On the existence of a generalized non-specific task-dependent network.

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Brain Networks

Background:

• Functional imaging reveals overlapping fronto-parietal activations across diverse cognitive tasks in healthy individuals.
• This overlap suggests a shared neural mechanism underlying task engagement, independent of specific task demands.
• The default mode network (DMN) is known for intrinsic neuronal activity during rest.

Purpose of the Study:

• To propose the existence of a generalized task-related cortical network, termed the extrinsic mode network (EMN).
• To describe the EMN's fronto-temporo-parietal distribution and its complementary relationship with the DMN.
• To explore the EMN's potential role in cognitive demand, novel information processing, and its implications for mental disorders.

Main Methods:

• Conceptualization of the EMN based on existing functional imaging data and observations.
• Comparative analysis of EMN and DMN activity patterns during task engagement versus task absence.
• Hypothesizing the EMN's involvement in generalized cognitive resource allocation.

Main Results:

• The extrinsic mode network (EMN) is hypothesized to be up-regulated during tasks requiring generalized cognitive resources, irrespective of task specifics.
• The EMN exhibits a fronto-temporo-parietal distribution, including key regions like the inferior frontal gyrus and parietal lobule.
• EMN activity is proposed to be inversely related to the DMN, with EMN up-regulation correlating with DMN down-regulation and vice versa.

Conclusions:

• The EMN functions as a generalized cortical network for extrinsic neuronal activity, crucial for task engagement.
• Dysregulation in EMN and DMN dynamics may underlie cognitive deficits observed in various mental health conditions, such as schizophrenia.
• Further research is needed to elucidate the interaction between the EMN and DMN within a unified brain system.