We've updated our privacy policy.

Blog | Data Notes

Visualizing NSRR data

To paraphrase the adage, a picture is worth a thousand numbers. In order to investigate some basic properties of NSRR datasets, here we generate a number of whole-dataset visualizations. To make sense of these images, we’ll employ a remarkably complex computational pattern recognition and dimension reduction framework, a.k.a. the human visual system. Keep reading

  0
By shaunpurcell on January 22, 2020 Jan 22, 2020 in Data Notes

UMAP clustering of NSRR data

Visualizing data is almost always useful, but this can be difficult when you have a lot of complex data. This is where dimension reduction techniques can play an important role. As described here, we applied one such technique to sleep EEG spectra from over 16,000 individuals in the NSRR, to get a feel for some of the sources of individual differences (both physiological and artefactual) in these data. Keep reading

  0
By shaunpurcell on May 28, 2019 May 28, 2019 in Data Notes

EEG polarity issues in the NSRR

Many analyses of sleep EEG data are effectively agnostic to the polarity of the EEG signal. That is, you could flip the signal (i.e. multiply every sample value by -1) and still obtain equivalent results, e.g. from most spectral analyses. For certain analyses that consider the phase of a signal, however, it will in fact matter that the polarity of the signal is correct. Keep reading

  1
By shaunpurcell on May 27, 2019 May 27, 2019 in Data Notes
Data Notes Posts
3