Dr. Sundeep Teki from Laboratoire des Systèmes Perceptifs, Ecole Normale Supérieure, Paris delivered a lecture on “Cortical bases of auditory figure-ground segregation” at the Centre for Neural and Cognitive Sciences (CNCS) in University of Hyderabad (UoH).


Talking to the students, faculty and staff, Dr. Teki says, “every day human beings are exposed to complex acoustic environments composed of multiple sound sources, for instance, while talking to a friend in a noisy and crowded bar. The separation of such mixtures of sounds into perceptually distinct sound sources is a highly complex task, also referred to as the ‘cocktail party problem’. In spite of being a topic of intense investigation for several decades, the neural bases of auditory object formation and segregation are still not clear.” In this work, he first described a novel stimulus to investigate neural processes underlying the detection of temporally coherent targets (‘figures’), i.e., which start and stop at the same time, from a random uncorrelated background (‘ground’). In contrast to simple tone sequences, segregation in this stochastic figure-ground stimulus can only be achieved by integrating across both frequency and time.

Later Dr. Teki presented evidence based on human psychophysics, modeling, functional MRI, Magneto encephalography and intra-cortical depth electrode recordings that support the temporal coherence theory of auditory scene analysis and suggest a critical role of the non-primary auditory cortex as well as higher-order parietal cortex in the segregation of complex acoustic scenes.