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Lecture 4

PSYC 2330 Lecture Notes - Lecture 4: Aplysia, Sensory Neuron, Motor Neuron


Department
Psychology
Course Code
PSYC 2330
Professor
Francesco Leri
Lecture
4

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PSYC 2330
Lecture 4
Tuesday, September 18, 2012
Experiments performed in the Aplysia have demonstrated that habituation is caused by:
a) Increase in withdrawal reflexive reactions
b) Reduction of interest in the task
c) Reduction of pool of synaptic vesicles
d) Expression of synaptic extracellular potassium
e) Increase in intracellular sodium
I guess C (Correct!)
Habituation & Sensitization
non-associative – means that the organism is not making an association between two events
Habituation is a decrease in the strength of a response after repeated presentation of a stimulus
that elicits the response
Examples
When you go outside it may initially be cold but you get used to it
When you change the lighting it is initially harder to see but you get used to it
Habituation is a form of learning because your response is changing
Sensitization refers to the increment in response ocurring upon repeated presentation of a
stimulus that reliably elicit the response
Examples
Essential oils can sensitize the skin
Noises that become increasingly annoying the more you hear them
Sensitization is also a form of learning because your response is changing
Sensitization can also occur when the organism is more sensitive to other emotional
reactions because of a heightened emotional state.
In habituation, the response goes down, and in sensitization the response goes up
Habituation is generally easier to understand and that we all experience on a regular basis
Sensitization and habituation are some of the most basic forms of learning for an organism
Sensitization and habituation occur biologically at all times
Aplysia is a slug with a very simple nervous system
their neurons are so few and so big that they can be seen under a regular microscope
Aplysia displays habituation and sensitization
Neuron and Synaplse
Neurons are the cells that do most of the work transmitting information from one area to
another
Neuronal processing represents human thought
How neurons are inerconnected represent the associations between stimuli
Connection between the button and the synapse is not physical in that there is space between
them. This tiny space is called the synaptic cleft.
The action potential travels to the presynaptic terminal and releases neurotransmitters into the
synaptic cleft
Most drugs that alter cognitive functions achieve their effects by changing regular synaptic
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