This article applies to:
E-Prime 3.0
Chronos
Detail
Experiment Author: Psychology Software Tools, Inc.
The Chronos Adapter for Neuroscan sample experiment illustrates how to use Task Events to send markers from the E-Prime experiment to the Neuroscan system.
Abstract
The sample experiment presents a Visual Oddball Task: each trial presents the letter "O" or "X" and the participant's task is to distinguish between these letters. 80% of the trials present the letter "O" and 20% of the trials present the letter "X". The experiment sends the marker value 1 when the letter "O" is shown and the value 128 when the letter "X" is shown.
The Chronos Adapter for Neuroscan provides access to 16 digital outputs (from Chronos to the SynAmps2/RT or Neuvo amp) as shown below:
The Grael 4K amp requires the Grael Trigger Module from Compumedics Neuroscan. Since the Grael 4K (with the Grael Trigger Module) only connects to the first 8 digital outputs on Chronos, this sample experiment sends markers on the 8th output, rather than the 16th output.
When Chronos sends a marker on its first digital output, the Neuroscan system receives the value on Trigger Bit 0 (pin 8). When Chronos sends a marker on its eighth digital output, the system receives it on Trigger Bit 7 (pin 1). To determine which Neuroscan Digital Input receives the Chronos output, do the following:
- Represent the integer marker being sent as a binary number.
- Map the binary number to Chronos's digital outputs to determine which outputs are set high (set to 1).
- Examine which Neuroscan Digital Inputs map to the Chronos Digital Outputs that are set high.
For example, the sample sends the integer value 1 when the stimulus = the letter "O":
- Integer value 1 equals the binary number 0000 0000 0000 0001 (Least Significant Bit is right-most bit).
- 0000 0000 0000 0001 sets the first Chronos digital output high; all other digital outputs are low.
- As shown in the table above, the first Chronos Digital Output maps to Neuroscan Trigger Bit 0.
The sample sends the integer value 128 when the stimulus = the letter "X":
- Integer value 128 equals the binary number 0000 0000 1000 0000.
- 0000 0000 1000 0000 sets the eighth Chronos digital output high; all other digital outputs are low.
- The eighth Chronos Digital Output maps to Neuroscan Trigger Bit 7.
NOTE: Extract all the files in the attached .zip file to the same folder. The sample experiment displays images that must be located in the same folder as the experiment.
Comments
0 comments
Please sign in to leave a comment.