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Neuroanatomy of language 4 DAY 12 – Sept 23, 2013

Neuroanatomy of language 4 DAY 12 – Sept 23, 2013. Brain & Language LING 4110-4890-5110-7960 NSCI 4110-4891-6110 Harry Howard Tulane University. Course organization. The syllabus, these slides and my recordings are available at http://www.tulane.edu/~howard/LING4110/ .

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Neuroanatomy of language 4 DAY 12 – Sept 23, 2013

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  1. Neuroanatomy of language 4DAY 12 – Sept 23, 2013 Brain & Language LING 4110-4890-5110-7960 NSCI 4110-4891-6110 Harry Howard Tulane University

  2. Brain & Language - Harry Howard - Tulane University Course organization • The syllabus, these slides and my recordings are available at http://www.tulane.edu/~howard/LING4110/. • If you want to learn more about EEG and neurolinguistics, you are welcome to participate in my lab. This is also a good way to get started on an honor's thesis. • The grades are posted to Blackboard.

  3. Brain & Language - Harry Howard - Tulane University Review The quiz was the review

  4. Brain & Language - Harry Howard - Tulane University EEG, ERP & MEG

  5. Brain & Language - Harry Howard - Tulane University The basic fact about dipoles A dipole has a direction … … which in cortex is perpendicular to its surface

  6. Brain & Language - Harry Howard - Tulane University But, what do we know about the shape of the cortex?

  7. Brain & Language - Harry Howard - Tulane University Inverse problems • Ideally, one would like to localize the precise neural sources that generate ERPs. • This is an example of an “inverse problem”, because it tries to deduce the cause of an observation from the observation itself: • “An inverse problem is a general framework that is used to convert observed measurements into information about a physical object or system that we are interested in.”

  8. + - + - Brain & Language - Harry Howard - Tulane University How to calculate the source of a dipole • How do we know which one is correct? • We can’t. There is no correct answer. • Dipole source localization is an ill-defined problem. • That is to say, the inverse solution to the dipole source-localization problem is impossible to compute with certainty, because any given scalp distribution could, in principle, be generated by any number of source configurations within the brain.

  9. Brain & Language - Harry Howard - Tulane University But … • … researchers have developed powerful tools that provide good estimates of dipole localization, given some reasonable assumptions.

  10. Brain & Language - Harry Howard - Tulane University LORETA • One such method is known as LORETA (low resolution brain electromagnetic tomography), which provides an estimate of the current distribution throughout the entire 3-dimensional space within the brain. • It does so by taking into account what is known about the structure of the brain and skull. • An example of a LORETA solution, mapped onto a normalized brain space, is provided above.

  11. Brain & Language - Harry Howard - Tulane University Comparison of EEG & MEG

  12. Brain & Language - Harry Howard - Tulane University Models of neurolinguistic function

  13. Brain & Language - Harry Howard - Tulane University Language areas of the brain

  14. Brain & Language - Harry Howard - Tulane University The Broca-Wernicke-Lichtheimmodel (of the LH)

  15. Brain & Language - Harry Howard - Tulane University The two main aphasiasIngram p. 49 Broca’s Wernicke’s C: What brings you to the hospital? Boy, I’m sweating, I’m awful nervous, you know, once in a while I get caught up, I can’t mention the tarripote, a month ago, quite a little, I’ve done a lot well, I impose a lot, while on the other hand, you know what I mean, I have to run around, look it over, trebbin and all that sort of stuff. • C: What brought you to the hospital? • P: yes … ah … Monday … ah … Dad … Peter Hogan, and Dad … ah … hospital … and ah … Wednesday … Wednesday … nine o’clock and ah Thursday … ten o’clock … doctors two … two … an doctors and … ah … teeth … yah … and a doctor an girl … and gums, an I.

  16. Brain & Language - Harry Howard - Tulane University NEXT TIME Ingram §4. ☞ Go over questions at end of chapter.

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