Cortical auditory distance representation based on direct-to-reverberant energy ratio.
Level 4 - case-series / case-control
Experimental within-subject human behavioral and neuroimaging study
PubMed 31809885 · doi:10.1016/j.neuroimage.2019.116436
What was done
Researchers conducted behavioral experiments and fMRI combined with computational modeling in a virtual acoustic environment. Frontal sound stimuli were presented at distances ranging from 15 to 100 cm with intensity varied randomly and independently of distance, isolating direct-to-reverberant energy ratio (DRR) cues in the absence of interaural level differences.
What was found
The abstract reports no numerical values, test statistics, or effect sizes. Behaviorally, participants accurately discriminated intensity-independent frontal sound distance, though accuracy was lower than for lateral stimuli. Neurally, sounds varying in frontal distance (compared to sounds varying only in intensity) increased bilateral activation in the posterior banks of Heschl's gyri, the planum temporale, and the posterior superior temporal gyrus.
Why it matters
It demonstrates that the human posterior auditory cortex processes auditory distance based on reverberation cues independently of sound level and binaural directional cues.
Limits
The abstract omits sample size, participant demographics, and numerical statistical measures. Stimuli were delivered in a virtual acoustic environment rather than natural free-field conditions.