Brain Imaging & Analysis Center

This is an integer used to specify various attributes of this stimulus. It is interpreted as a bit-coded value, where each binary bit (1, 2, 4, 8, …) controls a different option. The meaning of each bit is described below; combine properties by adding the values.

    Value   Meaning
     0      no special attributes
     1      record response-time for this stimulus. All responses will be recorded, 
               regardless of the value of this flag, but response-times will only be 
               calculated if this bit is set.       
     2      send ID value to output port (SHOWPORT) when stimulus starts
     4      center the stimulus at the specified location (otherwise LOC is lower left)
     8      replace this stimulus with a fixation cross when it is done (i.e., after 
               DURATION has elapsed or movie has ended)
    16      replace this stimulus with BACKIMAGE when it is done       
    32      erase this stimulus (paint over with BACK_COLOR) when it is done      
    64      add a fixation cross to visual stimulus when displayed
   128      allow time for preparing stimulus (for user-defined stimulus events)
   256      synchronize image stimulus with video refresh
   512      move image stimulus to transfer buffer before displaying on screen
  1024      move image stimulus to transfer buffer but don't display on screen 
  2048      use TRANSFERMODE when moving data to transfer buffer (assumes 512 unless 1024)
  4096      wait for a response (e.g. key press) before showing the stimulus (for debugging)
  8192      synchronize stimulus with physiological trigger  

There are other flag values not intended for users (these values may change):

 16384      change the text font for this stimulus (font number must be specified). 
               This bit is set automatically when font is specified.
 32768      change the text color for this stimulus (color must be specified).
               This bit is set automatically when color is specified.

The EVENTFLAG value appears as the 3rd argument in each Showplay event line in a paradigm parameter file (PPF). EVENTFLAG values can also be entered in the GLOBALFLAG variable; EVENTFLAG options stored in GLOBALFLAG will automatically apply to every stimulus event, without having to explicitly enter the value on every line.

See Also:
Globalflag, Backimage, Paradigm parameter file, Stimulus table

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