PT  - JOURNAL ARTICLE
AU  - Yu, Cheng-Long
AU  - Li, Jin-Nan
AU  - Gan, Ping
AU  - Wang, Li-Ping
AU  - Yang, Yue-Xiong
AU  - Yu, Da-Fu
AU  - Mao, Rong-Rong
AU  - Xu, Fu-Qiang
AU  - Zhou, Qi-Xin
AU  - Richter-Levin, Gal
AU  - Xu, Lin
AU  - Zhou, Heng
TI  - Developing of focal ischemia in the hippocampus or the amygdala reveals a regional compensation rule for fear memory acquisition
AID  - 10.1523/ENEURO.0398-20.2021
DP  - 2021 Mar 29
TA  - eneuro
PG  - ENEURO.0398-20.2021
4099  - http://www.eneuro.org/content/early/2021/03/27/ENEURO.0398-20.2021.short
4100  - http://www.eneuro.org/content/early/2021/03/27/ENEURO.0398-20.2021.full
AB  - Circuit compensation is often observed in patients with acute ischemic stroke, suggesting the importance of the interaction between brain regions. Also, contextual fear memory is an association between multisensory contexts and fearful stimuli, for which the interaction between the hippocampus and the amygdala is believed to be critical. To understand how focal ischemia in one region could influence the other region, we used a modified photo-thrombosis to induce focal ischemia in the hippocampus or the amygdala or both in freely-moving rats. We found that the learning curve and short-term memory were not affected in the rats although focal ischemia was induced 5 hrs before learning in either the hippocampus or the amygdala; these were impaired by the induction of ischemia in both the regions. Furthermore, the learning curve and short-term memory were impaired when ischemia was induced 24 hrs before learning in either the hippocampus or the amygdala when the synaptic transmission was altered in one region due to ischemia in the other region. These results suggest that the circuit compensation between the hippocampus and the amygdala is critical for fear memory acquisition.Significance StatementContextual fear memory needs the interconnection between the hippocampus and the amygdala. However, it is unclear whether and how the two regions produce circuit compensation under an ischemic situation. Here, we employed the developing of ischemia in the hippocampus or the amygdala or both in freely moving rats. We found that memory acquisition was not affected 5 hrs post-ischemia, but it was impaired 24 hrs post-ischemia when the synaptic transmission was impaired in one region due to ischemia in the other region. Furthermore, ischemia in both brain regions impaired memory acquisition. These results indicate a circuit compensation between the hippocampus and the amygdala in memory acquisition if one with ischemia does not affect the function of the other.