Functional connectivity during psychological stress in schizophrenia

CASTRO M. N.; BOCACCIO H.; DE PINO G.; SÁNCHEZ S. M.; DRUCAROFF L.; COSTANZO E. Y.; WAINSZTEIN A.; GUINJOAN S. M.; VILLARREAL M.

Buenos Aires

Workshop; IV Taller de Resonancia Magnética; 2018

It is known that environmental factors act on genetic vulnerability to produce active psychotic symptoms. We previously showed that patients have an abnormal brain activation and peripheral autonomic response to psychological stress1-2. We sought to characterize the brain connectivity networks of such stress response in schizophrenia. We studied the pattern of brain connectivity in relation to mental arithmetic stress paradigm in 20 patients (SZ) and 20 healthy controls (HC) aged 18 to 50 years, using 3T-fMRI. A block design with three 1-minute control task, 1-minute stress task and 1-minute post task was acquired. Pairwise Pearson correlations ρ were calculated between 90 AAL regions. A network based statistic (NBS) approach was used to calculate the reconfiguration networks in the presence of stress. Graph theory was used to describe those networks on binarized graph: degree, clustering, rich-club and assortativity coefficients, modularity, path length and hubs, using Brain Connectivity Networks (BTC). Patients with schizophrenia showed a different reconfiguration network in the presence of stress compared with HC, characterized by less extension, a deficit of provincial and connector hubs, and asymmetry. Moreover, this network had a path length similar to the null model, indicating a poor integration. It could be due to a widely distributed network with poor flexibility during control task that remains during stress task (modularity similar to the null model), and to a network with poor integration during stress task (path length similar to the null model). On the other hand, comparing both groups we observed an abnormality network in SZ patients during the reconfiguration in the presence of stress. This network was characterized by an asymmetric distribution and a deficit of connector and provincial hubs.These results suggest an abnormal dynamic of the networks related to stress that could explain the hyper-sensibility to stress characteristic in schizophrenia, and how environmental stressors would act on genetic predisposition to produce the emergence of psychotic symptoms.References:1 - Castro MN, Villarreal MF, Bolotinsky N, Papávero E, Goldschmidt M, Costanzo E, Drucaroff LJ, Wainsztein A, de Achával D, Pahissa J, Bär KJ, Nemeroff CB, Guinjoan SM. Schizophr Res. 2015, 168(1-2):313-21. 2 - Castro MN, Vigo DE, Chu EM, Fahrer RD, de Achával D, Costanzo EY, Leiguarda RC, Nogués M, Cardinali DP, Guinjoan SM. Schizophr Res, 2009; 109(1-3):134-40.