Fig. 4
From: Population coding of conditional probability distributions in dorsal premotor cortex
The PMd population jointly represents the distribution of upcoming reaches. a Left: The average normalized firing rate of all PR neurons, over time, as a function of relative angular hand position. For each neuron, the relative angular position is the preferred direction of the neuron minus the angular hand position. Activity is normalized and averaged across all PR neurons. Right: The average normalized firing rate in the 100 ms prior to target onset, plotted as a function of the relative angular hand position. b The distribution of upcoming movement directions relative to angular hand positions. This is duplicated from Fig. 1f for easy comparison with panel a. c, d Same as panels a and b, but for only for reaches starting near (within 2 cm of) the center. Note that panel d is duplicated from Fig. 1g. e Left: Position activity maps for example PR neurons with preferred movement directions that are oriented upwards. The position activity maps show the neurons’ activity as a function of hand position (blue is low; yellow is high) from −100 to 50 ms surrounding target onset. Right: The sum of the position maps for all PR neurons, when their preferred directions are oriented upwards. f A map showing the probability that the next movement will be upwards, as a function of initial hand position. g Preferred reach directions for all PR neurons, when space is rotated so that their preferred hand angular position is oriented to be at the bottom (270°). h A histogram of preferred reach directions of all PR neurons relative to their preferred angular hand position (the reach PD minus the preferred angular hand position)
