, a UCLA assistant professor of neurology, andcolleagues note that while approximately 4 percent of the cerebralcortex was intersected by the rod's passage, more than 10 percentof Gage's total white matter was damaged. The passage of thetamping iron caused widespread damage to the white matterconnections throughout Gage's brain, which likely was a majorcontributor to the behavioral changes he experienced. Because white matter and its myelin sheath - the fatty coatingaround the nerve fibers that form the basic wiring of the brain -connect the billions of neurons that allow us to reason andremember, the research not only adds to the lore of Phineas Gagebut may eventually lead to a better understanding of multiple braindisorders that are caused in part by similar damage to theseconnections. "What we found was a significant loss of white matter connectingthe left frontal regions and the rest of the brain," said Van Horn,who is a member of UCLA's Laboratory of Neuro Imaging (LONI). "Wesuggest that the disruption of the brain's 'network' considerablycompromised it. This may have had an even greater impact on Mr.Gage than the damage to the cortex alone in terms of his purportedpersonality change." LONI is part of an ambitious joint effort with MassachusettsGeneral Hospital and the National Institutes of Health to documentthe trillions of microscopic links between every one of the brain's100 billion neurons - the so-called "connectome." And becausemapping the brain's physical wiring eventually will lead to answersabout what causes mental conditions that may be linked to thebreakdown of these connections, it was appropriate, as well ashistorically interesting, to take a new look at the damage toGage's brain. Since Gage's 189-year-old skull, which is on display in the WarrenAnatomical Museum at Harvard Medical School, is now fragile andunlikely to again be subjected to medical imaging, the researchershad to track down the last known imaging data, from 2001, which hadbeen lost due to various circumstances at Brigham and Women'sHospital, a teaching affiliate of Harvard, for some 10 years. The authors were able to recover the computed tomographic datafiles and managed to reconstruct the scans, which revealed thehighest-quality resolution available for modeling Gage's skull.Next, they utilized advanced computational methods to model anddetermine the exact trajectory of the tamping iron that shotthrough his skull. Finally, because the original brain tissue was,of course, long gone, the researchers used modern-day brain imagesof males that matched Gage's age and (right) handedness, then usedsoftware to position a composite of these 110 images into Gage'svirtual skull, the assumption being that Gage's anatomy would havebeen similar. Van Horn found that nearly 11 percent of Gage's white matter wasdamaged, along with 4 percent of the cortex. "Our work illustrates that while cortical damage was restricted tothe left frontal lobe, the passage of the tamping iron resulted inthe widespread interruption of white matter connectivity throughouthis brain, so it likely was a major contributor to the behavioralchanges he experienced," Van Horn said. "Connections were lostbetween the left frontal, left temporal and right frontal corticesand the left limbic structures of the brain, which likely hadconsiderable impact on his executive as well as his emotionalfunctions." And while Gage's personality changed, he eventually was able totravel and find employment as a stagecoach driver for several yearsin South America. Ultimately, he died in San Francisco, 12 yearsafter the accident. Van Horn noted a modern parallel. "The extensive loss of white matter connectivity, affecting bothhemispheres, plus the direct damage by the rod, which was limitedto the left cerebral hemisphere, is not unlike modern patients whohave suffered a traumatic brain injury ," he said. "And it is analogous to certain forms of degenerativediseases, such as Alzheimer's disease or frontal temporal dementia , in which neural pathways in the frontal lobes are degraded, whichis known to result in profound behavioral changes." Van Horn noted that the quantification of the changes to Gage'sbrain's pathways might well provide important insights for clinicalassessment and outcome-monitoring in modern-day brain traumapatients. Additional References Citations. We are high quality suppliers, our products such as Fishing Barometer Watch , Hiking Compass Manufacturer for oversee buyer. To know more, please visits Digital Altimeter Compass.
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