Converting juvenile into adult plasticity: A role for the brain’s extracellular matrix
European Journal of Neuroscience. 2010-05-24; 31(12): 2156-2165
DOI: 10.1111/j.1460-9568.2010.07253.x
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Gundelfinger ED(1), Frischknecht R, Choquet D, Heine M.
Author information:
(1)Leibniz Institute for Neurobiology, Magdeburg, Germany.
In higher vertebrates, the extracellular matrix (ECM) wrapping cells of the adult
brain differs significantly from that of the developing and juvenile brain. The
mature ECM is established at the end of critical periods for wiring and it
restricts the regenerative potential and constrains the plasticity of the adult
brain. In particular, perineuronal nets, elaborate ECM structures that surround
distinct neurons and wrap synapses, are hallmarks of the adult brain and seem to
massively affect brain plasticity. Why have these, at first glance futile,
limitations evolved? What is the return for these drawbacks? What are the
mechanisms of restriction and how is adult plasticity implemented? Recent
progress both at the systemic level and at the molecular physiological level has
shed some new light on these questions. In this review we will survey the
evidence for potential functions of the adult ECM in making established brain
features, including imprinted memories, resistant to extinction, and we will
discuss potential mechanisms by which the ECM limits juvenile and implements
adult plasticity. In particular we will focus on some aspects of adult ECM
function. First we will discuss its influence on diffusion of cations in the
extracellular space and on volume transmission, second we will consider its
potential role in regulating the lateral diffusion of cell surface receptors and
finally we will discuss mechanisms to locally modulate ECM functions.