Your brain has a remarkable ability to extract and process biological cues from the deluge of visual information. It is highly sensitive to the movements of living things, especially those of other people – so much so that it conjures the illusion of movement from a picture of a moving body. Although static, such pictures trigger dynamic representations of the body, ‘motor images’ containing information about movement kinematics and timing. Researchers at the Institute of Cognitive Neuroscience in London now show that biological motion is processed unconsciously, and that the speed of apparent motion alters the perception of time.
Play around with this point light display and you’ll see that your brain has specialized mechanisms dedicated to recognizing and visually processing the human body and its movements. The demo shows that the brain is adept at inferring structure from motion, so thatwe readily perceive biological motion even when a minimum amount of information about the body is available. It also shows that the motions of the body contain information about sex, weight, emotional state and even some personality traits, and that we can extract this information effortlessly.
The human gut contains a diverse community of bacteria which colonize the large intestine in the days following birth and vastly outnumber our own cells. These intestinal microflora constitute a virtual organ within an organ and influence many bodily functions. Among other things, they aid in the uptake and metabolism of nutrients, modulate the inflammatory response to infection, and protect the gut from other, harmful micro-organisms. A new study by researchers at McMaster University in Hamilton, Ontario now suggests that gut bacteria may also influence behaviour and cognitive processes such as memory by exerting an effect on gene activity during brain development.
Jane Foster and her colleagues compared the performance of germ-free mice, which lack gut bacteria, with normal animals on the elevated plus maze, which is used to test anxiety-like behaviours. This consists of a plus-shaped apparatus with two open and two closed arms, with an open roof and raised up off the floor. Ordinarily, mice will avoid open spaces to minimize the risk of being seen by predators, and spend far more time in the closed than in the open arms when placed in the elevated plus maze.