The dichotic listening task is the most widely used paradigm measuring language lateralization. The original non-forced condition consists of different consonant-vowel syllables, i.e. /ba/ and /ga/ presented to the left and right ear, respectively. Most subjects tend to report the syllable presented to the right ear: This so-called right ear advantage reflects left-hemispheric dominance for language. In the forced-attention conditions, subjects are instructed to only attend to input from one ear. Previous studies from the Biopsychology and other labs indicate that heritability is low, which is in line with an epigenetic contribution to language lateralization. The Brandler-Paracchini model of hemispheric asymmetries proposes that genes establishing ciliogenesis and bodily asymmetries affect the development of brain midline structures and language lateralization. KIAA0319 is a promising candidate gene, as it is involved in asymmetrical language processing and ciliogenesis. Here, a group of researchers from the Biopsychology and the Genetic Psychology Department analyzed DNA methylation in the KIAA0319 promoter region to investigate whether epigenetic markers of language lateralization can be identified in non-neuronal tissue. DNA methylation in the KIAA0319 promoter region was predictive for performance in the forced-left and forced-right conditions, but not for performance in the non-forced condition. This is consistent with an effect of DNA methylation on cognitive aspects of language lateralization within the context of the Brandler-Paracchini model of hemispheric asymmetries.

Schmitz J, Kumsta R, Moser D, Güntürkün O, Ocklenburg S. KIAA0319 promoter DNA methylation predicts dichotic listening performance in forced-attention conditions. Behavioural Brain Research. 2018 337: 1-7.