The hippocampus is critical for contextual memory and has recently been implicated in various kinds of social memory. Traditionally, studies of hippocampal context coding have manipulated elements of ...the background environment, such as the shape and color of the apparatus. These manipulations produce large shifts in the spatial firing patterns, a phenomenon known as remapping. These findings suggest that the hippocampus encodes and differentiates contexts by generating unique spatial firing patterns for each environment a subject encounters. However, we do not know whether the hippocampus encodes social contexts defined by the presence of particular conspecifics. We examined this by exposing rats to a series of manipulations of the social context, including the presence of familiar male, unfamiliar male and female conspecifics, in order to determine whether remapping is a plausible mechanism for encoding socially‐defined contexts. Because the dorsal and ventral regions of the hippocampus are thought to play different roles in spatial and social cognition, we recorded neurons in both regions. Surprisingly, we found little evidence of remapping in response to manipulation of the social context in either the dorsal or ventral hippocampus, although we saw typical remapping in response to changing the background color. This result suggests that remapping is not the primary mechanism for encoding different social contexts. However, we found that a subset of hippocampal neurons fired selectively near the cages that contained the conspecifics, and these responses were most prevalent in the ventral hippocampus. We also found a striking increase in the spatial information content of ventral hippocampal firing patterns. These results indicate that the ventral hippocampus is sensitive to changes in the social context and neurons that respond selectively near the conspecific cages could play an important, if not fully understood role in encoding the conjunction of conspecifics, their location and the environment.
Frederic Bartlett's schema theory is still widely misunderstood as claiming that remembering is inevitably unreliable. However, according to the logic of his schema theory, remembering should, in ...relation to certain kinds of material, be relatively reliable. In this study we examined whether a "well-worn" urban myth (the Vanishing Hitchhiker) could be exempt from the fate of other material used in Bartlett's own research on serial reproduction. Supporting Bartlett's ideas, we found that recall of the Hitchhiker story was better (if not perfect) over a series of five reproductions than recall of the classic War of the Ghosts. Recall was also better for a strict (as opposed to a lenient) audience, in line with another prediction from Bartlett's social theory of remembering. Notwithstanding this, we conclude with some critical remarks on the serial reproduction method as an approach to cultural memory.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Inputs from the ventral hippocampus (vHIP) to the medial prefrontal cortex (mPFC) are implicated in several neuropsychiatric disorders. Here, we show that the vHIP-mPFC projection is hyperactive in ...the
knockout mouse model of the autism spectrum disorder Rett syndrome, which has deficits in social memory. Long-term excitation of mPFC-projecting vHIP neurons in wild-type mice impaired social memory, whereas their long-term inhibition in Rett mice rescued social memory deficits. The extent of social memory improvement was negatively correlated with vHIP-evoked responses in mPFC slices, on a mouse-per-mouse basis. Acute manipulations of the vHIP-mPFC projection affected social memory in a region and behavior selective manner, suggesting that proper vHIP-mPFC signaling is necessary to recall social memories. In addition, we identified an altered pattern of vHIP innervation of mPFC neurons, and increased synaptic strength of vHIP inputs onto layer five pyramidal neurons as contributing factors of aberrant vHIP-mPFC signaling in Rett mice.
Coordinated intracellular and extracellular signaling is critical to synapse development and functional neural circuit wiring. Here, we report that unesterified docosahexaenoic acid (DHA) regulates ...functional synapse formation in vivo via retinoid X receptor α (Rxra) signaling. Using Rxra conditional knockout (cKO) mice and virus-mediated transient gene expression, we show that endogenous Rxra plays important roles in regulating spinogenesis and excitatory synaptic transmission in cortical pyramidal neurons. We further show that the effects of RXRA are mediated through its DNA-binding domain in a cell-autonomous and reversible manner. Moreover, unesterified DHA increases spine formation and excitatory synaptic transmission in vivo in an Rxra-dependent fashion. Rxra cKO mice generally behave normally but show deficits in behavior tasks associated with social memory. Together, these results demonstrate that unesterified DHA signals through RXRA to regulate spinogenesis and functional synapse formation, providing insight into the mechanism through which DHA promotes brain development and cognitive function.
Display omitted
•Retinoid X receptor Rxra regulates spinogenesis and excitatory synaptic transmission•RXRA effect is reversible, cell autonomous, and postsynaptic and requires DNA-binding domain•Rxra contributes to sensory experience-induced expression of immediate early genes•Unesterified DHA promotes spinogenesis and synaptic transmission via RXRA
Cao et al. measure spinogenesis and synaptic transmission in Rxra cKO mice following injection of unesterified docosahexaenoic acid (DHA). They demonstrate that unesterified DHA signals via RXRA to regulate spinogenesis and functional synapse formation, providing insight into the mechanism through which DHA promotes brain development and cognitive function.
Social recognition memory (SRM) is crucial for reproduction, forming social groups, and species survival. Despite its importance, SRM is still relatively little studied. Here we examine the ...participation of the CA1 region of the dorsal hippocampus (CA1) and the basolateral amygdala (BLA) and that of dopaminergic, noradrenergic, and histaminergic systems in both structures in the consolidation of SRM. Male Wistar rats received intra-CA1 or intra-BLA infusions of different drugs immediately after the sample phase of a social discrimination task and 24-h later were subjected to a 5-min retention test. Animals treated with the protein synthesis inhibitor, anisomycin, into either the CA1 or BLA were unable to recognize the previously exposed juvenile (familiar) during the retention test. When infused into the CA1, the β-adrenoreceptor agonist, isoproterenol, the D1/D5 dopaminergic receptor antagonist, SCH23390, and the H2 histaminergic receptor antagonist, ranitidine, also hindered the recognition of the familiar juvenile 24-h later. The latter drug effects were more intense in the CA1 than in the BLA. When infused into the BLA, the β-adrenoreceptor antagonist, timolol, the D1/D5 dopamine receptor agonist, SKF38393, and the H2 histaminergic receptor agonist, ranitidine, also hindered recognition of the familiar juvenile 24-h later. In all cases, the impairment to recognize the familiar juvenile was abolished by the coinfusion of agonist plus antagonist. Clearly, both the CA1 and BLA, probably in that order, play major roles in the consolidation of SRM, but these roles are different in each structure vis-à-vis the involvement of the β-noradrenergic, D1/D5-dopaminergic, and H2-histaminergic receptors therein.
Neste artigo revisitamos um conjunto de estudos sobre as representações sociais da história nacional realizados junto de jovens em Angola, Brasil, Cabo Verde, Guiné-Bissau, Moçambique, Portugal e ...Timor-Leste. Em cada um desses países foram recolhidos dados com vista a examinar as representações sociais da história nacional e as emoções associadas aos acontecimentos considerados mais marcantes, entre os quais se destacaram os referentes ao processo de colonização e as guerras de libertação. Os resultados apontam para ambiguidades, ambivalências e contradições nas representações sociais da história que “liga” os países de língua oficial portuguesa. De um modo geral, observa-se um “desencontro” das memórias sobre o passado colonial. Esse desencontro das memórias sobre o “passado comum” é particularmente evidente quando comparamos as memórias históricas de jovens angolanos e de jovens portugueses: enquanto os participantes portugueses destacam os descobrimentos os participantes angolanos destacam a escravatura, o tráfico de escravos e os massacres. Tomando de empréstimo a expressão de Mia Couto (2009), globalmente os resultados espelham Luso(A)fonias e demonstram o quão desafiante é a escuta ativa de outras fonias.
Recognizing and remembering another individual in a social context could be beneficial for individual fitness. Especially in agonistic encounters, remembering an opponent and the previous fight could ...allow for avoiding new conflicts. Considering this, we hypothesized that this type of social interaction forms a long-term recognition memory lasting several days. It has been shown that a second encounter 24 h later between the same pair of zebrafish males is resolved with lower levels of aggression. Here, we evaluated if this behavioral change could last for longer intervals and a putative mechanism associated with memory storage: the recruitment of NMDA receptors. We found that if a pair of zebrafish males fight and fight again 48 or 72 h later, they resolve the second encounter with lower levels of aggression. However, if opponents were exposed to MK-801 (NMDA receptor antagonist) immediately after the first encounter, they solved the second one with the same levels of aggression: that is, no reduction in aggressive behaviors was observed. These amnesic effect suggest the formation of a long-term social memory related to recognizing a particular opponent and/or the outcome and features of a previous fight.
Resumen: El estudio tiene por objetivo contribuir a la reflexión respecto de las modalidades en que la memoria social de acontecimientos traumáticos vinculados a la violencia política es tramitada ...entre las generaciones. Esta problemática es actualmente objeto de examen desde diversas áreas disciplinares. El presente estudio se concentra en los aportes derivados de la indagación psicoanalítica respecto de la transmisión de la vida psíquica y en las contribuciones de los estudios sobre memoria social. Además, explora investigaciones respecto de creaciones literarias que interrogan el pasado reciente. Se sostiene la hipótesis de que el trabajo de la memoria propiciado desde estas producciones artísticas integra un uso de la ficción de carácter político y transformador, que va más allá del testimonio y que interroga los apuntalamientos identitarios y éticos de las generaciones. Las principales conclusiones de la investigación resaltan la importancia de la idea de anterioridad por sobre la de interioridad como fundamento del trabajo identitario y la idea de espacio generacional, como un ámbito de transmisión y construcción de sentidos compartidos, que moviliza diversos recursos y modos de elaboración.
Encravada no meio do sertão piauiense, a Fábrica de Manteiga e Queijo das Fazendas Nacionais do Piauí, localizada no atual município de Campinas do Piauí, foi a primeira no ramo de laticínios do ...Nordeste e a segunda do Brasil, configurando-se como um marco da industrialização nacional. O objetivo deste artigo é evidenciar, sob o viés da Arqueologia Histórica e da Arqueologia Industrial, essa antiga edificação como um artefato remanescente da industrialização brasileira, que se mantém persistente na memória social da população local. Observou-se que até hoje a fábrica continua sendo reconhecida como uma referência para a cidade de Campinas do Piauí, outrora localidade Campos, considerando que a ocupação humana da área se deu no entorno da edificação fabril, estando intimamente ligada à instalação, ápice e declínio desta. A relação construída entre a comunidade campinense e a edificação mostra-se como uma trama que envolve memórias individuais e coletivas, acontecimentos e um lugar. Assim, a antiga fábrica é elemento participante da vida cotidiana local, que estabelece uma constante conexão entre o passado e o presente.
PDF
