Chronos Adapter for Magstim EGI EEG [42580]

This article applies to:

E-Prime 3.0

Chronos

Detail

Experiment Author: Psychology Software Tools, Inc.

The Chronos Adapter for Magstim EGI EEG sample experiment illustrates how to use Task Events to send markers from the E-Prime experiment to the Magstim EGI EEG amplifier.

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 Magstim EGI EEG provides access to 8 digital outputs (from Chronos to the Magstim EGI amplifier) as shown below:

When Chronos sends a marker on its first digital output, the amplifier receives the value on DIN 1 (pin 1). When Chronos sends a marker on its eighth digital output, the amplifier receives it on Trigger In 9 (pin 9).  To determine which Magstim EGI DIN receives the Chronos output, do the following:

1. Represent the integer marker being sent as a binary number (see INFO: Choosing a marker value to send from E-Prime to an external device [42529] for more information on integer and binary numbers).
2. Map the binary number to Chronos's digital outputs to determine which outputs are set high (set to 1).
3. Examine which Magstim EGI EEG DIN and pin maps to the Chronos digital outputs that are set high.

For example, the sample sends the integer value 1 when the stimulus = the letter "O":

1. Integer value 1 equals the binary number 0000 0001 (Least Significant Bit is right-most bit).
2. 0000 0001 sets the first Chronos digital output high; all other digital outputs are low.
3. As shown in the table above, the first Chronos Digital Output maps to DIN 1/pin 1.

The sample sends the integer value 128 when the stimulus = the letter "X":

1. Integer value 128 equals the binary number 1000 0000.
2. 1000 0000 sets the eighth Chronos digital output high; all other digital outputs are low.
3. The eighth Chronos Digital Output maps to DIN 8/pin 9.

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.

See Also:

E-Prime Extensions for Net Station  - simplifies the experiment development, integration, and participant experience when integrating with Brain Product's EEG systems

Chronos Custom Adapters for other Magstim EGI amplifiers:

• Chronos Adapter for Magstim EGI EEG-TMS [42581]