Assessing the functional role of frontal eye fields in voluntary and reflexive saccades using continuous theta burst stimulation

S. Can Gürel, Miguel Castelo-Branco, Alexander T. Sack, Felix Duecker*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

4 Citations (Web of Science)

Abstract

The frontal eye fields (FEFs) are core nodes of the oculomotor system contributing to saccade planning, control, and execution. Here, we aimed to reveal hemispheric asymmetries between left and right FEF in both voluntary and reflexive saccades toward horizontal and vertical targets. To this end, we applied fMRI-guided continuous theta burst stimulation (cTBS) over either left or right FEF and assessed the consequences of this disruption on saccade latencies. Using a fully counterbalanced within-subject design, we measured saccade latencies before and after the application of cTBS in eighteen healthy volunteers. In general, saccade latencies on both tasks were susceptible to our experimental manipulations, that is, voluntary saccades were slower than reflexive saccades, and downward saccades were slower than upward saccades. Contrary to our expectations, we failed to reveal any TMS-related effects on saccade latencies, and Bayesian analyses provided strong support in favor of a TMS null result for both tasks. Keeping in mind the interpretative challenges of null results, we discuss possible explanations for this absence of behavioral TMS effects, focusing on methodological differences compared to previous studies (task parameters and online vs. offline TMS interventions). We also speculate about what our results might reveal about the functional role of FEF.

Original languageEnglish
Article number944
Number of pages11
JournalFrontiers in Neuroscience
Volume12
DOIs
Publication statusPublished - 14 Dec 2018

Keywords

  • frontal eye field
  • continuous theta burst stimulation
  • reflexive saccades
  • voluntary saccades
  • oculomotor control
  • TRANSCRANIAL MAGNETIC STIMULATION
  • SUPERIOR COLLICULUS
  • CHRONIC LESIONS
  • MOVEMENTS
  • ATTENTION
  • CORTEX
  • HUMANS
  • VARIABILITY
  • DEVIATION
  • FIXATION

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