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Datasets

Sebastian

@s_urchs (slack: @surchs)

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Before we start:

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If you ask yourself...

how

  • do I choose a good dataset?
  • do I find open datasets?
  • do I get the data?
  • do I work with the data?

then this is for you!

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How do I choose a good dataset?

Ask yourself:

  • How easy can I get access?
  • How “raw” is it?
  • How useful is it?

Copied liberally from Chris Gorgolewski’s slides (@chrisgorgo)

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Ease of access

Signed Data Usage Agreement

Access through managed database

“Just get it”

Direct download

“It’s right there”

Hard

Easy

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How raw is the data set

Organized

Preprocessed

Derivatives

  • DICOM
  • Idiosyncratic organization
  • Must be converted
  • Ideally standard organization (BIDS)
  • Text-based metadata
  • Must be preprocessed
  • Minimally or fully preprocessed
  • Standardized organization
  • Data Quality metrics
  • Must be analyzed
  • Statistical maps
  • Summary metrics

More control

Less work

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How useful is the data set

Data Quality

  • Is there a publication describing the data
  • Did other studies re-use the data
  • Ask around

Meta Data Quality

  • Are the data well described (inclusion, acquisition, processing)
  • Are the metrics available that you are interested in?
  • How much missing data are there?

Data Cost

  • How large is the data set (storage space, download)
  • Are the data preprocessed?
  • Could you preprocess them (time, resources, knowledge) ?

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How do I find open datasets

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FCP-INDI

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Open-Neuro

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Canadian Open Neuroscience Portal

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openMorph

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nilearn

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How do I get the data

“I just want the data”

“I’m just testing things”

“I want to know what happened to my data”

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Nilearn example

  1. Pick a dataset
  2. Ask nilearn to get it
  3. Load the data

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Nilearn - pick a dataset

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Nilearn - get the data

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Nilearn - access the data

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Nilearn - access the data

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Amazon S3 example

  1. Pick a dataset
  2. Login to the bucket
  3. Download the data

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Amazon S3 - pick a dataset

  • Go to https://openneuro.org/, search for ‘midnight’

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�

  • Click ‘download’

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Amazon S3 - pick a dataset

  • Copy the AWS S3 path

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�

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Amazon S3 - get the data

  • Enter the info from openneuro in the “Path” field.

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�

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  • Copy the line from openneuro
  • Replace “sync” with “ls”

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How do I work with the data

  1. Respect the data
    1. Sign and follow data usage agreement
    2. Securely store identifiable information
    3. Cite the data source

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How do I work with the data

  • Respect the data
    • Sign and follow data usage agreement
    • Securely store identifiable information
    • Cite the data source
  • Document what you do
    • Where did you download from?
    • What command did you use (script if possible)
    • How did you select data?
    • What processing did you use?

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How do I work with the data

  • Respect the data
    • Sign and follow data usage agreement
    • Securely store identifiable information
    • Cite the data source
  • Document what you do
    • Where did you download from?
    • What command did you use (script if possible)
    • How did you select data?
    • What processing did you use?
  • Organize your project
    • Use version control!
    • Use virtualization
    • Follow standards (BIDS)
    • You will thank yourself later

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I want more

data

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More databases

https://zenodo.org/

Repository for data associated with publication

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Digital object identifier

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Any license

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Hosted by CERN (cool)

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https://figshare.com/

Repository for data

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Digital object identifier

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Creative Commons license

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Has commercial side

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https://datasetsearch.research.google.com/

Dataset search engine

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Doesn’t store anything

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Let’s you search other databases

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Preprocessed data

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Longitudinal / reproducibility data

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Derivative data

https://neurovault.org/

Repository of statistical maps of completed studies

http://neurosynth.org/

Aggregated activation data maps with keyword search

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Neurosynth-genes has the gene expression data from the Allen brain institute

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Good people to talk to

https://neurostars.org/

Great resource for asking question and getting feedback

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Cool data that take longer to get

https://www.ukbiobank.ac.uk/

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> 100.000 individuals

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Deep meta data

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Genetics (prospective whole genome sequencing)

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Extensive imaging data

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Medical records

http://portal.brain-map.org/

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Human brain gene expression maps

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Histological and developmental atlases

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Extensive mouse data

https://db.humanconnectome.org/

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Very high resolution data

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Publicly available data for 1200 healthy individuals

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Long, repeat imaging data (task and resting state)

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Deep meta data

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Share that brain

Katherine Karlsgodt, 2019