Schematic illustration of the research focus and the logic of the experiments undertaken.

<p>(A) A schematic diagram that illustrates motion direction, speed, and axis in the case of an apparent motion stimulus, in which each bulb is lighted sequentially in rightward direction at different times without any actual position changes (no real motion involved but a series of retinotopic activations in space and time, i.e. motion trajectory). The sequential retinotopic activations by flashes can lead to the perception of direction, axis, and speed. (B) The experimental approach. Direction-selective population and single-cell responses to random-dot motion from cat early visual areas 17 and 18 were acquired by the combination of intrinsic-signal optical imaging and single-unit recordings. Arrows inside the figure demonstrate the definition of motion direction that ranges from 0° to 360°. Note that motion axis is the same for dots moving in opposite directions and ranges from 0° to 180°. Examples of results from areas 17 and 18 are demonstrated.