Abstract
Sensory thalami are central sensory pathway stations for information processing. Their role for human cognition and perception, however, remains unclear. Recent evidence suggests an involvement of the sensory thalami in speech recognition. In particular, the auditory thalamus (medial geniculate body, MGB) response is modulated by speech recognition tasks and the amount of this task-dependent modulation is associated with speech recognition abilities. Here we tested the specific hypothesis that this behaviorally relevant modulation is present in the MGB subsection that corresponds to the primary auditory pathway (i.e., the ventral MGB [vMGB]). We used ultra-high field 7T fMRI to identify the vMGB, and found a significant positive correlation between the amount of task-dependent modulation and the speech recognition performance across participants within left vMGB, but not within the other MGB subsections. These results imply that modulation of thalamic driving input to the auditory cortex facilitates speech recognition.
Impact statement Ultra-high field neuroimaging dissects the ventral medial geniculate body (vMGB) of the primary auditory pathway from other MGB subregions and reveals that vMGB top-down modulation is relevant for speech recognition.
Footnotes
Reworked the manuscript and incorporated reviewer suggestions. Performed additional computations and these results are now in the manuscript. Formatting also changed slightly.