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Disconnecting the dots: Encoding the episodic memory engram| title | Disconnecting the dots: Encoding the episodic memory engram |
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| start_date | 2023/05/02 |
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| schedule | 16h15-17h45 |
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| online | yes |
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| visio | https://univ-grenoble-alpes-fr.zoom.us/j/92229286091?pwd=aGpnKzBSRm5GdTRNdHQ1cEFhREx3Zz09 |
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| location_info | On zoom |
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| summary | Memory is central to cognition. It allows us to learn new tasks, navigate the world, and make decisions based on past experience. There is general agreement that when we experience an event, an engram is created, which encodes information from the event, and later enables us to retrieve these details. But what is the nature of this engram, and how is it able to store information? My aim in this talk is to present a novel view of the engram based on recent advances in optogenetics. The orthodox view of engram encoding claims that the engram is stored in a neural network in virtue of connection strengths between neurons, and that patterns of activation instantiate different episodic memories. This implies that the reactivation of synaptic connections are vital for retrieving a memory. I present evidence from optogenetics which suggests that this is not the case, hence putting pressure on the idea that the engram is stored in virtue of connection strengths. Optogenetics is a technique whereby individual neurons can be tagged and then reactivated artificially. For example, experiments with mice expose them to a chamber where they receive foot shocks (fearful condition), after which experimenters can reproduce the fearful behaviour in a novel chamber by artificially reactivating the neurons which were activated in the original chamber. I argue that experimental results indicate that memory resides inside the neuron, as (1) reactivating the neuron reproduces the encoded behaviour. Another experiment tests whether inhibiting the consolidation process, widely thought of as necessary to stabilise the engram, prevents the artificial reactivation of memory. I argue that results here also suggest that memory resides inside the neuron, as (2) inhibiting the consolidation process does not negatively affect the reproduction of the behaviour. Hence, results from optogenetics speak against the orthodox view of engram storage. Having put the new view on the table, I highlight how there are still many details that need to be ironed out before it is as explanatorily powerful as the orthodox view, and I suggest possible fruitful ways forward. |
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| responsibles | Righetti, Werning, Kourken, Andonovski |
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Workflow history| from state (1) | to state | comment | date |
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| submitted | published | | 2023/04/20 14:14 UTC |
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