Volume 87 June 2002

Pages 2700-2714: Tanaka M and Lisberger SG, "Role of arcuate frontal cortex of monkeys in smooth pursuit eye movements. II. Relation to vector averaging pursuit." Figures 2-4, 6, 8, and 10 were inadvertently published as black and white images in the print issue. The correct color versions of these figures are presented here, with the original legends. Also, the online version of this article now contains the correct Figs. 2-4, 6, 8, and 10 and thus departs from the print publication with respect to these corrections. (See http://jn.physiology.org/cgi/content/full/87/6/2700)

View larger version (31K): [in this window] [in a new window]   Fig. 2. Summary of the variability of eye velocity during single-target and double-target motions. A: each point plots data from a single trial according to the horizontal and vertical eye velocity measured 250 ms after target motion onset. Black symbols show data from single-target motions. The red and blue symbols indicate responses to double-target motion, with the final target motion in the preferred or opposite direction for the neuron under study, respectively. The oblique line was computed by linear regression on the data from single-target motions. B: smoothed histograms showing the normalized distribution of component eye velocity along the preferred axis of the neuron under study. Thick black curves show the normalized distributions of measurements made 250 ms after the onset of target motion for single-target motions and the red curve shows the distribution of the same measure for double-target motions. The black dashed curve shows the smoothed distribution of eye velocity measured at the onset of target motion for all trials. Each curve connects values derived in 0.1°/s bins. C: the 2 traces show the time course of the SD of component eye velocity. Black dashed and red solid traces show data for single-target and double-target motions, respectively. The downward arrow indicates the time of the initiation of pursuit for single-target motions. D: bold traces show averages of the SD of component eye velocity across multiple experiments. Averages were aligned on the initiation of pursuit. Black dashed and red solid traces show data from single-target and double-target motions, respectively. The fine, dashed traces show the mean ± SD of the SDs, and indicate interexperimental variation.

View larger version (43K): [in this window] [in a new window]   Fig. 3. Examples of the responses during double-target and single-target motions for neurons from the 3 major groups in our sample. A: vector-averaging neuron. B: winner-take-all neuron. C: vector-summation neuron. In each column, the rasters are sorted and grouped by 4 different target conditions. From top to bottom the groups show the following: double-target motion with the final tracking target motion in the preferred direction of the neuron under study; double target motion with the final tracking target motion in the opposite direction; single-target motion in the preferred direction; single target motion in the opposite direction. The curves at the bottom of each column plot the time course of spike density for each condition. The red and blue traces indicate responses to double-target motion, with the final target motion in the preferred or opposite direction for the neuron under study, respectively. The black traces summarize responses from single-target controls. The data are aligned on target motion onset, which is indicated by the vertical lines.

View larger version (17K): [in this window] [in a new window]   Fig. 4. Quantitative analysis of the responses during double-target and single-target motions for neurons from the 3 major groups in our sample. A: vector-averaging neuron. B: winner-take-all neuron. C: vector-summation neuron. The time courses of the neuronal responses for these neurons are shown in Fig. 3. Each point plots data from one trial and shows firing rate as a function of component eye velocity along the preferred axis of the neuron under study, respectively. The neuronal responses were measured from 90-250 ms after target motion onset. Eye velocity was measured 250 ms after target motion onset. Black circles show responses to single-target motions at 5, 10, and 20°/s. Large open circles with error bars show the mean and SD of the responses to each target velocity. Colored symbols show data from double-target trials with both targets moving at 20°/s. Red and blue symbols show responses when the final tracking target moved in the preferred or the opposite direction for the neuron under study. The horizontal dashed line in each panel shows mean baseline firing rate measured in a 300-ms interval immediately before target motion onset.

View larger version (20K): [in this window] [in a new window]   Fig. 6. Data from a single site showing the effect of microstimulation in the FPA on the responses to single-target (A, C, and E) and double-target (B, D, and F) motions. A-D: averages of eye velocity showing the time courses of pursuit initiation. A and B show the actual responses. Solid traces show the responses to target motion during electrical stimulation, and the dotted trace shows the response to electrical stimulation during fixation. The arrow indicates the small eye movement evoked by electrical stimulation. C and D show the corrected responses after subtraction of the response to stimulation during fixation. Continuous traces show the responses to target motion presented during stimulation, and the dashed traces show the responses to target motion in the absence of stimulation. The black bars on the horizontal scale show the time of electrical stimulation. E and F: each point shows measurements from a single trial and plots vertical vs. horizontal eye velocity measured 180 ms after target motion onset in single-target trials (E) and in double-target trials (F). The blue symbols show data from nonstimulation controls, and the red symbols show data from stimulation trials. The continuous, slightly oblique lines are the same in E and F and were obtained by linear regression on the blue points in E.

View larger version (20K): [in this window] [in a new window]   Fig. 8. Quantitative comparison of the predictions of each model with the actual distribution of responses to double-target motions for one stimulation site. A and B: smoothed distributions of the responses to target motion in nonstimulation controls (A) and stimulation trials (B). Each curve shows the normalized distribution of eye velocity along the axis of eye movements evoked by target motion in the control trials. Each curve connects the values for the data grouped into 0.1°/s bins. Black and colored curves show data from single-target and double-target trials. C: the red curve is identical to that in D and shows the distribution of eye velocity during averaging of pursuit with electrical stimulation. The 3 black curves show the normalized distributions predicted by the 3 models. Continuous, dashed, and dotted curves were obtained from Models 1, 2, and 3, respectively.

View larger version (38K): [in this window] [in a new window]   Fig. 10. Effect of microstimulation at one site in the FPA on vector averaging for double-target motions in orthogonal directions. A and B plot horizontal and vertical eye velocity measured at 180 ms after target motion onset for nonstimulation control trials (A) and stimulation trials (B). The blue dots show the responses in single-target trials, and the red dots show those in double-target trials. Each target moved along horizontal or vertical meridian at 20°/s. The short line starting from the origin of B indicates the eye velocity evoked by electrical stimulation during fixation of a stationary target. C: means of the responses to target motion in 8 stimulation conditions (filled symbols) and 8 nonstimulation controls (open symbols). Responses during microstimulation were measured only after subtracting the eye velocity evoked during fixation from the responses measured in stimulation trials with target motion. The blue symbols plot data from single-target trials, and the red symbols plot data from double-target trials. Each pair of connected points shows the responses to a given target motion in the presence or absence of stimulation. D: prediction errors of the 3 models for this stimulation site. The dashed lines show the errors computed from 4 possible orthogonal double-target motions. The filled symbols connected with bold lines indicate means of the prediction errors across all 4 double-target motions. Error bars indicate ±1 SD.