Did you know violinists, when compared to other people, have greater development in the area of their brains linked to their fingers which guide the bow across the strings of their instrument? Though more pronounced in musicians, one thing is true for all of us — each of our fingers, toes, indeed each and every region of our bodies owns and transforms a specific amount of real estate, so to speak, in the somatosensory cortex (related to touch) of our brains. For many, then, it comes as no surprise that a new study finds smartphone users differ from people with conventional cellphones in one region of their brains: the area associated with movement of a thumb across a touchscreen.

“The digital technology we use on a daily basis shapes the sensory processing in our brains — and on a scale that surprised us,” said Dr. Arko Ghosh, a neuroscientist from the Institute of Neuroinformatics of the University of Zurich. In the past, Ghosh has studied changes in the brain and movement following spinal cord injury.

Mapping Connections Between Brain And Body

If a scientist were to stimulate a particular area of your sensory cortex, say with a weak electric current, this would produce either a tingling or a movement in a specific part of your body. The fact is a map, referred to as the homunculus map, could be drawn showing the link between parts of your body and pinpoint areas of your brain. Routinely, touch, pressure, pain, and temperature information — sensory data — is carried to the somatosensory cortex of your brain along neural roadways paved by the spinal cord, brainstem, and thalamus. From there, your somatosensory cortex receives, integrates, and sends messages to other parts of your brain. Ultimately, the entire process of sensation configures this region of your brain, and so creates a unique map that is you.

So, might a scientist, through the use of brain scanning equipment, read our individual brain maps and discover how we use our bodies? This is the question underlying the current experiment, in which Ghosh focused on how finger movements trigger and shape the sensorimotor cortex. With his co-researchers from the University of Fribourg, he used electroencephalography (EEG) to measure the cortical brain activity in 37 right-handed people, of whom 26 used touchscreen smartphones and 11 old cellphones. Placing 62 electrodes on volunteers’ heads, his results revealed how the brain mapping of touchscreen smartphone users differed from that of people with conventional cellphones.

In short, he demonstrated how the brain can be transformed by the more frequent use of one particular body part, one particular action.

“At first glance, this discovery seems comparable to what happens in violinists," Ghosh explained.

Soon enough, though, the researchers discovered very real differences between violinists and smartphone users. Strangely, how long or short someone had owned and used a smartphone did not influence how strong or weak the signal appeared in the area of the brain mapping to the thumb; it was simply a matter of how much the device had been used in the past 10 days. With the violinists, however, the strength of their brain activity depended on the age at which they started playing.

Secondly, a linear connection existed between activation in the brain and the most recent use of a smartphone, while earlier studies of violinists showed no evidence of the same. Perhaps our brains’ day-to-day plasticity differs from longer-term plasticity?

"In conclusion, touchscreen phone use reorganized the representation of the fingertips in the somatosensory cortex," noted Ghosh and his co-authors.

Source: Gindrat AD, Chytiris M, Balerna M, Rouiller E, Ghosh E. Use-dependent cortical processing from fingertips in touchscreen phone users. Current Biology. 2014.