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flicker plaid

Dynamic random line stimulus (RLS)

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Summary

This plaid stimulus consists of the sum of two random line stimulus (RLS) patterns. One RLS pattern translates coherently while the other changes line contrast randomly. Thus, this stimulus lacks coherently moving intersection features that are present in many other more conventional plaid stimuli. This stimulus was introduced by Quaia, Optican and Cumming (2016, J Neurosci).

Examples

• rls_plaid.stm - 2017 May 11 - Movie (.mov) - Vertical moving plus 45 deg static.

Parameters

• nbar - number of bars in each RLS pattern.

• bar_width_pix - bar width (pix) of each component bar.

• bar_length - length of bars (deg).

• border - distance (pix) from bar borders for anti-aliasing.

• direction - orientation of bars (0...360 deg). This becomes an ofset if mask_direction (rather than mask_dir_offset) is used to define an drifting mask.

• distrib - distribution of bar luminance values: 2-binary, 3-ternary.

• dwell - duration of each bar value (raw tscale time units).

• seed - randomization seed for flickering bar pattern.

• contrast - contrast of the RLS.

• mask_speed - speed of drift (deg/s) of RLS mask.

• mask_direction - to set the direction of drift of the mask, using this or mask_dir_offset (below). If this is used, the direction parameter above becomes an offset value.

• mask_dir_offset - to set the direction of drift of the mask, using this or mask_direction (above). If this is used, it is an offset relative to the direction parameter above.

• mask_distrib - distribution of mask bar luminance values: 2-binary, 3-ternary.

• mask_seed - randomization seed for mask bar pattern.

• mask_contrast - contrast of mask

• ... -

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