Browsing by Author "Lara Vásquez, Ariel Fernando"

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    Cortical dynamics underlying social behavior in dominance hierarchy and spatial navigation
    (2020) Lara Vásquez, Ariel Fernando; Espinosa, Nelson; Morales, Cristian; Moran, Constanza; Billeke, Pablo; Gallagher, Joseph; Strohl, Joshua J.; Huerta, Patricio T.; Fuentealba, Pablo
    Rodents establish dominance hierarchy as a social ranking system in which one subject acts as dominant over all the other subordinate individuals. Dominance hierarchy regulates food access and mating opportunities, but little is known of its significance in collective behavior, for instance during navigation for foraging or migration. Here, we implemented a simplified goal-directed spatial navigation task in mice and found that the social context exerts significant influence on individual decision-making, even when efficient navigation rules leading to reward had been previously learned. Thus, decision-making and consequent task performance were strongly dependent on contingent social interactions arising during collective navigation, yet their influence on individual behavior was outlined by dominance hierarchy. Dominant animals did not behave as leaders during navigation; conversely, they were most sensitive to social context. Social ranking in turn was reflected in the neural activity and connectivity patterns of the prefrontal cortex and hippocampus, both in anesthetized and behaving mice. These results suggest that the interplay between contingent social interactions and dominance hierarchy can regulate behavioral performance, supported by the intrinsic matrix of coordinated activity in the hippocampal-prefrontal circuit.
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    Dentate Gyrus Somatostatin Cells are Required for Contextual Discrimination during Episodic Memory Encoding
    (2021) Morales Rojas, Cristian Enrique; Morici, Juan Facundo; Espinosa, Nelson; Sacson, Agostina; Lara Vásquez, Ariel Fernando; García Pérez, M. A.; Bekinschtein, Pedro; Weisstaub, Noelia V.; Fuentealba, Pablo
    Memory systems ought to store and discriminate representations of similar experiences in order to efficiently guide future decisions. This problem is solved by pattern separation, implemented in the dentate gyrus (DG) by granule cells to support episodic memory formation. Pattern separation is enabled by tonic inhibitory bombardment generated by multiple GABAergic cell populations that strictly maintain low activity levels in granule cells. Somatostatin-expressing cells are one of those interneuron populations, selectively targeting the distal dendrites of granule cells, where cortical multimodal information reaches the DG. Nonetheless, somatostatin cells have very low connection probability and synaptic efficacy with both granule cells and other interneuron types. Hence, the role of somatostatin cells in DG circuitry, particularly in the context of pattern separation, remains uncertain. Here, by using optogenetic stimulation and behavioral tasks in mice, we demonstrate that somatostatin cells are required for the acquisition of both contextual and spatial overlapping memories.
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    Intrinsic cortical dynamics in the hippocampus-PFC system and social interactions during collective navigation in a decision-making task
    (2020) Lara Vásquez, Ariel Fernando; Fuentealba, Pablo; Pontificia Universidad Católica de Chile. Facultad de Medicina
    Environmental sensory inputs and previously learned information to guide decision-making during complex behaviors such as foraging or navigation. Social mammals forage collectively, yet little is known about the influence of social interactions in decision-making during collective spatial navigation. To achieve efficient decision-making, social animals engaging in collective behavior must balance inherent and contingent factors, yet this process is not well understood. Here, I implemented a simplified spatial navigation task in rodents to assess the role of social interactions and found that they exert a powerful influence on individual decision-making. Indeed, instead of prioritizing memory-based pertinent information, mice shifted their decisions according to contingent social interactions arising during collective navigation. Dominance hierarchy, a form of a social ranking system, was an intrinsic social interaction relevant to organize the timing of behavior during collective navigation. Thus, individual task accuracy was dependent on the density of animals collectively moving during spatial navigation. Finally, dominance hierarchy correlated with brain-state specific coordinated activity expressed as larger hippocampal sharp-wave ripples associated with higher prefrontal firing rates, suggesting reinforced synaptic cortical coupling. These results suggest that both contingent and intrinsic social interactions modulate behavioral performance and are correlated with enhanced activity and connectivity patterns in the hippocampo-prefrontal circuit.
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    Midline thalamic neurons are differentially engaged during hippocampus network oscillations
    (2016) Lara Vásquez, Ariel Fernando; Espinosa, Nelson; Durán, Ernesto; Stockle, Marcelo; Fuentealba, Pablo
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    Prenatal Stress Down-Regulates Reelin Expression by Methylation of Its Promoter and Induces Adult Behavioral Impairments in Rats
    (2015) Palacios García, Ismael José; Lara Vásquez, Ariel Fernando; Montiel, Juan F.; Díaz Véliz, Gabriela F.; Sepúlveda, Hugo; Utreras, Elías; Montecino, Martín; González Billault, Christian; Aboitiz, Francisco