RT Journal Article
SR Electronic
T1 Cortical auditory distance representation based on direct-to-reverberant energy ratio
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 769380
DO 10.1101/769380
A1 Norbert Kopco
A1 Keerthi Kumar Doreswamy
A1 Samantha Huang
A1 Stephanie Rossi
A1 Jyrki Ahveninen
YR 2019
UL http://biorxiv.org/content/early/2019/09/23/769380.abstract
AB Auditory distance perception and its neuronal mechanisms are poorly understood, mainly because 1) it is difficult to separate distance processing from intensity processing, 2) multiple intensity-independent distance cues are often available, and 3) the cues are combined in a context-dependent way. A recent fMRI study identified human auditory cortical area representing intensity-independent distance for sources presented along the interaural axis (Kopco et al., PNAS, 109, 11019-11024). For these sources, two intensity-independent cues are available, interaural level difference (ILD) and direct-to-reverberant energy ratio (DRR). Thus, the observed activations may have been contributed by not only distance-related, but also direction-encoding neuron populations sensitive to ILD. Here, the paradigm from the previous study was used to examine DRR-based distance representation for sounds originating in front of the listener, where ILD is not available. In a virtual environment, we performed behavioral and fMRI experiments, combined with computational analyses to identify the neural representation of distance based on DRR. The stimuli varied in distance (15-100 cm) while their received intensity was varied randomly and independently of distance. Behavioral performance showed that intensity-independent distance discrimination is accurate for frontal stimuli, even though it is worse than for lateral stimuli. fMRI activations for sounds varying in frontal distance, as compared to varying only in intensity, increased bilaterally in the posterior banks of Heschl's gyri, the planum temporale, and posterior superior temporal gyrus regions. Taken together, these results suggest that posterior human auditory cortex areas contain neuron populations that are sensitive to distance independent of intensity and of binaural cues relevant for directional hearing.HighlightsPosterior auditory cortices (AC) are sensitive to frontally presented distance cuesThese effects are independent of intensity- and direction-related binaural cuesfMRI activations to frontal distance cues are found in the right and left ACThe frontal reverberation-related auditory distance cues are behaviorally relevant