Every day our brains are flooded by stimulation - sounds, sights and smells. At the same time, we are constantly engaged in an inner dialogue, ruminating about the past, musing about the future. Somehow the brain filters all this input instantly, selecting some things for long- or short-term storage, discarding others and focusing in on what's most important at any given instant.
How this competition is resolved across multiple sensory and cognitive regions in the brain is not known; nor is it clear how internal thoughts and attention decide what wins in this continual contest of stimulation.
Now a collaboration between UCLA scientists and colleagues from the California Institute of Technology has shown that humans can actually regulate the activity of specific neurons in the brain, increasing the firing rate of some while decreasing the rate of others. And study subjects were able to do so by manipulating an image on a computer screen using only their thoughts.
Reporting in the Oct. 28 issue of the journal Nature, UCLA professor of neurosurgery Itzhak Fried and Caltech neuroscientist Christof Koch, along with colleagues, recorded the activity of single neurons in patients implanted with intracranial electrodes (for clinical reasons) and demonstrated that humans regulate the activity of their neurons to intentionally alter the outcome of all this stimulation.