Fig. 4.

Example of selection probabilities and selected options throughout the first 316 s of the first free-spelling block, session T6 day 493. During this time, participant T6 spelled the phrase, “Free speech is one of the most important rights.” Top to bottom: successive panels show increasing time resolution of a region outlined in red. Three top rows in each panel display the periods during which the FlashSpeller button was green after selecting an option (Feedback), presenting an option (Option), and empty during transition between options (Transition). Fourth row shows the click probability with a probability threshold. Rows five through seven show three neural features selected for decoding, one for each component. The last row shows all 50 neural features selected for decoding. HFC, high-frequency component; IFC, intermediate-frequency component; LFC, low-pass filtered component.