Reservoir Computing Properties of Neural Dynamics in Prefrontal Cortex
Fig 10
Reservoir and dACC population PCA-projected trajectories of successive trials in a problem show attractor-like dynamics.
Trajectory colors represent trials of each phase, reddish colors for search and blueish colors for repetition. A. Model population trajectories of average activity without context neuron (dimensions 1, 2 and 3; 93% of variance explained). All trajectories show a similar cyclic shape showing the successive events of a trial. Search and repeat trajectories are only separated after feedback and seem to collapse into a single trajectory at the middle of the next trial. B. Same as A with context neuron version of the model (89% of variance explained). Search and repeat trajectories form two well separated cyclic trajectories resembling two distinct attractors. COR1 and COR4 trials were the transition trials between the two sets of trajectories. C. dACC neural population trajectories of average activity for successive trials of a problem on dimension 1 and 2 of the PCA (51% of variance explained with both dimensions). Points represent successive 100ms of averaged activity. Trajectories show a cyclic pattern representing the path of activity in a trial. Search and repeat trajectories seem to overlap mostly between target appearance and touch events. D. Same as C with dimension 1 and 3 instead (42% of variance explained). Search and repeat trajectories are well separated suggesting an attractor like encoding of phase at the population level. (PA: principal axis, VE: variance explained)