Dr. Supratim Rayibro
Assistant Professor Centre for Neuroscience, Indian Institute of Science, Bangalore, India
Biography: Dr. Supratim Ray received a B.Tech in Electrical Engineering from IIT Kanpur and a PhD in Biomedical Engineering from the Johns Hopkins University. His postdoctoral training was in the department of Neurobiology at Harvard Medical School. He joined the Center for Neuroscience in June 2011 and is an Associate Faculty in the Electrical Engineering Department since 2012.
His lab studies the mechanisms of attention, i.e., our ability to focus on behaviorally interesting and relevant stimuli while ignoring others. In particular, he is interested in particular brain rhythms thought to be associated with higher order cognitive functions such as attention.
Lecture 1 (Tutorial): Local field potential (LFP)
I will discuss the origin and properties of local field potential, which is obtained by low-pass filtering the brain signal recorded from a microelectrode.
Lecture 2 (Tutorial): Overview of signal processing techniques to study brain signals
I will discuss various techniques to characterize the different oscillations present in brain signals. In particular, I will discuss the basics of Fourier Transform, Multi-taper method and Matching Pursuit.
Lecture 3 (Research): Role of Gamma Oscillations in processing of Natural Stimuli
Brain signals often show oscillations at different frequencies, which are tightly coupled to different behavioral states. We are interested in a high-frequency oscillation called “gamma” (30-80 Hz), which is modulated by high-level cognitive processes such as attention, memory, and meditation. Although gamma can be induced by presenting specific visual stimuli such as small achromatic gratings that robustly drive the cells in the visual cortex, whether natural images also generate gamma oscillations in the visual cortex remains controversial. Unlike achromatic gratings, natural stimuli have discontinuities along many dimensions, are colorful, and cover a large visual area. I will discuss the effect of these three modifications on gamma oscillations, and discuss implications regarding their role in the processing of natural images.