<p>I think the treatment of the “Reptile Brain's” power given by Big Bang really sells it short. Your question immediately brought to my mind a 2009 profile by the <em>Washington Post's</em> Gene Weingarten of parents who leave their children in the car to die, all by accident.</p>

<p>It's a long and difficult read, and it took me quite some time to dig it up again since I had forgotten the publication, the author, and the title: but it comes highly recommended from me (<a href="http://articles.washingtonpost.com/2009-03-08/news/36840402_1_courtroom-tissue-class-trip" rel="nofollow">read “Fatal Distraction” on washingtonpost.com</a>)</p>

<p>The first page that speaks directly to your question is <a href="http://articles.washingtonpost.com/2009-03-08/news/36840402_1_courtroom-tissue-class-trip/4" rel="nofollow">this one</a>, making reference to the basal ganglia in the brain. A brief excerpt:</p>

<blockquote>
  <p>Ordinarily, says [University of South Florida Cognitive Neuroscience Professor David] Diamond, this delegation of duty [between the so-called reptile brain and higher-order brain function] “works beautifully, like a symphony. But sometimes, it turns into the '1812 Overture.' The cannons take over and overwhelm.”</p>
</blockquote>

<p>At a risk of doing a disservice by gross oversimplification of a fascinating and complex topic: the main thrust of the article's insight into cognition is that in rare circumstances, intelligent, emotionally healthy, and responsible parents may find themselves in circumstances where their basal ganglia take over their brain to such a great extent that they are capable of forgetting that their own children exist.</p>

<p>So if the reptile brain has such potential for destruction, albeit rarely to such a great extent, what is its purpose? Clearly in the majority of cases its functioning is very beautiful. When you walk you do not have to think analytically and poetically about every step you take. Your basal ganglia take care of this for you. This is Sagan's “ritual” reference.</p>

<p>If you need an emotional reason to accept that the reptile brain is real, read the Washington Post article. It'll stick with you. If you have more questions about the modern theories underpinning its machanisms, Dr. Diamond is not hard to get a hold of—he lists his contact information <a href="http://psychology.usf.edu/faculty/diamond/" rel="nofollow">here</a>.</p>

CC BY-SA 3.0
2013-10-05T13:41:27.453Z
2013-10-05T13:41:27.453Z
Ryan Prior
<p>The reptilian brain is the oldest part of the <a href="http://en.wikipedia.org/wiki/Triune_brain">triune brain</a>. And the triune brain is a unified account of brain function and brain evolution. </p>

<p>The story goes like this. The brain can be divided into three sections:</p>

<ul>
<li>The reptilian brain, named so because it encompasses structures that did not change much from reptile to man. It includes the basal ganglia and cerebellum, and controls pretty much everything that a reptile can do: breathing, walking, appetite, sensation, simple motor reactions to the environment, etc.</li>
<li>The mammalian brain (sometimes called paleomammalian), which encompasses structures that are unique to mammals but similar across mammalian species. These structures belong to the limbic system and are dedicated to processing emotion and memory. Anything your cat can do, should be either in the reptilian or the mammalian brain. Anything it can't do, is in the third part of the triune brain.</li>
<li>The neocortex, found in primates, which is involved in higher order functions such as language.</li>
</ul>

<p>Now, this is an oversimplification both structurally and functionally. For example, birds don't fit this theory very well because they don't have much of a limbic system, but do have some impressive problem solving skills. And functionally, these functions are interrelated in man, who can, for example, experience moral disgust which bridges higher-order and emotional functions. This is why the triune brain is the kind of thing you would find in an undergraduate psychology textbook, but it's not the kind of thing neuroscientists talk about among themselves.  </p>

CC BY-SA 3.0
2013-10-05T20:29:41.777Z
@what: I actually think it's a useful educational model. Something like the Bohr model of the atom :) There is some essence to it which is true, such that older functions are more robust in the face of environmental effects. It is also quite intuitive I find. And it is certainly true that older pathways don't simply cease to exist now that we have a higher-lever way of processing information.
Ana
CC BY-SA 3.0
2013-10-05T14:41:00.047Z
2013-10-06T15:34:18.120Z
2013-10-06T15:34:18.120Z
Ana
<p>As a Carl Sagan fan, I remember (in Cosmos TV shoe) "territoriality, aggression and ritual" are products of the reptile brain while higher-level stuff like loyalty, planning for future are mammalian, which implies different brain regions for each functions.</p>

<p>Even Sheldon Cooper has something to say about this:</p>

<blockquote>
  <p>Penny’s emotional responses originate from the primitive portion of
  the brain known as the Amygdala, while speech is centred in the much
  more recently developed Neocortex. The former can <strong>easily overpower</strong>
  the latter giving scientific credence to the notion of being rendered
  speechless.</p>
</blockquote>

<p>And said by on-screen and off-screen neuroscientist and science consultant Mayim Bialik:</p>

<blockquote>
  <p>So says your prefrontal cortex. But meanwhile, the limbic system of
  your brain is calculating that if another woman is attracted to
  Leonard, it must be because he’s desirable.</p>
</blockquote>

<hr>

<p>It implies that the brain is composed of three parts, with vast differences in development, can overpower each other and process stimuli independently.</p>

<p>What exactly is the reptile brain and do modern theories prove such a concept?</p>

<evolution><brain-development>
what is the reptile brain?
Jesvin Jose
# what is the reptile brain?

(Asked by: username_0 on 2013-09-28)

As a Carl Sagan fan, I remember (in Cosmos TV shoe) "territoriality, aggression and ritual" are products of the reptile brain while higher-level stuff like loyalty, planning for future are mammalian, which implies different brain regions for each functions.

Even Sheldon Cooper has something to say about this:

> Penny’s emotional responses originate from the primitive portion of
> the brain known as the Amygdala, while speech is centred in the much
> more recently developed Neocortex. The former can **easily overpower**
> the latter giving scientific credence to the notion of being rendered
> speechless.

And said by on-screen and off-screen neuroscientist and science consultant Mayim Bialik:

> So says your prefrontal cortex. But meanwhile, the limbic system of
> your brain is calculating that if another woman is attracted to
> Leonard, it must be because he’s desirable.

---

It implies that the brain is composed of three parts, with vast differences in development, can overpower each other and process stimuli independently.

What exactly is the reptile brain and do modern theories prove such a concept?

**Tags:** evolution, brain-development


---

## 2 answers

### Answer by username_2 on 2013-10-05. Score: 12 | Accepted answer

The reptilian brain is the oldest part of the [triune brain](http://en.wikipedia.org/wiki/Triune_brain). And the triune brain is a unified account of brain function and brain evolution.

The story goes like this. The brain can be divided into three sections:

* The reptilian brain, named so because it encompasses structures that did not change much from reptile to man. It includes the basal ganglia and cerebellum, and controls pretty much everything that a reptile can do: breathing, walking, appetite, sensation, simple motor reactions to the environment, etc.
* The mammalian brain (sometimes called paleomammalian), which encompasses structures that are unique to mammals but similar across mammalian species. These structures belong to the limbic system and are dedicated to processing emotion and memory. Anything your cat can do, should be either in the reptilian or the mammalian brain. Anything it can't do, is in the third part of the triune brain.
* The neocortex, found in primates, which is involved in higher order functions such as language.

Now, this is an oversimplification both structurally and functionally. For example, birds don't fit this theory very well because they don't have much of a limbic system, but do have some impressive problem solving skills. And functionally, these functions are interrelated in man, who can, for example, experience moral disgust which bridges higher-order and emotional functions. This is why the triune brain is the kind of thing you would find in an undergraduate psychology textbook, but it's not the kind of thing neuroscientists talk about among themselves.

> **Comments:**
> **username_2**: @what: I actually think it's a useful educational model. Something like the Bohr model of the atom :) There is some essence to it which is true, such that older functions are more robust in the face of environmental effects. It is also quite intuitive I find. And it is certainly true that older pathways don't simply cease to exist now that we have a higher-lever way of processing information.  

---

### Answer by username_1 on 2013-10-05. Score: 3

I think the treatment of the “Reptile Brain's” power given by Big Bang really sells it short. Your question immediately brought to my mind a 2009 profile by the *Washington Post's* Gene Weingarten of parents who leave their children in the car to die, all by accident.

It's a long and difficult read, and it took me quite some time to dig it up again since I had forgotten the publication, the author, and the title: but it comes highly recommended from me ([read “Fatal Distraction” on washingtonpost.com](http://articles.washingtonpost.com/2009-03-08/news/36840402_1_courtroom-tissue-class-trip))

The first page that speaks directly to your question is [this one](http://articles.washingtonpost.com/2009-03-08/news/36840402_1_courtroom-tissue-class-trip/4), making reference to the basal ganglia in the brain. A brief excerpt:

> Ordinarily, says [University of South Florida Cognitive Neuroscience Professor David] Diamond, this delegation of duty [between the so-called reptile brain and higher-order brain function] “works beautifully, like a symphony. But sometimes, it turns into the '1812 Overture.' The cannons take over and overwhelm.”

At a risk of doing a disservice by gross oversimplification of a fascinating and complex topic: the main thrust of the article's insight into cognition is that in rare circumstances, intelligent, emotionally healthy, and responsible parents may find themselves in circumstances where their basal ganglia take over their brain to such a great extent that they are capable of forgetting that their own children exist.

So if the reptile brain has such potential for destruction, albeit rarely to such a great extent, what is its purpose? Clearly in the majority of cases its functioning is very beautiful. When you walk you do not have to think analytically and poetically about every step you take. Your basal ganglia take care of this for you. This is Sagan's “ritual” reference.

If you need an emotional reason to accept that the reptile brain is real, read the Washington Post article. It'll stick with you. If you have more questions about the modern theories underpinning its machanisms, Dr. Diamond is not hard to get a hold of—he lists his contact information [here](http://psychology.usf.edu/faculty/diamond/).


---

