Effect of optogenetic modification of neural activity in the frontal eye field and the lateral intraparietal area of the macaque monkey.

It has long been the ultimate dream for neuroscientists to take control of specific neurons within a neural circuit. With the advent of optogenetics this was achieved. Optogenetics is a neuromodulation technique that combines genetics and optics to control the activity of individual neurons in freely moving animals. First, neurons are reengineered so that they react to light. Light-sensitive ion-channels (opsins) are expressed in the neurons and when illuminated by specific wavelengths they allow ions to enter or leave the neuron. This ion flow changes the membrane potential which, depending on the type of opsin, results in a de- or hyperpolarization of the respective neurons. Moreover, by using specific viral vectors and promotor genes, specific neurons can be targeted. Unlike any other method, it is possible to alter neural activity on a millisecond time scale. I propose using optogenetics to explore the functional role of neurons in two cortical ‘attention’ areas of the monkey during a demanding target detection task with distractors. One area (FEF) is located in frontal and the other (LIP) in parietal cortex. Light-sensitive hyperpolarizing proteins will be expressed in both areas, which allow us to inactivate (e.g. only excitatory) neurons. I will explore the functional differences between these areas by inactivating both areas separately during different stages of target detection trials while interrogating the behavioral and brain-wide functional consequences.