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Sheridan CL, Bonner L, Crystal JD. Replay of incidentally encoded novel odors in the rat. Anim Cogn 2024; 27:43. [PMID: 38874623 PMCID: PMC11178560 DOI: 10.1007/s10071-024-01880-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 05/28/2024] [Accepted: 05/29/2024] [Indexed: 06/15/2024]
Abstract
Although events are not always known to be important when they occur, people can remember details about such incidentally encoded information using episodic memory. Sheridan et al. (2024) argued that rats replayed episodic memories of incidentally encoded information in an unexpected assessment of memory. In one task, rats reported the third-last item in an explicitly encoded list of trial-unique odors. In a second task, rats foraged in a radial maze in the absence of odors. On a critical test, rats foraged in the maze, but scented lids covered the food. Next, memory of the third-last odor was assessed. The rats correctly answered the unexpected question. Because the odors used in the critical test were the same as those used during training, automatically encoding odors for the purpose of taking an upcoming test of memory (stimulus generalization) may have been encouraged. Here, we provided an opportunity for incidental encoding of novel odors. Previously trained rats foraged in the radial maze with entirely novel odors covering the food. Next, memory of the third-last odor was assessed. The rats correctly answered the unexpected question. High accuracy when confronted with novel odors provides evidence that the rats did not automatically encode odors for the purpose of taking an upcoming test, ruling out stimulus generalization. We conclude that rats encode multiple pieces of putatively unimportant information, and later replayed a stream of novel episodic memories when that information was needed to solve an unexpected problem.
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Affiliation(s)
- Cassandra L Sheridan
- Department of Psychological & Brain Sciences, Indiana University, Bloomington, IN, USA
| | - Lauren Bonner
- Department of Psychological & Brain Sciences, Indiana University, Bloomington, IN, USA
| | - Jonathon D Crystal
- Department of Psychological & Brain Sciences, Indiana University, Bloomington, IN, USA.
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Sheridan CL, Lang S, Knappenberger M, Albers C, Loper R, Tillett B, Sanchez J, Wilcox A, Harrison T, Panoz-Brown D, Crystal JD. Replay of incidentally encoded episodic memories in the rat. Curr Biol 2024; 34:641-647.e5. [PMID: 38218186 DOI: 10.1016/j.cub.2023.12.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/03/2023] [Accepted: 12/13/2023] [Indexed: 01/15/2024]
Abstract
Although events are not always known to be important when they occur, people can remember details about such incidentally encoded information using episodic memory. Importantly, when information is explicitly encoded for use in an expected test of retention (as in most assessments in animals), it is possible that it is used to generate a planned action1,2,3; thus, the remembered action can occur without remembering the earlier episode. By contrast, when a test is unexpected, transforming information into an action plan is unlikely because the importance of the information and the nature of the test are not yet known. Thus, accurate performance in an unexpected test after incidental encoding documents episodic memory.1,2,3,4,5,6,7,8 Here, we present evidence that rats replay episodic memories of incidentally encoded information in an unexpected assessment of memory. In one task,9 rats reported the third-last item in an explicitly encoded list of trial-unique odors. In a second task,10 rats foraged in a radial maze in the absence of odors. On a critical test, rats foraged in the radial maze, but scented lids covered the food. Next, memory of the third-last odor was assessed. All participating rats correctly answered the unexpected question. These results suggest that rats encoded multiple pieces of putatively unimportant information, and later they replayed a stream of episodic memories when that information was needed to solve an unexpected problem. We propose that rats replay episodic memories of incidentally encoded information, which documents a critical aspect of human episodic memory in a non-human animal.
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Affiliation(s)
- Cassandra L Sheridan
- Department of Psychological and Brain Sciences, Indiana University, 1101 E 10(TH) ST, Bloomington, IN 47405-7007, USA
| | - Stephen Lang
- Department of Psychological and Brain Sciences, Indiana University, 1101 E 10(TH) ST, Bloomington, IN 47405-7007, USA
| | - Mya Knappenberger
- Department of Psychological and Brain Sciences, Indiana University, 1101 E 10(TH) ST, Bloomington, IN 47405-7007, USA
| | - Cami Albers
- Department of Psychological and Brain Sciences, Indiana University, 1101 E 10(TH) ST, Bloomington, IN 47405-7007, USA
| | - Ryleigh Loper
- Department of Psychological and Brain Sciences, Indiana University, 1101 E 10(TH) ST, Bloomington, IN 47405-7007, USA
| | - Baily Tillett
- Department of Psychological and Brain Sciences, Indiana University, 1101 E 10(TH) ST, Bloomington, IN 47405-7007, USA
| | - Jonah Sanchez
- Department of Psychological and Brain Sciences, Indiana University, 1101 E 10(TH) ST, Bloomington, IN 47405-7007, USA
| | - Alyssa Wilcox
- Department of Psychological and Brain Sciences, Indiana University, 1101 E 10(TH) ST, Bloomington, IN 47405-7007, USA
| | - Tess Harrison
- Department of Psychological and Brain Sciences, Indiana University, 1101 E 10(TH) ST, Bloomington, IN 47405-7007, USA
| | - Danielle Panoz-Brown
- Department of Psychological and Brain Sciences, Indiana University, 1101 E 10(TH) ST, Bloomington, IN 47405-7007, USA
| | - Jonathon D Crystal
- Department of Psychological and Brain Sciences, Indiana University, 1101 E 10(TH) ST, Bloomington, IN 47405-7007, USA.
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Layfield D, Sidell N, Abdullahi A, Newman EL. Dorsal hippocampus not always necessary in a radial arm maze delayed win-shift task. Hippocampus 2019; 30:121-129. [PMID: 31453652 DOI: 10.1002/hipo.23141] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 05/06/2019] [Accepted: 06/12/2019] [Indexed: 11/07/2022]
Abstract
Spatial working memory is important for foraging and navigating the environment. However, its neural underpinnings remain poorly understood. The hippocampus, known for its spatial coding and involvement in spatial memory, is widely understood to be necessary for spatial working memory when retention intervals increase beyond seconds into minutes. Here, we describe new evidence that the dorsal hippocampus is not always necessary for spatial working memory for retention intervals of 8 min. Rats were trained to perform a delayed spatial win shift radial arm maze task with an 8-min delay between study and test phases. We then tested whether bilateral inactivation of the dorsal hippocampus between the study and test phases impaired behavioral performance at test. Inactivation was achieved through a bilateral infusion of lidocaine. Performance following lidocaine was compared to control trials, in which, sterile phosphate buffered saline (PBS) was infused. Test performance did not differ between the lidocaine and PBS conditions, remaining high in each. To explore the possibility that this insensitivity to inactivation was a result of overtraining, a second cohort of animals received substantially less training prior to the infusions. In this second cohort, lidocaine infusions did significantly impair task performance. These data indicate that successful performance of a spatial win-shift task on the 8-arm maze need not always be hippocampally dependent.
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Affiliation(s)
- Dylan Layfield
- Department of Psychological and Brain Sciences, Indiana University, Indiana
| | - Nathan Sidell
- Department of Psychological and Brain Sciences, Indiana University, Indiana
| | - Afnan Abdullahi
- Department of Psychological and Brain Sciences, Indiana University, Indiana
| | - Ehren L Newman
- Department of Psychological and Brain Sciences, Indiana University, Indiana
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Woldemichael BT, Jawaid A, Kremer EA, Gaur N, Krol J, Marchais A, Mansuy IM. The microRNA cluster miR-183/96/182 contributes to long-term memory in a protein phosphatase 1-dependent manner. Nat Commun 2016; 7:12594. [PMID: 27558292 PMCID: PMC5007330 DOI: 10.1038/ncomms12594] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 07/13/2016] [Indexed: 12/24/2022] Open
Abstract
Memory formation is a complex cognitive function regulated by coordinated synaptic and nuclear processes in neurons. In mammals, it is controlled by multiple molecular activators and suppressors, including the key signalling regulator, protein phosphatase 1 (PP1). Here, we show that memory control by PP1 involves the miR-183/96/182 cluster and its selective regulation during memory formation. Inhibiting nuclear PP1 in the mouse brain, or training on an object recognition task similarly increases miR-183/96/182 expression in the hippocampus. Mimicking this increase by miR-183/96/182 overexpression enhances object memory, while knocking-down endogenous miR-183/96/182 impairs it. This effect involves the modulation of several plasticity-related genes, with HDAC9 identified as an important functional target. Further, PP1 controls miR-183/96/182 in a transcription-independent manner through the processing of their precursors. These findings provide novel evidence for a role of miRNAs in memory formation and suggest the implication of PP1 in miRNAs processing in the adult brain.
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Affiliation(s)
- Bisrat T Woldemichael
- Laboratory of Neuroepigenetics, University of Zurich/Swiss Federal Institute of Technology, Brain Research Institute, Neuroscience Center Zürich, Zurich CH-8057, Switzerland
| | - Ali Jawaid
- Laboratory of Neuroepigenetics, University of Zurich/Swiss Federal Institute of Technology, Brain Research Institute, Neuroscience Center Zürich, Zurich CH-8057, Switzerland
| | - Eloïse A Kremer
- Laboratory of Neuroepigenetics, University of Zurich/Swiss Federal Institute of Technology, Brain Research Institute, Neuroscience Center Zürich, Zurich CH-8057, Switzerland
| | - Niharika Gaur
- Laboratory of Neuroepigenetics, University of Zurich/Swiss Federal Institute of Technology, Brain Research Institute, Neuroscience Center Zürich, Zurich CH-8057, Switzerland
| | - Jacek Krol
- Friedrich Miescher Institute for Biomedical Research, Basel CH-4048, Switzerland
| | - Antonin Marchais
- Institute of Agricultural Sciences, Swiss Federal Institute of Technology, Zurich CH-8092, Switzerland
| | - Isabelle M Mansuy
- Laboratory of Neuroepigenetics, University of Zurich/Swiss Federal Institute of Technology, Brain Research Institute, Neuroscience Center Zürich, Zurich CH-8057, Switzerland
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Bratch A, Kann S, Cain JA, Wu JE, Rivera-Reyes N, Dalecki S, Arman D, Dunn A, Cooper S, Corbin HE, Doyle AR, Pizzo MJ, Smith AE, Crystal JD. Working Memory Systems in the Rat. Curr Biol 2016; 26:351-5. [PMID: 26776732 DOI: 10.1016/j.cub.2015.11.068] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 11/19/2015] [Accepted: 11/30/2015] [Indexed: 11/29/2022]
Abstract
A fundamental feature of memory in humans is the ability to simultaneously work with multiple types of information using independent memory systems. Working memory is conceptualized as two independent memory systems under executive control [1, 2]. Although there is a long history of using the term "working memory" to describe short-term memory in animals, it is not known whether multiple, independent memory systems exist in nonhumans. Here, we used two established short-term memory approaches to test the hypothesis that spatial and olfactory memory operate as independent working memory resources in the rat. In the olfactory memory task, rats chose a novel odor from a gradually incrementing set of old odors [3]. In the spatial memory task, rats searched for a depleting food source at multiple locations [4]. We presented rats with information to hold in memory in one domain (e.g., olfactory) while adding a memory load in the other domain (e.g., spatial). Control conditions equated the retention interval delay without adding a second memory load. In a further experiment, we used proactive interference [5-7] in the spatial domain to compromise spatial memory and evaluated the impact of adding an olfactory memory load. Olfactory and spatial memory are resistant to interference from the addition of a memory load in the other domain. Our data suggest that olfactory and spatial memory draw on independent working memory systems in the rat.
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Affiliation(s)
- Alexander Bratch
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405-7007, USA
| | - Spencer Kann
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405-7007, USA
| | - Joshua A Cain
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405-7007, USA
| | - Jie-En Wu
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405-7007, USA
| | - Nilda Rivera-Reyes
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405-7007, USA
| | - Stefan Dalecki
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405-7007, USA
| | - Diana Arman
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405-7007, USA
| | - Austin Dunn
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405-7007, USA
| | - Shiloh Cooper
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405-7007, USA
| | - Hannah E Corbin
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405-7007, USA
| | - Amanda R Doyle
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405-7007, USA
| | - Matthew J Pizzo
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405-7007, USA
| | - Alexandra E Smith
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405-7007, USA
| | - Jonathon D Crystal
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405-7007, USA.
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