University of Oulu

Olkoniemi, H., Hurme, M., & Railo, H. (2023). Neurologically healthy humans’ ability to make saccades toward unseen targets. Neuroscience, 513, 111–125. https://doi.org/10.1016/j.neuroscience.2023.01.014

Neurologically healthy humans’ ability to make saccades toward unseen targets

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Author: Olkoniemi, Henri1,2; Hurme, Mikko2,3; Railo, Henry2,3
Organizations: 1Division of Psychology, Faculty of Education and Psychology, University of Oulu, Finland
2Department of Psychology and Speech Language Pathology, University of Turku, Finland
3Turku Brain and Mind Centre, University of Turku, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.6 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe2023032132707
Language: English
Published: Elsevier, 2023
Publish Date: 2023-03-21
Description:

Abstract

Some patients with a visual field loss due to a lesion in the primary visual cortex (V1) can shift their gaze to stimuli presented in their blind visual field. The extent to which a similar “blindsight” capacity is present in neurologically healthy individuals remains unknown. Using retinotopically navigated transcranial magnetic stimulation (TMS) of V1 (Experiment 1) and metacontrast masking (Experiment 2) to suppress conscious vision, we examined neurologically healthy humans’ ability to make saccadic eye movements toward visual targets that they reported not seeing. In the TMS experiment, the participants were more likely to initiate a saccade when a stimulus was presented, and they reported not seeing it, than in trials which no stimulus was presented. However, this happened only in a very small proportion (∼8%) of unseen trials, suggesting that saccadic reactions were largely based on conscious perception. In both experiments, saccade landing location was influenced by unconscious information: When the participants denied seeing the target but made a saccade, the saccade was made toward the correct location (TMS: 68%, metacontrast: 63%) more often than predicted by chance. Signal detection theoretic measures suggested that in the TMS experiment, saccades toward unseen targets may have been based on weak conscious experiences. In both experiments, reduced visibility of the target stimulus was associated with slower and less precise gaze shifts. These results suggest that saccades made by neurologically healthy humans may be influenced by unconscious information, although the initiation of saccades is largely based on conscious vision.

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Series: Neuroscience
ISSN: 0306-4522
ISSN-E: 1873-7544
ISSN-L: 0306-4522
Volume: 513
Pages: 111 - 125
DOI: 10.1016/j.neuroscience.2023.01.014
OADOI: https://oadoi.org/10.1016/j.neuroscience.2023.01.014
Type of Publication: A1 Journal article – refereed
Field of Science: 3112 Neurosciences
515 Psychology
Subjects:
Funding: This research was supported by a grant from the Ella and Georg Ehrnrooth Foundation awarded to Henri Olkoniemi, and a grants from the Academy of Finland (grant #308533) awarded to Henry Railo and (grant #338712) to Henri Olkoniemi. We would like to thank Teemu Laine for technical help with Experiment 1.
Academy of Finland Grant Number: 338712
Detailed Information: 338712 (Academy of Finland Funding decision)
Dataset Reference: The data and the R-scripts are made available using the Open Science Framework https://osf.io/6wncf/.
  https://osf.io/6wncf/
Copyright information: © 2023 The Author(s). This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
  https://creativecommons.org/licenses/by/4.0/