Human Brain and Behaviour
18 September 2012
Organization or Structure of the Human Brain
Cerebral Cortex- takes up vast majority of the human brain
- Cerebral Hemisphere is made up of different lobes
- The basic structure of the brain, human brain is not smooth, there is not enough space in our
skull for a smooth brain, it starts off smooth but as we get older it starts to fold, because it
constantly develops new neurons. It has formed in a sense little mountains and little valleys.
- The first one is a sulci or sulcus, these are the valleys, if they are really huge they are called
- The mountains are known as Guyri or Guyrus
- First thing you should realize if you look at the top of it you would see the brain is divided into
two in the centre, there is the right hemisphere and the left hemisphere. They are not exactly
alike. We often call it the right brain and the left brain.
- The right side of the brain receives information from the left side of your body and controls the
left side of the brain. Basically each side of the brain receives information and controls the
opposite side of the body.
- The two sides are divided by the longitudinal fisher, it is a very large sulcas.
- The two hemispheres are connected to each other they are just separated at the top.
- The connecting pathway is the carpus collosum. It is the part that connects the two hemisphere
as you move from the top to the bottom.
- The fibres from the right side is connected adjacent to the left side.
- There are three main sulsi- one is the longitudinal fisher, the second one is the central sulcas or
(central fisher) then the other lard sulcas is the sylvian fisher or (lateral fisher)
- Longitudinal- separates the right hemisphere from the left
- Central- separates the anterior and posterior lobes
- Sylvian- runs at the side of the brain and separates the temporal lobe
The types of lobes
- Cerebral Cortex is divided into four lobes. Technically each hemisphere has four lobes. However
they are identical on each side, so you just consider the four types
- The four lobes is the frontal lobe, the parietal lobe, occipital lobe and the temporal lobe.
- Each lobe has one major primary function
- Within each lobe there are two types of tissue in the cortex. They are known as the primary
cortex and associational cortex. - The primary cortex is responsible for some basic input or output function. Association cortex is
responsible for higher order functions. Primary just gets information and processes a abit.
Association actually thinks about it. Association cortex is more recently evolved. It is more the
thought process, the more evolved the organism is the more association cortex they have. Frogs
and snakes have primary cortex, while humans have a great amount of association cortex.
- Another way people tried to organize the brain is by putting numbers on it. Brodmann put
numbers on the different areas of the brain, these numbers have been very important because
it is like a map, it tells you exactly where you are. However he put the numbers on it but he was
able to pin point specific regions of the brain.
- Frontal Lobe- begins at the anterior portion of the brain and goes backwards to the central
sulcus. Its primarily involved in motor control, motor means muscles, so it’s the portion that
controls your muscles. It is also involved in planning and inhibition of inappropriate behaviours
(eg. not telling your boss off). Brodmann’s area 4 and 6 are the primary area of the frontal
cortex, and the stuff infront of it is the association cortex.
- Parietal Lobe- it starts are the central sulcus and moves back until it hits the occipital lobe, its
primary function is to receive information from the somato senses (the body). Whether your
finger is hot,