Author
Michael A. Yassa
Other affiliations: Hôpital Maisonneuve-Rosemont, Johns Hopkins University, University of California ...read more
Bio: Michael A. Yassa is an academic researcher from University of California, Irvine. The author has contributed to research in topics: Hippocampal formation & Dentate gyrus. The author has an hindex of 39, co-authored 142 publications receiving 7450 citations. Previous affiliations of Michael A. Yassa include Hôpital Maisonneuve-Rosemont & Johns Hopkins University.
Papers published on a yearly basis
Papers
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TL;DR: This review summarizes data from electrophysiological recordings, lesion studies, immediate-early gene imaging, transgenic mouse models, as well as human functional neuroimaging that provide convergent evidence for the involvement of particular hippocampal subfields in pattern separation.
1,134 citations
TL;DR: The view that increased hippocampal activation in aMCI is a dysfunctional condition and that targeting excess hippocampal activity has therapeutic potential is supported.
732 citations
TL;DR: A behavioral impairment in pattern separation was found in a sample of healthy older adults compared with young controls and a specific functional deficit in the CA3/dentate network contributes to memory difficulties with aging, which is consistent with recent fMRI and behavioral reports in healthy aging.
Abstract: There is widespread evidence that memory deteriorates with aging, however the exact mechanisms that underlie these changes are not well understood. Given the growing size of the aging population, there is an imperative to study age-related neurocognitive changes in order to better parse healthy from pathological aging. Using a behavioral paradigm that taxes pattern separation (the ability to differentiate novel yet similar information from previously learned information and thus avoid interference), we investigated age-related neural changes in the human hippocampus using high-resolution (1.5 mm isotropic) BOLD fMRI. Recent evidence from animal studies suggests that hyperactivity in the CA3 region of the hippocampus may underlie behavioral deficits in pattern separation in aged rats. Here, we report evidence that is consistent with findings from the animal studies. We found a behavioral impairment in pattern separation in a sample of healthy older adults compared to young controls. We also found a related increase in CA3/dentate gyrus activity levels during an fMRI contrast that stresses pattern separation abilities. In a detailed analysis of behavior, we also found that the pattern of impairment was consistent with the predictions of the animal model, where larger changes in the input (greater dissimilarity) were required in order for elderly adults to successfully encode new information as distinct from previously learned information. These findings are also consistent with recent fMRI and behavioral reports in healthy aging, and further suggest that a specific functional deficit in the CA3/dentate network contributes to memory difficulties with aging.
479 citations
TL;DR: The hypothesis that patients with amnestic MCI have deficits in pattern separation, along with hyperactive fMRI BOLD activity in the CA3 region of the hippocampus, is tested and may be evidence for a dysfunctional encoding mechanism, consistent with the predictions of computational models of hippocampal learning.
444 citations
TL;DR: The BPS-O task provides a sensitive measure for observing changes in memory performance across the lifespan and may be useful for the early detection of memory impairments that may provide an early signal of later development to mild cognitive impairment.
408 citations
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9,362 citations
01 Jan 1964
TL;DR: In this paper, the notion of a collective unconscious was introduced as a theory of remembering in social psychology, and a study of remembering as a study in Social Psychology was carried out.
Abstract: Part I. Experimental Studies: 2. Experiment in psychology 3. Experiments on perceiving III Experiments on imaging 4-8. Experiments on remembering: (a) The method of description (b) The method of repeated reproduction (c) The method of picture writing (d) The method of serial reproduction (e) The method of serial reproduction picture material 9. Perceiving, recognizing, remembering 10. A theory of remembering 11. Images and their functions 12. Meaning Part II. Remembering as a Study in Social Psychology: 13. Social psychology 14. Social psychology and the matter of recall 15. Social psychology and the manner of recall 16. Conventionalism 17. The notion of a collective unconscious 18. The basis of social recall 19. A summary and some conclusions.
5,690 citations
TL;DR: This is the first study to use a consistent transformation framework to provide a reproducible evaluation of the isolated effect of the similarity metric on optimal template construction and brain labeling, and to quantify the similarity of templates derived from different subgroups.
3,491 citations
Columbia University1, University of Oxford2, Nathan Kline Institute for Psychiatric Research3, New York University4, University College London5, University of Pennsylvania6, University of California, Los Angeles7, University of Iowa8, McGill University9, French Institute of Health and Medical Research10, French Institute for Research in Computer Science and Automation11, John Radcliffe Hospital12, Imperial College London13, Mauna Kea Technologies14
TL;DR: This study is the largest evaluation of nonlinear deformation algorithms applied to brain image registration ever conducted and suggests that the findings are generalizable to new subject populations that are labeled or evaluated using different labeling protocols.
2,214 citations