Document Type: Original Research


1 MSc, Department of Radiology, School of Medicine, AJA University of Medical Science, Tehran, Iran

2 MD, Department of Radiology, School of Medicine, AJA University of Medical Science, Tehran, Iran

3 PhD, Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran

4 PhD, Department of Neuroscience, School of Science and Advanced Technologies in Medicine, Hamadan University of Medical Sciences, Hamadan, Iran

5 PhD, Department of Biomedical Engineering, School of Medicine, Kermanshah University of Medical Sciences (KUMS), Kermanshah, Iran

6 PhD, Health Research Center, Kermanshah University of Medical Sciences (KUMS), Kermanshah, Iran

7 PhD, Department of clinical phycology, School of Medicine, AJA University of Medical Science, Tehran, Iran


Background: Cognitive control of brain regions can be determined by the tasks involving the cognitive control such as the color word Stroop task. Stroop task define the reduction in function in incongruent condition, which requires more attention and control of competitive responses.
Objective: The purpose of this study was to evaluate the activity of brain using the Modified Conflict Stroop Task in Military Personnel.
Material and Methods: In this applied experimental study, to specify the activity of different regions of brain in response to conflict Persian color-word Stroop task, 20 healthy persons participated in this study. To evaluate selective attention, the traditional color-word Stroop Task Model was modified, and the Stroop test was designed in high- and low-threat zones. We used functional magnetic resonance imaging (fMRI) to evaluate the brain activation during the Stroop task performance. The color-word Stroop task consists of incongruent, congruent, and neutral conditions, and the subjects were requested to carefully choose the correct answer.
Results: The mean response time was longer in incongruent condition (867.6±193.5ms) compared to congruent and neutral conditions. Analysis of neuroimaging data revealed that the brain conflict-related regions are activated by the Stroop interference. In incongruent trial, the superior frontal gyrus (SFG) and inferior frontal gyrus (IFG) showed the most active and stronger BOLD responses. In congruent trials, the activation in the brain was less and had difference compared with incongruent trials.
Conclusion: Our result offers that the frontal cortex and the anterior cingulate cortex are sensitive to different trials of Persian Stroop task. Using modified Stroop task, we determined the brain responses to the selective attention test.


  1. Schacter DL. The seven sins of memory: insights from psychology and cognitive neuroscience. American psychologist. 1999;54(3):182. doi: 10.1037//0003-066x.54.3.182. PubMed PMID: 10199218 .
  2. Aron AR, Durston S, Eagle DM, Logan GD, Stinear CM, Stuphorn V. Converging evidence for a fronto-basal-ganglia network for inhibitory control of action and cognition. J Neurosci. 2007;27(44):11860-4. doi: 10.1523/JNEUROSCI.3644-07.2007. PMID: 17978025. PubMed PMCID: PMC6673355.
  3. Nee DE, Wager TD, Jonides J. Interference resolution: insights from a meta-analysis of neuroimaging tasks. Cogn Affect Behav Neurosci. 2007;7(1):1-17. doi: 10.3758/cabn.7.1.1. PubMed PMID: 17598730.
  4. Botvinick MM, Braver TS, Barch DM, Carter CS, Cohen JD. Conflict monitoring and cognitive control. Psychological review. 2001;108(3):624-52. doi: 10.1037/0033-295X.108.3.624.
  5. Laird AR, McMillan KM, Lancaster JL, et al. A comparison of label-based review and ALE meta-analysis in the Stroop task. Human brain mapping. 2005;25(1):6-21. doi: 10.1002/hbm.20129. PubMed PMID: 15846823. PubMed PMCID: PMC6871676.
  6. Egner T. Congruency sequence effects and cognitive control. Cogn Affect Behav Neurosci. 2007;7(4):380-90. doi: 10.3758/cabn.7.4.380. PubMed PMID: 18189011.
  7. Stroop JR. Studies of interference in serial verbal reactions. Journal of experimental psychology. 1935;18(6):643-62.
  8. Lezak MD, Howieson DB, Loring DW, Fischer JS. Neuropsychological assessment. USA: Oxford University Press; 2004.
  9. Banich MT, Milham MP, Jacobson BL, et al. Attentional selection and the processing of task-irrelevant information: insights from fMRI examinations of the Stroop task. Prog Brain Res. 2001;134:459-70. doi: 10.1016/s0079-6123(01)34030-x. PubMed PMID: 11702561.
  10. Miller EK, Cohen JD. An integrative theory of prefrontal cortex function. Annu Rev Neurosci. 2001;24:167-202. doi: 10.1146/annurev.neuro.24.1.167. PubMed PMID: 11283309.
  11. Williams JM, Mathews A, MacLeod C. The emotional Stroop task and psychopathology. Psychol Bull. 1996;120(1):3-24. doi: 10.1037/0033-2909.120.1.3. PubMed PMID: 8711015.
  12. Carter CS, Mintun M, Cohen JD. Interference and facilitation effects during selective attention: an H215O PET study of Stroop task performance. Neuroimage. 1995;2(4):264-72. doi: 10.1006/nimg.1995.1034. PubMed PMID: 9343611.
  13. Kane MJ, Engle RW. Working-memory capacity and the control of attention: the contributions of goal neglect, response competition, and task set to Stroop interference. J Exp Psychol Gen. 2003;132(1):47-70. doi: 10.1037/0096-3445.132.1.47. PubMed PMID: 12656297.
  14. Han K, Kim IY, Kim JJ. Assessment of cognitive flexibility in real life using virtual reality: a comparison of healthy individuals and schizophrenia patients. Comput Biol Med. 2012;42(8):841-7. doi: 10.1016/j.compbiomed.2012.06.007. PubMed PMID: 22770745.
  15. Sharini H, Riyahi Alam N, Jalalvandi M, et al. Assessment of Motor Cortex in Active, Passive and Imagery Wrist Movement Using Functional MRI. J Biomed Phys Eng. 2020.
  16. Rajapakse JC, Piyaratna J. Bayesian approach to segmentation of statistical parametric maps. IEEE Transactions on biomedical engineering. 2001;48(10):1186-94. doi: 10.1109/10.951522.
  17. Wang Y, Rajapakse JC. Contextual modeling of functional MR images with conditional random fields. IEEE transactions on medical imaging. 2006;25(6):804-12. doi: 10.1109/TMI.2006.875426.
  18. Goebel R, Roebroeck A, Kim DS, Formisano E. Investigating directed cortical interactions in time-resolved fMRI data using vector autoregressive modeling and Granger causality mapping. Magn Reson Imaging. 2003;21(10):1251-61. doi: 10.1016/j.mri.2003.08.026. PubMed PMID: 14725933.
  19. Zheng X, Rajapakse JC. Learning functional structure from fMR images. Neuroimage. 2006;31(4):1601-13. doi: 10.1016/j.neuroimage.2006.01.031. PMID: 16540348.
  20. Sheth SA, Abuelem T, Gale JT, Eskandar EN. Basal ganglia neurons dynamically facilitate exploration during associative learning. J Neurosci. 2011;31(13):4878-85. doi: 10.1523/JNEUROSCI.3658-10.2011. PubMed PMID: 21451026. PubMed PMCID: PMC3486636.
  21. Sheth SA, Mian MK, Patel SR, Asaad WF, et al. Human dorsal anterior cingulate cortex neurons mediate ongoing behavioural adaptation. Nature. 2012;488(7410):218-21. doi: 10.1038/nature11239. PubMed PMID: 22722841. PubMed PMCID: PMC3416924.
  22. Kim C, Chung C, Kim J. Task-dependent response conflict monitoring and cognitive control in anterior cingulate and dorsolateral prefrontal cortices. Brain Res. 2013;1537:216-23. doi: 10.1016/j.brainres.2013.08.055. PubMed PMID: 24012877.
  23. Kim C, Johnson NF, Gold BT. Conflict adaptation in prefrontal cortex: now you see it, now you don’t. Cortex. 2014;50:76-85. doi: 10.1016/j.cortex.2013.08.011. PubMed PMID: 24074459. PubMed PMCID: PMC3872513.
  24. Casey BJ, Thomas KM, Welsh TF, et al. Dissociation of response conflict, attentional selection, and expectancy with functional magnetic resonance imaging. Proc Natl Acad Sci U S A. 2000;97(15):8728-33. doi: 10.1073/pnas.97.15.8728. PubMed PMID: 10900023. PubMed PMCID: PMC27016.
  25. Jalalvandi M, Riahi Alam N, Sharini H, Hashemi H, Kohzad S. Optical Imaging of the Motor Cortex in the Brain in Order to Determine the Direction of the Hand Movements Using Functional Near-Infrared Spectroscopy (fNIRS). Iranian Journal of Medical Physics. 2018;15(Special Issue-12th. Iranian Congress of Medical Physics):152. doi:10.22038/ijmp.2018.12653.
  26. Jalalvandi M, Riahi Alam N, Sharini H. Optical Imaging of Brain Motor Cortex Activation During Wrist Movement Using Functional Near-Infrared Spectroscopy (fNIRS). Arch Neurosci. 2019. doi: 10.5812/ans.90089.
  27. Harrivel AR, Weissman DH, Noll DC, Peltier SJ. Monitoring attentional state with fNIRS. Front Hum Neurosci. 2013;7:861. doi: 10.3389/fnhum.2013.00861. PubMed PMID: 24379771. PubMed PMCID: PMC3861695.
  28. Pratt N, Willoughby A, Swick D. Effects of working memory load on visual selective attention: behavioral and electrophysiological evidence. Front Hum Neurosci. 2011;5:57. doi: 10.3389/fnhum.2011.00057. PubMed PMID: 21716633. PubMed PMCID: PMC3115462.
  29. Adorni R, Gatti A, Brugnera A, Sakatani K, Compare A. Could fNIRS promote neuroscience approach in clinical psychology? Front Psychol. 2016;7:456. doi: 10.3389/fpsyg.2016.00456. PubMed PMID: 27065924. PubMed PMCID: PMC4811970.
  30. Prakash RS, Erickson KI, Colcombe SJ, et al. Age-related differences in the involvement of the prefrontal cortex in attentional control. Brain Cogn. 2009;71(3):328-35. doi: 10.1016/j.bandc.2009.07.005. PubMed PMID: 19699019. PubMed PMCID: PMC2783271.
  31. Peterson BS, Kane MJ, Alexander GM, et al. An event-related functional MRI study comparing interference effects in the Simon and Stroop tasks. Brain Res Cogn Brain Res. 2002;13(3):427-40. doi: 10.1016/s0926-6410(02)00054-x. PubMed PMID: 11919006.
  32. Song Y, Hakoda Y. An fMRI study of the functional mechanisms of Stroop/reverse-Stroop effects. Behav Brain Res. 2015;290:187-96. doi: 10.1016/j.bbr.2015.04.047. PubMed PMID: 25952963.
  33. Banich MT, Milham MP, Atchley R, Cohen NJ, et al. fMRI studies of Stroop tasks reveal unique roles of anterior and posterior brain systems in attentional selection. J Cogn Neurosci. 2000;12(6):988-1000. doi: 10.1162/08989290051137521. PubMed PMID: 11177419.
  34. MacDonald AW, Cohen JD, Stenger VA, Carter CS. Dissociating the role of the dorsolateral prefrontal and anterior cingulate cortex in cognitive control. Science. 2000;288(5472):1835-8. doi: 10.1126/science.288.5472.1835. PubMed PMID: 10846167.
  35. Derrfuss J, Brass M, Neumann J, Von Cramon DY. Involvement of the inferior frontal junction in cognitive control: Meta-analyses of switching and Stroop studies. Hum Brain Mapp. 2005;25(1):22-34. doi: 10.1002/hbm.20127. PubMed PMID: 15846824. PubMed PMCID: PMC6871679.
  36. Brass M, Ruge H, Meiran N, Rubin O, et al. When the same response has different meanings: recoding the response meaning in the lateral prefrontal cortex. Neuroimage. 2003;20(2):1026-31. doi: 10.1016/S1053-8119(03)00357-4. PubMed PMID: 14568472.
  37. Pardo JV, Pardo PJ, Janer KW, Raichle ME. The anterior cingulate cortex mediates processing selection in the Stroop attentional conflict paradigm. Proc Natl Acad Sci U S A. 1990; 87(1): 256–259. doi: 10.1073/pnas.87.1.256. PubMed PMID: 2296583. PubMed PMCID: PMC53241.
  38. Peterson BS, Skudlarski P, Gatenby JC, Zhang H, et al. An fMRI Study of Stroop Word-Color Interference: Evidence for Cingulate Subregions Subserving Multiple Distributed Attentional Systems. Biol Psychiatry. 1999;45(10):1237-58. doi: 10.1016/s0006-3223(99)00056-6. PubMed PMID: 10349031.
  39. Jonides J, Smith EE, Koeppe RA, Awh E, et al. Spatial working memory in humans as revealed by PET. Nature. 1993;363(6430):623-5. doi: 10.1038/363623a0. PubMed PMID: 8510752.
  40. Qiu J, Luo Y, Wang Q, Zhang F, Zhang Q. Brain mechanism of Stroop interference effect in Chinese characters. Brain Research. Brain Res. 2006;1072(1):186-93. doi: 10.1016/j.brainres.2005.12.029. PubMed PMID: 16443198.
  41. Mai JK, Paxinos G. The human nervous system. Academic press; 2011.
  42. Boisgueheneuc FD, Levy R, Volle E, et al. Functions of the left superior frontal gyrus in humans: a lesion study. Brain. 2006;129(12):3315-28. doi: 10.1093/brain/awl244. PubMed PMID: 16984899.
  43. Yousef Pour M, Masjoodi S, Fooladi M, et al. Identification of the Cognitive Interference Effect Related to Stroop stimulation: using Dynamic Causal Modeling of Effective Connectivity in Functional Near-Infrared Spectroscopy (fNIRS). J Biomed Phys Eng. 2020.