title: Default mode of brain function in monkeys.
abstract: Human neuroimaging has revealed a specific network of brain regions-the default-mode network (DMN)-that reduces its activity during goal-directed behavior. So far, evidence for a similar network in monkeys is mainly indirect, since, except for one positron emission tomography study, it is all based on functional connectivity analysis rather than activity increases during passive task states. Here, we tested whether a consistent DMN exists in monkeys using its defining property. We performed a meta-analysis of functional magnetic resonance imaging data collected in 10 awake monkeys to reveal areas in which activity consistently decreases when task demands shift from passive tasks to externally oriented processing. We observed task-related spatially specific deactivations across 15 experiments, implying in the monkey a functional equivalent of the human DMN. We revealed by resting-state connectivity that prefrontal and medial parietal regions, including areas 9/46d and 31, respectively, constitute the DMN core, being functionally connected to all other DMN areas. We also detected two distinct subsystems composed of DMN areas with stronger functional connections between each other. These clusters included areas 24/32, 8b, and TPOC and areas 23, v23, and PGm, respectively. Such a pattern of functional connectivity largely fits, but is not completely consistent with anatomical tract tracing data in monkeys. Also, analysis of afferent and efferent connections between DMN areas suggests a multisynaptic network structure. Like humans, monkeys increase activity during passive epochs in heteromodal and limbic association regions, suggesting that they also default to internal modes of processing when not actively interacting with the environment.
authors: Laboratory for Neuro-Psychophysiology, K.U. Leuven Medical School, Leuven 3000, Belgium.
authors: Dante
authors: D
authors: Mantini
authors: Annelis
authors: A
authors: Gerits
authors: Koen
authors: K
authors: Nelissen
authors: Jean-Baptiste
authors: JB
authors: Durand
authors: Olivier
authors: O
authors: Joly
authors: Luciano
authors: L
authors: Simone
authors: Hiromasa
authors: H
authors: Sawamura
authors: Claire
authors: C
authors: Wardak
authors: Guy A
authors: GA
authors: Orban
authors: Randy L
authors: RL
authors: Buckner
authors: Wim
authors: W
authors: Vanduffel
mesh_terms: D000465:Algorithms; D000818:Animals; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology*; D016000:Cluster Analysis; D003627:Data Interpretation, Statistical; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D000882:Haplorhini / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000033:anatomy & histology / Q000502:physiology; D012146:Rest / Q000502:physiology