Mismatched Negativity Oddball Task

Technical Manual

Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond

Created: January 25, 2015

Last Modified: January 01, 2023 by K. Borchert (katjab@millisecond.com), Millisecond

Script Copyright © Millisecond Software, LLC

Background

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.

Duration

7 minutes

Description

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.

Procedure

- 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

Stimuli

Tones created in Audacity by Millisecond

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

Instructions

can changed under section Editable Code -> Editable Instructions

Summary Data

File Name: mismatchednegativityoddball_summary*.iqdat

Data Fields

NameDescription
inquisit.version Inquisit version number
computer.platform Device platform: win | mac |ios | android
startDate Date the session was run
startTime Time the session was run
subjectId Participant ID
groupId Group number
sessionId Session number
elapsedTime Session duration in ms
completed 0 = Test was not completed
1 = Test was completed

Raw Data

File Name: mismatchednegativityoddball_raw*.iqdat

Data Fields

NameDescription
build Inquisit version number
computer.platform Device platform: win | mac |ios | android
date Date the session was run
time Time the session was run
subject Participant ID
group Group number
session Session number
blockCode Name of the current block
blockNum Number of the current block
trialCode Name of the current trial
trialNum Number of the current trial
stimType 1 = standard; 2 = oddball
stimulusitem1/stimulusitem.2 The presented stimuli in order of trial presentation
elapsedTime Session duration in ms

Parameters

The procedure can be adjusted by setting the following parameters.

NameDescriptionDefault
isi Interstimulus interval (isi) in ms
(isi: time between offset of one stimulus and onset of another)
300ms
standardDuration Duration of the standard tone in ms 25
oddballDuration Duration of the oddball tone in ms
if these durations are changed, the corresponding soundfiles also need to change
50