Psychophysiological an fMRI correlates to stress response: a pylot study

A pilot study C. Pruneti, N. Vanello, R. Morese, C. Gentili, F. Fontana, E. Ricciardid, C. Fante, M. Paterni, P. Pietrini, M. Guazzelli, L. Landini, E.M. Ferdeghini a Department of Psychology, University of Parma, Parma, Italy b Department of Information Engineering, University of Pisa, Pisa, Italy c Unit of Clinical Psychology, AUO Pisa, Department of Psychiatry, Neurobiology, Pharmacology, and Biotechnologies, University of Pisa, Pisa, Italy d Laboratory of Clinical Biochemistry and Molecular Biology, Department of Experimental Pathology, Medical Biotechnologies, Infectivology, and Epidemiology, University of Pisa, Pisa, Italy e Institute of Clinical Physiology, CNR, Pisa, Italy Recently, prefrontal cortex (PFC) has been identified as one of the crucial area of integration of behavioural and physiological responses to stress. Here we investigated the neural correlates of psychological stress induced by a problem-solving task through the correlation between peripheral skin conductance measures with central functional data (functional magnetic resonance imaging —fMRI). Skin conductance level (SCL) and skin conductance response (SCR) are related to the activity of the sympathetic system, and are thought to be connected to autonomic arousal, emotional and attentional processing. Six healthy subjects (3F, mean age=27±7) were enrolled in the study after consent. Each subject underwent a psychophysiological stress profile (Fuller, 1974) before fMRI acquisition sessions along with administration of standardized tests (Cognitive Behavioral Assessment, 16–Personality Factor- 5, Pisa Stress, Symptom Questionnaires). Statistical descriptive analysis of acquired data, highlighted that these subjects present heterogeneous psychological and psychophysiological characteristics. The fMRI task consisted in an adapted version of the Raven Progressive Matrices 47 test, based on two different patterns involving analogic and abstract logic thinking, and it was selected to evaluate some consequences on brain activity of attention, orientation, reflex and response to stress. Subjects had to solve each of the 36 matrices, presented at increasing difficulty level, within 20 s, and were instructed to choose among available answers by using MR-compatible buttons. During fMRI data acquisition, SCL and SCR were recorded with an fMRI compatible device and used as regressors, in a general linear model, along with task-related regressors, i.e matrices presentation and button presses. Group t-tests on task-related regressors of interest, highlighted activation (pb0.001) in bilateral dorsolateral prefrontal cortices (attentional and cognitive processes), premotor and motor cortex (button press), right precuneus and left occipital medial cortex (visuospatial processing), and subcortical structures. While no significant activation was related to SCL, SCR changes were significantly associated to bilateral precentral cortex, probably due to a correlation between button presses and SCR time course, to right inferior frontal gyrus, right medial frontal gyrus, bilateral superior frontal gyri and left anterior cyngulate, related to attentional and decision making processes. Preliminary results confirm previous findings on the neural correlates of psychological stress, and underline the usefulness of this experimental design in highlighting the interaction between cognitive function and neurovegetative arousal system during stressful tasks. doi:10.1016/j.ijpsycho.2008.05.06