title: An epigenetic induction of a right-shift in hippocampal asymmetry: selectivity for short- and long-term potentiation but not post-tetanic potentiation.
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.
authors.affiliation: Department of Psychology, University of New Mexico, Albuquerque, New Mexico 87131, USA. akaysha@unm.edu
authors.forename: Akaysha C
authors.initials: AC
authors.lastname: Tang
authors.forename: Bende
authors.initials: B
authors.lastname: Zou
authors.forename: Bethany C
authors.initials: BC
authors.lastname: Reeb
authors.forename: John A
authors.initials: JA
authors.lastname: Connor
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001522:Behavior, Animal; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation / Q000379:methods; D004777:Environment; D044127:Epigenesis, Genetic / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology*; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000502:physiology* / Q000528:radiation effects; D008297:Male; D008954:Models, Biological; D009473:Neuronal Plasticity / Q000502:physiology*; D051381:Rats; D013997:Time Factors