Synaptic Plasticity

Question 1

Learning:

Answer 1

Learning involves the acquisition of new information, beha our or abilities through experience.
It may occur with or without conscious awareness and is e denced by change in beha our, knowledge or brain function. For learning to have occurred, the new knowledge or skill must be retained in memory.
● Therefore - Learning and Memory go hand in hand.In order for us to learn, it needs to be retained in our memory.
○ When a person learns, a physical synaptic and neural response occurs.

Question 2

Plasticity:

Answer 2

From birth through to the end of life, neurons and the connections between them change in response to our experiences.
● They change to represent and store this information so that we can learn and remember.
This fundamental and very important ability to change is referred to as neural plasticity, neuroplasticity, or plasticity.
● There are two types of neuroplasticity; developmental and adaptive.
○ Developmental plasticity is that which occurs naturally across the
lifespan. There are certain critical periods that enable greater developmental plasticity.
○ Adaptive plasticity is that which occurs as a result of brain damage or trauma. Utilising critical periods for developmental plasticity helps enable greater adaptive plasticity.

Question 3

Changes to Connections between Neurons:

Answer 3

Learning involves the establishment and strengthening of neural connections at the synapse.
● Learning results in the creation of cell assemblies (interconnected groups of neurons that form networks or pathways)
● When neurotransmitters are repeatedly sent across the synaptic gap the pre and post synaptic neurons are activated which strengthens the synaptic connection between them
Neural plasticity at the level of the synapse is called…
Synaptic Plasticity: the ability of the synapse to change over time
● Synaptic plasticity is possible as a result of three specific neural processes,
known as: Sprouting, Rerouting & Pruning

Question 4

Sprouting:

Answer 4

● Sprouting is the creation of new extensions on a neuron to allow it to make new connections with other neurons
● This occurs through the growth of nerve endings (‘sprouts’) on axons or dendrites

Question 5

Rerouting:

Answer 5

Rerouting occurs when new connections are made between neurons to create alternate neural pathways.
● These alternate ‘routes’ may be entirely new neural pathways or connections to other pathways in the brain.

Question 6

Pruning:

Answer 6

Pruning is the elimination of weak, ineffective or unused synapses (and therefore connections to other neurons).
● ‘Prune’ the information that is no longer needed or used

Question 7

Long Term Potentiation (LTP):

Answer 7

Long-Term Potentiation: refers to the long- lasting strengthening of synaptic connections, resulting in enhanced or more effective synaptic transmission
● Strengthens synaptic connections
● Makes the post synaptic neuron more likely to fire
● The more frequently the neurons activated the stronger the connection ➡
● Enables a person to learn new things
● Increase in synaptic strength through high frequency stimulation of the
neural pathway

Question 8

Long Term Depression (LTD)

Answer 8

Long-Term Depression a long-lasting decrease in the strength of synaptic transmission.
● Resulting from a lack of stimulation of pre-and post synaptic neurons
● The post synaptic neuron becomes less responsive to the neurotransmitter
● Is the reduction of the efficiency of synaptic connections.
PURPOSE
● It is thought this may enable the elimination of connections no longer required (EG: refinement of skills)
● May allow correction of thinking/beha our when mistaken or learning a new skill
● May assist in blocking unwanted memory of certain thoughts, feelings or beha ours

Question 9

LTP & LTD continued

Answer 9

● Given glutamate’s excitatory effect, it has a tal role in LTP and LTD
○ Generally, the more o en that glutamate can excite an adjacent neuron,
the more it contributes to LTP (and ce versa for LTD).
● Collectively, long-term potentiation, long-term depression, sprouting,
rerouting and pruning modify connections between neurons and are
therefore considered fundamental when learning information.
Similarities between LTP & LTD:
● Both are acti ty dependent; that is, more or less acti ty
● Both involve glutamate
● Both occur at glutamate synapses
● Both involve changes in excitability
● Both have long-lasting effects
● Both are forms of long-lasting neural plasticity.