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Jung JH, Wang Y, Mocle AJ, Zhang T, Köhler S, Frankland PW, Josselyn SA. Examining the engram encoding specificity hypothesis in mice. Neuron 2023; 111:1830-1845.e5. [PMID: 36990091 DOI: 10.1016/j.neuron.2023.03.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 02/07/2023] [Accepted: 03/06/2023] [Indexed: 03/30/2023]
Abstract
According to the encoding specificity hypothesis, memory is best recalled by retrieval cues that overlap with training cues. Human studies generally support this hypothesis. However, memories are thought to be stored in neuronal ensembles (engrams), and retrieval cues are thought to reactivate neurons in an engram to induce memory recall. Here, we visualized engrams in mice to test whether retrieval cues that overlap with training cues produce maximal memory recall via high engram reactivation (engram encoding specificity hypothesis). Using variations of cued threat conditioning (pairing conditioned stimulus [CS] with footshock), we manipulated encoding and retrieval conditions along multiple domains, including pharmacological state, external sensory cue, and internal optogenetic cue. Maximal engram reactivation and memory recall occurred when retrieval conditions closely matched training conditions. These findings provide a biological basis for the encoding specificity hypothesis and highlight the important interaction between stored information (engram) and cues available at memory retrieval (ecphory).
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Affiliation(s)
- Jung Hoon Jung
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada
| | - Ying Wang
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Andrew J Mocle
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Tao Zhang
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada
| | - Stefan Köhler
- Department of Psychology, University of Western Ontario, London, ON N6A 5C2, Canada; The Brain and Mind Institute, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Paul W Frankland
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Psychology, University of Toronto, Toronto, ON M5S 3G3, Canada; Child & Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, ON M5G 1M1, Canada
| | - Sheena A Josselyn
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Psychology, University of Toronto, Toronto, ON M5S 3G3, Canada.
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Schmid D, Qazi A, Scott NM, Tomporowski PD. The effects of physical activity timing and complexity on episodic memory: A randomized controlled trial. PSYCHOLOGY OF SPORT AND EXERCISE 2023; 64:102332. [PMID: 37665816 DOI: 10.1016/j.psychsport.2022.102332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 10/12/2022] [Accepted: 11/06/2022] [Indexed: 09/06/2023]
Abstract
The role of two types of acute physical activity (PA) bouts were assessed on young adults' free-recall and recognition memory in two experiments, which differed in the temporal relation of PA and word encoding. Before or following training on the Rey Auditory Verbal Learning Task, participants performed a simple two-step dance, a complex four-step dance, or remained seated. Hypotheses proposed that PA prior to encoding and complex PA would enhance PA's mnemonic benefits. Memory assessed post-PA, 24 h, and 7 days after training indicated that timing and complexity of PA did not impact free-recall or recognition memory. Findings differ from a previous study showing complex PA benefited motor learning more than simple PA (Tomporowski & Pendleton, 2018). The inconsistency may be due to different working memory processes underlying consolidation and retrieval of procedural or episodic information. Theory-based explanations regarding memory storage and retrieval are proposed to elucidate this selective process.
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Affiliation(s)
| | - Ahmed Qazi
- Kinesiology Department, University of Georgia, USA
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