Holtmaat A, Svoboda K. Experience-dependent structural synaptic plasticity in the mammalian brain. Nat Rev Neurosci 10: 647-658

Department of Basic Neurosciences, Medical Faculty, University of Geneva, Switzerland.
Nature Reviews Neuroscience (Impact Factor: 31.43). 10/2009; 10(9):647-58. DOI: 10.1038/nrn2699
Source: PubMed


Synaptic plasticity in adult neural circuits may involve the strengthening or weakening of existing synapses as well as structural plasticity, including synapse formation and elimination. Indeed, long-term in vivo imaging studies are beginning to reveal the structural dynamics of neocortical neurons in the normal and injured adult brain. Although the overall cell-specific morphology of axons and dendrites, as well as of a subpopulation of small synaptic structures, are remarkably stable, there is increasing evidence that experience-dependent plasticity of specific circuits in the somatosensory and visual cortex involves cell type-specific structural plasticity: some boutons and dendritic spines appear and disappear, accompanied by synapse formation and elimination, respectively. This Review focuses on recent evidence for such structural forms of synaptic plasticity in the mammalian cortex and outlines open questions.

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Article: Holtmaat A, Svoboda K. Experience-dependent structural synaptic plasticity in the mammalian brain. Nat Rev Neurosci 10: 647-658

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    • "T he central nervous system (CNS) of adult mammals is assembled during developmental neurogenesis, and its architectural specificity is maintained through a vast cohort of membrane-bound and extracellular matrix molecules (Gumbiner 1996; Bonfanti 2006). Although CNS structure is sculpted by experience-dependent synaptic plasticity at different postnatal developmental stages (critical periods) (see Sale et al. 2009) and, to a lesser extent, during adulthood (Holtmaat and Svoboda 2009), the neural networks are rather stabilized in the " mature " nervous tissue (Spolidoro et al. 2009). The differentiated cellular elements forming adult neural circuitries remain substantially unchanged in terms of their number and types, because cell renewal/addition in the CNS is very low. "
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    • "Interestingly, spine changes in layer-5 pyramidal cells of visual cortex outlast sensory experience (Hofer et al., 2008), thus providing a structural substrate for the psychological phenomenon known as memory savings (Ebbinghaus, 1913). As synaptic structure and synaptic weight are closely correlated (Matsuzaki et al., 2001; Holtmaat and Svoboda, 2009), the memory savings mediated by structural spine plasticity (Hofer et al., 2008) are reminiscent of those provided by our unified plasticity model. Here we have focused on neocortical data. "
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