title: Progression of activity and structural changes in the anterior cingulate cortex during remote memory formation.
abstract: The progression of activity and structural changes in the anterior cingulate cortex during remote contextual fear memory formation was measured by imaging c-fos expression and dendritic spines following retrieval tests administered at six post-training time points (days 1, 5, 7, 14, 21, 36). Here we report that conditioned mice exhibit robust freezing at each time point. C-fos expression starts to augment on day 5, showing a monotonic increase over the successive time points, and then stabilized in relation to the higher freezing scores. The first significant increase in mean spine density emerges on day 7. By day 14, the net number of spines remained stable, yet the distribution of single neuron spine density becomes progressively more homogeneous. Our findings reveal that activity changes precede structural remodeling of neurons in the neocortex while remodeling coherence develops gradually in cortical neuron ensembles.
authors.affiliation: Istituto di Biologia Cellulare e Neurobiologia, Consiglio Nazionale delle Ricerche, Rome, Italy; Neuroscience Department, The Scripps Research Institute, Jupiter 33458, FL, USA.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Aceti
authors.affiliation: Istituto di Biologia Cellulare e Neurobiologia, Consiglio Nazionale delle Ricerche, Rome, Italy; Program in Neurosciences and Mental Health, The Hospital for Sick Children Toronto, ON, Canada.
authors.forename: Gisella
authors.initials: G
authors.lastname: Vetere
authors.affiliation: Istituto di Biologia Cellulare e Neurobiologia, Consiglio Nazionale delle Ricerche, Rome, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Novembre
authors.affiliation: Istituto di Biologia Cellulare e Neurobiologia, Consiglio Nazionale delle Ricerche, Rome, Italy; Program in Neurosciences and Mental Health, The Hospital for Sick Children Toronto, ON, Canada.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Restivo
authors.affiliation: Istituto di Biologia Cellulare e Neurobiologia, Consiglio Nazionale delle Ricerche, Rome, Italy; Istituto di Ricovero e Cura a Carattere Scientifico, Fondazione Santa Lucia, Rome, Italy. Electronic address: martine.teule@cnr.it.
authors.forename: Martine
authors.initials: M
authors.lastname: Ammassari-Teule
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D003213:Conditioning, Psychological; D049229:Dendritic Spines / Q000502:physiology*; D046352:Freezing Reaction, Cataleptic / Q000502:physiology; D006179:Gyrus Cinguli / Q000378:metabolism / Q000502:physiology*; D008297:Male; D057567:Memory, Long-Term / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*
chemical_list: D016760:Proto-Oncogene Proteins c-fos
keywords: Dendritic spine density; Neocortex; Remodeling coherence; Remote memory