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An epigenetic induction of a right‐shift in hippocampal asymmetry: Selectivity for short‐ and long‐term potentiation but not post‐tetanic potentiation
Author(s) -
Tang Akaysha C.,
Zou Bende,
Reeb Bethany C.,
Connor John A.
Publication year - 2008
Publication title -
hippocampus
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.767
H-Index - 155
eISSN - 1098-1063
pISSN - 1050-9631
DOI - 10.1002/hipo.20370
Subject(s) - long term potentiation , neuroscience , synaptic plasticity , neocortex , hippocampus , psychology , excitatory postsynaptic potential , neuroplasticity , developmental plasticity , hippocampal formation , metaplasticity , plasticity , medicine , inhibitory postsynaptic potential , physics , receptor , thermodynamics
Abstract In humans, it is well established that major psychological functions are asymmetrically represented between the left and right cerebral cortices. The developmental origin of such functional lateralization remains unknown. Using the rat as a model system, we examined whether exposing neonates briefly to a novel environment can differentially affect synaptic plasticity in the left and right hippocampi during adulthood. During the first 3 weeks of life, one half of the pups from a litter spent 3 min daily away from their familiar home environment (Novel) while their littermates remained in that familiar environment (Home). At adulthood (7‐months old), post‐tetanic potentiation (PTP) of excitatory post‐synaptic potentials (EPSPs), a very short‐lasting form of plasticity, was greater among the Novel than the Home rats in both left and right hippocampi. In contrast, the novelty‐induced increases in short‐ and long‐term potentiation (STP, LTP), two relatively longer‐lasting forms of plasticity, were found only in the right hippocampus. These findings demonstrate that a phase‐selective asymmetry in hippocampal synaptic plasticity can be induced epigenetically by seemingly small systematic differences in early life environment. The selectivity of this asymmetry for the longer‐lasting forms of synaptic plasticity suggests that the observed asymmetry in plasticity may contribute specifically to an asymmetric learning process which, in turn, may contribute to a functional asymmetry in the neocortex. © 2007 Wiley‐Liss, Inc.