Disruption of contralateral inferior parietal cortex by 1 Hz repetitive TMS modulates body sway following unpredictable removal of sway-related fingertip feedback

Leif Johannsen, Franziska Hirschauer, Waltraud Stadler, Joachim Hermsdörfer

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Contact with an earth-fixed reference augments sway-related feedback and leads to sway reduction during upright standing. We investigated the effect of repetitive transcranial magnetic stimulation (rTMS) over the left hemisphere inferior parietal gyrus (IPG) as well as middle frontal gyrus (MFG) on the progression of sway following right-hand finger tip contact onset and removal. In two experimental sessions, 12 adults received 20 min of 1 Hz rTMS stimulation at 110% passive motor threshold over the left MFG and left IPG, respectively. Before and after each stimulation interval, participants' body sway was assessed in terms of antero-posterior Center-of-Pressure (CoP) velocity. Passive touch onset and removal were timed at random intervals by controlling the vertical position of a contact plate. Progression of sway was evaluated across 6s before to 6s after each contact event. Following both contact onset and removal, a temporary increase in sway above baseline without contact was observed. After removal overshoot was especially prominent. While steady-state sway was not altered by stimulation, rTMS over the left IPG reduced overshoot compared to pre-stimulation; thus, improving sway progression on haptic deprivation. We discuss our finding in the light of altered transient postural disorientation due to intermodal sensory conflict, illusion of backwards falling and tactile attention capture.

Original languageEnglish
Pages (from-to)13-8
Number of pages6
JournalNeuroscience Letters
Volume586
Early online date3 Dec 2014
DOIs
Publication statusPublished - 23 Jan 2015

Keywords

  • TMS
  • IPG
  • MFG
  • Body sway
  • Sensory reorganisation

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