Auditory object

boundary detection

A visual object might be easy to define and understand, but objects perceived via audition are also important. Auditory object analysis refers to the process of perceiving the auditory world that requires, amongst other process, the fundamental perceptual process of detecting boundaries between auditory objects.

​Thus a fundamental question in auditory perception is how does the brain detect boundaries between objects that contain multiple spectro-temporally varying components. This requires mechanisms that detect changes in the statistical rules governing object regions in frequency-time space. However, the dynamics underlying the identification of discontinuities at object boundary is not well known.

​​Here is a visual summary of this project

My MEG project aims to understand the dynamics underlying auditory object boundary detection in humans using synthetic stimulus that we call "Acoustic Textures", where boundaries were created by changing the underlying spectro-temporal coherence. I observed a very slow (<1 Hz) drift in the neuro-magnetic signal. The response evoked by this drift signal was source localized to Heschl's Gyrus bilaterally which was shown in the previous fMRI study to be involved in the detection of auditory object boundaries. This low frequency drift signal is consistent with a precision based predictive coding account of perceptual inference.