Multiple neuronal networks mediate sustained attention

Abstract

& Sustained attention def icits occur i n several neuropsychi- atric di sorders. However, the underlying neurobiol ogical mechani sms are stil l i ncompletely understood. To that end, f unctional MRI was used to investi gate the neural substrates of sustained attention (vigil ance) usi ng the rapid vi sual i nformation processi ng (RVIP) task in 25 healthy vol unteers. In order to better understand the neural networks under- l yi ng attentional abil ities, brai n regions where task-induced acti vati on correlated wi th task perf ormance were i denti fi ed. Perf ormance of the RVIP task activated a network of frontal, parietal, occipital, thal amic, and cerebell ar regi ons. Deacti va- ti on during task perf ormance was seen in the anterior and posteri or ci ngul ate, i nsul a, and the l ef t temporal and parahippocampal gyrus. Good task performance, as def ined by better detection of target stimul i, was correl ated with enhanced acti vati on i n predomi nantly right fronto-parietal regi ons and with decreased activation in predominantl y lef t temporo-l imbi c and cingulate areas. Factor analysi s revealed that these performance-correlated regions were grouped i nto two separate networks compri sed of positively acti vated and negatively activated i ntercorrelated regi ons. Poor perf ormers f ail ed to signif icantly acti vate or deactivate these networks, whereas good performers either acti vated the positi ve or deactivated the negative network, or did both. The f act that both increased activation of task-specifi c areas and increased deactivati on of task- irrelevant areas mediate cogniti ve f unc- ti ons underlying good RVIP task perf ormance suggests two i ndependent circuits, presumably ref lecting diff erent cogni - ti ve strategi es, can be recruited to perform this vigilance task.