Active Projects

Effect of Background Lightness on Contrast Perception

Does the perceived contrast of a grating vary with the luminance or lightness of its background? Suppose that we superimpose grating patterns on patches with equal luminace but different lightness (see Figure: in each image, the squares with gratings are identical), what happens to the perceived contrast of those gratings? Is contrast perception affected by context-dependent lightness? In this series of studies, using psychophysical and functional magnetic resonance imaging (fMRI) methods we seek answers to these questions. Read more

Predictive Processing in Visual Perception

As the sensory information we experience is often ambiguous or noisy, we would expect that recognition of a stimulus may sometimes be very difficult, because there may be several interpretations of it. However, our visual system usually come up with a single interpretation very quickly, because our prior knowledge facilitates perception while we make decisions. In this work, we investigate how prior knowledge and expectations affect early visual processes, which is distinct from motor and cognitive components of a decision-making process. We use psychophysics, computational modeling and fMRI to unravel the effect of expectation on visual perception and the computational mechanisms underlying those effects. Read more

Center-surround Interaction in Motion Processing

Non-local Effects of Size Adaptation

Retinotopic mapping using population receptive field methods

Temporal and spatial independence of fMRI responses using fast fMRI techniques