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  • This is the human brain while apparently doing nothing.

  • When you think you're just sitting quietly, letting your mind wander, a set of regions comprising 20% of your brain kicks into action.

  • This is the default mode network.

  • Wait a second, that's weird. Like, what are those brain regions doing?

  • They must be doing something.

  • The mysterious pattern of activity inside this network indicates that the so-called resting brain is hard at work.

  • Maybe it's not just an idling default state, maybe it's involved in some more interesting processes.

  • The discovery of this network has revolutionized our understanding of the human brain, and it possibly holds the secret to what makes you uniquely you.

  • Obviously a number of exciting questions remain.

  • In the 1920s, German psychiatrist Hans Berger invented the electroencephalogram, or EEG, a machine which records the brain's electrical activity.

  • When Berger took readings of subjects at rest, the EEG revealed something unexpected.

  • The brain wave patterns changed, but didn't stop.

  • Berger theorized that the human brain was never truly inactive, but his ideas failed to gain much traction.

  • Seventy years later, a team at Washington University found an intriguing pattern of brain activity in neuroimaging studies of subjects performing active tasks, like reading aloud.

  • While the areas that are active varied depending on the task demands and context, the areas that were deactivated were quite common.

  • These inactive regions, including the medial prefrontal cortices, posterior cingulate cortex, and the angular gyrus, were already known to researchers, and commonly associated with things like emotion, language, and memory.

  • A second neuroimaging study, led by neurologist Marcus Reichel, confirmed the findings.

  • These areas were turned off when the mind concentrated on something external, but became engaged when quietly at rest.

  • So it's kind of doing the opposite of what most of the brain does.

  • They called this resting activity the brain's default mode.

  • In 2001, when it came out, some people thought it was totally nuts.

  • A few years later, neurologist Vinod Menon and a team at Stanford studied subjects at rest using functional magnetic resonance imaging, or fMRI.

  • They found not only the same regional brain activation, but also an underlying connectivity between these regions.

  • And these are not just isolated regions, but they couple together in particular ways.

  • And we put all this stuff together and we said, well, this is something we should call the default mode network, which actually functions as a network.

  • Brain networks work like a symphony, a complex arrangement of coordinated individual parts which come together to perform a specific function, which they couldn't produce alone.

  • You know, there's networks related to movement or vision or hearing, and then there's sort of higher order ones related to things like attention.

  • But the default mode network's function was enigmatic at first.

  • We didn't know what it was doing and why it was doing what it was doing.

  • For the last two decades, researchers have chipped away at the enigma, implicating the default mode network, or DMN, in several key areas of cognition, each of which involves a specific coordination between the DMN's different regions.

  • There's sometimes regions that come in and out and maybe affiliate with the network in the service of certain goals.

  • One important function involves memory.

  • The default mode network is preferentially connected to the hippocampus, which is the critical structure for making new memories.

  • Including the formation and recall of what are called episodic memories, which are autobiographical memories about our past experiences.

  • The sum of all your memories that are relevant to you.

  • And also perspective memories, or thinking about what we intend to do in the future.

  • Sometimes we're basically drawing on the past events to imagine the future.

  • The DMN is involved with another important form of memory, semantic memory.

  • Semantic memory is knowledge that we have acquired as distinguished from individual events.

  • These are long-term memories, general knowledge about the world we inhabit, the processing of facts, concepts, and language.

  • The default mode network is also connected to self-awareness and social cognition.

  • Things like thinking about your friends and the attributes of your friends and thinking about yourself and your place in society.

  • Which requires an interior theory of mind.

  • Thinking about what other people are thinking.

  • Like you're constantly running a model of someone you're talking to about what they're thinking and feeling in response to what you're saying.

  • And that's really important because if you're way off, you lose a friend or you could get punched.

  • Absent external stimuli, the default mode network turns inward.

  • The DMN switches or defaults to an internally focused thought process such as self-reflection, daydreaming, mind-wandering.

  • When mind-wandering, we're often recalling personal experiences and envisioning the future.

  • All of these kinds of complex and interesting introspective and evaluative types of processing tends to engage the default network.

  • While the default mode network may switch on when the rest of the brain switches off, it isn't independent.

  • The default mode network does not function in isolation.

  • It's both excited and suppressed by other systems.

  • Like the salience network, a key cognitive control network responsible for switching attention.

  • Which would go off right now if the fire alarm went off in the building.

  • That one seems to go up when the default goes down.

  • The disruption of this normal push and pull, the switching between the DMN and other networks, is implicated in abnormal brain function.

  • Individuals may not be attending to external stimuli when they should.

  • They may be attending to internal stimuli when they should not.

  • It turns out that the default mode network is impacted in major ways in virtually every psychiatric disorder.

  • Menon has developed a theory that a disruption to the dynamic between the DMN, the salience network, and a third brain network plays a role in a range of psychiatric disorders, including schizophrenia, Alzheimer's disease, and depression.

  • The nature of the deficits is different across disorders.

  • We don't fully understand them, but the notion that the DMN is disrupted and its interactions with other core cognitive control systems is disrupted, there's very broad evidence for that.

  • However, recent research on the therapeutic effects of psilocybin, the active component of magic mushrooms, has shown promise.

  • It's got great potential for treating depression and other neuropsychiatric disorders, likely because it boosts neuroplasticity.

  • An fMRI study by a team at Washington University revealed a desynchronization or scrambling of the default mode network while on psilocybin.

  • One of the researchers participated in the study and experienced this firsthand.

  • The boundaries become blurred. I lost my sense of space completely, and then I lost myself.

  • The brain scans revealed massive temporary changes.

  • Your functional brain organization, your functional networks, they're kind of like your fingerprint or your face in the sense that truly, it's not to be cheesy, they're unique, like yours is unique.

  • Giving people psilocybin makes it so that their brain changes so much that my brain and your brain on psilocybin are more similar to each other than my brain not on psilocybin to my brain on psilocybin. That's wild.

  • And the experience of having a scrambled default mode network revealed something else.

  • Part of the effects that people report, which are more strongly focused around effects on your sense of time, space, and sense of self and your memories,

  • I think that solidifies this idea that that's one of the main functions or sets of functions of the default mode network.

  • While many of the individual elements of the default mode network are now better understood, the larger question remains, what does the entire network accomplish?

  • In some sense, the DMN is where I think, and we need certainly a lot more evidence, is where all of these critical components come together to create a unifying sense of the self.

  • The default mode network enables us to weave together an internal narrative, a story of who we are that shapes how we perceive ourselves and interact with others.

  • It's like the simulation that you're always running, that's you.

  • Microsoft Mechanics www.microsoft.com www.microsoft.com

This is the human brain while apparently doing nothing.

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B2 US network default brain mode psilocybin berger

What Your Brain Is Really Doing When Doing 'Nothing' : The Default Mode Network

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    VoiceTube posted on 2024/09/07
Video vocabulary

Keywords

specific

US /spɪˈsɪfɪk/

UK /spəˈsɪfɪk/

  • adjective
  • Precise; particular; just about that thing
  • Concerning one particular thing or kind of thing
  • Clearly defined or identified.
  • Stated clearly and in detail, leaving no room for confusion or doubt.
  • Relating to a particular thing.
  • Relating to a particular species, structure, etc.
cognitive

US /ˈkɑɡnɪtɪv/

UK /ˈkɒgnətɪv/

  • adjective
  • The process of knowing and remembering
  • Relating to cognition; concerned with the act or process of knowing, perceiving, etc.
  • Relating to the mental processes of perception, memory, judgment, and reasoning.
  • Relating to cognition; concerned with the act or process of knowing, perceiving, etc.
  • Relating to the mental processes of thinking, understanding, learning, and remembering.
  • Relating to the ability to think and reason.
  • Relating to the development of mental abilities and processes.
  • Relating to the functions of the brain involved in thinking and reasoning.
  • Relating to a type of therapy that focuses on changing thought patterns.
  • Relating to the scientific study of the mind and its processes.
relevant

US /ˈrɛləvənt/

UK /ˈreləvənt/

  • adjective
  • Having an effect on an issue; related or current
  • Closely connected or appropriate to the matter at hand.
  • Having significant and demonstrable bearing on the matter at hand.
individual

US /ˌɪndəˈvɪdʒuəl/

UK /ˌɪndɪˈvɪdʒuəl/

  • noun
  • Single person, looked at separately from others
  • A single human being as distinct from a group.
  • A single thing or item, especially when part of a set or group.
  • A person, especially one of a specified kind.
  • A particular person or thing distinguished from others of the same kind.
  • A person, especially one of specified character.
  • A competition for single people.
  • adjective
  • Made for use by one single person
  • Having a distinct manner different from others
  • Relating to, or characteristic of, a single person or thing.
  • Having a striking or unusual character; original.
  • Single; separate.
  • Made for or relating to a single person or thing.
  • Having a striking personal quality or style.
  • Relating to, or characteristic of, a single person or thing.
  • Single; separate.
process

US /ˈprɑsˌɛs, ˈproˌsɛs/

UK /prə'ses/

  • verb
  • To organize and use data in a computer
  • To deal with official forms in the way required
  • To prepare by treating something in a certain way
  • To adopt a set of actions that produce a result
  • To convert by putting something through a machine
  • noun
  • Dealing with official forms in the way required
  • Set of changes that occur slowly and naturally
  • A series of actions or steps taken in order to achieve a particular end.
  • A systematic series of actions directed to some end
  • A summons or writ to appear in court or before a judicial officer.
  • A series of actions or steps taken in order to achieve a particular end.
  • other
  • To perform a series of mechanical or chemical operations on (something) in order to change or preserve it.
  • To deal with (something) according to a particular procedure.
  • Deal with (something) according to a set procedure.
  • To perform a series of mechanical or chemical operations on (something) in order to change or preserve it.
  • To perform a series of operations on (data) by a computer.
  • Take (something) into the mind and understand it fully.
  • other
  • Deal with (something, especially unpleasant or difficult) psychologically in order to come to terms with it.
depression

US /dɪˈprɛʃən/

UK /dɪ'preʃn/

  • noun
  • Medical condition of a lack of vitality
  • Period of unemployment and low economic activity
  • A long and severe recession in an economy or market.
  • A long and severe recession in an economy or market.
  • An area of low atmospheric pressure, typically associated with unsettled weather.
  • A sunken place or hollow on a surface.
  • other
  • A mental condition characterized by feelings of severe despondency and dejection.
  • A mental health condition characterized by persistent sadness and loss of interest.
  • A state of feeling sad, without hope, or enthusiasm.
  • A state of feeling sad, without hope, or enthusiasm.
critical

US /ˈkrɪtɪkəl/

UK /ˈkrɪtɪkl/

  • adjective
  • Making a negative judgment of something
  • Being important or serious; vital; dangerous
  • Most important part
  • Expressing adverse or disapproving comments or judgements.
  • Expressing adverse or disapproving comments or judgments.
  • Exercising or involving careful judgment or observation.
  • Expressing adverse or disapproving comments or judgments.
  • Being in or verging on a state of crisis or emergency.
  • Expressing adverse or disapproving comments or judgments.
  • Expressing adverse or disapproving comments or judgments.
  • Relating to or denoting a point at which a sudden change occurs.
  • Of decisive importance with reference to the success or failure of something.
  • (of a sick or injured person) seriously ill or injured.
reveal

US /rɪˈvil/

UK /rɪ'vi:l/

  • verb
  • To show something that was hidden before
pattern

US /ˈpætən/

UK /'pætn/

  • noun
  • Model to follow in making or doing something
  • Colors or shapes which are repeated on objects
  • Regular repeated behavior
  • A model or guide for making something.
  • A regular or repeated way in which something happens or is done.
  • A consistent and recurring way of behaving.
  • A set of paper shapes used as a guide for cutting cloth when making clothes.
  • An arrangement or sequence.
  • A excellent example or model.
  • verb
  • To copy the way something else is made
  • other
  • To decorate with a pattern.
  • To use as a model or guide.
evidence

US /ˈɛvɪdəns/

UK /'evɪdəns/

  • noun
  • Factual proof that helps to establish the truth
  • Facts, objects, or signs that show that something exists or is true.
  • other
  • Facts, objects, or signs that make you believe that something exists or is true.
  • Information presented in court to prove or disprove alleged facts.
  • other
  • To indicate clearly; to be evidence of.
  • To show clearly; prove.
  • other
  • Facts, objects, or signs that make you believe that something is true.
  • Information used in a court of law to prove something.