Eye-Target Position

During Trial or Continuous mode, this panel animates the movement of the eye, the turntable (aka Chair), and one or two fixation targets. The visual field is represented as a two-dimensional plot with the origin at the center and spanning ±25 degrees. Fixed horizontal and vertical axes intersect at the origin; tick marks are placed every 5 degrees along each axis. There are no axis or tick mark labels, and the user cannot change the axis ranges or the tick mark interval. Each locus on the plot is represented by a colored marker. Marker positions are updated approximately once every 30 milliseconds, yielding a reasonably smooth animation of target and/or eye motion during an experiment.

The user can show or hide any of the five distinct loci currently supported by Maestro. Right-click anywhere on the Eye-Target Position panel (except the title bar) to invoke a popup context menu, as seen in the accompanying screenshot.

Select any item in the menu to toggle the on/off state of the corresponding locus; a check mark appears before the label of each locus that is currently displayed.

    • Eye : Position of the eye, based on the dedicated analog inputs HGPOS (horizontal gaze position) and VEPOS (vertical eye position). Represented by a filled white square.

    • Eye2 : Position of a "second" eye, based on the dedicated analog inputs HGPOS2 and VEPOS2. This is a special-purpose signal that may not be used in all rigs (in our human psychophysics rig, it is used to display the output of a second, independent eye tracker; in another rig, HGPOS2 monitors a second independent measure of head position). Represented by a filled magenta square.

    • Fix1 : Position of fixation target #1, whenever such a target is designated. Represented by a hollow yellow square. If the fixation target #1 is currently undefined, the symbol is hidden.

    • Fix2 : Position of fixation target #2, whenever such a target is designated. Represented by a hollow red square. If the fixation target #2 is currently undefined, the symbol is hidden.

    • Chair : Rotational position of the turntable, or animal Chair. Represented by a solid green square. Obviously, there is no real y-coordinate associated with this locus. By convention, the y-coordinate is set to a fixed constant that puts the green square near the bottom of the panel.

    • Track: Current position of the designated cursor tracking target (Continuous mode only). Represented by a solid cyan square.

At application startup, both the Eye and Fix1 markers are initially turned on. Note that the tick marks and the various locus markers grow in size as the panel is made larger. The exact position of each marker coincides with its geometric center, not one of the corners.