Lecture 1

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Published on 16 Mar 2011
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PSYB65H3 Lec 1 (Sept 13, 2010)
Global Organization of the Human Brain
Central Nervous System (CNS) Spinal Cord & Brain
Peripheral Nervous System (PNS) all other nervous that serves the rest of the
When drawn schematically, the human brains overall organization is very similar to
any higher order mammal
Brain stem = very lose term, something that holds the brain by
Medulla and cerebellum = two major areas of the brain
Sensory motor integration sends in sensory input and sends out motor output
Balance ability to stand erect
Sticks out at the back of the brain
Basic life processes keeps a person alive at the most basic level, eg. Heart rate,
breathing, etc
Reticular Formation
Sleep / wakefulness cycles
Damage results in a coma (most likely)
Forebrain the most anterior part of the brain
Biggest in the human brain, relative to other parts of the brain
Huge central portion of the forebrain
Major relay center, particular in humans and higher mammals conveys
information to the appropriate place in the neocortex
Controls life functions (but not primitive functions) that keeps the individual alive
eg. Thirst, hungry, territoriality, sexual behavior
Anything that feels good
Limbic System
Deals with emotions and emotionality
Allows animals to feel an emotion
PSYB65H3 Lec 1 (Sept 13, 2010)
Cerebral Cortex
Most anterior structure (very front of the brain), not connected to anything but
curves back and covers everything
Also known as the neocortex
Involved in higher intellectual functions speech, reasoning, intelligence, etc.
Comprises of most of the human brain (~85%)
Evolution of the Human Brain
As we developed greater intellectual ability, nuclei were developed (got bigger) so
that more information could be processed
Developed these bumps (excess neurons, nuclei) that contained cells that
were linked to specific pathways
We have developed as humans a bigger cerebral cortex that gives us intellectual
abilities and problem solving
We dont have the biggest cerebral cortex, elephants do
If compared by cortex to body size, dolphins are dominant; humans are
Size of the structure are directly related to the importance and use of that particular
function in that particular species
Olfactory bulb processes smell; relatively big in rats whom are dependent on smell
Human Brain Development
You as a species as your are born til you mature go through the same evolutionary process
as the developing of the species”
Humans have gills and tails that are resorbed during our developing
At 3 weeks,
Certain nuclei begins to develop
7 weeks forebrain is beginning to get larger
9 weeks forebrain continues to get bigger and folds upon itself, cerebral cortex (although
starts off at the anterior portion of the brain) begins to develop and as there is not enough
room in the human skull as it develops, it pushes against the skill and bends around the
skull; virtually covers everything except the cerebellum
As the brain develops, more and more brain cells are developed (and as skull remains to be
cramped), the brain folds
PSYB65H3 Lec 1 (Sept 13, 2010)
Macleans Triune Theory
There are three basic components to the human brain
The human brain is really three brains in one (three basic components):
Reptilian Brain brain stem basic things that keep species alive have
began existing in reptiles and that we havent thrown that away yet
(humans still have it)
Old-mammalian Brain (Paleo-mammalian Brain) limbic system on top of
the basic things that we still are, we added on the ability to be emotional
(emotional repertoire); those are found in old mammals and we havent
thrown it away, we still have it in our brain
New-mammalian Brain (Neo-mammalian Brain) process intellectual
functioning (higher intellectual functioning) allows problem solving, read,
write, language, and plan which has been added on to our older part of the