Selim Onat

My main occupation is Neuroscience.

In the past, I have been interested on how the visual system processes natural scenes. To this end, I have recorded naturalistic movies using micro-cameras carried by cats while they were actively exploring a natural environment. I used these movies to train neuronal networks in an unsupervised manner and compared learnt features to the known properties of neurons in visual cortex. I also used these videos as stimuli during physiological recordings to gain insights on the principles of natural signal processing in the visual cortex.

Recently, I started working on how humans make generalizations based on what they have previously learnt. To this end, 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.

The Famous Lenna appears in Woody Allen Movie

Anybody who has ever read a book or paper about Sobel Filters, kernels and digital filtering in the context of image processing should have seen at least once the following test image.

This is the famous Lena picture. But who is Lena? Interestingly, back then in 1973 Woody Allen used the same photograph in one of his famous movies, The Sleeper. This funny coincidence unrevealed the origin of this test picture, well at least for me. It is actually taken from Playboy Magazine as Woody Allen says in the movie. Following a quick search I was able to find this funny internet article (, which is just about Lena's history in science. This also explains why the image is generally so strangely cut.