@article {213,
	title = {Sparse and distributed coding of episodic memory in neurons of the human hippocampus.},
	journal = {Proc Natl Acad Sci U S A},
	volume = {111},
	year = {2014},
	month = {2014 Jul 1},
	pages = {9621-6},
	abstract = {<p>Neurocomputational models hold that sparse distributed coding is the most efficient way for hippocampal neurons to encode episodic memories rapidly. We investigated the representation of episodic memory in hippocampal neurons of nine epilepsy patients undergoing intracranial monitoring as they discriminated between recently studied words (targets) and new words (foils) on a recognition test. On average, single units and multiunits exhibited higher spike counts in response to targets relative to foils, and the size of this effect correlated with behavioral performance. Further analyses of the spike-count distributions revealed that (i) a small percentage of recorded neurons responded to any one target and (ii) a small percentage of targets elicited a strong response in any one neuron. These findings are consistent with the idea that in the human hippocampus episodic memory is supported by a sparse distributed neural code.</p>
},
	keywords = {Epilepsy, Hippocampus, Humans, Memory, Episodic, Models, Neurological, Neurophysiological Monitoring, Neuropsychological Tests},
	issn = {1091-6490},
	doi = {10.1073/pnas.1408365111},
	author = {Wixted, John T and Squire, Larry R and Jang, Yoonhee and Papesh, Megan H and Goldinger, Stephen D and Kuhn, Joel R and Smith, Kris A and Treiman, David M and Steinmetz, Peter N}
}
@article {183,
	title = {Selection of distinct populations of dentate granule cells in response to inputs as a mechanism for pattern separation in mice.},
	journal = {Elife},
	volume = {2},
	year = {2013},
	month = {2013},
	pages = {e00312},
	abstract = {<p>The hippocampus is critical for episodic memory and computational studies have predicted specific functions for each hippocampal subregion. Particularly, the dentate gyrus (DG) is hypothesized to perform pattern separation by forming distinct representations of similar inputs. How pattern separation is achieved by the DG remains largely unclear. By examining neuronal activities at a population level, we revealed that, unlike CA1 neuron populations, dentate granule cell (DGC) ensembles activated by learning were not preferentially reactivated by memory recall. Moreover, when mice encountered an environment to which they had not been previously exposed, a novel DGC population-rather than the previously activated DGC ensembles that responded to past events-was selected to represent the new environmental inputs. This selection of a novel responsive DGC population could be triggered by small changes in environmental inputs. Therefore, selecting distinct DGC populations to represent similar but not identical inputs is a mechanism for pattern separation. DOI:http://dx.doi.org/10.7554/eLife.00312.001.</p>
},
	keywords = {Animals, Behavior, Animal, Brain Mapping, CA1 Region, Hippocampal, Conditioning (Psychology), Cues, Dentate Gyrus, Environment, Fear, Gene Expression Regulation, Genes, Reporter, Memory, Memory, Episodic, Mental Recall, Mice, Inbred BALB C, Mice, Inbred C57BL, Mice, Transgenic, Neural Pathways, Neurons, Pattern Recognition, Physiological, Time Factors},
	issn = {2050-084X},
	doi = {10.7554/eLife.00312},
	author = {Deng, Wei and Mayford, Mark and Gage, Fred H}
}
