The
Modified
Stroop
Task
as
a
Réunion Ambulatoires SAS, 8.5.2006
Smoking-Related Cue
Effects on Frontal and Gastrocnemius EMG
Presented at
Daniele Fabio Zullino1, Enrico Cancela1, Emmanuelle Frésard2, Yasser Khazaal2, Anne Chatton1,
Manuela Bertolini1, Rodolphe Soulignac1, Thomas Rathelot1, Djamel Benguettat1, Riaz Khan1
1Division
of substance abuse, University Hospitals of Geneva, Switzerland
2Clinical Research Unit, University Department for Adult Psychiatry, Lausanne, Switzerland
Introduction

Addictive drug-use is largely controlled by automatic processes, presenting
all the typical characteristics of automatisms : speed, autonomy, and lack of
control.

Besides being measurable through behavior and self-report in humans,
stimulus-response associations can also be seen by means of physiological
changes.

Addicted individuals exhibit an attentional bias to stimuli related to their
addiction. One of the most frequently used paradigms to test attentional
biases is the Stroop task, and especially its modified version.

Outside of addiction research, the Stroop Color-Word Task has also often
been used as standardized laboratory stressor in psychophysiology
research.

Three broad categories of stimuli can experimentally be used to reinstate
drug-seeking/taking behavior: drug priming, drug cues and stressors

Yet, the Stroop taks may represent a particularly useful model for drugrelated cues as it combines a drug cue itself (the words) and additionally an
unspecific stressor (the task).


The physiological data was collected via a ProComp+/Biograph
psychophysiological data acquisition system produced by Thought
Technology, Montreal, Canada via a PRO-SB interface. Subjects’
recordings were analyzed via the Biograph version 2.1 data-collection
program. For Surface electromyography MyoScan-Pro Triode electrodes
(silver/silver chloride) were used at a sampling rate of 32/sec. Frontalis and
gastrocnemius EMG activity (in microvolts) were be obtained following
preparation of the skin and placement of the electrodes over the respective
muscle groups. The two muscle groups were chosen, as the frontalis may
reflects primarily affective states and the gastrocnemius reflects general
level of tension.

Outcome: Difference of the maximal EMG amplitudes, where the maximal
amplitude = maximum potential of the stimulus period - mean potential of
the preceding relaxation period
Results

The objective of the present study was to test the psychophysiological
effects of a specifically modified Stroop task on smokers.
Methods

In a multivariate GLM using the two EMG traces as dependent variables
and the smoking status as a fixed factor, the multivariate test revealed a
significant effect of the smoking status (F=3.927; p=0.050) and the
smokers showed a significantly higher maximal amplitude difference
between the two task periods than non-smokers for both, frontalis EMG
(F=5.48; p=0.031) and gastrocnemius EMG (F=5.49; p=0.031).
12 nonsmokers and 11 smokers were submitted to a 30-minutes laboratory
session, during which they were submitted to two 120-second periods of
modified Stroop tasks.
Smoking related
Smoking related
Smoking related
Smoking related
Neutral
Neutral
3 min
CHAISE
CRAYON
MARCHER
PARAPLUI
ARBRE
Relaxation
2 min
Relaxation
60
200
40
3 min
BOUFÉE
REPAS
ALLUMER
PAUSE
APÉRITIF
Stroop
neutral words
300
Stroop
smoking related
words
mV
2 min
V
5 min
100
0
Relaxation
20
0
-20
Nonsmoker

Neutral
Neutral
The smoking-related words list (15 words) was generated in a preceding
pilot study with 39 smokers evaluating their valence as craving cues.
Smoking related words included 3 semantic categories: (a) Activity of
smoking, (b) Tobacco products and smoking paraphernalia, (c) Smoking
context.
Smoker
M. frontalis
(Affective tension)
Nonsmoker
Smoker
M. gastrocnemius
(General tension)
Conclusions
Neutral words
Chaise
Chair
Table
Table
Fleur
Flower
Chapeau
Hat
Crayon
Pencil
Soulier
Shoe
Assis
Seated
Pierre
Stone
Salade
Salad
Marche
Walk
Pomme
Apple
Bateau
Ship
Genou
Knee
Lire
Reading
Tapis
Rug

The modified Stroop task is a useful stressor to induce skin temperature
reductions

Besides the general stress reaction induced by the task using neutral
words, smoking related words induce a more marked temperature fall in
smokers compared to nonsmokers (= supplementary effect of the
semantic content as drug specific cue).

The modified Stroop task represent a particularly useful model for drugrelated cues as it combines a drug cue itself (the words) and additionally
an unspecific stressor (the task) which can easily be controlled for.
Smoking related words
Paquet
Pack
Apéritif
Aperitif
Café
Coffee
Abstinence
Abstinence
Cendrier
Ashtray
Allumer
Lightening
Bar
Bar
Nicotine
Nicotine
Fumée
Smoke
Bouffée
Puff
Repas
Meal
Cigarette
Cigarette
Pause
Pause
Soirée
Party
Tabac
Tobacco
Service d’abus de substances - Département de Psychiatrie