Article Figures & Data
Figures
- Figure 1.
Events in the 4-NA choice saccade task are shown. Color-location associations on which monkeys were trained before recording sessions in the FEF were shown as a reminder of the associations at the beginning of each trial. The alternative array also indicated how many alternatives are available for the trial. The colors of the alternatives were then turned to gray, rendering them indiscriminate at the time of the cue onset. After a further delay, the cue shown at the center was one of the alternative colors presented shown in the array at the beginning of the trial. The monkey was required to make a saccade to the target location that was associated with the cue color, for a liquid reward. One- and two-NA choice trials were similar except that the alternative target array contained only one or two targets, instead of four as shown here.
- Figure 2.
Two visual neurons are shown as examples of NA effect on the visual response. The cell whose activity is shown in the left column had transient responses that were slightly decreased as the NA increased. The icons on the left illustrate that the same target appeared in the RF of the cell in all NA conditions. These icons show the experimental conditions near the start of each trial when the eyes were fixed on the central gray target and the array of potential targets had just been presented (zero time on the horizontal axes). It was the presence of the other potential targets outside of the field that was correlated with the decremented response. Compare 4-NA and 1-NA conditions, for example. The neuron shown in the right column had a more prominent lowered visual response as NA increased. In all plots the curves at the top are the average spike density functions for the set of trials shown below in the rasters of spike discharge.
- Figure 3.
Changes in activity of a visuomotor neuron are shown for different saccade directions and NA conditions. Data shown in raster plots are aligned on cue onset (dashed vertical lines). Bottom traces in each raster plot show either horizontal (HEM) or vertical (VEM) eye positions for that block of trials. The average spike density traces for the various NA conditions are shown in the plots at the bottom. Spike density data are aligned on saccade onset in each lowest plot and on cue onset in the plots second row from the bottom. The black horizontal bars in the two bottom rows of plots indicate the times during the trials when there was a significant difference in activity between the NA conditions.
- Figure 4.
A motor neuron was tested on various NA conditions using our choice saccade paradigm. The perisaccadic activities for saccades toward the RF were invariant despite changes in NA of the choice saccade task. The icons show the viewing conditions after the colored cue was turned on at the fixation point and a saccade is made (zero time on the horizontal axes) to the neutral gray target associated with the cue color. The arrangement of data are the same as in Figure 2 except the traces added at the bottom of each panel show the radial eye positions for each set of trials.
- Figure 5.
Visual (top row), cue-related (middle row), and perisaccadic (bottom row) responses are compared between 1-NA and 4-NA conditions for visual (left column), visuomotor (middle column), and motor cells (right column) in the FEF. Each circle represents data from an individual neuron. Solid circles indicate that the difference of activity between 1-NA and 4-NA conditions is significantly different (p < 0.01, Kruskal–Wallis ANOVA test). The shaded sector in each panel marks the 95% confidence region for linear regression of 4-NA activity on 1-NA activity in all cells, whereas the sector bounded by two solid lines demarcates that for linear regression of 1-NA activity on 4-NA activity. The dotted lines indicate a relationship with unity slope. The first number in each panel is the total number of cells of that type and the number following in parentheses is the number of individual cells with significantly different activity for the two NA conditions.
- Figure 6.
Population activities during the choice saccade task are shown for visual (n = 33), visuomotor (n = 71), motor (n = 36), and nonresponsive (n = 25) cells. Activities after the onset of the potential target array, after the cue onset, and around the time of saccade onset are shown in panels in the three rows from the top to the bottom, respectively. In each panel, activities in different NA conditions of the choice task and in the delayed saccade task are coded by different colors (same coding scheme as in Fig. 3, except for the delayed saccade condition which is coded black). The portions of the traces where the activities were significantly different from base line are shown with thickened curves. The black bars near the bottom of each plot indicate the times during the trials when there was a significant difference in activity between the NA conditions of the choice saccade task. The small vertical tick marks at the bottom of each plot in the lower two rows show the median times of saccade latency for data aligned on cue onset (middle row) or median time of cue onset (lower row).
- Figure 7.
Two cells classified as visual in the delayed saccade task that exhibited significant perisaccadic activities in 4-NA choice trials are shown. The cell in A showed a phasic visual response that dissipated during the delay period, whereas the one in B had a tonic visual activity that lasted until the offset of the fixation spot. The neural activities are aligned with respect to the onset of target array, cue, and saccade in the left, middle, and right columns, respectively. The activities in the delayed saccade task and the choice saccade task with different NAs are shown in the panels of each row. Spike rasters were sorted in a descending order of response times.
- Figure 8.
Modulation in the cue-related population activity for visuomotor and motor neurons in FEF as a function of response direction with respect to the direction of the center of the RF. Data is aligned on cue onset (dashed vertical lines). Same color coding scheme for NA condition as in Figures 3 and 6. The portions of the traces where the activities were significantly different from base line are shown with thickened curves. The small vertical tic marks at the bottom of each plot show the median times of saccade latency.
- Figure 9.
The onset of direction discrimination in perisaccadic activities and mean RT of recorded trials are plotted for individual visuomotor and motor cells. The discrimination times are shown with respect to the cue onset (top) and the saccade response (bottom). Different NA data are denoted by the color. Single dots represent data from individual units, nonvertical lines regressions over the cell population for each NA. Vertical lines crossing the regression lines demarcate the average RT over the population. All regression slopes in the top were not different from zero: the slope values and 95% confidence intervals were −0.11 (−0.37 ∼ 0.14), 0.14 (−0.12 ∼ 0.41), and 0.15 (−0.03 ∼ 0.33) in 1-, 2-, and 4-NA conditions, respectively, for visuomotor cells, and −0.02 (-0.38 ∼ 0.35), 0.01 (-0.37 ∼ 0.40), and 0.03 (-0.20 ∼ 0.25) for motor cells. In contrast, the slopes in the bottom were all significantly different from zero: the slope values and 95% confidence intervals were −0.73 (−1.1 ∼ −0.38), −0.66 (−1.0 ∼ −0.28), and −0.52 (−0.76 ∼ −0.28) in 1-, 2-, and 4-NA conditions, respectively, for visuomotor cells, and −0.86 (μ1.25 ∼ −0.47), −0.64 (-0.93 ∼ −0.36), and −0.49 (−0.79 ∼ −0.19) for motor cells. w.r.t., With respect to.
