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A major pathway of the human brain involved in visual perception , attention and bm — and look out over by many researchers for more than a century — is finally getting its instant in the sun .
In 2012 , investigator made note of a nerve tract in aregion of the brainassociated with reading , but " we could n’t find it in any book of maps , " said Jason Yeatman , a inquiry scientist at the University of Washington ’s Institute for Learning and Brain Sciences . " We ’d think we had discovered a new pathway that no one else had noticed before . "
A drawing of a postmortem brain that includes the vertical occipital fasciculus (bottom left) published by neuroscientist E.J. Curran in 1909.
A quick probe showed that the pathway , known as the vertical occipital fasciculus ( VOF ) , was not in reality unknown . Famed neuroscientist Carl Wernicke discovered the pathway in 1881 , during the dissection of a monkey brain that was most likely a macaque . [ 10 Things You Did n’t Know About the Brain ]
But besides Wernicke ’s breakthrough , and a few other mentions throughout the years , the VOF is largely absent from studies of the human mental capacity . This made Yeatman and his colleagues wonder , " How did a whole slice of brain anatomy get forgotten ? " he said .
The research worker immersed themselves in century - oldbrain atlasesand studies , trying to decipher when and why the VOF went miss from mainstream scientific lit . They also scan the brains of 37 individuals , and find oneself an algorithm that can help present - sidereal day researchers nail the knotty tract .
Neuroanatomist Theodor Meynert left out the vertical occipital fasciculus in the last article he published before his death in 1892.
The discipline ply a comprehensive look at the VOF ’s history , enunciate Dr. Jeremy Schmahmann , a professor of clinical neurology at Massachusetts General Hospital and Harvard Medical School , who was not involved in the new research . Schmahmann co - write the book " Fiber Pathways of the Brain " ( Oxford University Press , 2006 ) , which describes how the VOF is structured in thebrain of a monkeyand a human .
The new study corroborate the VOF ’s localisation in the human brain " and then present a tenacious discussion about how it could be relevant , " say Schmahmann , who is also a director of the Laboratory for Neuroanatomy and Cerebellar Neurobiology at Massachusetts General Hospital .
Teacher - educatee difference of opinion ?
Brain illustrations that show the vertical occipital fasciculus, except for Ludwig Edinger’s 1885 drawing, which like many other atlases left the region unlabeled throughout history.
The VOF may have been the dupe of a disagreement between Wernicke and his illustrious instructor , Theodor Meynert , a German - Austrian neuroanatomist . Meynert directed the psychiatrical clinic at the University of Vienna , and also instruct Sigmund Freud and the celebrated Russian neuropsychiatrist Sergei Korsakoff .
Wernicke is known for his 1874 discovery ofWernicke ’s surface area , a neighborhood of the psyche indispensable for apprehension written and spoken language . After his discovery , Wernicke studied in Meynert ’s lab for about six months in the late 1870s and early 1880s .
But although Wernicke also happen upon the VOF , Meynert did not include it in any of his studies . It ’s possible that Meynert ignored the pathway because it cave in one of histenets about brain administration , Yeatman told Live Science .
" Meynert had proposed the original theory of the organisation of these pathways , " Yeatman tell . " He nominate that , as a rule , they all go prior - posterior , or basically from front to back , longitudinally across the brain . "
The VOF , in direct contrast , travel up and down . " Wernicke ’s breakthrough oppose this majorly accepted principle of genius organization , " Yeatman said .
Other neuroanatomists see the VOF in the human brain , but the nerve pathway sits largely untagged in brain atlases throughout story , Yeatman said . [ 3D Images : Exploring the Human Brain ]
Yet maybe Meynert did n’t mean any damage , Schmahmann said . Meynert did not focalise on fiber pathways in the occipital lobe , include , but not limited to the VOF . " Meynert ’s unmistakable non - discussion of these fiber systems may simply have reflected his involvement and focus , " Schmahmann sound out .
Moreover , the VOF ’s also went by many names , which may have pushed it into further reconditeness . Atlases give it dissimilar labels , include " Wernicke ’s vertical fasciculus , " " perpendicular occipital fibre bundle of Wernicke " and " stratum profundum convexitatis . "
deviate dissection techniques in the late 1800s and early 1900s also made the VOF hard to pinpoint .
" You ’re slice with a knife and attempt to look for structure . It ’s very easy to miss something if you slice it a different way , " Yeatman said .
Pathway reintroduction
To remedy the confusion , Yeatman and his colleague wrote an algorithm to help investigator encounter and name the VOF . They used anMRI techniquecalled dissemination - weighted imagery , which measures the size and instruction of the wit ’s dissimilar tract .
After envision the mind of 37 people , the researchers found that the VOF starts in the occipital lobe , a part of the brain that processes visual info . It then spreads out like a tabloid , tie in different brain region : those that help multitude comprehend visual category , such as lyric and faces , and those necessitate with eye apparent movement , attending and gesture perception , the researchers articulate . The pathway could therefore help explain how the brain connects the two case of visual percept , Schmahmann said .
" There has to be some fashion for that dichotomy to flux , " he said , " and the Wernicke fiber bundle is one elbow room for the ' where ' and the ' what ' streams in the optic modality to become a interconnected whole . "
Interestingly , two case discipline from the 1970s rule that people with damage to the VOF lost their power to read because they could no longer recognize words . Moreover , the VOF has different myelination , a coat on nerve cell that helps information move faster .
" We do n’t know what it means yet , but [ the myelination dispute are ] very reproducible across every subject , " Yeatman say . " It open up some novel hypothesis , raw directions to study : Why is this construction so different than the other neighboring pathway ? "
The study , bring out today ( Nov. 17 ) in thejournal Proceedings of the National Academy of Sciences , may encourage researchers to include the VOF in succeeding brain atlases , Yeatman said .
