Browsing by Author "Caneo, Mauricio"

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    Optogenetic Suppression of Lateral Septum Somatostatin Neurons Enhances Hippocampus Cholinergic Theta Oscillations and Local Synchrony
    (2023) Espinosa, Nelson; Alonso, Alejandra; Caneo, Mauricio; Moran, Constanza; Fuentealba, Pablo
    The septal complex regulates both motivated and innate behaviors, chiefly by the action of its diverse population of long-range projection neurons. A small population of somatostatin-expressing GABAergic cells in the lateral septum projects deep into subcortical regions, yet on its way it also targets neighboring medial septum neurons that profusely innervate cortical targets by ascending synaptic pathways. Here, we used optogenetic stimulation and extracellular recordings in acutely anesthetized transgenic mice to show that lateral septum somatostatin neurons can disinhibit the cholinergic septo-hippocampal pathway, thus enhancing the amplitude and synchrony of theta oscillations while depressing sharp-wave ripple episodes in the dorsal hippocampus. These results suggest that septal somatostatin cells can recruit ascending cholinergic pathways to promote hippocampal theta oscillations.
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    Sleep-dependent decorrelation of hippocampal spatial representations
    (2024) Valdivia, Gonzalo; Espinosa, Nelson; Lara-Vasquez, Ariel; Caneo, Mauricio; Inostroza, Marion; Born, Jan; Fuentealba, Pablo
    © 2024 The Author(s)Neuronal ensembles are crucial for episodic memory and spatial mapping. Sleep, particularly non-REM (NREM), is vital for memory consolidation, as it triggers plasticity mechanisms through brain oscillations that reactivate neuronal ensembles. Here, we assessed their role in consolidating hippocampal spatial representations during sleep. We recorded hippocampus activity in rats performing a spatial object-place recognition (OPR) memory task, during encoding and retrieval periods, separated by intervening sleep. Successful OPR retrieval correlated with NREM duration, during which cortical oscillations decreased in power and density as well as neuronal spiking, suggesting global downregulation of network excitability. However, neurons encoding specific spatial locations (i.e., place cells) or objects during OPR showed stronger synchrony with brain oscillations compared to non-encoding neurons, and the stability of spatial representations decreased proportionally with NREM duration. Our findings suggest that NREM sleep may promote flexible remapping in hippocampal ensembles, potentially aiding memory consolidation and adaptation to novel spatial contexts.