Postural reflexes evoked by tapping forehead and chest

• Published in: Experimental brain research Vol. 138; no. 4; pp. 446 - 451
• Main Authors: Bötzel, Kai, Feise, Patrick, Kolev, Ognew, Krafczyk, Siegbert, Brandt, Thomas
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01.06.2001; Springer Nature B.V
• Subjects: Adult; Biological and medical sciences; Chest; Efferent Pathways - physiology; Electromyography; Forehead - innervation; Forehead - physiology; Fundamental and applied biological sciences. Psychology; Head Movements - physiology; Humans; Leg; Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration; Movement - physiology; Muscle contraction; Muscle Contraction - physiology; Muscle, Skeletal - innervation; Muscle, Skeletal - physiology; Muscles; Neurologic Examination; Physical Stimulation; Postural Balance - physiology; Posture; Posture - physiology; Proprioception; Proprioception - physiology; Reflex - physiology; Reflexes; Spinal Cord - physiology; Thorax - innervation; Thorax - physiology; Vertebrates: nervous system and sense organs; Vestibular Nuclei - physiology; Vestibular system; Vestibule, Labyrinth - physiology; Human; Sensorimotor coordination; Proprioception; Lower limb; Perturbation; Vestibulospinal reflex; Mechanical stimulus; Vestibular system; Motor control; Posture
• ISSN: 0014-4819; 1432-1106
• DOI: 10.1007/s002210100726

We investigated whether a tap with a reflex hammer to the forehead can elicit responses in the leg muscles and whether vestibular stimulation is the crucial prerequisite for eliciting these responses. We also measured the postural changes caused by the tap and by the compensatory, presumably reflex-like reactions of the subject. Tap-evoked activity of leg muscles was easily elicited during upright stance in normal subjects and was also seen in two subjects without vestibular function. The pattern of muscle activation clearly showed a counteraction to the tap-evoked perturbation of stance. Taps applied to the chest elicited similar reflexes. Since these two conditions imply a different activation of the vestibular apparatus, the vestibular input alone cannot account for the observed leg muscle reflexes. We suggest that multisensory reflex pathways that integrate vestibular and proprioceptive inputs account for these reflexes.