NEUROSCIENCE: Where the Brain Monitors the Body

Researchers haven't known exactly where in the brain all the signals that allow an animal to keep track of its limbs are located, but now a team may have located some of the neurons that first make these multisensory connections. On page 1782, researchers report evidence that a small region of the parietal cortex of the monkey brain known as area 5 may enable the monkey to integrate many sources of information about its body and thereby update its mental model of what the body is doing. The researchers based this conclusion on their finding that some area 5 neurons fire at their fastest rates when the visual feedback from a monkey's arm matches the sensory feedback, an indication that the neurons are sensitive to both streams of information.