Dorsal attention network
The task-positive network (TPN) is a network of areas in the human brain that typically responds with activation increases to attention-demanding tasks in functional imaging studies.[1] The task-positive network encompasses regions of the dorsal attention system, but in addition includes dorsolateral and ventrolateral prefrontal regions, the insular cortex, and the SMA/pre-SMA.[1] Notably, the nodes of this network are also correlated during rest (i.e., in the absence of any task).[1] The task-positive network is anti-correlated with the default mode network.[1][2]
During rest the TPN has been claimed to subserve intermittent "external awareness", defined as the conscious perception through different sensory modalities of one's surrounding environment[further explanation needed].[3]
Function
During performance of attention-demanding tasks, prefrontal and parietal structures comprising the task-positive network are characterized by increases in activation; in contrast, default mode network structures, including posterior cingulate[further explanation needed] and medial prefrontal cortices, are characterized by decreased activity. During wakeful rest, the opposite pattern emerges, with the default mode network becoming more active and the task-positive network less active.[4]
References
- ^ a b c d Fox, M. D.; Snyder, A. Z.; Vincent, J. L.; Corbetta, M.; Van Essen, D. C.; Raichle, M. E. (2005). "From The Cover: The human brain is intrinsically organized into dynamic, anticorrelated functional networks". Proceedings of the National Academy of Sciences. 102 (27): 9673–9678. doi:10.1073/pnas.0504136102. ISSN 0027-8424. PMC 1157105. PMID 15976020.
- ^ Fransson, P. (2005). "Spontaneous low-frequency BOLD signal fluctuations: an fMRI investigation of the resting-state default mode of brain function hypothesis". Human Brain Mapping. 26 (1): 15–29. doi:10.1002/hbm.20113.
- ^ Vanhaudenhuyse, Audrey; Demertzi, Athena; Schabus, Manuel; Noirhomme, Quentin; Bredart, Serge; Boly, Melanie; Phillips, Christophe; Soddu, Andrea; Luxen, Andre; Moonen, Gustave; Laureys, Steven (1 March 2011). "Two Distinct Neuronal Networks Mediate the Awareness of Environment and of Self". Journal of Cognitive Neuroscience. 23 (3): 570–578. doi:10.1162/jocn.2010.21488. PMID 20515407.
- ^ Hamilton, J.Paul (2011). "Default-Mode and Task-Positive Network Activity in Major Depressive Disorder: Implications for Adaptive and Maladaptive Rumination" (PDF). Biological Psychiatry. 70: 327–333. doi:10.1016/j.biopsych.2011.02.003. PMC 3144981. Retrieved 6 June 2014.