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.
Researchers at the Hebrew University of Jerusalem have developed a miniature image-guided robot for use during keyhole neurosurgery.
The MiniAture Robot for Surgical Applications (MARS) was designed and developed by Leo Joskowicz and his colleagues at the Hebrew University’s Computer Aided Surgery and Medical Image Processing Laboratory. It measures 5 x 5 x 8.5 cm and weighs just one quarter of a kilogram.
The MARS device can be mounted on the patient’s head using a clamp, or attached directly to the skull with two small screws. It positions itself with respect to the structures being operated on. It is programmed to do so using data obtained pre-operatively by computed tomography (CT) or functional magnetic resonance imaging (fMRI). The robot can then be used by surgeons to target neuroanatomical structures. This targeting is at least as accurate, if not more so, than that of existing neurosurgical robots – structures in the brain can be targeted to within 1 mm.
This will provide improved dexterity for surgeons as they guide their instruments towards target structures in the brain. MARS is already being used for spinal and orthopaedic surgery, and has proved to be safe. It could also be used for procedures such as brain biopsies, the draining of cerebral hemorrhage, and the insertion and placement of catheters or implants containing electrodes.