Humans have the remarkable ability to selectively pay attention to some details while ignoring others in their environment. This capacity for selective attention is critical for survival and essential for complex tasks. Problems with controlling and directing attention, such as attention deficit hyperactivity disorder (ADHD), can affect individuals' ability to function normally. Attentional mechanisms have been studied at several different recording scales - from single neurons in monkeys to diffuse population measures such as electro- or magneto-encephalography (EEG/MEG) in humans. However, the relationship between signals recorded from such different scales is poorly understood. Dr. Supratim Ray's long term goal is to understand these mechanisms by linking such diverse signals. In particular, his lab is interested in brain rhythms such as alpha and gamma oscillations, which can be recorded at multiple levels and are modulated by attentional load. The lab also collaborates with neurosurgeons who record from humans (undergoing epilepsy treatment) using specialized electrodes while they are engaged in an attention task. These findings could have applications in diagnosis of brain disorders and in brain-machine interfaces. The lab is also interested in developing signal-processing tools to study brain signals.