Modulation of the Contrast Response Function by Electrical Microstimulation of the Macaque Frontal Eye Field
Name
Ekstrom-2009-Modulation of the Co.pdf
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Author(s)
Ekstrom, Leeland B.
Roelfsema, Pieter R.
Arsenault, John T.
Kolster, Hauke
Vanduffel, Wim
Date Issued
August 2009
Journal
Journal of Neuroscience
Publisher
Society for Neuroscience
Citation
Ekstrom, L. B. et al. “Modulation of the Contrast Response Function by Electrical Microstimulation of the Macaque Frontal Eye Field.” Journal of Neuroscience 29.34 (2009) : 10683-10694. © 2009 Society for Neuroscience
Version
Final published version
Abstract
Spatial attention influences representations in visual cortical areas as well as perception. Some models predict a contrast gain, whereas others a response or activity gain when attention is directed to a contrast-varying stimulus. Recent evidence has indicated that microstimulating the frontal eye field (FEF) can produce modulations of cortical area V4 neuronal firing rates that resemble spatial attention-like effects, and we have shown similar modulations of functional magnetic resonance imaging (fMRI) activity throughout the visual system. Here, we used fMRI in awake, fixating monkeys to first measure the response in 12 visual cortical areas to stimuli of varying luminance contrast. Next, we simultaneously microstimulated subregions of the FEF with movement fields that overlapped the stimulus locations and measured how microstimulation modulated these contrast response functions (CRFs) throughout visual cortex. In general, we found evidence for a nonproportional scaling of the CRF under these conditions, resembling a contrast gain effect. Representations of low-contrast stimuli were enhanced by stimulation of the FEF below the threshold needed to evoke saccades, whereas high-contrast stimuli were unaffected or in some areas even suppressed. Furthermore, we measured a characteristic spatial pattern of enhancement and suppression across the cortical surface, from which we propose a simple schematic of this contrast-dependent fMRI response.
MIT Department
Harvard University--MIT Division of Health Sciences and Technology
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1523/jneurosci.0673-09.2009
