Three Networks of the Brain?

[dsmart]

Can anyone verify if the following statements are scientifically accurate? I'm writing an article and would like to verify before I begin spreading the word.

• Is it true that the various regions of the brain are interconnected by three networks (default network, task network, control network)?
• To oversimplify for the average reader, could these networks be compared to a light switch (the task being our "on" mode, the default being our "off" mode, and the control acting as the switch itself, moderating between the two)?
• The default network is associated with sense of self, often referred to as the selfing network
• The default network and the task network are anti-correlated, activity in one decreases activity in the other

 

Thanks!

Edited January 12, 2017 by dsmart

[iNow]

No to all

[DrmDoc]

Can anyone verify if the following statements are scientifically accurate? I'm writing an article and would like to verify before I begin spreading the word.

• Is it true that the various regions of the brain are interconnected by three networks (default network, task network, control network)?
• To oversimplify for the average reader, could these networks be compared to a light switch (the task being our "on" mode, the default being our "off" mode, and the control acting as the switch itself, moderating between the two)?
• The default network is associated with sense of self, often referred to as the selfing network
• The default network and the task network are anti-correlated, activity in one decreases activity in the other

 

Thanks!

 

To your initial question, the answer is no; therefore, your remaining questions are moot. What was or is your source for this three network idea? For a more accurate perspective, I suggest you begin here with Large Scale Brain Networks and Biological Neural Networks for more detail. You might also want to acquaint yourself with Neuropsychology and it functional approach to brain study. I hope this helps.

[dsmart]

Okay, you say the answer is no, but how can you be so sure? The research seems to point in the other direction.

 

I discovered the idea initially from Gary Weber, but like you, I was skeptical. I wanted to do more research and ask the experts. That's my reason for posting.

(begin at 20:17 for his talk on default network, and 24:23 where he introduces the three networks).

 

The Default Mode Network (DMN) seems to be a prominent idea as there's extensive information listed on Wikipedia.

https://en.wikipedia.org/wiki/Default_mode_network

There seems to be a lot of information provided for its existence, however the criticism listed in the final section confirms that the idea is not yet universally accepted. For what reason, I'm not sure. But just because something isn't "universally accepted" doesn't mean science hasn't found evidence of its existence.

 

Additionally, this article from NCBI mentions the Task Network as the "second major network" of the brain. This seems pretty offish.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4017816/

 

That being said, I'm not finding much of anything for the "Control Network", the third network of the brain as Gary cites in his video. Perhaps there's no evidence for it yet.

 

Any new thoughts on the above?

 

Thanks again for jumping in!

[Endy0816]

Gurus are unreliable sources.

 

Some of those are real concepts though. DMN, task positive. DMN is even listed along with a number of others on the large scale brain networks link above.

Edited January 12, 2017 by Endy0816

[DrmDoc]

As I understand, the idea of three neural networks is merely a characterization of three brain states rather than active or actual neural networks within our nervous system, which consists primarily of two: The central and peripheral nervous system with the latter subdivided into several others. The video by Mr. Weber discusses a theoretical model of brain function proposed by Andrews-Hanna, et. al., in a 2014 paper. In that paper, the authors propose a distinction between their idea of a "Default Network" and a theorized "Default Mode" idea stating that "We use default network instead of default mode because the latter refers to passive states, which may obscure the adaptive functions of the network. The former is meant to emphasize its role as a large-scale brain system whose functions may extend beyond the resting state." The latter "default mode" was first described as a model of brain function in a 2001 paper (Raichle,M.E.etal.2001. A default mode of brain function. Proc. Natl. Acad. Sci. U.S.A. 98: 676–682). A further discussion of default network research can be found here.

 

In my opinion, this idea of distinct neural networks is best described as brain states or modes of activation rather than dedicated networks with separate on/off switches. True networks are verified by real afferent/efferent neurophysiological links rather than concurrency in activations and deactivations through functional observations. Neural networks refer to real neural links that perform specific or dedicated tasks. Much of the tasks described under this default network model is ascribable to our parasympathetic nervous system, IMO, which is a subdivision of our peripheral nervous system.

 

Although certain areas of the brain are observed as active during a particular brain state or mode, those areas may also be active during others unrelated states or modes. For example, our brain is just as active amid its dreaming state as it is while conscious, excluding prefrontal function depending on dream type. Those brain areas active while dreaming cannot be described as a dedicated "dreaming network" because those areas are also active when we are awake. Simply stated, there are no neural networks specifically dedicated to the three brain states in your references. Much of what our brain does and doesn't do is controlled by the thalamus--perhaps our most misunderstood brain structure, in my opinion.

Edited January 12, 2017 by DrmDoc

[dsmart]

@DrmDoc - thank you for your response! This is wonderfully detailed information and it's pretty clear that the light switch analogy doesn't lend well to the brain in such a direct "on/off" sense. But allow me to clarify.

 

Retrospectively, what I meant by "on" and "off" modes were not necessarily in relation to brain networks or modes, but rather those times in our lives when we are highly engaged ("on") vs. the times we are disengaged from a mental perspective ("off"). It sounds like what I'm looking for is what you've mentioned: the sympathetic (SNS) and parasympathetic nervous systems (PNS). Fight or flight vs. rest and digest.

 

So maybe my follow-up question then is this: when we are highly engaged in life from a subjective experience perspective (actively focused on a single task rather than ruminating on the past or the future), is that the SNS at work? When I say highly engaged, I don't necessarily envision it as being "fight or flight" since that's more an inducer of stress, but perhaps that is still under the role of the SNS. I'm thinking more of being in a flow state.

 

What can be said from a scientific perspective of these two "states" of subjective human experience (flow vs. not-flow, active vs. passive, etc.)? Perhaps I've left the neuroscience umbrella of study, but I'd still be interested in your thoughts.

[DrmDoc]

I believe you are asking about executive functions, which are mediated by our central nervous system (CNS) primarily through our prefrontal cortex. Rather than a system of nerves, the prefrontal is a neural structure whose functional matrix adds a quality to our cognition and behaviors that enables focused activities and pursuits. Regardless of what behaviors we engage, those behaviors are governed by neural structures comprising our CNS whose commands are executed through its connections to the various subdivisions of our neural system. Other than our enteric nervous system, no other neurological system in our body exercises a similar degree of independent governance. The governance of our behaviors resides within the various structure of the brain. Our various nervous systems are merely the dedicated neural links through which our brain executes its governance.