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Experience‐dependent plasticity of zinc‐containing cortical circuits during a critical period of postnatal development
Author(s) -
Land Peter W.,
ShamallaHannah Lorraine
Publication year - 2002
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.10229
Subject(s) - barrel cortex , sensory deprivation , neuroscience , somatosensory system , biology , period (music) , sensory system , cortex (anatomy) , glutamatergic , biological neural network , axon , neuropil , synaptic plasticity , cerebral cortex , neuroplasticity , anatomy , central nervous system , glutamate receptor , biochemistry , physics , receptor , acoustics
Distinctive subsets of glutamatergic neurons in cerebral cortex sequester the transition metal zinc within the synaptic vesicles of their axon terminals. In the present study we used histochemical localization of synaptic zinc to investigate normal postnatal development and experience‐dependent plasticity of zinc‐containing circuits in somatosensory barrel cortex of rats. First, we found that zinc‐containing cortical circuits are dynamically reorganized between postnatal day (P) 0 and P28. Whereas most cortical laminae exhibited idiosyncratic increases in zinc histochemical staining with advancing age, lamina IV barrels were darkly reactive early in life and then lost much of their complement of synaptic zinc during postnatal weeks 2–4. Second, we established that sensory experience plays a major role in sculpting the zinc‐containing innervation of cortical barrels. Trimming a particular facial whisker arrested the normal postnatal decline in synaptic zinc in the corresponding, deprived barrel. This resulted in more intense zinc staining in deprived barrels compared with adjacent, nondeprived barrels. Notably, the influence of experience on development of zinc circuits was most robust during a critical period extending from about P14, when an effect of whisker trimming first could be observed, through P28, after which time chronic deprivation no longer resulted in heightened levels of synaptic zinc in lamina IV. These findings indicate that sensory input can have a marked influence on development of cortical circuits, including those within lamina IV, throughout the first postnatal month. J. Comp. Neurol. 447:43–56, 2002. © 2002 Wiley‐Liss, Inc.