Septal parvalbumin-expressing (PV) and calbindin-expressing (CB) projections inhibit low-threshold and fast-spiking interneurons, respectively, in the medial entorhinal cortex (MEC). We investigate how the two inputs control neuronal activity in the MEC in freely moving mice. Stimulation of PV and CB terminals causes disinhibition of spatially tuned MEC neurons, but exerts differential effects on temporal coding and burst firing. Thus, recruitment of PV projections disrupts theta-rhythmic firing of MEC neurons, while stimulation of CB projections increases burst firing of grid cells and enhances phase precession in a cell-type-specific manner. Inactivation of septal PV or CB neurons differentially affects context, reference, and working memory. Together, our results reveal how specific connectivity of septal GABAergic projections with MEC interneurons translates into differential modulation of MEC neuronal coding.
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http://dx.doi.org/10.1016/j.celrep.2021.108801 | DOI Listing |
J Neurosci
January 2025
Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada, K1N 6N5
GABAergic neurons in basal forebrain (BF) nuclei project densely to all layers of the mouse main olfactory bulb (OB), the first relay in odor information processing. However, BF projection neurons are diverse and the contribution of each subtype to odor information processing is not known. In the present study, we used retrograde and anterograde tracing methods together with whole-brain light-sheet analyses, patch-clamp recordings coupled with optogenetic and chemogenetic approaches during spontaneous odor discrimination, and go/no-go odor discrimination/learning tests to characterize the synaptic targets in the OB of BF calretinin-expressing (CR+) GABAergic cells and to reveal their functional implications.
View Article and Find Full Text PDFAlzheimers Dement
January 2025
Key Laboratory of Biomedical Engineering of Hainan Province, School of Biomedical Engineering, Hainan University, Sanya, China.
Introduction: Alzheimer's disease (AD) is the most common neurodegenerative disease, characterized by damage to cortical circuits. However, the mechanisms underlying AD-associated changes in long-range circuits remain poorly understood.
Methods: In this study, we used viral tracing and fluorescence micro-optical sectioning tomography (fMOST) imaging to investigate whole-brain changes in the input circuit of the frontal cortex of 5×FAD mice.
J Neuroinflammation
January 2025
Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA.
The thrombolytic protease tissue plasminogen activator (tPA) is expressed in the CNS, where it regulates diverse functions including neuronal plasticity, neuroinflammation, and blood-brain-barrier integrity. However, its role in different brain regions such as the substantia nigra (SN) is largely unexplored. In this study, we characterize tPA expression, activity, and localization in the SN using a combination of retrograde tracing and β-galactosidase tPA reporter mice.
View Article and Find Full Text PDFOrphanet J Rare Dis
January 2025
Department of Rheumatology and Immunology, The First Affiliated Hospital, Fujian Medical University, Fuzhou, 350005, Fujian, China.
Background: Intestinal Behçet's syndrome (IBS) has high morbidity and mortality rates with serious complications. However, there are few specific biomarkers for IBS. The purposes of this study were to investigate the distinctive metabolic changes in plasma samples between IBS patients and healthy people, active IBS and inactive IBS patients, and to identify candidate metabolic biomarkers which would be useful for diagnosing and predicting IBS.
View Article and Find Full Text PDFBrain Struct Funct
January 2025
Behavioral Neuroscience Laboratory, Department of Psychology, Boğaziçi University, Bebek, 34342, Istanbul, Turkey.
Theta oscillations of the mammalian amygdala are associated with processing, encoding and retrieval of aversive memories. In the hippocampus, the power of the network theta oscillation is modulated by basal forebrain (BF) GABAergic projections. Here, we combine anatomical and computational approaches to investigate if similar BF projections to the amygdaloid complex provide an analogous modulation of local network activity.
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