Selim Onat

I am a neuroscientist working currently on how humans make generalizations based on what they have previously learnt. To do so, I am using a variety of methodologies including fMRI (1), autonomous (2), as well as eye-movement recordings (3).

This research emanates from the well-established field of "stimulus generalization" following mainly the "lineage" of Hovland, Hull and Roger Shepard (4), and including the more recent computational work of Josua Tenenbaum (5). Furthermore, it integrates work on anxiety disorders, as it is believed that these mechanisms are impaired in people suffering from anxiety problems.

In the past, I have been working on how the nervous system processes natural scenes both at the electrophysiological and sensory-motor level. Since the times of Hubel and Wiesel, visual processing had been
overwhelmingly studied with artificial stimuli such as moving edges. However this type of stimuli suffer from an ecological validity problem, as they only rarely occur in real-life. We therefore investigated cortical processing during viewing of natural movies. This previous work focused on visual processing using mostly the technique of voltage-sensitive dye imaging and eye-tracking.

Singing Gabors: Visual stimulus locking of EEG is modulated by temporal congruency of auditory stimuli

























In this study, we used the Singing Gabors.

These consist of Gabor functions, where one of the parameters (here orientation parameter) is modulated either in a congruent or incongruent way with the audio signal.

Guess which of the following videos is the congruent one:







In the congruent case, the audio signal's frequency changes simultaneously with  the orientation of the Gabor. This leads (in my case) to a vivid illusion of agency, meaning that I perceive the animated Gabor function as if it was producing the sound itself (the paper deals with much simpler questions though).

In the incongruent case, the audio signal is orthogonal to the changes in the orientation parameter of the Gabor function. Still it is interesting to realize how human perception is biased for fusing these two as if they were congruent.