Frame Parameters

The five stimulus parameters known as “frame” parameters can be used to specify the spatial and temporal limits and resolution of the stimulus. They define a frame within which the stimulus is defined. The frame parameters are not required, and are ignored, when the stimulus is used with a model, because the model file specifies these values with its own set of parameters (specifically, xn, yn, tn, sscale and tscale). However, when a stimulus is to be manipulated independently of a model, for example when making a movie of a stimulus for viewing, then these frame parameters are required.

The frame parameters are as follows

• stim_frame_xn - width of frame in which to place stimulus (pix)
• stim_frame_yn - height of frame in which to place stimulus (pix)
• stim_frame_tn - duration of frame in which to place stimulus (pix)
• stim_frame_sscale - degrees/pixel
• stim_frame_tscale - sec/pixel