Exploring a psychophysical signature of frequency-dependent spectrotemporal resolution tradeoff in humans

Physiological studies provide evidence for a fundamental tradeoff between spectral and temporal resolution in the auditory system. For example, cochlear filters with sharper frequency tuning typically exhibit poorer temporal resolution due to longer integration times. However, in the central nucleus of the inferior colliculus, this tradeoff is not simply inherited from the periphery but reorganized along the tonotopic axis: neurons with low characteristic frequencies tend to show high temporal resolution, i.e., sensitivity to rapid modulations, but broad frequency tuning, while neurons with high characteristic frequencies display sharper spectral tuning at the expense of lower temporal resolution. In humans, little is known about how sensitivity to spectrotemporal modulations depends on the frequency content of the carrier signal. This study investigates whether our perceptual sensitivity to spectrotemporal modulations is shaped by this frequency-dependent spectrotemporal resolution tradeoff of midbrain neurons. Specifically, we examine how sensitivity to spectrotemporal modulations varies as a function of carrier frequency (low versus high), across combinations of slow versus fast temporal rates and low versus high spectral densities. The results may shed light on how spectrotemporal information is represented across frequency channels in the human central auditory system and inform models of auditory perception.