PSYB65H3 Lecture Notes - Lateral Sulcus, Medial Longitudinal Fissure, Central Sulcus
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PSYB65 LECTURE 2
-as you move more forward in the brain the structures get more and more complex
-cerebral cortex tapkes up the vast majority of the human brain
-if the patient gets a stroke within the brain stem , they end up passing because there
is no chance of survival
-dealing with higher brain funciton
-cerebral hemispheres, what they do and how they are organized
-meningescoverings of the brain
basic structure of the brain
-human brain is not smooth
-there is not enough space in our skull for a smooth brain. As the brain develops it
starts off smooth but as it grows and develops, ther e isnt enough room for it to grow.
If there isnt enough space, it will fold upon itself (paper). The brain is folded in
among itself and forms mountains and valleys (sulci (sulcus) these are the valleys)
-if its really huge its referred to as a fissure.
-the mountains are known as gyrus or guyri
-the organization of brain: look at the top of the brain, the brain is divided by the
middle into two hemispheres.
-brain is seperated into a right hemisphere and a left hemisphere.
-right and left hemispheres arent exactly the same
-right hemisphere recieves information from (right brain) controls the left hand
side of the body and controls informaiton from the left hand side of the body
-each side of the BRAIN recieves and controls informaiton from the other side of the
body. Right side controls left and the left side controls right side.
-everything crosses over. If the person has paralysis in the left side of the body, it
means that they had a tumour in their right brain.
-longitudinal fissure divides the two hemispheres (longitudinal sulcus)
-corpus callosum connects the two hemispheres (connecting fibre pathway)
-fibre pathways cross over the corpus collosum. Each part of the right ahemisphere is
connected with the adjacent part of the left hemisphere. (similarpart). Right occipital
lobe is connected with the left occipital lobe.
-three main sulci: longitudinal fissure which seperates the two hemispheres, the
central sulcus (central fissure)-which sepearates the front of the brain from the back,
(seperates the frontal lobe from the parietal lobe) (anterior and posterior)
-another large sulcus is the sylvian sulcus or sylvian fissure (seperates the temporal
-cerebral cortex is divided into four lobes
-FRONTAL, parietal, occipital , temporal
-each lobe has a main primary function.
-within each lobe , there are two types of tissue within the cortex. Each portion of the
cortex has two types of tissue
each lobe has both of these: primary cortex , and associatonal cortex
-the primary cortex, is responsible for performing basic input or output funciton.
It is the area that is responsible for the primary input/outuput fucntion of that lobe.
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-nervous system gets information from the enviornment. And the informaiton is later
association cortex is for HIGHER ORDER FUNCTIONS. Which is involved
in more complex functions.
association cortex is more recently evolved . Primitive organisms only have
primary components of the brain and are incapable of more sophisticated
types of thinking (abrasct like writng poetry, making deicisions, reading, etc)
-associatonalthought processes of the brain, the more evolved the organism
the more associational the cortex there is (the ratio is higher)
-humans have a small primary area and a HUGE associational cortex
-frogs don’t have as much computing energy as humans do.
-BRODMANN: mapped the brain
-put numbers on the different areas of the brain, which helped locate the different
areas of the brain. Was able to pinpoint specific regions of the brain.
-frontal lobebegins in the anterior portion of the brain and goes back to the central
-its primarily involved in motor movement (muscle) what makes you move, the
portion of the brain which controls your muscles (allows you to walk, move hands
-associaton cortex: planning and inhibition of innappropriate behaviours
-delayed gratification: not doing everything you want in that moment
-long term planning for movement , life goals , jobs, plans (etc) ,
you want to be succesful in life, so you go to university , get a good job, etc
-(central sulcus 1,2,3)
-pre-central gyrus (in front of the central sulcus) that is the primary area (broadmans
area is 4,6 is the pre-central gyrus)primary strip in the motor cortex (OR CALLED
THE primary motor area)
-everything in front of the precentral gyrus is the association cortex
-primary motor strip is not randomly organized - there is a motor humunculous , if
we take a slice through the middle of the motor strip the part
-side of the brain controls lips (etc for other parts of the body)
-face is paralyzed on the right hand side. The tumour is on THE LEFT HAND SIDE,
and in the frontal lobe (paralysis) , what BRODMANN’s areas (4,6), what gyrus
-wheree is the tumour? Its on the side (since that is the side that controls the face)
-PARIETAL LOBE: anterior boundary is the central sulcus and it moves back until it
hits the occipital cortex.
-its primary function is to receive information from the non-specialized senses
(somatosensory senses) (45 min)
-its primary strip
-post central gyrusprimary strip in the parietal cortex. (somatosensory and the
-all the rest is the associational cortex
-BROADMANS AREA (numbers 1,2,3) is the primary somatosensory strip in the
parietal lobe and 4,6 are motor , and are separated by the central sulcus
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