Information
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This folder contains the ECoG data from 2 subjects performing a visual task used in the publications of Hermes et al., 2015, Cerebral Cortex "Stimulus Dependence of Gamma Oscillations in Human Visual Cortex" and Hermes et al., 2017, PLOS Biology “Neuronal synchrony and the relation between the blood-oxygen-level dependent response and the local field potential”.
Contact: Dora Hermes (dorahermes@gmail.com)


Citing this dataset
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If you use this data as a part of any publications, please use the following citation:
[1] Hermes D, Miller KJ, Wandell BA, Winawer J (2015). Stimulus dependence of gamma oscillations in human visual cortex. Cerebral Cortex 25(9):2951-9. https://doi.org/10.1093/cercor/bhu091
[2] Hermes D, Nguyen M, Winawer J. (2017). Neuronal synchrony and the relation between the BOLD response and the local field potential. PLOS Biology 15(7). https://doi.org/10.1371/journal.pbio.2001461

This dataset was made available with the support of the Netherlands Organization for Scientific Research www.nwo.nl under award number 016.VENI.178.048 to Dora Hermes and the National Institute Of Mental Health of the National Institutes of Health under Award Number R01MH111417 to Natalia Petridou and Jonathan Winawer. The ECoG data collection was facilitated by the Stanford Human Intracranial Cognitive Electrophysiology Program (SHICEP).


License
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This dataset is made available under the Public Domain Dedication and License \\nv1.0, 
whose full text can be found at \\nhttp://www.opendatacommons.org/licenses/pddl/1.0/.


Task Description
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Subjects were presented with images presented on a computer screen. The images spanned about 25x25 degrees of visual angle. Subjects fixated on a dot in the center of the screen that alternated between red and green, changing colors at random times. Subject 1 pressed a button when the fixation dot changed color. Subject 2 fixated on the dot but did not make manual responses because these responses were found to interfere with visual fixation.


Dataset and Stimuli
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This data is organized according to the Brain Imaging Data Structure specification. A community- driven specification for organizing neurophysiology data along with its metadata. For more information on this data specification, see https://bids-specification.readthedocs.io/en/stable/

Each subject has their own folder (e.g., `sub-01`) which contains the raw EcoG data for that subject, as well as the metadata needed to understand the raw data and event timing. In addition, the `stimuli/` folder contains the .png files of the presented images.

Stimuli
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Stimuli including high contrast vertical gratings (0.16, 0.33, 0.65, or 1.3 duty cycles per degree square wave) and noise patterns (spectral power distributions of k/f^4; k/f^2; and k/f^0).

Raw data
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Raw data is stored with the Brainvision data format. This can be read in to memory with the following tools:

* Python: The `pybv` package (https://github.com/bids-standard/pybv)
* Matlab: BrainVision analyzer (https://www.mathworks.com/products/connections/product_detail/brainvision-analyzer.html)


