Page 171 - The Power of Light, Colour and Sound for Health and Wellness draft

When dopaminergically intensifed, the saccades5 are also associated with letting loose of neighbouring parts of the psycho-motor apparatus such as neck and shoulders (see picture below) which are, just like the eyes, usually kept stiff among persons with bad eyesight, especially by the myopes, most probably due to the depletion of dopamine popularly known as anxiety and frustration.
Refexive covert orienting: the visual grasp refex. This fgure illustrates the postulated pathway for the visual grasp refex in man. In a macaque, time-locked EMG responses recorded in the ipsilateral splenius capitis and deltoid, occur 80–90 ms following the sudden appearance of a cue in the visual feld in a test of refexive covert orienting. Responses are most marked when there is a gap of 200 ms between the fxation target and onset of the cue. The onset of a saccade is not invariable and, if it does occur, the neck and shoulder muscle activity may precede saccade onset. The short latency phasic dopamine response is also included indicating the effect of salient events signaled to the substantia nigra pars compacta. Blue arrows indicated inhibition; red arrows indicate excitation. (DLSC - intermediate and deep laminae of the superior colliculus; EMG - electromyographic; RF - reticular formation; ipsilat - ipsilateral; contralat - contralateral; SLSC - superfcial laminae of superior colliculus; SNPR - substantia nigra pars reticulata; SNPC - substantia nigra pars compacta. (Picture and text taken from Michael Hutchinson et al., Cervical Dystonia: A Disorder of the Midbrain Network for Covert Attentional Orienting, Frontiers in Neurology, April 2014)
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5 The general role of dopamine in stimulating motor behavior belies a considerable degree of specifcity in its motor actions. For example, at normal arousal levels, dopamine stimulates: 1. Exploratory (seeking) behavior more than proximal social grooming; 2. Anticipatory (appetitive) behavior more than consummatory behavior; 3. Sexual activity more than feeding; 4. Active male sexual behavior (mounting) more than receptive female behavior (lordosis); 5. Saccadic (ballistic) eye movements more than smooth-pursuit eye movements; Previc, ibid. p.39-40
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