Vestibulo-emotional reflex (VER)  is the one of vestibular reflexes, linked human physiology and emotions. Physiology and pathology of vestibular system and vestibular apparatus were researched by Robert Bárány receiving the 1914 Nobel Price in Physiology. The vestibular system, which contributes to our balance and our sense of spatial orientation, is the sensory system that provides the dominant input about movement and equilibrioception.
Vertical human head position controlled by vestibular system by the means of head-neck anatomy. Two month old child begins to poise the head in vertical position on reflex level, firstly performs visible movements for it. Adult people also performs micromovements for poise vertical head position, because it is impossible to coordinate vertical mechanical balance of heavy object without movements. The trajectory of 3D head movement is enough complicated [2,3] and used for different vestibular reflexes researches and human health diagnostics, because vestibular system links with sensory system, nervous system and every part of human body. Vestibulo-ocular reflex (VOR) is a reflex eye movement that stabilizes images on the retina during head movement by producing an eye movement in the direction opposite to head movement, thus preserving the image on the center of the visual field.
Sensory systems code for four aspects of a stimulus; type (modality), intensity, location, and duration. Certain receptors are sensitive to certain types of stimuli (for example, different mechanoreceptors respond best to different kinds of touch stimuli, like sharp or blunt objects). Receptors send impulses in certain patterns to send information about the intensity of a stimulus (for example, how loud a sound is). The location of the receptor that is stimulated gives the brain information about the location of the stimulus (for example, stimulating a mechanoreceptor in a finger will send information to the brain about that finger). The duration of the stimulus (how long it lasts) is conveyed by firing patterns of receptors. Vestibular system as typical sensory system reacts to stimulus. But gravitation is constantly working stimulus, so vertical head coordination becomes constantly working and reflex process. This is the main physiology difference between vertical head coordination and any other sensory process that works sometimes.
This difference transfers vertical head coordination into typical physiological process as heart rate (HR) measured by ECG and blood pressure, brain activity measured by electroencephalography (EEG), or thermoregulation measured by galvanic-skin respond (GSR). Biological evolution used head vertical coordination for energy regulation, because natural head movement is ideal vibration movement with high energy range.The other sample of nature vibration process for energy regulation is dog tail wagging, but humans have not tail and head movement is more optimal for it. It is understandable, that more high frequency head movement requests more energy, than low frequency movement. On sensor level it means, that signals send from vestibular receptors to autonomic nervous system, brain and muscles are going with different time delay, depends on biochemical human state. That means dependence between emotional state and vestibular head coordination, or vestibulo-emotional reflex. Simple schematic view on the VER display the picture:
VERHuman head moves slowly when person is calm and still (white head image).
Human head moves fast and frequently when person is active, aggressive, anxiety and nervous (red head image).
Of course it is simplified expression of VER and head movement. Real trajectory of three dimensional head movement is more complicated and every head point has own trajectory. Real facial-head 3d-form is also more complicated than circle. So real VER determines dependence of spatial-temporal movement energy distribution controlled by vestibular system from the emotional human state. This dependence visualized by vibraimage displays spatial-temporal movement energy distribution for the accumulated time period.
1. Viktor Minkin, Nikolay Nikolaenko. Application of the VibraImage technology and systems for the analysis of motor activity and the study of the functional state of the human body. Med Tekh. 2008 (4). Springer New York, Received: 24 March 2008 Published online: 21 November 2008
2. Gary D. Paige, Laura Telford, Scott H. Seidman, and Graham R. Barnes, Human Vestibuloocular Reflex and Its Interactions With Vision and Fixation Distance During Linear and Angular Head Movement, The Journal of Neurophysiology Vol. 80 No. 5 November 1998, pp. 2391-2404, Copyright ©1998 by the American Physiological Society
3. W. P. Medendorp, B.J.M. Melis, C.C.A.M. Gielen, and J.A.M. Van Gisbergen, Off-Centric Rotation Axes in Natural Head Movements: Implications for Vestibular Reafference and Kinematic Redundancy, The Journal of Neurophysiology Vol. 79 No. 4 April 1998, pp. 2025-2039, Copyright ©1998 The American Physiological Society