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Activities and Seminars

Tom Bever & Roeland Hancock, University of Arizona, USA.
 
Date: Sep 13, 2011

What: Familial Handedness, Behavior and the Brain: more than one normal neurolinguistic system.

When: Tuesday, September 13th, 10:00am

Who: Prof. Tom Bever & Dr. Roeland Hancock , University of Arizona, USA.

Where: BCBL, Paseo Mikeletegi 69, Floor 2.

Summary:

We have been studying the behavioral and neurological differences in language and cognitive organization in right handed people with (FS+) and without (FS-) familial left handedness. New results involve the use of a genetic model of the probability of being left handed, based on ca. 2,500 family pedigrees that include several generations. This model is statistically reliable, and also converges on an estimate of the heritability of left handedness that is consistent with models based on twin studies (ca. 22%). Various results with right handers correlate with the pedigree-based likelihood of their having been left handed (“P.LH”)

Free spontaneous EEG. P.LH correlates positively with interhemispheric coherence between left hemisphere frontal electrodes and various right hemisphere electrodes in all rhythm ranges. P.LH correlates negatively with intrahemispheric coherence between left hemisphere frontal electrodes and other left hemisphere electrodes in all rhythm ranges, especially gamma. We suggest that these findings are consistent with the(expected) presence of greater inter hemispheric connectivity between the left and right hemisphere in FS+ people, and greater within-hemisphere connectivity in the left hemisphere for FS- people. Activation to word probes from immediately prior sentences P.LH correlates positively with P200 in the right hemisphere frontal electrodes. P.LH correlates negatively with P200 in the left hemisphere frontal electrodes. These results complement and extend our prior behavioral findings showing that lexical processing has priority over syntactic processing in FS+ people, and our fMRI results showing that lexical processing elicits faster responses than syntactic processes selectively in the right hemisphere of FS+ people. There are serious implications for normal variation in the neurological organization of language. The FS+/FS- differences and the correlations with P.LH open up a new method for investigating the relation between genetic background and language organization.