Figure 2.

A. Spike density functions for visual transient (VT, n = 32), visual sustained (VS, n = 32), visuomotor transient (VmT, n = 16), and visuomotor sustained (VmS, n = 18) neurons in response to 7 repeated stimuli (shown as small dark bars at bottom of trace) in the center of each neuron's response field. B. Color coding of intensity of neural activity in response to the 7 stimuli (time of the response to a given stimulus on the horizontal, response to each stimulus descending vertically, color coded for normalized spike rate). Note the shift in onset latency with each stimulus repetition. C. Changes in mean response onset latency across stimulus number for each neural type. D. Changes in peak response magnitude across stimulus number for each neural type, normalized to the response on the first stimulus. E. Population spike density waveforms in response to the first target stimulus, aligned on response onset to show the early (transient) and later (sustained) components of the visual response. F. Normalized mean sustained activity (50 ms to 100 ms after onset of visual response) is plotted for the 7 stimuli for VS and VmS neuron populations. G,H. Scatter plots showing the relationship between the response to the first and second stimulus for the transient peak (G) and sustained portion (H) of the neural response. Standardized major axis regression analysis revealed that this relationship had a slope greater than unity for the peak activity (F test, F(1,96)=72.32, p < .01), but not for the sustained activity (F test, F(1,48)=0.99, p = 0.32).