Coffee could be slowly changing how the brain responds to touch and one’s own body movements, a small new study suggests. Millions worldwide take a cup of coffee in the morning to increase wakefulness, alleviate fatigue, and improve concentration and focus. Normal doses of about a cup or two of daily coffee have between 50 and 400 mg of its active ingredient caffeine. Exactly how higher doses of coffee affect the brain’s perception of touch remains less studied. Now, a new study has assessed how normal and high doses of caffeine affect a specific brain process. This brain process is assessed using a method called short-latency afferent inhibition (SAI), in which a mild electrical shock is sent to the wrist shortly before sending a magnetic pulse into the brain. The sensory signal from the wrist travels up the arm and enters the brain’s somatosensory area, and milliseconds later, the magnetic pulse hits the nearby motor cortex to trigger a thumb twitch.…