Effects of age and expertise on tactile perception: Investigation of underlying neural mechanisms using transcranial direct current stimulation

• Applicants: Professor Dr. Ben Godde; Professor Dr. Ahmed Karim
• Subject Area: Biological Psychology and Cognitive Neuroscience ; Cognitive, Systems and Behavioural Neurobiology
• Term: from 2018 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 407249047

• Final Report Year: 2023

Final Report Abstract

With this project we examined effects of transcranial direct current stimulation (tDCS) on tactile perception and accompanied event-related potentials (ERPs) as well as its modulation by age and tactile expertise. We confirmed reduced baseline performance in tactile perception and increased early somatosensory ERP (P1/N1) amplitudes, indicating intracortical disinhibition, in older (OA) as compared to young adults (YA). Tactile expertise acquired through playing an instrument for many years counteracted these age effect in older musicians significantly. Anodal tDCS known to facilitate neural excitability resulted in enhanced performance similarly in YA and OA. No modulatory effect of tactile expertise was revealed. Against our hypothesis, for YA, N1 amplitudes were reduced after anodal as compared to sham stimulation. For OA, N1 peak amplitudes did not differ between tDCS conditions. However, the frontal P300 peak amplitude was enhanced after anodal tDCS, potentially indicating better recruiting of cognitive resources for compensation. Our results confirm that performance deficits in tactile perception with increasing age can be counteracted by tactile expertise. However, against our hypotheses, tactile expertise did not modulate effects of tDCS on behavioral and neurophysiological outcomes. The question of whether with high baseline N1 amplitudes ceiling effects prevent or mask any effects in OA or how exactly age and expertise modulate tDCS effects on somatosensory neural processing requires further research.

Publications

• Effects of tDCS on Tactile Perception Depend on Tactile Expertise in Both Musicians and Non-Musicians. Brain Sciences, 10(11), 843.
  Godde, Ben; Dadashev, Lev & Karim, Ahmed A.
  
• Does Transcranial Direct Current Stimulation Improve Tactile spatial discrimination? A Systematic Review and Meta-Analysis. Center for Open Science.
  Khalil, Radwa; Daniels, Marieatou; Karim, Ahmed & Godde, Ben
  
• Evaluating the mobile MUSE EEG headband for studying resting state EEG and event-related potentials.. Center for Open Science.
  Godde, Ben
  
• How can we reach sustainable effects with transcranial brain stimulation? Keynote lecture at the 2nd International Upper Egypt Neuropschiatry Conference
  Karim, A. A.
  
• Less might be more: 1mA but not 1.5mA of tDCS improves tactile orientation discrimination. IBRO Neuroscience Reports, 15, 186-192.
  Khalil, Radwa; Karim, Ahmed A. & Godde, Ben