Introduction: Crohn's disease (CD) is a chronic intestinal disorder characterized by overproduction of inflammatory cytokines and recurrent abdominal pain. In CD patients, chronic perceived psychological stress may increase the incidence of symptoms and of subsequent disease relapses (Mawdsley et al. 2005; Agostini et al. 2010). To test whether psychological stress in CD is related to abnormal brain activity, we used fMRI to compare brain network modulated by cognitive stress in CD patients and in healthy controls. Methods: Eighteen right-handed CD patients (10 female; mean age= 32 yrs ) and eighteen right-handed healthy controls (11 female; mean age= 28 yrs ) underwent a block fMRI study. The functional protocol consisted in two repeated runs, each comprised of 3 blocks of the Stroop colour-word test (Stroop 1935).Three blocks of a control condition (i.e. colour and word meaning were identical) were also included. Task difficulty and hence its stressfulness was manipulated decreasing the stimulus presentation time over the three different blocks (1500, 1300, and 1100 ms, respectively). A conventional analysis was used to test the attentional effect (Stroop task vs control condition). Furthermore, in order to compare stressor-evoked changes between groups, a parametric analysis was performed using the percentages of correct responses as a regressor. Data were acquired with a Philips Achieva system at 3T. Thirty axial slices were acquired (in-plane matrix: 80x80; TR: 2000 ms; slices 3mm each with a 1mm gap; voxel size: 3x3x4 mm TR = 2000 ms; 3 runs, 240 volumes each). Data analysis was carried out using the SPM5 package. Results: Behavioral data (accuracy and reaction times) did not shown any significant differences between patients and controls. As to functional data, the main activated regions for the Stroop task included the dorsolateral prefrontal cortex as well as the inferior parietal cortex on the left side for both groups. In the parametric analysis, controls showed activation that positively correlated with response accuracy in a bilateral neural network comprising the posterior cingulate, the parahippocampal and the lingual gyri (Figure 1). No specific activation was found for the CD group in the parametric analysis.Conclusions: In healthy subjects, the successful monitoring of the stressful/attentional task was positively related to the activity of a bilateral posterior network. These areas are part of the system responsible for the executive aspects of attentional selection (Banich et al. 2000), which imposes an attentional ''set'' for the task-relevant information- that is, which sets a top-down bias for selecting certain types of information (e.g., color). Despite a good performance in the Stroop task, no correlation pattern with the behavioural data was found in CD patients: no brain region selctively increased its functional activity as accuracy increased, thus suggesting an impaired modulation of the resources needed to perform the task. Further research will be necessary to find out whether abnormal activity in this brain network may be the link between the psychological stress and inflammatory exacerbations.References Agostini, A., et al. (2010). "Parental bonding and inflammatory bowel disease." Psychosomatics 51(1): 14-21. Banich, M. T., et al. (2000). "fMri studies of Stroop tasks reveal unique roles of anterior and posterior brain systems in attentional selection." Journal of Cognitive Neuroscience 12(6): 988-1000. Mawdsley, J. E., et al. (2005). "Psychological stress in IBD: new insights into pathogenic and therapeutic implications." Gut 54(10): 1481-91. Stroop, J. A. (1935). "Studies of interference in serial verbal reactions." Journal of Experimental Psychology 18: 643–662.
|Titolo:||Lack of attentional resources modulation in chronic stress: an fMRI study on Crohn’s disease.|
|Autori:||Benuzzi, F.; Agostini, A.; Zucchelli, M.; Farinelli, V.; Filippini, N.; Campieri, M.; Nichelli, P.|
|Data di pubblicazione:||2012|
|Appare nelle tipologie:||Poster|
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