# Brain Networks By [Bhau](https://paragraph.com/@bhau) · 2022-02-03 --- **Our Brains are powered by Networks.** ![](https://storage.googleapis.com/papyrus_images/845eb856918131d5cb93ae6974cef0b4cf0ccc0ae069b7b8ae27209bd8514413.jpg) Take the tour below to learn more. ### Electricity… ![This GIF depicts the flow of electricity inside a brain at a Micro scale.](https://storage.googleapis.com/papyrus_images/1e6c5562205acfb64ef46fed72f2168241c598ab01b44e7de7cc195f8087133a.gif) This GIF depicts the flow of electricity inside a brain at a Micro scale. …flows along **neurons** in the brain. There are **86 billion** neurons inside this floating jelly, and they connect with each other along numerous junctions known as **synapses**. ### Our Brains… ![This GIF depicts the flow of electricity inside a brain at a Macro scale.](https://storage.googleapis.com/papyrus_images/1faebf6136c68a1bebe200cfb838bec8cf84b2af32da44b590a62e557a2f9e7b.gif) This GIF depicts the flow of electricity inside a brain at a Macro scale. …are highly sophisticated super-computers that _dynamically_ respond to **process information** in our environments. This is done by **_transmitting electricity_** throughout neurons (like the ones above), using chemical messengers known as **_Neurotransmitters_**. ### Four Lobes… ![](https://storage.googleapis.com/papyrus_images/c66c3b9c7927e3c9f20848baf5401d014db45e8554167d0aebea7c4aa27f3e29.png) …are partitioned in our brains according to **_Structure_** and **_Function_**. E.g., the **Occipital lobe** specializes in **_processing visual information_** to help us see. ### The Frontal lobe… ![](https://storage.googleapis.com/papyrus_images/7a1a556138aa7aaf0253b013e6bb42ff90202071989194dddc84daccd338e6e7.jpg) …houses the **Prefrontal Cortex**, commonly referred to as the “**_Seat of Judgment._**” **Rational thinking** and related mental faculties needed for **day-to-day functioning** are the result of **Activity** in this region. What is Activity? ----------------- [![]({{DOMAIN}}/editor/youtube/play.png)](https://www.youtube.com/watch?v=gMsMfVhxe94) **Neurons** that **_fire_** require **Oxygen** for **_energy_**, which is delivered to them through the blood. This is called the **blood oxygen level dependent** (**BOLD**) response, and it is detected using **Functional** Magnetic Resonance Imaging (**fMRI**). When **_more blood flows to a brain region_** relative to other areas, it is said to be **Active**. ![](https://storage.googleapis.com/papyrus_images/1e5fa2475a3132a34cb3227b5ab0de68bcd6586ef3fe817bb38041aedc3a83a8.png) This is how we know the Function of… ------------------------------------ ![](https://storage.googleapis.com/papyrus_images/c38a140c68ded6957d089d155c4140c964c26126fc63111793113c5c72e38842.png) The prefrontal cortex (PFC). Numerous publications ([E.g. _Figure 4 above;_](https://pubmed.ncbi.nlm.nih.gov/27145923/) [Jagtap et al](https://pubmed.ncbi.nlm.nih.gov/27145923/)) show how the PFC **activates** during tasks requiring **_Executive Functioning_**. The **_dorsal_** PFC (**dPFC**) activates when our **Sustained Attention** is demanded. ### But… ![](https://storage.googleapis.com/papyrus_images/cde6b23bcde6da91017280ced4552dceb5780af6eeb2d90478e62974eb4dcd26.jpg) brain regions, like the dPFC, **do not activate _alone_**. Because everything in the brain is **_intricately connected_**, many regions **activate together** (E.g. the SPC co-activates with the dPFC while sustaining attention; _Figure 4 above_). ### Functional network = Regions Activate Together ![](https://storage.googleapis.com/papyrus_images/ca5c1e404e5faf525f8c7dd586da4b99c1b23038437f635d0e74f83b06a7bd55.jpg) When blood flows to **several areas** at the same time, these regions are said to be **_functionally connected_** as part of a **Functional Network**. As a result, many [**Large-Scale Brain Networks**](https://en.wikipedia.org/wiki/Large-scale_brain_networks) have been discovered. ### Task-positive networks (TPN)… ![](https://storage.googleapis.com/papyrus_images/edbe3ae9f2a87c4214ce978e07821c7d87e69e02891991fdd238da4dea67ebf2.jpg) …such as the [**Central Executive Network**](https://en.wikipedia.org/wiki/Frontoparietal_network), are active when we are consciously, or **_volitionally_**, performing tasks that demand our **Presence** and **Focus**. You can think of it _loosely_ as **Willpower**. Therefore [**Task-Positive Networks**](https://en.wikipedia.org/wiki/Task-positive_network#:~:text=The%20task%2Dpositive%20network%20is,tasks%20in%20functional%20imaging%20studies.) (**TPNs**) are essentially **Attention Networks**, and nearly all of them rely on the **Prefrontal Cortex** (**PFC**). ### Default Mode network (DMN) ![Default Mode Network.jpg](https://storage.googleapis.com/papyrus_images/c4d1c3371f2b96ff9e4a0d532b294a94257cb7df01723d3e90499bfe5141026d.webp) Default Mode Network.jpg On the other hand, the [**Default Mode Network**](https://en.wikipedia.org/wiki/Default_mode_network) (**DMN**) is active when we’re on **_Auto-pilot_**. Mind-wandering, reminiscing, contemplating, and self-reflecting are the result of DMN activity. Technically, this is a **Task-Negative Network** (**TNN**). These are important things we all need to do on a daily basis, but an excess of anything can become problematic. **Can we be outwardly present and inside our own minds at the same time?** -------------------------------------------------------------------------- No, we cannot…because of Anti-Correlation ----------------------------------------- ![](https://storage.googleapis.com/papyrus_images/68644493a7bab75fe8593325a51a0728473e3c90dcfa0189edcd87feb7cdc19b.webp) The human brain is [intrinsically organized into dynamic, anti-correlated networks](https://www.pnas.org/content/102/27/9673). When Task-Positive Networks - like the **Attention Networks** - **activate** and “come **online**,” Task-Negative Networks - like the **Default Mode Network** - **_de-activate_** and “go **_offline_**.” ### Dynamic equilibrium ![](https://storage.googleapis.com/papyrus_images/9b1f2195dd0368834cee3b7247d207c9fd8eaa813f7a2e62ecbe261370197b94.jpg) **_Balanced_** and **_Harmonious_** **Network Activity** is **_important_** for our **Well-Being**. **Healthy** brains can **_easily_** switch network activity back and forth. Studies have shown this is **_not the case_** in many **Psychiatric Disorders**. ### Dis-Equilibrium ![](https://storage.googleapis.com/papyrus_images/9fdedb28c97d8c4f9d16ddb2d84eb6e13e8df5e15b0879704d8b8e10d77f46b5.jpg) Default Mode Network activity is **_abnormally increased_** or **dys-regulated** in people suffering from **mental illness**. The DMN **hijacks** the brain’s ability to activate Attention Networks. This leads to **dis-equilibrium** and widespread **_network dysfunction_**. [**TMS can reverse this**](https://paradigm-psychiatry.com/communityblog/how-does-tms-relieve-depression)**.** --- *Originally published on [Bhau](https://paragraph.com/@bhau/brain-networks)*