Hybrid dedicated and distributed coding in PMd/M1 provides separation and interaction of bilateral arm signals
Fig 3
Firing rate traces of example neurons and population means.
(A-C) Trial-averaged firing rates for three neurons from the left hemisphere. Each line color represents a different target according to the color-coding in the top right. The time windows used to represent each phase in the analysis are indicated by the horizontal bars at the top, and the modulation strength values for each phase are included as annotations (M). Traces display mean +/- SEM. (A) An M1 unit exclusively modulated during ipsilateral movements. Instruct arm preference of -0.84, Move arm preference -0.99. (B) A PMd unit with both Instruct and Move phase modulation for both arms. Instruct arm preference of 0.56, Move arm preference 0.11. (C) A PMd unit with modest contralateral modulation during the Instruct phase and strong contralateral modulation during movement, but no modulation on ipsilateral trials. Instruct arm preference of 0.63, Move arm preference 0.97. (D,E) Mean firing rates for PMd and M1 populations, +/- SEM. The full distributions of modulation and arm preference values for the two populations are provided in Fig 4. These means were calculated over all units and targets; as such, the means reflect the net excitation-inhibition, which is not the same as the modulation strength.