A major challenge in studying the cognitive functions of the nervous system is to understand the neuronal basis and the circuitry underlying these complex operations. Deficits in many cognitive functions such as attention and working memory are observed in mental disorders such as attention deficit hyperactivity disorder (ADHD), autism, and schizophrenia. To date, the level of detail at which neurobiologists can describe the chain of events giving rise to cognitive functions is very rudimentary. Much of the intense interest in understanding cognitive functions is motivated by the hope that it might be possible to understand these complex functions at the level of neurons and neural circuits. Our research is focused precisely on understanding the neural circuits and biological mechanisms that are necessary and sufficient to drive fundamental cognitive functions.