Native Language Affects Functional Organization of the Male Auditory Cortex.

Abstract:
Humans are known to be selectively sensitive to the phonemes of their native language. We tested if differences in linguistic background are reflected in cortical processing of simple non-verbal auditory stimuli. Responses to 1-kHz 50-ms tones, delivered alternately to the left and right ear with an interstimulus interval of 0.8-1 s, were recorded in adult German and Finnish female and male subjects, 10 in each group, using whole-head magnetoencephalography (MEG). All subjects had a fully monolingual background in at least two generations. The robust responses peaking at about 100 ms after tone onset (N100m) did not differ between Finnish and German women. In contrast, German men showed significantly stronger auditory responses in the left, language-dominant hemisphere than Finnish men. We propose that the prominent left-hemisphere activation in German males reflects the higher frequency resolution required for distinguishing between German than Finnish vowels, and that the effect of native language in male but not in female auditory cortex derives from more pronounced functional lateralization in men. The present data demonstrate that the influence of native language can extend to auditory cortical processing of pure-tone stimuli with no linguistic content, and that this effect is conspicuous in the male brain.