Task-related hemodynamic responses in human early visual cortex are modulated by task difficulty and behavioral performance
- New York University, United States
- National Institute of Mental Health, United States
- University of Washington, United States
- National Institutes of Health, United States
Abstract
Early visual cortex exhibits widespread hemodynamic responses in the absence of visual stimulation, which are entrained to the timing of a task and not predicted by local spiking or local field potential (LFP). Such task-related responses ('TRRs') covary with reward magnitude and physiological signatures of arousal. It is unknown, however, if TRRs change on a trial-to-trial basis according to behavioral performance and task difficulty. If so, this would suggest that TRRs reflect arousal on a trial-to-trial timescale and covary with critical task and behavioral variables. We measured fMRI-BOLD responses in the early visual cortex of human observers performing an orientation discrimination task consisting of separate easy and hard runs of trials. Stimuli were presented in a small portion of one hemifield, but the fMRI response was measured in the ipsilateral hemisphere, far from the stimulus representation and focus of spatial attention. TRRs scaled in amplitude with task difficulty, behavioral accuracy, reaction time, and lapses across trials. These modulations were not explained by the influence of respiration, cardiac activity, or head movement on the fMRI signal. Similar modulations with task difficulty and behavior were observed in pupil size. These results suggest that TRRs reflect arousal and behavior on the timescale of individual trials.
Data availability
All data and code are available at osf.io/8fp35 (DOI: 10.17605/OSF.IO/8FP35)
Article and author information
Author details
Charlie S Burlingham
Funding
National Eye Institute (R01-EY025330)
- David J Heeger
National Institute of Mental Health (ZIA-MH-002909)
- Elisha Merriam
National Eye Institute (T32-EY007136)
- Charlie S Burlingham
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Human subjects: Informed consent, and consent to publish, was obtained from all human participants. The consent and experimental protocol were in compliance with the safety guidelines for MRI research, and were approved by both the University Committee on Activities involving Human Subjects at New York University (RB-FY2016-158), and the Institutional Review Board at the National Institutes of Health (93-M-0170, ClinicalTrials.gov identifier: NCT00001360).
Copyright
This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.
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Task-related hemodynamic responses in human early visual cortex are modulated by task difficulty and behavioral performance
eLife 11:e73018.
https://doi.org/10.7554/eLife.73018
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