Human balance control during cutaneous stimulation of the plantar soles

Previous work on human postural control of upright stance, performed in the absence of visual and vestibular orientation cues, suggests that somatosen sory cues in the feet enable subjects to maintain equilibrium during low-fr equency platform tilts. Here we confirm earlier studies which indicated tha t stimulation of plantar cutaneous mechanoreceptors can lead to postural re sponses. Yet, this stimulation did not modify considerably the postural rea ctions of normal subjects and vestibular loss patients during platform tilt s. We therefore suggest that it is necessary to differentiate between (i) c ues from plantar cutaneous receptors involved in exteroceptive functions, l ike the evaluation of the support structure or of relative foot-to-surface motion, a nd (ii) cues from deep receptors which subserve proprioceptive fu nctions like the control of center of pressure shifts within the limits of the foot support base. (C) 2001 Elsevier Science Ireland Ltd. All rights re served.