PSYB65H3 Lecture Notes - Lateral Sulcus, Recapitulation Theory, Cerebral Cortex
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PSYB65- LECTURE 01: INTRODUCTION
- Read book normal vs. Diseases brain function
- 2 exams – midterm (40%) & final (60%) - on both textbook & lecture
o Non cumulative – if midterm written
o Cumulative – if midterm not written
- Lecture slides – on intranet or www.utsc.utoronto.ca/~psyb65
NERVOUS SYSTEM
- 2 major parts Central & Peripheral Nervous System ( CNS & PNS)
- CNS – brain & spinal cord
- PNS- all other nerves expect of brain & spinal – that serves rest of body all the nerves that
goes out from the brain & spinal cord
- No dividing line/ part b/w brain & spinal cord
o Spinal cord simply goes into the foramen magnum (hole in the back of brain) &
continues on to the brain
BRAIN
- When looking at brain – see mostly cerebral cortex & cerebellum but there is a lot you can’t
see
- In turns of Overall organization – human’s brain look similar to that of rats, mice, cats
o Overall organization – forebrain, midbrain, hindbrain
- Forebrain – also known as Telencephalon/ Diencephalon
- Midbrain – also known as Mesencephalon
- Hindbrain – also known as Metencephalon/ Myelencephalon
1St – Hindbrain (from the back)
- Gold/orange colour – base (fairly simple) – back of brain sometime talk about it as brain stem
- Major components : Cerebellum & Medulla
- Cerebellum ( it kind of sticks out of brain stem)– involved in sensory motor integration ( it takes
sensory input mostly motor output)
o E.g. balance, manoeuvre, stand erect
o Damage to this look like a “drunk” – moments are jerky & uncoordinated
- Medulla (inside the brain core)– involved in basic life processes
o E.g. heart rate, respiration (in brain steam) keeps you alive at the most basic level
o Don’t want to damage tumour, stroke – usually result in death
2nd – Midbrain
- Greyish/green
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- Primary “structure” : Reticular Formation –area composed of # of different nuclei involved in
sleep-wake cycle circadian cycle wakes us up & put us back to sleep
o Damage most likely lead to coma
3rd – Forebrain
- Makes most of brain area most anterior portion of brain it is sub categorize
- This is evolution in human favoured in terms of mass – it is mostly forebrain
- Several parts :
o Mid- centre portion– thalamus – this is relay centre from s & some processing ,
particularly in humans & higher level mammals
Since we have this big cortex when it got bigger – have to have relay centre
to convey info up to appropriate place in neo-cortex
Info from every sensory system in the body is sent to thalamusthen relay to
cortex – for major processes
o Underneath thalamus hypothalamus - “good” stuff in life – controls life function
but not the primitive ones such as heart beat
4Fs ( finding, feeding, fighting, F sex) this is not just in primates – keep
species alive – e.g. thirst, hunger, territoriality, sexual behaviour
o Move forward (beyond thalamus & hypothalamus) Limbic system (deep inside neo-
cortex)– made up of # of diff structures: Amygdala, Hippocampus , hypothalamus is
partially involved & most people argue Olfactory bulb involved
Things involved in emotions & emotionality hippocampus, medulla,
hypothalamus
Dog has big Limbic system vs. Snake --> feel more emotions
o At the very front Most anterior portion cerebral cortex / neo-cortex not connect
to anything curves back & cover everything & also known as neo-cortex
it is big & begins to fold involved in higher brain function most of human
brain e.g. speech , reasoning, IQ, info-processing
Functions that are mostly very specific to humans
EVOLUTION OF BRAIN
- Reptiles exist before humans w/ dinosaur brain haven’t change much
- Look at Dog fish & goldfish brain is fairly simple
- w/ evolution get greater ability to decipher info from environment make sense out of it &
use it to survive
o Animals that could do that start developing Nuclei (able to process more info got larger)
– developed in anterior portion of NS like bumps involved in increasing # of cell that
are associated w/ particular pathwaydeveloped more nuclei survived
- In turtle forebrain bigger < rat bigger < human bigger
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o Humans evolved much larger cerebral cortex (humans don’t have the biggest cortex
comparing cortex size w/ body weight it is dolphins ) Neo-cortex is dominant for
survival
- Generally size of structure& development relates to the important & the use of function of
that part of species (more developed)
o E.g. rat – olfactory bulb bigger compared to human info about smell they depend
on heavily on smell such as for sexual behaviour
BRAIN DEVELOPMENT
- Generally “ontogeny recapitulates phylogeny” – what individual goes through from
development (ontogeny – conceive to adult) is similar to our development as species
o Same for brain development from conceive to adult:
at 3 weeks very primitive brain & started to develop some bumps at front
(nuclei start to develop)
7 weeks Forebrain is starting to get larger & by 9 weeks it getting bigger &
starts folding upon itself back (cover rest of brain)
At birth Neo-cortex cover everything (except cerebellum) and starts to move
forward to front Neo-cortex is not smooth it has mountains & valleys)
- Neo-Cortex is the newest structure most powerful begins @ most anterior part of brain
- Generally MacLean’s theory – Triune : 3 basic component to the Human brain(3 brains in 1)
o 1st – oldest reptilian brain brain stem to thalamus – breath, heart rate, defend
territory, sexual reproduction basic for survival – back to reptiles & still exists in
human
o 2nd – old mammalian brain (Paleo-mammalian brain) – limbic system : add ability to be
emotional (more complex in humans ) still exists in human
o 3rd – Neo-mammalian brain – process higher intellectual functioning –e.g. problem
solving skills, language been added to the older parts of brain
- In terms of clinician think of stroke: if a person comes in w/ stroke in Cerebral cortex, better
call therapist if it is in the midbrain, better call ambulance if it is the brain stem (reptilian
brain) , better call morgue (they are not going to live)
PSYB65 – LECTURE 02: CEREBRAL CORTEX
CEREBRAL CORTEX
- in greater detail divided into lobes Not smooth surface in humans try to add on cells
(evolution pressure) move back & fold (groves) mountains & valleys gives boundaries
o Valley – called sulcus/ sulci
o Mountain – called gyrus/gyri
- Top of brain 2 side of brain is not connected directly is connected by board fibre pathway
called Corpus Callosum Divided into 2 hemisphere :
o Right : control left side of body & gets info from this side as well