title: Mushroom spine dynamics in medium spiny neurons of dorsal striatum associated with memory of moderate and intense training.
abstract: A growing body of evidence indicates that treatments that typically impair memory consolidation become ineffective when animals are given intense training. This effect has been obtained by treatments interfering with the neural activity of several brain structures, including the dorsal striatum. The mechanisms that mediate this phenomenon are unknown. One possibility is that intense training promotes the transfer of information derived from the enhanced training to a wider neuronal network. We now report that inhibitory avoidance (IA) induces mushroom spinogenesis in the medium spiny neurons (MSNs) of the dorsal striatum in rats, which is dependent upon the intensity of the foot-shock used for training; that is, the effect is seen only when high-intensity foot-shock is used in training. We also found that the relative density of thin spines was reduced. These changes were evident at 6 h after training and persisted for at least 24 h afterward. Importantly, foot-shock alone did not increase spinogenesis. Spine density in MSNs in the accumbens was also increased, but the increase did not correlate with the associative process involved in IA; rather, it resulted from the administration of the aversive stimulation alone. These findings suggest that mushroom spines of MSNs of the dorsal striatum receive afferent information that is involved in the integrative activity necessary for memory consolidation, and that intense training facilitates transfer of information from the dorsal striatum to other brain regions through augmented spinogenesis.
authors.affiliation: Departamento de Neurobiología Conductual y Cognitiva, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Queretaro, 76230, Mexico.
authors.forename: Paola C
authors.initials: PC
authors.lastname: Bello-Medina
authors.affiliation: Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, Puebla, 72570, Mexico.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Flores
authors.affiliation: Departamento de Neurobiología Conductual y Cognitiva, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Queretaro, 76230, Mexico.
authors.forename: Gina L
authors.initials: GL
authors.lastname: Quirarte
authors.affiliation: Center for the Neurobiology of Learning and Memory,University of California, Irvine, CA 92697-3800; Department of Neurobiology and Behavior, University of California, Irvine, CA 92697-3800 prado@unam.mx jlmcgaugh@uci.edu.
authors.forename: James L
authors.initials: JL
authors.lastname: McGaugh
authors.affiliation: Departamento de Neurobiología Conductual y Cognitiva, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Queretaro, 76230, Mexico; prado@unam.mx jlmcgaugh@uci.edu.
authors.forename: Roberto A
authors.initials: RA
authors.lastname: Prado Alcalá
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal; D003342:Corpus Striatum / Q000166:cytology* / Q000502:physiology*; D049229:Dendritic Spines; D008297:Male; D008568:Memory; D000069077:Memory Consolidation; D057567:Memory, Long-Term; D009474:Neurons / Q000166:cytology* / Q000502:physiology*; D009714:Nucleus Accumbens / Q000166:cytology / Q000502:physiology; D051381:Rats; D013663:Teaching
keywords: accumbens; dendritic spines; dorsal striatum; intense training; memory consolidation