Sistema Nervioso Central Flashcards
divergent pathway
one presynaptic neuron branches to affect a larger number of postsynaptic neurons
convergent pathway
many presynaptic neurons provide input to influence a smaller number of postsynaptic neurons
neuroplasticity
how the nervous system changes in response to experience
ex. when we form new memories or learn new things
changes in synapses and/or other parts of neurons that affect how information is processed and transmitted in the nervous system
in what direction does neuroplasticity go
in both directions:
1. potentiation
2. depression
potentiation
the strength of information flowing through a particular part of the nervous system can increase
potentiates the responses of cells
depression
the strength of information flowing through a particular part of the nervous system can decrease
depresses the response of cells to other cells in the nervous system
when is the amount of neuroplasticity the highest and when is it lowest
highest during the development of the nervous system
lowest after the development of the nervous system
when does neuroplasticity increase and how
neuroplasticity transiently increases following nervous system injury
what happens with action potentials during potentiation and how does this occur
parts and chains of neurons that are used often grow stronger, making each action potential have a larger effect on the target cell
what happens during depression
parts and chains of neurons grow weaker
types of neuroplasticity (where can it occur)
- synaptic neuroplasticity
- structural neuroplasticity
synaptic potentiation
happens at the synapse and increases the response in the target cell per action potential that’s reaching the axon terminal
ex. 1: more neurotransmitter may be released by the axon terminal into the synaptic cleft to the post-synaptic target cell with the specific neurotransmitter receptors
ex. 2: there may be an increase in the number of neurotransmitter receptors of the post-synaptic cell’s membrane
the types of neurotransmitter receptors or the responses that occur through second messengers may also change (they may become more sensitive, so that they produce a bigger response to the neurotransmitter released by the axon terminal)
structural neuroplasticity
occurs at the level of entire cells, where the total number of synapses between a neuron and its target cell are changed
types of synaptic neuroplasticity
- synaptic potentiation
- synaptic depression
synaptic depression
the amount of neurotransmitter released into the synaptic cleft from the axon terminal decreases per action potential
there is less of a response in the target cell to an action potential reaching the axon terminal
the neurotransmitter receptors may decrease in number
the neurotransmitter receptors or the second messengers may change so that the target cell becomes less responsive to the neurotransmitter
structural potentiation
the number of synapses between two neurons increases
the dendrites get longer or grow more branches (become more complex)
the pre-synaptic neuron can grow more axon branches and terminals, so that it forms more synaptic connections with the post-synaptic neuron’s dendrites
structural depression
dendrites lose length or branches (become shorter and simpler)
axon terminals may be lost (may become simpler)
whole neurons may be lost
pruning
neurons or parts of neurons are lost because they’re not very active
does synaptic neuroplasticity contribute to short or long term potentiation and depression
both short and long term
does structural neuroplasticity go along with short or long term potentiation or depression
long term
synaptic plasticity
the ability of the nervous system to change activity at synapses
the ability to change circuit connections and function in response to sensory input and past experience
plasticity of human brain networks, which easily restructure themselves as the result of sensory input, learning, emotion, and creativity
cognition
the thinking process of the brain
uses sensory input to the brain and information already stored in memory
controls most of our motor activity
what types of matter does the central nervous system (CNS) contain
- gray matter
- white matter
what is gray matter made of
unmyelinated nerve cell bodies
