Association between scalp hair-whorl direction and hemispheric language dominance.
Asymmetry is a common phenomenon in higher organisms. In humans, the cortical representation of language exhibits a high degree of asymmetry with a prevalence of about 90% of left hemispheric dominance, the underlying mechanisms of which are largely unknown. Another sign that exhibits a form of lateralization is the scalp hair-whorl direction, which is either clockwise or anti-clockwise. The scalp hair-whorl develops from the same germ layer as the nervous system, the ectoderm, between the 10th and 16th week in utero and has been shown to be associated with various neurodevelopmental disorders. Here, we use an established fMRI paradigm to examine the association of a solely biological marker of asymmetry, hair-whorl direction and language lateralization. We show that the mechanism that influences hair-whorl direction and handedness [Klar, A.J.S., 2003. Human handedness and scalp hair-whorl direction develop from a common genetic mechanism. Genetics 1651, 269-276.] also affects cerebral language dominance.
Weber
Bernd
B
Department of Epileptology, University of Bonn, Sigmund-Freud-Str. 25, 53105 Bonn, Germany. Bernd.Weber@ukb.uni-bonn.de
Hoppe
Christian
C
Faber
Jennifer
J
Axmacher
Nikolai
N
Fliessbach
Klaus
K
Mormann
Florian
F
Weis
Susanne
S
Ruhlmann
Jürgen
J
Elger
Christian E
CE
Fernández
Guillén
G
D000328:Adult; D000465:Algorithms; D001931:Brain Mapping; D007839:Functional Laterality / Q000502:physiology*; D006197:Hair / Q000033:anatomy & histology*; D006801:Humans; D007802:Language; D008279:Magnetic Resonance Imaging; D008297:Male; D011597:Psychomotor Performance / Q000502:physiology; D012535:Scalp / Q000033:anatomy & histology*; D014705:Verbal Behavior / Q000502:physiology*