Mapping the tonotopic organization in human auditory cortex with minimally salient acoustic stimulation.

ABSTRACT: Despite numerous neuroimaging studies, the tonotopic organization in human auditory cortex is not yet unambiguously established. In this functional magnetic resonance imaging study, 20 subjects were presented with low-level task-irrelevant tones to avoid spread of cortical activation. Data-driven analyses were employed to obtain robust tonotopic maps. Two high-frequency endpoints were situated on the caudal and rostral banks of medial Heschl's gyrus, while low-frequency activation peaked on its lateral crest. Based on cortical parcellations, these 2 tonotopic progressions coincide with the primary auditory field (A1) in lateral koniocortex (Kl) and the rostral field (R) in medial koniocortex (Km), which together constitute a core region. Another gradient was found on the planum temporale. Our results show the bilateral existence of 3 tonotopic gradients in angulated orientations, which contrasts with colinear configurations that were suggested before. We argue that our results corroborate and elucidate the apparently contradictory findings in literature.

SUBMITTER: Langers DR 

PROVIDER: S-EPMC3412441 | biostudies-literature | 2012 Sep

REPOSITORIES: biostudies-literature