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Inside the Emotional Brain: The Limbic System Explained · Professor Peterson’s Psychology Classroom

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  Welcome to this edition of Psychology Explained by Dr.
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  Curtis Peterson, who is trying to bring psychology alive
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  for us all. All right, so where we're going to start
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  for this section is we're going to start looking at the brain and dissecting
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  the different parts and what they are.
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  And we're going to start with the most basic
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  parts of the brain, the, the parts that
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  most species that have a brain have.
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  And when we get to this higher area, this area
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  we call the cortex, we'll find that the
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  cortex size and even shape become
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  very species-specific.
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  Okay, but let's start with everything
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  that every species has
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  if they have a brain. Okay,
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  every species that has a brain has a brainstem.
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  Okay, which is this area that
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  kind of comes right here and down here,
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  um, and kind of connects the larger area
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  of the brain with the spinal cord.
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  Okay, this area is important because it supports
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  our fundamental life functions. Okay, so the
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  example given in, in the slide is our sleep-wake
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  arousal cycle, but it also alerts us to things like
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  hunger. It does a lot of things regulating
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  with the heart and regulatory
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  hormonal functions. And so,
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  and if you remember in the beginning of the class, it is
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  within the reticular formation that
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  our primary area that comes alive
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  when we're looking at an intimate partner,
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  this area, and then this area right here,
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  which is the, uh, the, the,
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  the kind of the area between the limbic
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  system and the cortical system all become active.
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  Okay. And so
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  these mainly have a regulatory function.
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  Okay. Species who have
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  some kind of organization about them.
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  So we're talking about species Mammals,
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  reptiles,
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  trying to think, canine,
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  all of those types of animals also
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  have a limbic system. Okay, with many
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  of the same parts that the human brain has.
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  So this isn't actually right, the amygdala is
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  actually right here. So we need to correct this on our,
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  our, our slide. The hippocampus is
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  actually right here. The hypothalamus
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  is actually behind here, around here.
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  And the cingulate gyrus is actually in
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  this area right here. So these, these,
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  this graph isn't very good at accuracy.
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  I just want to just say that. But what
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  is the limbic system? It's,
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  it's primarily considered kind of the emotion engine of
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  the human brain and of
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  other species as well that have a limbic system.
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  It's a rapid processing environmental signal
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  into emotional responses. So if you remember,
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  other than, uh, our sense of smell,
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  all of our senses come into the
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  limbic system first before it comes
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  up to the higher cortical areas where we have a conscious
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  experience. And if you remember, I talked about, you know,
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  that fight or flight, about slapping someone and then deciding
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  not to. And how your, your limbic system
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  was basically preparing you, uh,
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  to either act aggressively or
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  to run. That fight-flight kind of thing.
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  Okay, the, the areas that
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  are of significance, of course, is the amygdala.
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  Okay, the amygdala is associated
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  with many emotions, but primarily it's associated
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  with the emotion of fear and threat.
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  Okay, and then it kind of modulates the other
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  emotions. Okay, so whenever we have something
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  that we're fearful or threatful of, that is the area of the brain
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  that becomes active and again prepares
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  us for fight or flight. Okay, the hippocampus
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  is consolidations of new memory and supporting
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  things like identity formation. This area,
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  uh, you will— if, if we had an anatomically correct,
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  uh, uh, limbic system,
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  sets just right behind the amygdala.
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  Okay. And this is an important
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  kind of aspect. Our best-formed
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  memories are done during
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  emotionally arousing experiences.
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  Okay. So many
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  of us may not remember a math
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  lecture unless we had a really mean math
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  teacher. But we will
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  remember the first person
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  we kissed, the happy
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  childhood memories,
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  some of the trauma that could have occurred in
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  this region. Quinceañeras, I can't ever
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  say that right, uh, in the Mexican American
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  culture, those events become
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  re— rememberable. Those less emotionally arousing
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  events tend to be, tend to stagnate.
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  Okay. And that is kind of the relationship
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  of this emotion system is memories
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  that are made emotional and memorable.
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  Tie with our emotion system and become
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  tighterly bound than
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  other memories that we have. Okay,
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  this also accounts for what's called the positivity effect
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  of the human brain. Okay, and that
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  is over time, we tend
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  to remember more happy events
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  and good events than we do bad events.
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  Okay, so if you want to think about a
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  parent coming to the end of life and
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  the older, now adult,
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  is evaluating their parent, okay,
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  they may have been the crappiest parent
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  they could have ever been.
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  But because of this association in the brain,
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  we tend to, um,
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  remember less of the bad and
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  remember more of the good.
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  Okay, now I'm not going to say this is universal.
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  This is just the trend or the tendency.
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  Okay, so I can think of someone I know that,
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  um, her, her dad
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  was evil to her. He used to whip her with,
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  uh, electric wires.
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  Uh, he nicknamed her Moose because he
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  didn't think she was as beautiful as her
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  sisters. And then she— he got his, his sons to
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  brothers basically to do the same thing and taunt her.
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  He was just an awful human being.
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  But now in her later years, she,
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  she tends to only remember those positive
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  things about her dad and about how,
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  um, that he was all in all a good
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  person. Okay, and so that tends
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  to be a tendency we grow towards.
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  Again, not everyone, a super
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  traumatized brain and everything else can retain and
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  a sense of this, a fixed trauma identity
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  where the person's identity is slept in their
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  trauma tend to not experience
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  this type of experience. But in general,
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  this is kind of what happens. The hypothalamus
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  regulates physiological drives such as hunger, thirst, and sex.
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  And, uh, this— it really via what's known as the enteric
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  system, which releases the hormones such
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  as those necessary for hunger
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  and thirst and, and those of the hormones
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  testosterone and, and, uh,
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  female hormones.
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  Um, oh my goodness, I forget at this moment.
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  I apologize. The thalamus is a sensory
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  relay station, so it really is that central
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  area of the brain that sensory information comes into and
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  it decides where it goes. And then the singular gyrus,
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  gyrus, uh,
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  integrates emotions and cognition.
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  And this is where things like empathy and moral reasoning come
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  into play. Okay, one interesting thing
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  that, again, speaking of the relationships between
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  these parts, is research,
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  for example, on Alzheimer's. When does a person
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  start to lose a sense of themselves,
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  meaning their identity? Okay,
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  meaning what is occurring, who I
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  am, who is I. I am Curtis.
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  I'm, uh, I'm a husband. I'm a father.
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  I'm a teacher. All of those things. When during
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  the dementia process does that
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  start to begin? Okay.
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  And we think, thought, thought for a long time that
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  it would happen in the hippocampus and in this
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  area right here in the prefrontal cortex where we
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  form our identity as well. And we really think about
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  it and integrate it. Interestingly, it's when,
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  but what we actually found is that we start to
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  lose a sense of ourself when the moral
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  reasoning neural tracts coming out of the cingulate
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  gyrus start to deteriorate and become compromised.
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  So this is an interesting thing. We lose a sense of
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  ourself when we lose our sense of moral reasoning.
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  Something to kind of think about, um, when you think
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  about who we are as individuals. So,
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  okay, that's enough. We— so that's the limbic system.
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  Thank you for joining us for this Psychology Explained.
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  I hope you'll join us in later episodes where we can— we'll
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  continue to investigate the human mind and psychology.