Caustic Regular Dr. Rob Tarzwell joins Joe, Toren, and Kevin in the premiere episode of our new series: “Caustic Anatomy Class”, this episode focusing on the master control of it all: the brain! We’ll talk about the history of brain knowledge, an introduction to the brain’s structure, brain-eating amoebas, the “creepy threesome”, several people walking and talking without a large part of their brain, brain tapeworms, and The Man With Two Brains and a skull-full of pop culture!

Music: “Scatter Brain” by Frankie Masters And His Orchestra

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Anatomy of the Brain
collated by Caustic researcher Cory

The most common method used to divide the brain, is based on the three main regions that developed in the embryonic state:

The Forebrain (or prosencephalon)

  • the cerebrum (telencephalon)
  • thalamus
  • hypothalamus and pineal gland among other features (diencephalon, or interbrain).
The Midbrain (or mesencephalon)

located near the very center of the brain between the interbrain and the hindbrain, is composed of a portion of the brainstem.

The Hindbrain (or rhombencephalon)

Consists of the remaining brainstem (myelencephalon) as well as our cerebellum and pons (metencephalon).


Brain cells can be broken into two groups:

  1. Neurons, or nerve cells, are the cells that perform all of the communication and processing within the brain.
  2. Neuroglia, or glial cells, act as the helper cells of the brain; they support and protect the neurons. In the brain there are four types of glial cells:
  • Astrocytes which protect neurons by filtering nutrients out of the blood and preventing chemicals and pathogens from leaving the capillaries of the brain.  They have also been observed to turn into neurons by virtue of the stem cell characteristic pluripotency.
  • Oligodendrocytes wrap the axons of neurons in the brain to produce the insulation known as myelin.
  • Microglia act much like white blood cells by attacking and destroying pathogens that invade the brain.
  • Ependymal cells line the capillaries of the choroid plexuses and filter blood plasma to produce cerebrospinal fluid.

The tissue of the brain can be broken down into two major classes: gray matter and white matter.

  • Gray matter is made of mostly unmyelinated neurons, most of which are interneurons. The gray matter regions are the areas of nerve connections and processing.
  • White matter is made of mostly myelinated neurons that connect the regions of gray matter to each other and to the rest of the body.

Myelinated neurons transmit nerve signals much faster than unmyelinated axons do. You could imagine your brain’s gray matter as suburbs and businesses, and the white matter as the express highway, carrying information to be processed.

Parts of the Brain

Cerebrum

The cerebrum is the largest portion of the brain, and is responsible for most of the brain’s function. It is divided into four sections:

  1. Frontal Lobe: Controls several elements including creative thought, problem solving, intellect, judgment, behavior, attention, abstract thinking, physical reactions, muscle movements, coordinated movements, smell and personality.
  2. Parietal Lobe: This lobe focuses on comprehension. Visual functions, language, reading, internal stimuli, tactile sensation and sensory comprehension are monitored here.
    • Sensory Cortex – This receives information relayed from the spinal cord regarding the position of various body parts and how they are moving. This middle area of the brain can also be used to relay information from the sense of touch, including pain or pressure which is affecting different portions of the body.
    • Motor Cortex– This helps the brain monitor and control movement throughout the body. It is located in the top, middle portion of the brain.
  3. Temporal Lobe: Controls visual and auditory memories. It includes areas that help manage some speech and hearing capabilities, behavioral elements, and language.
    • Wernicke’s Area – This portion of the temporal lobe is formed around the auditory cortex. While scientists have a limited understanding of the function of this area, it is known that it helps the body formulate and understand speech.
  4. Occipital Lobe: Helps to control vision.
    • Broca’s Area – Functions linked to the production of speech and language.

Cerebellum

This is commonly referred to as “the little brain,” and is considered to be older than the cerebrum on the evolutionary scale. The cerebellum controls essential body functions such as balance, posture and coordination.

Limbic System

The limbic system contains glands which help relay emotions. Many hormonal responses that the body generates are initiated in this area. The limbic system includes the amygdala, hippocampus, hypothalamus and thalamus.

  • Amygdala: The amygdala helps the body responds to emotions, memories and fear.
  • Hippocampus: Used for learning memory, specifically converting temporary memories into permanent memories which can be stored within the brain. The hippocampus also helps people analyze and remember spatial relationships, allowing for accurate movements.
  • Hypothalamus: The hypothalamus region of the brain controls mood, thirst, hunger and temperature. It also contains glands which control the hormonal processes throughout the body.
  • Thalamus: The Thalamus is located in the center of the brain. It helps to control the attention span, sensing pain and monitors input that moves in and out of the brain to keep track of the sensations the body is feeling.

Brain Stem

All basic life functions originate in the brain stem, including heartbeat, blood pressure and breathing. The brain stem consists of midbrain, pons and medulla.

  • Midbrain: The midbrain, also known as the mesencephalon is made up of the tegmentum and tectum. These parts of the brain help regulate body movement, vision and hearing.
  • Pons: Links to the cerebellum to help with posture and movement. It interprets information that is used in sensory analysis or motor control. The pons also creates the level of consciousness necessary for sleep.

Medulla: The medulla or medulla oblongata maintains vital body functions such as the heart rate and breathing.

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Showing 12 comments
  • Charles Insandiego

    /pedantry/

    Michelangelo, not Leonardo. You got the wrong turtle.

    /end pedantry/

  • bred

    Yay, new episode! Here’s the first thing I thought of when I saw the topic:

    “brain attack scene” from Fiend without a Face (1958).

  • Kabur Naj

    A few years back there was a mysterious illness that afflicted several workers at a hog processing plant in Minnesota. It turned out to be brain-related, and quite cringe-inducing. You can read about it in a NY Times article (http://www.nytimes.com/2008/02/05/health/05pork.html), but I think Norm Sherman’s summary of the NY Times piece at the beginning of Drabblecast #51 is well worth a listen (http://www.drabblecast.org/2008/02/13/drabblecast-51-crimson/).

    Lovecraft fans might also enjoy lots of other Drabblecast episodes (including the Halloween story in #136, “The Great Old Pumpkin”) and also Norm Sherman’s ballad “Heartache Over Innsmouth”.

  • HimAgain

    That was a particularly informative one thanks guys.
    I’m disappointed that I do not possess the latent potential to melt things with my fully active brain but at the same time I take comfort in the knowledge that if Steve Gator is still up and about then the periodic blows to the head I have been known to suffer at work will not impede me over much.

    Also totally got to support Joe on the Man with Two Brains that was a delightfully bizarre movie.
    Especially when the good doctor starts considering bumping off a very accommodating prostitute and harvesting her for his disembodied lady love only to have second thoughts.

    “I can’t do this”
    “Sure you can I don’t mind…. wait whats the syringe for?”
    “Its window cleaner.”
    “What does that do?”
    “It kills your brain last”
    “I don’t mind”

  • Miss Felis

    I’m a neuroscience grad student, so I was delighted to listen to this episode. Doctor Rob was great, as always!

    Also, cerebrospinal fluid is salty and a little bit bitter (judging by the taste of artificial cerebral spinal fluid, which we make to mimic CSF as closely as possible). It actually does taste quite a bit like watery snot (for example, snot after you’ve been crying a lot or out running in the cold. It’s pretty gross!)

    • HimAgain

      Dare I ask why you were drinking cerebral spinal fluid?
      Are you a brain vampire?

  • Derek Weber

    In the news: Oliver Sacks, well known psychiatrist, announces he has terminal cancer. 🙁

    http://www.theguardian.com/uk-news/2015/feb/20/oliver-sacks-reveals-terminal-cancer

  • Claes H

    Thank you for another great episode! And it’s great to hear Dr. Rob again!

    About the “only using 10% of our brain”-myth:
    Something i’ve heard about the brain is that we only use, on average, 10% of it (or it’s capacity) at any given time. Meaning all of the brain isn’t active at once since the resources needed would be quite high. I believe this is the origin of the hard-to-kill myth.
    I sadly don’t have a source for that statement, but maybe someone who know’s a bit more about the whole matter *cough*DrRob*cough* could maybe enlighten us.

  • claw

    ‘Je ne suis pas un oisseau! Je suis un homme!’ ~ the Tick.

    other pop culture with brains: MST3K’s has Brain Guy, of the alien race known as the Observers who delusionally believe thay have transcended the need for a physical body and live as independent, all powerful brains in dishes carried around by their bodies. in one episode they do a delightful barbershop song called ‘When I Held Your Brain In My Arms’

    The Gamesters of Triskellion were also a trio of world rulers that wagered quatludes (sp) on the gladitorial fights of their slaves on an ep of classic Star Trek. oh and let’s not for get the ‘Spock’s Brain’ ep. wherein we discover that Dr McKoy can control complex motor functions of Mr Spock’s body with the equivalent of a tv remote accompanied by inexplicable tick-tick-tick noises.

    and Pinky and the Brain have ‘the Brain Song’

  • lissakaye81

    Hi, I wanted to say that there is a technique known as tissue expansion where they insert a balloon under the scalp and slowly inflate it with saline to expand the scalp to cover large head wounds where they can place an implant to look like a normal a skull for reconstructive surgery. It’s pretty interesting. I saw it a long time ago on a young black girl but can not remember her name. There was also a case of a young man who was accidentally shot by a store owner at close range with a shot gun that blew off almost half of his brain, who later graduated college that was a pretty amazing example of “miracle recoveries”. Here is the story on youtube: https://www.youtube.com/watch?v=z7TcugWqyaI Thought you would find this interesting.

  • Evan

    I know this has probably been said already, as this episode is older, but: The Colin Farrell Recall isn’t meant to be a remake of the classic Arnold Schwarzenegger flick. It’s meant to be true to Mr. Dick’s short story, which inspired the movie to begin with. Most of the stuff in the first movie was made up, aside from the humdrum existence Quaid is living after having his memories replaced, and him going to Recall to get some fancy fake memories put in causing shit to get real. And, c’mon, Biel and Beckinsale in the same movie? Nothin wrong with that!