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Lecture

PSYB65H3 Lecture Notes - Limbic System, Reticular Formation, Peripheral Nervous System


Department
Psychology
Course Code
PSYB65H3
Professor
Ted Petit

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of 2
PSYB65
Human Brain and Behaviour
Lecture 1
11th September 2012
- Deals with Patients with brain damage and brain diseases
- Your brain is grey cells, it creates a phenomenon because it is just little neurons that creates
thoughts, and emotions and consciousness
- The brain is divided into the central nervous system (CNS) and the Peripheral nervous system
(PNS)
- The brain and the spinal cord make up the central nervous system
- The Peripheral nervous system is everything else. Sends information out to control the muscles
of your feet, arms etc.
- The spinal cord is continous with the brain, if you take it apart you cant tell where one ends and
one begins. It is all just one big nervous system
- Once you are in the brain, there are many ways of subdividing the brain
- The simplest way is dividing it into the forebrain, the midbrain and the hindbrain.
- The hindbrain composed of a lot of things. The two major things are the cerebellum (involved
with sensory motor integration; receives sensory information and determines what actions
needs to be done, when you have damage to this people have problems standing up, they look
like they are drunk) The other thing that is major is the Medulla ( it looks like a cauliflower stuck
out from a stick, it is responsible for basic life processes that is keeping you alive at the most
basic level, talking about heart beat and respirtation)
- The next major component is the Midbrain- one important thing that is located there is the
reticular formation, it is very important for controlling sleep wakefulness cycles what is referred
to circadian rhythms. What do you call someone that doesn’t wake up, someone that is in a
coma, they have a damage circadian rhythm.
- Then as you move forward the next structure is the forebrain- starting from the back of it the
one in the centre is the thalamus, beneath it is the hypothalamus. Thalamus is a relay centre, it
stops there, and then it is relayed on to a new place. The hypothalamus controls life processes in
a more complex way, it keeps the species alive over a more long period of time, it is responsible
for eating behaviour, drinking, it is also involved in territoriality where we fight over resources.
The other thing it controls is sex, which involves finding a mate, females exert a smell and the
male finds that smell and responds to it, reproductive behaviour is also controlled in it. Basically
if it feels good it is responsible by the hypothalamus (eating, drinking, sexual behaviour)
- As we keep moving forward we come across the limbic system is composed of the amygdale,
the hippocampus and the hypothalamus. Limbic system tight structure that involves emotion
and emotionality
- As we keep moving forward we come across the cerebral cortex, it is the most anterior
structure. It is the Neocortex (meaning new) . Its one component of the brain, covers up the
physical aspect of the brain, this gives us intellectual reasoning and gives us the ability to store
information. All of these intellectual pursuits are more humanistic. They are the only ones with
this intellectual and that’s because of the cerebral cortex
Evolution of the Brain
- Dogfish- it looks like a spinal cord that starts to develop. There was a certain nuclei that formed
in the anterior system of the front of the body and it is what we refer to as the brain.
- Then when you move to Dogfish to turtle, then to goldfish to rat, the brain looks bigger. The
more evolved the species , the more intelligent the species.
- Also we realized that the size of the structure is directly related to the function and importance
of that particular function to that species. Eg. Rats deal a lot with smell, and if you look at their
brain, the part that deals with smell is the largest.
How are our brains developed when we are born?
- Brain at 3 weeks bumps start to develop in the hindbrain while aging
- Ontogenetic development- is the development in the womb
- As you continue development you have a tail that is resorbed, it represents steps that we went
through to be where we are today
- At 7 weeks, we get more and more bumps the cerebral cortex gets bigger
- At 9 weeks the cerebral cortex gets so big that it starts pushing the skull, and expands
- The other thing that you notice is as the cortex move backwards and hits the back of the skull it
has nowhere else to go, so it starts to crunch itself, and folds upon itself.