title: Dissociation of reach-related and visual signals in the human superior colliculus.
abstract: Electrophysiological and micro-stimulation studies in non-human animal species indicated that the superior colliculus (SC) plays a role in the control of upper limb movements. In our previous work we found reach-related signals in the deep superior colliculus in humans. Here we show that also signals in more dorsal locations are correlated with the execution of arm movements. We instructed healthy participants to reach for visual targets either presented in the left or in the right visual hemifield during an fMRI measurement. Visual stimulation was dissociated from movement execution using a pro- and anti-reaching task. Thereby, we successfully differentiated between signals at these locations induced by the visual input of target presentations on the one hand and by the execution of arm movements on the other hand. Extending our previous report, the results of this study are in good agreement with the observed anatomical distribution of reach-related neurons in macaques. Obviously, reach-related signals can be found across a considerable depth range also in humans.
authors.affiliation: Centre for Neurology, Division of Neuropsychology, Hertie-Institute for Clinical Brain Research, Centre for Integrative Neuroscience, Eberhard Karls University, Tübingen, Germany. marc.himmelbach@uni-tuebingen.de
authors.forename: Marc
authors.initials: M
authors.lastname: Himmelbach
authors.forename: Walter
authors.initials: W
authors.lastname: Linzenbold
authors.forename: Uwe J
authors.initials: UJ
authors.lastname: Ilg
mesh_terms: D000328:Adult; D001132:Arm / Q000502:physiology; D001931:Brain Mapping; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology*; D013477:Superior Colliculi / Q000502:physiology*; D055815:Young Adult
keywords: Humans; Reaching; Superior colliculus; Vision; fMRI