Several lines of evidence suggest an important implication of proprioceptive signals in bodily self-consciousness. By manipulating proprioceptive signals using muscle vibration, here, we investigated whether such effects depend on the vibration frequency by testing three different vibratory stimuli applied at the lower limbs (20, 40 and 80 Hz). We thus explored whether frequency-specific proprioceptive interference that has been reported in postural or motor tasks will also be found for measures of bodily self-consciousness. Self-identification (questionnaires) and visuotactile integration (asking participants to make tactile discriminations) were quantified during synchronous and asynchronous stroking conditions that are known to manipulate bodily self-consciousness. We found that even though muscle vibrations were applied at the same body location in all cases, 20 Hz vibrations did not alter the magnitude of self-identification and visuotactile integration, whereas 40 and 80 Hz vibrations did. These frequency-specific effects extend earlier vibration effects on motor and postural tasks to bodily self-consciousness. We suggest that the observed changes in bodily self-consciousness are due to altered proprioceptive signals from the lower limbs and that these changes depend on the tuning of Ia fibres to muscle vibration.
aLaboratory of Cognitive Neuroscience, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne
bDepartment of Neurology, University Hospital, Geneva, Switzerland
Correspondence to Estelle Palluel, Laboratory of Cognitive Neuroscience, Brain–Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 19, 1015 Lausanne, Switzerland Tel: +41 216 931 771; fax: +41 216 931 770; e-mail: firstname.lastname@example.org
Received December 26, 2011
Accepted January 25, 2012