Fig. 1.

Population analysis of ACC neuronal firing properties with respect to task epochs on a trial when an animal performed with no errors and a trial when the same animal made six errors. (A) Illustration of the delayed win-shift radial arm maze with the separate task epochs chosen. (B, C) MUA space representation. Each color-coded dot represents the state of the network (i.e., the iFR population vector of all recorded neurons) in a 200-ms time bin at some time point during the task. The blue and green dots are from 1-s periods centered around the points of arm entries (threshold crossings) for correct arm choices during the training phase (TrC) and test phase (TsC), respectively. The yellow dots are from 1-s time periods centered around the points of arm entries for incorrect choices during the test phase (TsI). The brown and red dots are from 1-s periods starting 200 ms before the points where the animal's nose reached a food cup during the training phase (TrR) and test phase (TsR), respectively. The smaller light gray, dark gray, and black dots represent delay (Dl), training (Tr), and test phase (Ts) epochs, respectively, excluding those periods defined by the choice and reward events. The axes of this 3D projection correspond to the simultaneous activation and mutual suppression of several units. (D) iFR prototypes showing for each task epoch the average deviation of the iFR of each neuron from the grand average across all task epochs from the same trials as in B and C with no errors (D, Left) and six errors (D, Right). (E) White lines represent the Gaussian smoothed iFRs of 5 units from the 0-error trial (Upper) and 1 unit from the six-error trial (Lower) as the trial progressed from the training phase (dark gray) through the delay (light gray) to the test phase (black). Units were selected based on the prototypes in D. Blue and green vertical lines represent the points of arm entries, whereas brown and red lines indicate points of reward during the training and test phase, respectively.