Return to the Mismatched Negativity Oddball Task page

Script Author: Katja Borchert, Ph.D. ( for Millisecond Software, LLC
Date: 02-25-2015
last updated:  11-18-2015 by K.Borchert for Millisecond Software LLC

Copyright ©  11-18-2015 Millisecond Software


This script implements the Mismatched Negativity Oddball Paradigm as published in

Bramon,E., Croft, R.J, McDonald, C., Virdi, G.K., Gruzelier, J.G., Torsten Baldeweg, T., Sham, P.C.,
Frangou, S. & Murray, R.M. (2004). Mismatch negativity in schizophrenia: a family study. 
Schizophrenia Research, 67, 1– 10.

Participants sit in comfortable chairs while the script plays a series of tones (mix of Standard and Oddballs) 
to them over headphones. Participants are instructed to keep their eyes open and to disregard the sounds.
Different portsignals are sent for Standard and Oddball sounds.

The default data stored in the data files are:

(1) Raw data file: 'MismatchedNegativityOddball_raw*.iqdat' (a separate file for each participant)

build:							Inquisit build
computer.platform:				the platform the script was run on
date, time, subject, group:		date and time script was run with the current subject/groupnumber 
blockcode, blocknum:			the name and number of the current block
trialcode, trialnum: 			the name and number of the currently recorded trial
									(Note: not all trials that are run might record data; by default data is collected unless /recorddata = false is set for a particular trial/block) 
/stimtype: 						1 = standard; 2 = oddball
stimulusitem:					the presented stimuli in order of trial presentation

(2) Summary data file: 'MismatchedNegativityOddball_summary*.iqdat' (a separate file for each participant)

script.startdate:				date script was run
script.starttime:				time script was started
script.subjectid:				subject id number
script.groupid:					group id number
script.elapsedtime:				time it took to run script (in ms)
computer.platform:				the platform the script was run on
/completed:						0 = script was not completed (prematurely aborted); 1 = script was completed (all conditions run)


- script runs 3 blocks block.MNO of 400 trials each
- each block.MN0 randomly selects the order of 340 standard (85%) and 60 oddball sounds (15%)
- standard sounds play for 25ms and oddball sounds play for 50ms
- an interstimulus interval (isi) of 300ms (editable parameter) is added to each sound
- port signals that coincide with the onset of stimuli are sent along with type of tone

Tones created in Audacity by Millisecond Software LLC

standard: 1000hz, 25ms duration, 5-ms rise/fall time
oddball: 1000hz, 50ms duration, 5-ms rise/fall time
(both should be played at 80db)

can changed under section Editable Code -> Editable Instructions

check below for (relatively) easily editable parameters, stimuli, instructions etc. 
Keep in mind that you can use this script as a template and therefore always "mess" with the entire code to further customize your experiment.

The parameters you can change are:

/isi:				interstimulus interval (isi) in ms (default: 300ms)
					(isi: time between offset of one stimulus and onset of another)

/standardduration:	duration of the standard tone in ms (default: 25)
/oddballduration:	duration of the oddball tone in ms (default: 50)
						Note: if these durations are changed, the corresponding soundfiles also need to change

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