UC Berkeley neuroscientists have tracked the progress of a thought through the brain, showing clearly how the prefrontal cortex at the front of the brain coordinates activity to help us act in response to a perception. Recording the electrical activity of neurons directly from the surface of the brain, the scientists found that for that for a simple task, such as repeating a word presented visually or aurally, the visual and auditory cortexes reacted first to perceive the word. The prefrontal cortex then kicked in to interpret the meaning, followed by activation of the motor cortex in preparation for a response. During the half-second between stimulus and response, the prefrontal cortex remained active to coordinate all the other brain areas.

Source: What does a thought look like? – ScienceBlog.com