Synaptic Connections

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The weakening of synaptic connections is not the only mechanism involved in transience, there is also evidence that complete synaptic elimination either through shrinkage or loss of spines can be responsible for a portion of natural forgetting. This relationship between synaptic elimination and natural forgetting has been observed in the nematode C. elegans. In C. elegans associative learning induces synapse growth at a specific neuron. However, after a few hours the modified synapse shrinks and reverts back to its original native state, this change back to its native state is also accompanied by the loss of the associative memory. [6] This means that if there many instances of synapse shrinking occurring over time it can lead to a…show more content…
These rearrangements are integral to the adaptive nature of the brain and crucial to its many functions. However, having a continuous stream of new synapse appearing and modifying the connectivity patterns of a finite space must lead to the removal of some data in order to maintain an efficient system; this means that processes that promote the remodeling of the brain also promote instability within some of the connections and in turn transience. [3] This promotion of transience by neurogenesis has been observed and confirmed by various recent studies of rodents. One of these studies observed the stability of perforant path-dentate gyrus long-term potentiation in awake, active rats. Researchers in this study monitored the strength of perforant path-dentate gyrus in multiple rats over several weeks. They found that in the control group the rat’s long-term potentiation reverted back to baseline within approximately a week, but in the group of rats that were irradiated in order to eliminate hippocampal neurogenesis, long-term potentiation was prolonged with potentiation still observable after 2 weeks. [7] These results show a strong correlation between the promotion of neural connection re-arranging via neurogenesis and inducing the decay of long-term potentiation, conversely the prevention of neural connection re-arranging was shown to promote persistence of long-term potentiation. A second study involving mice was also
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