Suppression and facilitation of human neural responses
Abstract
Efficient neural processing depends on regulating responses through suppression and facilitation of neural activity. Utilizing a well-known visual motion paradigm that evokes behavioral suppression and facilitation, and combining 5 different methodologies (behavioral psychophysics, computational modeling, functional MRI, pharmacology, and magnetic resonance spectroscopy), we provide evidence that challenges commonly held assumptions about the neural processes underlying suppression and facilitation. We show that: 1) both suppression and facilitation can emerge from a single, computational principle - divisive normalization; there is no need to invoke separate neural mechanisms, 2) neural suppression and facilitation in the motion-selective area MT mirror perception, but strong suppression also occurs in earlier visual areas, and 3) suppression is not primarily driven by GABA-mediated inhibition. Thus, while commonly used spatial suppression paradigms may provide insight into neural response magnitudes in visual areas, they should not be used to infer neural inhibition.
Data availability
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Data from: Suppression and facilitation of human neural responsesAvailable at Dryad Digital Repository under a CC0 Public Domain Dedication.
Article and author information
Author details
Funding
National Eye Institute (F32 EY025121)
- Michael-Paul Schallmo
- Scott Murray
National Institute of Mental Health (R01 MH106520)
- Raphael A Bernier
- Scott Murray
National Institute of Biomedical Imaging and Bioengineering (P41 EB015909)
- Richard AE Edden
National Eye Institute (T32 EY007031)
- Michael-Paul Schallmo
- Scott Murray
National Institute of Biomedical Imaging and Bioengineering (R01 EB016089)
- Richard AE Edden
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Human subjects: Subjects provided written informed consent prior to participation and were compensated for their time. All experimental procedures were approved by the University of Washington Institutional Review Board (protocol #s: 556, 1678, 28148), and conformed to the ethical principles for research on human subjects from the Declaration of Helsinki.
Copyright
© 2018, Schallmo et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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