Brain-Computer Interfaces: Principles and Practice - Wolpaw, Jonathan  ## Metadata - Author: **Wolpaw, Jonathan** - Full Title: Brain-Computer Interfaces: Principles and Practice - Category: #articles - URL: https://readwise.io/reader/document_raw_content/72559302 ## Highlights - Th e surface Laplacian (see also chapter 7, in this volume) improves spatial resolution by making the electrode more sen- sitive to activity from sources that are superfi cial, radial, and localized underneath the electrode and less sensitive to activity from sources that are deep or broadly distributed (i.e., of low spatial frequency). Th e surface Laplacian is the second spatial derivative of the scalp potential in both surface directions (lat- itude and longitude on a sphere). It is an estimate of current density entering ([View Highlight](https://read.readwise.io/read/01h7m0tnvk2j5q1ta1cn0hmtvd))