Attention is highly critical tp our conscious experience. A failure to focus or to shift attention can be devastating, and may contribute to neurological and psychiatric diseases such as attention deficit hyperactivity disorder (ADHD), dyslexia, and schizophrenia. Experiments from the Desimone lab and others have shown that attention alters neural activity in many visual areas and synchronizes activity across brain regions. There is increasing evidence for the presence of top-down modulatory mechanisms mediating attention. However, the precise neural circuitry underlying these effects is largely unl