title: Use-dependent cortical processing from fingertips in touchscreen phone users.
abstract: Cortical activity allotted to the tactile receptors on fingertips conforms to skilful use of the hand. For instance, in string instrument players, the somatosensory cortical activity in response to touch on the little fingertip is larger than that in control subjects. Such plasticity of the fingertip sensory representation is not limited to extraordinary skills and occurs in monkeys trained to repetitively grasp and release a handle as well. Touchscreen phones also require repetitive finger movements, but whether and how the cortex conforms to this is unknown. By using electroencephalography (EEG), we measured the cortical potentials in response to mechanical touch on the thumb, index, and middle fingertips of touchscreen phone users and nonusers (owning only old-technology mobile phones). Although the thumb interacted predominantly with the screen, the potentials associated with the three fingertips were enhanced in touchscreen users compared to nonusers. Within the touchscreen users, the cortical potentials from the thumb and index fingertips were directly proportional to the intensity of use quantified with built-in battery logs. Remarkably, the thumb tip was sensitive to the day-to-day fluctuations in phone use: the shorter the time elapsed from an episode of intense phone use, the larger the cortical potential associated with it. Our results suggest that repetitive movements on the smooth touchscreen reshaped sensory processing from the hand and that the thumb representation was updated daily depending on its use. We propose that cortical sensory processing in the contemporary brain is continuously shaped by the use of personal digital technology.
authors.affiliation: Domain of Physiology, Fribourg Cognition Center, Department of Medicine, University of Fribourg, Chemin du Musée 5, Fribourg 1700, Switzerland.
authors.forename: Anne-Dominique
authors.initials: AD
authors.lastname: Gindrat
authors.affiliation: Domain of Physiology, Fribourg Cognition Center, Department of Medicine, University of Fribourg, Chemin du Musée 5, Fribourg 1700, Switzerland; Institute of Neuroinformatics, University of Zurich and ETH Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland.
authors.forename: Magali
authors.initials: M
authors.lastname: Chytiris
authors.affiliation: Domain of Physiology, Fribourg Cognition Center, Department of Medicine, University of Fribourg, Chemin du Musée 5, Fribourg 1700, Switzerland; Institute of Neuroinformatics, University of Zurich and ETH Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland.
authors.forename: Myriam
authors.initials: M
authors.lastname: Balerna
authors.affiliation: Domain of Physiology, Fribourg Cognition Center, Department of Medicine, University of Fribourg, Chemin du Musée 5, Fribourg 1700, Switzerland.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Rouiller
authors.affiliation: Institute of Neuroinformatics, University of Zurich and ETH Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland; Neuroscience Center Zurich, University of Zurich and ETH Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland; Institute of Cognitive Neuroscience, University College London, 17 Queen Square, London WC1N 3AR, UK. Electronic address: arko@ini.uzh.ch.
authors.forename: Arko
authors.initials: A
authors.lastname: Ghosh
mesh_terms: D000328:Adult; D040421:Cell Phone; D002540:Cerebral Cortex / Q000502:physiology*; D004569:Electroencephalography; D005260:Female; D005385:Fingers / Q000502:physiology*; D006801:Humans; D008297:Male; D055698:Touch Perception / Q000502:physiology*; D055815:Young Adult