Fig. 2. Neurons in PPC encode both the goal and trajectory of movements.

(A) The pie chart indicates the proportion of units that encode trajectory exclusively, goal exclusively, or mixed goal and trajectory. Insets show the activity (mean ± SE) for three example neurons. The lighter hue indicates response to the direction evoking maximal response; the darker hue indicates response for the opposite direction. Data taken from masked trials to avoid visual confounds (Fig. 1A). (B) Small populations of informative units allow accurate classification of motor goals from delay-period activity (when no visible target is present). Using a greedy algorithm, an optimized neural population for data combined across multiple days shows that >90% classification is possible with fewer than 30 units. (C) Temporal dynamics of goal representation. Offline analysis depicting accuracy of target classification through time [300-ms sliding window, 95% confidence interval (CI)]. Significant classification occurs within 190 ms of target presentation. (D) Similar to (B) but for trajectory reconstructions. All data taken from the MMR task (Fig. 1A).