Fig. 9.

Correlation across neurons between the time index measured in the long delay task and the rank index measured in the serial action task. Correlation analysis was carried out on three-dimensional vectors as described in the text. However, for graphic presentation, each neuron contributed three time indexes from the long delay task, (M − B)/(M + B), (E − B)/(E + B), and (E − M)/(E + M), where B, M, and E represent firing rates during the beginning, middle, and end of the delay period, and three corresponding rank indexes from the serial action task, (2 − 1)/(2 + 1), (3 − 1)/(3 + 1), and (3 − 2)/(3 + 2), where 1, 2, and 3 represent firing rates during trial phases 1, 2, and 3.