Research Projects

My lab studies the neural basis of selective attention, with a focus on a brain rhythm called “gamma” (30-80 Hz), which is modulated by attentional load and is thought to be linked to high-level cognitive processes. Attentional mechanisms have been studied at several different recording scales – from single neurons in monkeys to diffuse population measures such as electro-encephalography (EEG) in humans. However, the relationship between signals recorded from such different scales is poorly understood. The long-term goal of my research is to elucidate the mechanisms of attention by linking the neural recordings obtained from these vastly different scales. This involves a) setting up of different recording “levels” in both monkeys and humans, and b) development of signal processing techniques to study the relationship between different brain signals. Establishment of this cross-species, cross-scale link between brain signals has far reaching applications, such as in Brain-Machine Interfacing (BMI) and clinical diagnosis of brain disorders. The first step towards this research is to have facilities to record from various scales, such that a complex behaviour like attention can be studied at both local and network level details. Most of the levels are invasive, involving surgical implantation of electrodes inside the brain of monkeys, which require a sophisticated surgical facility as well as elaborate training, stimulus presentation and recording facilities. During the period of this fellowship, I have developed a unique setup to simultaneously record from four scales of recording in monkeys (spikes, LFP, ECoG and EEG). Bridging brain signals across scales requires mathematical and signal processing tools, which are often studied only in one level and their limitations are not well understood at other levels. We conducted several studies to better understand these techniques. In addition, I worked on a collaborative project with my postdoctoral advisor, which yielded two papers. I also wrote two review papers on spike-LFP relationships and gamma oscillations. We were able to achieve all the aims and published >15 papers in high-impact journals such as PNAS, Journal of Neuroscience, Journal of Neurophysiology and Neural Computation. The collaborative and review work was published in Neuron, PLoS Biology, Trends in Neuroscience and Trends in Cognitive Science.