Table 1.

Numbers of recorded neurons as a function of their location (PMd or M1)^a

	PMd, no. (%)	M1, no. (%)
Total recorded cells	273	207
Total recorded cells in both slow and fast blocks	211	175
Monkey S	131	68
Monkey Z	80	107
Cells significantly modulated by sensory evidence (“decision” cells)	61/211	78/175
Cells significantly modulated by DD	63/211	53/175
Positively correlated	31/63	24/53
Decision cells significantly correlated with DD	18/61	25/78
Cells significantly modulated by movement speed	19/211	18/175
Monkey S	10	9
Monkey Z	9	9
Decision cells tested during the baseline period	61/61	78/78
Cells modulated by the blocks during the baseline period	34/61 (56)	46/78 (59)
Higher activity in the fast blocks during the baseline period	22/34 (65)	35/46 (76)
Decision cells with at least 5 easy trials in PT: DT > 400	40/61	50/78
Modulation by the blocks	6/40 (15)	9/50 (18)
Higher activity in the fast blocks	6/6 (100)	8/9 (89)
Decision cells with at least 5 ambiguous trials (PT or OT): DT > 600	47/61	63/78
Modulation by the blocks	10/47 (21)	9/63 (14)
Higher activity in the fast blocks	8/10 (80)	7/9 (78)
Decision cells with at least 5 misleading trials in OT: DT > 900	52/61	67/78
Modulation by the blocks	13/52 (25)	19/67 (28)
Higher activity in the fast blocks	9/13 (69)	16/19 (84)
Decision cells modulated by the blocks in at least one epoch	44/61 (72)	58/78 (74)
Higher activity in the fast blocks	30/44 (68)	47/58 (81)
Decision cells modulated around the peak of activity	33/61 (54)	32/78 (41)
Higher activity in the fast blocks	20/33 (61)	19/32 (59)

^a For each area, neuron counts are further classified based on their modulation by sensory evidence, DD, or movement speed. Finally, the numbers (and percentages) of units modulated by the block condition (slow vs fast) during the different epochs of the trial are summarized.