Optogenetic inhibition of medial entorhinal cortex inputs to the hippocampus during a short period of time right after learning disrupts contextual fear memory formation
Abstract Formation of temporal association memory and context-specific fear memory is thought to require medial entorhinal cortex (MEC) inputs to the hippocampus during learning events. However, whether the MEC inputs are also involved in memory formation during a post-learning period has not been d...
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Online Access: | https://doi.org/10.1186/s13041-020-00719-w |
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doaj-e1ae5a5a13e24916a8528da8862fe93a2021-01-10T12:39:00ZengBMCMolecular Brain1756-66062021-01-011411410.1186/s13041-020-00719-wOptogenetic inhibition of medial entorhinal cortex inputs to the hippocampus during a short period of time right after learning disrupts contextual fear memory formationMin Soo Kang0Jin-Hee Han1Department of Biological Sciences, KAIST Institute for the BioCentury, Korea Advanced Institute of Science and TechnologyDepartment of Biological Sciences, KAIST Institute for the BioCentury, Korea Advanced Institute of Science and TechnologyAbstract Formation of temporal association memory and context-specific fear memory is thought to require medial entorhinal cortex (MEC) inputs to the hippocampus during learning events. However, whether the MEC inputs are also involved in memory formation during a post-learning period has not been directly tested yet. To examine this possibility, we optogenetically inhibited axons and terminals originating from bilateral dorsal MEC excitatory neurons in the dorsal hippocampus for 5 min right after contextual fear conditioning (CFC). Mice expressing eNpHR3.0 exhibited significantly less freezing compared to control mice expressing EGFP alone during retrieval test in the conditioned context 1 day after learning. In contrast, the same optogenetic inhibition of MEC inputs performed 30 min before retrieval test did not affect freezing during retrieval test, excluding the possibility of non-specific deleterious effect of optical inhibition on retrieval process. These results support that contextual fear memory formation requires MEC inputs to the hippocampus during a post-learning period.https://doi.org/10.1186/s13041-020-00719-wMedial entorhinal cortexHippocampusContextual fear conditioning |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Min Soo Kang Jin-Hee Han |
spellingShingle |
Min Soo Kang Jin-Hee Han Optogenetic inhibition of medial entorhinal cortex inputs to the hippocampus during a short period of time right after learning disrupts contextual fear memory formation Molecular Brain Medial entorhinal cortex Hippocampus Contextual fear conditioning |
author_facet |
Min Soo Kang Jin-Hee Han |
author_sort |
Min Soo Kang |
title |
Optogenetic inhibition of medial entorhinal cortex inputs to the hippocampus during a short period of time right after learning disrupts contextual fear memory formation |
title_short |
Optogenetic inhibition of medial entorhinal cortex inputs to the hippocampus during a short period of time right after learning disrupts contextual fear memory formation |
title_full |
Optogenetic inhibition of medial entorhinal cortex inputs to the hippocampus during a short period of time right after learning disrupts contextual fear memory formation |
title_fullStr |
Optogenetic inhibition of medial entorhinal cortex inputs to the hippocampus during a short period of time right after learning disrupts contextual fear memory formation |
title_full_unstemmed |
Optogenetic inhibition of medial entorhinal cortex inputs to the hippocampus during a short period of time right after learning disrupts contextual fear memory formation |
title_sort |
optogenetic inhibition of medial entorhinal cortex inputs to the hippocampus during a short period of time right after learning disrupts contextual fear memory formation |
publisher |
BMC |
series |
Molecular Brain |
issn |
1756-6606 |
publishDate |
2021-01-01 |
description |
Abstract Formation of temporal association memory and context-specific fear memory is thought to require medial entorhinal cortex (MEC) inputs to the hippocampus during learning events. However, whether the MEC inputs are also involved in memory formation during a post-learning period has not been directly tested yet. To examine this possibility, we optogenetically inhibited axons and terminals originating from bilateral dorsal MEC excitatory neurons in the dorsal hippocampus for 5 min right after contextual fear conditioning (CFC). Mice expressing eNpHR3.0 exhibited significantly less freezing compared to control mice expressing EGFP alone during retrieval test in the conditioned context 1 day after learning. In contrast, the same optogenetic inhibition of MEC inputs performed 30 min before retrieval test did not affect freezing during retrieval test, excluding the possibility of non-specific deleterious effect of optical inhibition on retrieval process. These results support that contextual fear memory formation requires MEC inputs to the hippocampus during a post-learning period. |
topic |
Medial entorhinal cortex Hippocampus Contextual fear conditioning |
url |
https://doi.org/10.1186/s13041-020-00719-w |
work_keys_str_mv |
AT minsookang optogeneticinhibitionofmedialentorhinalcortexinputstothehippocampusduringashortperiodoftimerightafterlearningdisruptscontextualfearmemoryformation AT jinheehan optogeneticinhibitionofmedialentorhinalcortexinputstothehippocampusduringashortperiodoftimerightafterlearningdisruptscontextualfearmemoryformation |
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