New neurons and new memories: how does adult hippocampal neurogenesis affect learning and memory?

This is a Nature review article from 2010 written by Wei Deng, James Aimone and Fred Gage.

Timeline and processes involved in the development of a new hippocampal neuron

Freshly born neurons develop from neural progenitor cells in the subgranular zone of the hippocampus. Within the first week they differentiate into dentate granule cells and slowly migrate to the dentate gyrus. Within the second week they grow dendrites which extend to the CA3 region. These new neurons are still immature and upon receiving GABAergic input respond with slow rising and decay kinetics. Interestingly, administration of a GABA receptor agonist promotes dendrite growth of adult-born dentate granule cells, while a deprivation reduces the number of adult-born dentate granule cells surviving the second week after birth. During the third week after birth these dentate granule cells being to form connections with the surrounding neuronal network. By roughly day 16, synapses are formed. The development of both afferent and efferent synapses from newly generated dentate granule cells seems to involve targeting to pre-existing synaptic partners, which suggests a role for circuit activity in the integration of these new cells. Although the structural modification of dendritic spines and axonal boutons continues to occur as the adult-born dentate granule cells become older the basic physiological properties and synaptic plasticity at 8 weeks of age are indistinguishable from those of mature dentate granule cells. As discussed below, the unique physiological characteristics of adult-born dentate granule cells before 6 weeks of age enable these neurons to be discretely regulated by network activity and possibly to make distinct contributions to learning and memory.

New neurons and memory capacity: addition or replacement?

*for example, neurogenesis allows the network to avoid local minima, which are a problem with some learning rules* source 1 source 2.

While learning more about the hippocampus, I came across Marzieh Ghiasi’s blog post where she compiled a great list of resources to help in studying the anatomy of the brain. Please visit her blog to check it out!

To Be Continued…

This entry was posted in Literature. Bookmark the permalink.

Leave a Reply

Your email address will not be published. Required fields are marked *


You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>