Anatomical traces of vocabulary acquisition in the adolescent brain.
A surprising discovery in recent years is that the structure of the adult human brain changes when a new cognitive or motor skill is learned. This effect is seen as a change in local gray or white matter density that correlates with behavioral measures. Critically, however, the cognitive and anatomical mechanisms underlying these learning-related structural brain changes remain unknown. Here, we combined brain imaging, detailed behavioral analyses, and white matter tractography in English-speaking monolingual adolescents to show that a critical linguistic prerequisite (namely, knowledge of vocabulary) is proportionately related to relative gray matter density in bilateral posterior supramarginal gyri. The effect was specific to the number of words learned, regardless of verbal fluency or other cognitive abilities. The identified region was found to have direct connections to other inferior parietal areas that separately process either the sounds of words or their meanings, suggesting that the posterior supramarginal gyrus plays a role in linking the basic components of vocabulary knowledge. Together, these analyses highlight the cognitive and anatomical mechanisms that mediate an essential language skill.
Lee
HweeLing
H
Wellcome Department of Imaging Neuroscience, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom.
Devlin
Joseph T
JT
Shakeshaft
Clare
C
Stewart
Lauren H
LH
Brennan
Amanda
A
Glensman
Jen
J
Pitcher
Katherine
K
Crinion
Jenny
J
Mechelli
Andrea
A
Frackowiak
Richard S J
RS
Green
David W
DW
Price
Cathy J
CJ
D000293:Adolescent; D000328:Adult; D001921:Brain / Q000033:anatomy & histology* / Q000502:physiology*; D002648:Child; D005260:Female; D006801:Humans; D007804:Language Development; D007858:Learning / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D014825:Vocabulary; D014888:Wechsler Scales