Transcript Evolution and The Brain - Falcon Science

JOURNEY TO THE CENTER OF THE
BRAIN
Each region of the brain has distinct
structural and functional characteristics
that shape how the brain functions.
Guiding Questions
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What are the major
regions of the brain?
What are the major
functions of each
region of the brain?
How can damage to
the brain affect the
brain’s functions?
CNS vs. PNS
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Central Nervous System (CNS)
 Brain
and spinal cord
 Relays and processes
messages from senses
and organs
CNS vs. PNS

Peripheral Nervous System
 Everything
 Ex:
else
Neurons
 Interacts
with environment
 Carries messages between
organs and CNS
THE BRAIN!
Anatomy of the Brain
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The vertebrate brain has three main
parts which evolved in different
stages
 A vertebrate is any animal that
contains a spinal cord (Vertebrata)
Forebrain – Newest part of the brain;
found only in mammals
Midbrain – found in vertebrates only
Hindbrain – Oldest part of the brain
(found in reptiles…so we know it’s
really old!)
What does it do?
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Forebrain – the outer layer of the cerebrum,
which performs all of the “higher functions”
of the brain
The forebrain has two main components
Forebrain
Cerebral Cortex
1.
2.
3.
Planning
Thinking and reasoning
Sensory processing
Limbic System
1. Emotional/sensory processing
2. Learning and memory
“The new kid on the block”
THE NEOCORTEX (PART OF
THE CEREBRAL CORTEX)
The Neocortex
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1.
2.
3.
4.
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The Neocortex is the newest
part of the cerebral cortex.
Again this deals with higher
levels functions. It is divided
into four lobes or regions:
Frontal lobe
Parietal lobe
Temporal lobe
Occipital lobe
Cerebellum
Brain stem
These make
up the
Neocortex
Hindbrain
Different lobes do different jobs
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The four lobes process different types of information
Frontal lobe – processes information relayed from “lower” brain
areas concerned with movement and thinking. The frontal lobe
plans is also an integral part of personality.
Parietal lobe – higher processing of sensory information from
other brain areas and the spinal cord. Deals with direction, and
orientation in a 3-dimensional space. *Proprioception – having a
sense of your own body movements
Temporal lobe – processes auditory information. Concerned
with the production of speech and understanding spoken
language (and music). Also uses emotional cues of the
underlying limbic system to deal with facial recognition or “face
centers.”
Occipital lobe – Visual processing and perception.
Damage to the brain
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The case of Phineas Gage
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25-year old foreman who suffered severe brain
trauma when a piece of iron penetrated his skull
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He survived the injury and could even speak shortly
after the accident!
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However, profound changes occurred in his personality
and demeanor
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Once a highly-respected and responsible citizen, Gage
now became “irreverent, profane, and unreliable”. He
no longer followed through with plans and had little
respect for his friends and colleagues.
“He was no longer Gage”
Discussion Question: Phineas Gage

What part of Gage’s brain was destroyed by the
iron bar?
THE BRAIN STEM AND
CEREBELLUM
Hindbrain
The Brain Stem
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In humans, the brain controls the basic functions
of the body
Brain stem – controls respiration (breathing),
heart beat, digestion and circadian rhythm
(sleep cycle)
The Brain Stem is made up of the Pons (top)
and the Medulla Oblongata (bottom)
Evolved hundreds of millions (100,000,000)
years ago and is the “oldest”, most primitive
part of the brain
Amazingly, chickens can survive without a
head, as long as their brainstem is still intact!
Brainstem = Pons + Medulla
Oblongata)
Discussion Question: Chickens
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Why was the chicken able to survive for so long
without a head?
The Cerebellum
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The Cerebellum deals with balance,
coordination, and certain forms of
learning
Human cerebellum
Procedural learning – motor skills such
as riding a bike, driving, etc.
Relatively small in the human brain
compared to other animals such as the
rat
Considered to be part of the hindbrain
Rat cerebellum
The Emotional Brain
THE LIMBIC SYSTEM
What is the limbic system?
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Underneath the neocortex
Deals with homeostasis, digestion, emotions,
behavior and memory
Major parts include:
 Diencephalon (hypothalamus, thalamus)
 Amygdala
 Hippocampus
Hypothalamus
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Function:
 Regulates the autonomic
(automatic) nervous system
 Homeostasis (i.e. hunger, thirst,
temperature, pain, pleasure, sex
drive and aggression)
How it works: stress stimulates the
hypothalamus-pituitary-adrenal
(HPA) axis to release cortisol
 Cortisol is a steroid hormone
 It regulates breathing, pulse,
blood pressure and arousal in
response to stress
Hippocampus
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Lies in the medial temporal lobe and
consists of many packed neurons
Function:
 Converts “short-term” memories
into long-term memories
 May deal with memory/smell
When damaged: Alzheimer's,
hypoxia (lack of oxygyen), and
epilepsy (action potential overload)
 Inability to form new long-term
memories
Amygdala
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Found on the lower end of the
hippocampus near the
thalamus
Function:
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Emotional learning – processes
memories of emotional events
Stimulated by fear, aggression
When damaged:

Become calm and indifferent
A little boy named Albert was fond of white animals,
including rats. One day, James Watson made a loud,
unpleasant noise with a hammer while Albert was
looking at a white rat. He cried and seemed very
frightened. Now every time Albert sees a rat, even
when there is no noise, he starts to cry.
Albert’s amygdala has learned to associate white
rats with loud noises. This is called “fear
conditioning”