The Modified Stroop Task as a Smoking-Related Cue Effects on Frontal and Gastrocnemius EMG

1. The Modified Stroop Task as a Smoking-Related Cue Effects on Frontal and Gastrocnemius EMG Smoking related Smoking related Smoking related Neutral Smoking related Neutral Neutral Neutral 60 300 40 200 mV 20 V 100 0 0 -20 Nonsmoker Smoker Nonsmoker Smoker 5 min 2 min 3 min 2 min 3 min CHAISE CRAYON MARCHER PARAPLUI ARBRE BOUFÉE REPAS ALLUMER PAUSE APÉRITIF Relaxation Stroop neutral words Relaxation Stroop smoking related words Relaxation M. frontalis (Affective tension) M. gastrocnemius (General tension) 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 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 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 Presented at • 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 drug-related cues as it combines a drug cue itself (the words) and additionally an unspecific stressor (the task). • The objective of the present study was to test the psychophysiological effects of a specifically modified Stroop task on smokers. • 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 • 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). • Methods • 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. • 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. • Conclusions • 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 drug-related cues as it combines a drug cue itself (the words) and additionally an unspecific stressor (the task) which can easily be controlled for. Service d’abus de substances - Département de Psychiatrie