Your morning coffee could be silently altering how your brain processes touch, according to a small new study. Researchers found that caffeine appears to enhance the brain's ability to respond to tactile stimuli, potentially affecting movement control.
Study Details
Millions worldwide consume coffee daily to boost wakefulness and concentration. Normal doses of one to two cups contain between 50 and 400 mg of caffeine. However, the effects of higher doses on the brain's perception of touch have been less understood.
The study assessed a brain process called short-latency afferent inhibition (SAI). This involves sending a mild electrical shock to the wrist just before a magnetic pulse to the brain. The sensory signal travels to the somatosensory area, and milliseconds later, the magnetic pulse hits the motor cortex, triggering a thumb twitch. The brain typically suppresses the twitch through coordinated chemical messengers, acting as a filter to keep movements smooth.
Methodology
Researchers studied 20 healthy adults who received either 200 mg of caffeine or a placebo. Using non-invasive magnetic stimulation, they measured brain reactions. Results showed that caffeine increased the brain's ability to restrict muscle response after touch, indicating enhanced SAI.
Scientists suspect caffeine blocks adenosine receptors, leading to increased acetylcholine, a chemical messenger that coordinates senses and muscle movement. This aligns with findings that cholinergic-enhancing drugs like donepezil also enhance SAI.
Implications
“Caffeine's effect may result from its modulation of the cholinergic system,” researchers wrote, offering insights into its physiological action and potential ties to disorders like Alzheimer's and Parkinson's. Further studies with more participants and higher caffeine doses are planned.
“In light of the results discussed so far, subjects should continue to abstain from caffeine before SAI examinations,” they concluded.
