TPN vs. DMN – Neural Mechanisms and Mindfulness
July 6, 2017 ~ Written by: W.B. “Bud” Kirchner
“Dreams pass into the reality of action. From the actions stems the dream again; and this interdependence produces the highest form of living.” – Anias Nin
While it is generally agreed that anyone who practices mindfulness can ‘feel’ that it works – there is often a question in one’s mind especially a ‘business brain’ – is there a basis in fact/science? This is an issue I touched on in an earlier article (Daniel Kahneman Meets Dalai Lama) but I believe it warrants more attention.
This article and the following (TPN vs DMN – Brain Structure and Mindfulness) are intended to propose some context for discussion as they relate to the mindfulness impact on (1) neural mechanisms and (2) brain structure. I will also provide further reading resources in a future article.
One of my objectives here is to continue to present mindfulness without any quasi-spiritual connections.
As Stephen Batchelor put it in a somewhat provocative fashion: “[Mindfulness] is not concerned with anything transcendent or divine. It serves as an antidote to theism, a cure for sentimental piety, a scalpel for excising the tumor of metaphysical belief.”
It is interesting to note part of the underlying science is facilitated by a phenomenon first described in 1929 by a German scientist (Bergen) who confirmed the brain is electronically active even at rest thus enabling insights which (surprisingly!) showed there was considerable action in parts of resting brain. In this context see an earlier article (Why your gray and white matter matters).
Starting with the premise there is nothing simple when it comes to the brain – one would expect something as powerful as mindfulness would involve more than one functional area of the brain.
For now let’s focus on two networks – the default mode network (DMN) and task positive network (TPN).
“I have known a great many troubles but most of them never happened.” – Mark Twain
Twain, of course, captured in his folksy way – the pitfall that is the DMN.
I should qualify this to say that this is relatively “new” idea so while there is still some debate about some aspects of the concept, I believe it falls short of what might be called ‘controversy’ over the presence of DMN.
Before we get into the specifics – a few general concepts:
Default Mode Network
It’s called “default” because it is the network that is activated unless we are specifically engaged in task specific activity. In other words, you are not attending to physical activity, interacting with the world around you, or involved in a dialogue. Examples of some other components of default mode network (DMN) include:
- Mind-wandering – ‘monkey mind’
- Self-referencing helping us shape our view of ‘who we are’
- Imagining the future
- Understanding others – theory of mind
- Long term memory
- Reliving the past, or general rumination – day dreaming
It is important to note: A well-balanced DMN helps us plan activities, contemplate future activities that are based on past events, and remember important parts of your personal history: particularly autobiographic – episodic memories.
With the evolutionary development of the brain and of intellectual capabilities came the tradeoff that some of these functions could go too far and cause mental anguish. Thus, it is not considered to be a “happy state”. Nevertheless, it is sometimes linked to creativity not hard to believe if you think back to certain creative geniuses.
Complications in the default mode network have been linked to a collection of maladies, including Alzheimer’s disease, autism, bipolar disorder, PTSD, depression – the list goes on.
One of the best illustrations of the components and roles of these parts and how they interact is provided in the article Neuroscience of Mindfulness: Default Mode Network, Meditation & Mindfulness by Matthew Williams.
“Imagine that you are romantically interested in a coworker. Perhaps after a few days or weeks of gathering your courage, you decide to ask her out on a date. Your heart pounds and fear coats your upper lip with sweat as you await her response. But after an agonizing series of seconds that feel like minutes your romantic interest provides a resounding – No.”
“Later that day, as you sit down for dinner, you begin to process the events of that afternoon. Your mPFC/emotional sensor retrieves the memory of your romantic rejection formed by your hippocampus/memorizer. The memory is laden with fear and embarrassment courtesy of the amygdala/emoter. The PCC/emotional Integrator forces you to re-experience the bodily state of fear and embarrassment while the mPFC/emotional sensor replays the ordeal over and over again in your mind’s eye.”
Default Mode Network (Per Williams)
|Medial prefrontal cortex (mPFC)||
|Posterior cingulate cortex (PCC)||Emotional Integrator|
* Generally, medially oriented and spread throughout the brain.
As you might imagine certain aspects of this phenomena are hard to quantify but I have seen several sources propose that as much as 50% of your time can be spent in DMN and that as much as 80% of the ‘bad news’ that comes out of your ruminations never materializes.
Put another way by Susan L. Smalley, Ph.D. (Mind-wandering and mindfulness) we mind-wander to happy thoughts but we only do that about one third of the time; two-thirds of our mind-wandering thought content is stressful or neutral and that puts us in less happy moods.
“In your mind isn’t clouded by unnecessary things. This is the best season of your life.” – Wu-Men
Task Positive Network
“Only that day dawns to which we are awake.” – Henry David Thoreau, Walden
The TPN is active during ‘attention-demanding’ tasks and includes our conscious attention towards the external environment. This happens through our various senses, towards our internal condition, and to the intentional execution of physical and mental action.
Additional components of the TPN include:
- Task orientation
- Process sensory input
- Short term memory
- Abstract thought
With regard to TPN – again per Matthew Williams:
“Imagine that you are sitting down to meditate. You rest yourself comfortably on your meditation cushion and straighten your back. Your mind is still operating on the DMN as you relive a conversation from earlier in the day or worry about a project that is due at the end of the week. But then you engage the lPFC/Director and activate the TPN, silencing the DMN.”
“The lPFC/Director directs your attention away from your ruminative thoughts to your internal and external environment. The ACC/Attender facilitates this switch in attentional focus.”
Task Positive Network (Per Williams)
|Lateral prefrontal cortex (LPFC)||
|Anterior cingulate cortex (ACC)||Attender|
|Somatosensory cortex (S1)||External Sensor|
* Generally, laterally oriented and concentrated in prefrontal cortex.
It is important to note: the task positive network can be further divided into different sub-networks such as the salience network, dorsal attention network, and (left and right) executive networks. These networks may convey complex interactions with the DMN (Modulatory interactions between the default mode network and task positive networks in resting-state by Xin Di and Bharat B. Biswal). Put another way awareness of mind wandering was linked with activation in the salience network (SN).
For example: Sridharan and colleagues showed that the salience network (Seeley et al., 2007) activated the executive network which is part of the task positive network, and deactivated the DMN during both task performing conditions and resting-state (Sridharan, Levitin & Menon, 2008).
Together with the anatomical properties of the salience network regions, the results suggest that the salience network may modulate the relationship between the DMN and executive networks.
According to Matthew Williams (“Neuroscience of Mindfulness: Default Mode Network, Meditation & Mindfulness”:
“The salience network seems to be involved in determining how relevant a particular piece of information, or a thing you are looking at or thinking about, is to you.
The salience network makes us switch between the two others according to our needs.
The next time you feel helplessly lost in worry or self-recrimination remind yourself of the power of the TPN. Go for a walk, practice yoga, sense your breath, or engage fully in a conversation with a friend. You need not overpower your DMN to escape negative thoughts. You need only to intentionally engage your TPN and allow your natural physiology to disengage your DMN.”
Imagine conducting your business let alone living your life in this state of mind.
“Renew thyself completely each day; do it again, and again, and forever again.” Chinese admonishment cited by Thoreau in Walden.
According to Good at Task, Bad at People? By Sandeep Gautam:
“One good way to think about the difference between the TPN and the DMN is to think of the TPN as specialized for mechanistic, analytical and reasoning based interactions; while the DMN is specialized for mentalistic, empathetic and self and other referential social interactions.”
Neither is the TPN “good” nor the DMN “bad” however the balance between the two is a dynamic relationship.
- The networks span both hemispheres
- A key phenomenon is that they are counter to each other. Activation of one inhibits the other.
- A good analogy would be the inhale – exhale cycle
- Interestingly, sociopaths have the capability to have both the networks activated simultaneously
- DMN is fine until we use it to ruminate, self-blame, or worry.
- An evolutionary tool that helped us plan and learn from past experience became overkill with increased mental capabilities. Arguably a case of too much of a good thing?
About the Author: W.B. “Bud” Kirchner is a serial entrepreneur and philanthropist with more than 50 years of business success. He is not a scientist or an academic but he does have a diversified exposure to neuroscience, psychology and related cognitive sciences. Generally speaking, the ideas he expresses here are business-angled expansions of other people’s ideas, so when possible, he will link to the original reference.