Fig. 3: Attempted multi-finger movements are well-represented in the neural activity.

A Neural activity was recorded as T5 attempted 38 hand movements on the right hand, consisting of gestures from the American Sign Language (ASL) alphabet & single finger movements. Each movement was attempted 22 times in trials consisting of 1 s prep, 1 second move, and 2 s hold periods. Copyright © Meta Platforms Technologies, LLC and its affiliates. All rights reserved. B A confusion matrix, where the (i, j)th entry is colored by the percentage of trials where movement j was decoded when movement i was cued. A linear support vector classifier was used for decoding. Classification accuracy was 76%, substantially above the chance accuracy of 2.6%. C The same decoding analysis was applied to a collection of 80 combinatorial gestures, where four finger groups were varied independently (the ring and small fingers constrained to the same movement). Each finger group was independently cued to be flexed, extended, or idle (15 trials were collected per condition, with a 1 s preparatory and a 2 s movement period). Movements are indicated with the inset images, with flexion, idle, and extension indicated with black, gray, and white colors, respectively. The classification accuracy was 40%, substantially above the chance accuracy of 1.3%. Source data are provided in the Source Data file.