“Swiftly the head mass becomes an enchanted loom where millions of flashing shuttles weave a dissolving pattern, always a mean­ingful pattern though never an abiding one; a shifting harmony of subpatterns.”–Charles Sherrington, Man on His Nature, 1940.

When neurons join together into functional circuits, complex patterns of activity emerge that expand the infor­mation processing capacity of the nervous system and increase the diversity of behavior. These patterns are the language of neural circuits. To manipulate patterns of neurons in the preBötC, I applied an advanced optical technique, holographic photo­stimulation, which permits simulta­neous, spatiotemporally-precise targeting of multiple neurons with light.