Central Nervous System is made up of the brain and the spinal cord.
Peripheral Nervous System is broken down into a component called the somatic
Stretch information is received to the CNS through the somatic division in
Allows connectivity with CNS
Hierarchical Organization of the Central Nervous system:
View: *The Hierarchy:
Not Think of the Cerebral Cortex as the “big boss”, it tells everyone else what to do and
when to do it
entirely Think of the thalamus, basal ganglia, pons, and cerebellum as being second in
The brainstem is third in command
All signals must travel through brainstem to get to spinal cord
It’s a relay. Just conveys information Watch diving
Doesn’t do anything in terms of modifying signals bell and
The spinal cord is a “slave” system to all the above.
When someone has a problem with their cerebral cortex, they cannot do precision
movements but on power (gross) movement
Can only move hands and fingers at same time. Can’t pitch.
If brainstem is lesion, become locked-in. Because no signals can be sent to spinal
cord, you know what is going on around you but cant respond.
Luigi Galvani (18 Century):
Was interested in how muscles contract
Before it was believed that movement would occur by fluid in the body
Attached lightening rod to spinally prepared frogs and when there was a
thunderstorm, the frog would move.
It is believed that when young learn new skill, they develop more neurons
In adults, it is a new neural pathway to cause movement.
This is done by more dendrite and axon terminals
This is done by repeated practice
Myelin Sheath: allows for quicker electrical travel
Different types of neuron, have different thickness allowing for different
speeds of conduction Motor
AMN disease- damage in neuron in motor cortex- cerebral cortex
Speed of Nerve Conduction:
Interested in speed of nerve conduction
Used isolated muscle and motor nerve of a frog
Measured time between electrical stimulation and muscle contraction
He would isolate a muscle in a frog. Would get direct access through CNS
through the spinal cord and timed the amount of time needed for the
He would put the stimulus far away from cell body and close. By knowing
how long they took to contract and the differences between the contractions,
he could find out how quickly it was travelling.
Helmoholtz Findings: Estimate speed of human nerve conduction
Measured reaction time in response to electrical stimulus to two points (e.g.
Nerve conduction velocity very fast (35-60 m/s)
That speed is about 1/10 the speed of sound (speed of sound= 1238 km/h)
Diseases of the nerve:
1. Disease of the nerve influences amplitude of nerve conduction Alpha
E.g. Amyotrophic Lateral Sclerosis (ALS) or more commonly referred
to as Lou Gehrig’s disease disease is
Alpha motor neurons are sent more slowly also
known as a
2. Disease of the myelin influences conduction speed lower
Destroys the myelin in patches along the CNS motor
E.g. multiple sclerosis disease
Different types of Neurons: Upper
Differ in direction of travel: up or down motor
1. Motor (efferent) neurons disease
Transmit motor commands down the spinal cord
2. Sensory (afferent) neurons from
Transmit signals to, and up, the spinal cord problems
The Cerebral Cortex/ Cerebrum: neurons
Phrenology: different parts of your brain reflecting different emotions. Did so by say cortex.
if someone was hit with a sword in an area in his head, and he lost his courage: that
area related to courage
Bogus: not true
The center of our visual perception
Contains primary (V1) and secondary visual areas.
V1 is about the size of the credit card located in the back of our head.
Most visual information in our eyes ends up in V1.
Demonstrated phenomena known as cortical magnification
Does a very simple basic property of a viewed object
More neurons are devoted to center vision over peripheral
Allows us to read and look in high resolution
V2 is responsible for binocular vision
In V2 there is a class of neurons called binocular disparity neuron
Very specialized neuron which allow use to preserve depth (3D)
If prevented from seeing binocular vision then will not be able to see 3D V3(D) and V3(V):
Visual information travels through to V3(D) then travels to the parietal cortex
This visual pathway supports action
Visual information travels through to V3(V) to the temporal lobe
This visual pathway for perception
When use vision to make judgment such as that you have cup of
coffee/ different colours.
Able to identity sim ple geometric shape
Someone with a lesion
to V4 may not be able to tell the difference between a triag