Show Reference: "Direct visuomotor mapping for fast visually-evoked arm movements"

Direct visuomotor mapping for fast visually-evoked arm movements Neuropsychologia, Vol. 50, No. 14. (December 2012), pp. 3169-3173, doi:10.1016/j.neuropsychologia.2012.10.006 by Raymond F. Reynolds, Brian L. Day
    abstract = {In contrast to conventional reaction time ({RT}) tasks, saccadic {RT}'s to visual targets are very fast and unaffected by the number of possible targets. This can be explained by the sub-cortical circuitry underlying eye movements, which involves direct mapping between retinal input and motor output in the superior colliculus. Here we asked if the choice-invariance established for the eyes also applies to a special class of fast visuomotor responses of the upper limb. Using a target-pointing paradigm we observed very fast reaction times (<150 ms) which were completely unaffected as the number of possible target choices was increased from 1 to 4. When we introduced a condition of altered stimulus–response mapping, {RT} went up and a cost of choice was observed. These results can be explained by direct mapping between visual input and motor output, compatible with a sub-cortical pathway for visual control of the upper limb. \^{a}º We measured reaction time ({RT}) during visually-evoked pointing to jumping targets. \^{a}º {RT}'s were fast and completely unaffected by the number of target choices. \^{a}º A cost of choice became apparent during altered stimulus–response compatibility. \^{a}º Results are similar to saccadic {RT}'s suggesting a sub-cortical visuomotor pathway.},
    author = {Reynolds, Raymond F. and Day, Brian L.},
    doi = {10.1016/j.neuropsychologia.2012.10.006},
    issn = {00283932},
    journal = {Neuropsychologia},
    keywords = {biology, eye-saccades, motor, sc, visual},
    month = dec,
    number = {14},
    pages = {3169--3173},
    posted-at = {2012-10-17 14:37:56},
    priority = {2},
    title = {Direct visuomotor mapping for fast visually-evoked arm movements},
    url = {},
    volume = {50},
    year = {2012}

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The SC also seems to be involved in reaching and other forelimb-related motor tasks and has been associated with complex vision-guided arm-gestures in humans.