Adult-born granule cells (ABGCs) are involved in certain forms of hippocampus-dependent learning and memory. It has been proposed that young but functionally integrated ABGCs (4-weeks-old) specifically contribute to pattern separation functions of the dentate gyrus due to their heightened excitability, whereas old ABGCs (>8 weeks old) lose these capabilities. Measuring multiple cellular and integrative characteristics of 3- 10-week-old individual ABGCs, we show that ABGCs consist of two functionally distinguishable populations showing highly distinct input integration properties (one group being highly sensitive to narrow input intensity ranges while the other group linearly reports input strength) that are largely independent of the cellular age and maturation stage, suggesting that 'classmate' cells (born during the same period) can contribute to the network with fundamentally different functions. Thus, ABGCs provide two temporally overlapping but functionally distinct neuronal cell populations, adding a novel level of complexity to our understanding of how life-long neurogenesis contributes to adult brain function.
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http://dx.doi.org/10.7554/eLife.03104 | DOI Listing |
Cogn Neurodyn
December 2025
State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, #10 Xitucheng Road, Beijing, 100876 People's Republic of China.
The dentate gyrus (DG) in hippocampus is reported to perform pattern separation, converting similar inputs into different outputs and thus avoiding memory interference. Previous studies have found that human and mice with epilepsy have significant pattern separation defects and a portion of adult-born granule cells (abGCs) migrate abnormally into the hilus, forming hilus ectopic granule cells (HEGCs). For the lack of relevant pathophysiological experiments, how HEGCs affect pattern separation remains unclear.
View Article and Find Full Text PDFExp Physiol
January 2025
Department of Physiology, School of Medicine, University College Cork, Cork, Ireland.
Absence of the structural protein, dystrophin, results in the neuromuscular disorder Duchenne Muscular Dystrophy (DMD). In addition to progressive skeletal muscle dysfunction, this multisystemic disorder can also result in cognitive deficits and behavioural changes that are likely to be consequences of dystrophin loss from central neurons and astrocytes. Dystrophin-deficient mdx mice exhibit decreases in grey matter volume in the hippocampus, the brain region that encodes and consolidates memories, and this is exacerbated with ageing.
View Article and Find Full Text PDFMol Biol Cell
January 2025
Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, McGill University, Montréal, Québec H3G 1A3, Canada.
Aberrant adult hippocampal neurogenesis is implicated in neurological and mood disorders associated with dysregulation of the mechanistic target of rapamycin (mTOR). Understanding how the mTOR pathway shapes the functional development of different subpopulations of adult-born hippocampal neural stem cells will enable insight into potential therapeutic pathways for these disorders. Here we study how loss of TSC2, a regulator of mTOR pathway and a causal gene for tuberous sclerosis complex (TSC), affects dentate gyrus granule cell morphogenesis and hippocampal-dependent function.
View Article and Find Full Text PDFCogn Neurodyn
October 2024
Institute for Computational Neuroscience and Department of Science Education, Daegu National University of Education, Daegu, 42411 Korea.
Unlabelled: We are concerned about sparsely synchronized rhythms (SSRs), associated with diverse cognitive functions, in the hippocampal dentate gyrus. Distinctly, adult-born immature GCs (imGCs) emerge through neurogenesis, in addition to the mature granule cells (mGCs) (emerged in the developmental stage). In prior work, these mGCs and imGCs were found to exhibit their distinct roles in pattern separation and integration for encoding cortical inputs, respectively.
View Article and Find Full Text PDFNeural activity in the dentate gyrus (DG) is required for the detection and discrimination of novelty, context and patterns, amongst other cognitive processes. Prior work has demonstrated that there are differences in the activation of granule neurons in the supra and infrapyramidal blades of the DG during a range of hippocampal dependent tasks. Here we used an automated touch screen pattern separation task combined to temporally controlled tagging of active neurons to determine how performance in a cognitively demanding task affected patterns of neural activity in the DG.
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