Activity in the human superior colliculus relating to endogenous saccade preparation and execution

Michele Furlan, Andrew T Smith, Robin Walker

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Abstract

In recent years a small number of studies have applied functional imaging techniques to investigate visual responses in the human superior colliculus (SC) but few have investigated its oculomotor functions. Here, in two experiments, we examined activity associated with endogenous saccade preparation. We used 3T fMRI to record the hemodynamic activity in the SC while participants were either preparing or executing saccadic eye movements. Our results showed that not only executing a saccade (as previously shown) but also preparing a saccade produced an increase in the SC hemodynamic activity. The saccade-related activity was observed in the contralateral and to a lesser extent the ipsilateral SC. A second experiment further examined the contralateral mapping of saccade-related activity using a larger range of saccade amplitudes. Increased activity was again observed in both the contralateral and also ipsilateral SC that was evident for large as well as small saccades. This suggests that the ipsilateral component of the increase in BOLD is not due simply to small-amplitude saccades producing bilateral activity in the foveal fixation zone. These studies provide the first evidence of pre-saccadic preparatory activity in the human SC and reveal that fMRI can detect activity consistent with that of build-up neurons found in the deeper layers of the SC in studies of non-human primates.
Original languageEnglish
Pages (from-to)1048-1058
Number of pages11
JournalJournal of Neurophysiology
Volume114
Issue number2
DOIs
Publication statusPublished - 1 Aug 2015

Keywords

  • Superior colliculus
  • FMRI
  • human
  • presaccade activity
  • saccade amplitude

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