title: Infant avoidance training alters cellular activation patterns in prefronto-limbic circuits during adult avoidance learning: I. Cellular imaging of neurons expressing the synaptic plasticity early growth response protein 1 (Egr1).
abstract: Both positive feedback learning and negative feedback learning are essential for adapting and optimizing behavioral performance. There is increasing evidence in humans and animals that the ability of negative feedback learning emerges postnatally. Our work in rats, using a two-way active avoidance task (TWA) as an experimental paradigm for negative feedback learning, revealed that medial and lateral prefrontal regions of infant rats undergo dramatic synaptic reorganization during avoidance training, resulting in improved avoidance learning in adulthood. The aim of this study was to identify changes of cellular activation patterns during the course of training and in relation to infant pretraining. We applied a quantitative cellular imaging technique using the immunocytochemical detection of the activity marker early growth response protein 1 (Egr1) as a candidate contributing to learning-induced synaptic plasticity. We found region-specific cellular activity patterns, which indicate that during the acquisition phase, Egr1 expression is specifically elevated in cellular ensembles of the orbitofrontal, dorsal anterior cingulate and hippocampal CA1 region. During memory retrieval Egr1 expression is elevated in cellular ensembles of the dentate gyrus. Moreover, we, for the first time, show here that TWA training during infancy alters adult learning- and memory-related patterns of Egr1 expression in these brain regions. It is tempting to speculate that during infant learning, specific Egr1-expressing cellular ensembles are "tagged" representing long-term memory formation, and that these cell ensembles may be reactivated during adult learning.
authors.affiliation: Department of Zoology/Developmental Neurobiology, Otto von Guericke University, Leipziger Straße 44, Bldg. 91, 39120, Magdeburg, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Gröger
authors.affiliation: Department of Zoology/Developmental Neurobiology, Otto von Guericke University, Leipziger Straße 44, Bldg. 91, 39120, Magdeburg, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Mannewitz
authors.affiliation: FG Epigenetics and Structural Plasticity, Otto von Guericke University, Magdeburg, Germany.|Center for Behavioral Brain Science (CBBS), Magdeburg, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Bock
authors.affiliation: Department of Zoology/Developmental Neurobiology, Otto von Guericke University, Leipziger Straße 44, Bldg. 91, 39120, Magdeburg, Germany.
authors.forename: Tony Fernando
authors.initials: TF
authors.lastname: de Schultz
authors.affiliation: Department of Zoology/Developmental Neurobiology, Otto von Guericke University, Leipziger Straße 44, Bldg. 91, 39120, Magdeburg, Germany.
authors.forename: Katja
authors.initials: K
authors.lastname: Guttmann
authors.affiliation: Institute for Biology, Human Biology, University of Leipzig, 04103, Leipzig, Germany.
authors.forename: Gerd
authors.initials: G
authors.lastname: Poeggel
authors.affiliation: Department of Zoology/Developmental Neurobiology, Otto von Guericke University, Leipziger Straße 44, Bldg. 91, 39120, Magdeburg, Germany. katharina.braun@ovgu.de.|Center for Behavioral Brain Science (CBBS), Magdeburg, Germany. katharina.braun@ovgu.de.
authors.forename: Katharina
authors.initials: K
authors.lastname: Braun
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000502:physiology*; D002452:Cell Count; D051766:Early Growth Response Protein 1 / Q000378:metabolism*; D005260:Female; D008032:Limbic System / Q000502:physiology*; D008568:Memory / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology; D009473:Neuronal Plasticity; D009474:Neurons / Q000502:physiology*; D017397:Prefrontal Cortex / Q000502:physiology*; D051381:Rats
chemical_list: D051766:Early Growth Response Protein 1; C486110:Egr1 protein, rat
keywords: Memory encoding; Network plasticity; Neuronal ensembles