CRANIAL REFLEX
It is a fast, involuntary response to a stimulus. It uses the brain stem as an integrating center (the brain receives sensory information and generates a response). This is contrasted to a spinal reflex, when the response is generated in the spinal cord itself, and the brain only finds out a reflex has occurred after the fact.
An example of a cranial reflex would be the tracking movements of your eyes as you are reading this sentence. The dilation and contraction of your pupils in response to different levels of light is another cranial reflex.
CONDITIONED REFLEX
An automatic response established by training to an ordinarily neutral stimulus.
A Russian scientist called Pavlov trained dogs to expect food whenever he rang a bell. The dogs eventually produced saliva when they heard the bell ring.
1. The dog salivates naturally when given food.
2. Pavlov rings a bell every time the dog eats.
3. After much repetition the dog salivates when the bell rings, even
When there is no food.
This is an example of a conditioned reflex. The dogs were conditioned to salivate when the bell rang.
The food is called a primary stimulus.
The ringing bell is called a secondary stimulus.
A ringing bell does not normally cause salivation in dogs. However, when the ringing bell becomes a secondary stimulus, it does cause salivation, even though the dog will not be able to eat the bell as food. This is now called a conditioned reflex. In a conditioned reflex the final response (salivation) has no direct connection with the stimulus (ringing bell).
