scholarly journals Retrograde amnesia of contextual fear conditioning: Evidence for retrosplenial cortex involvement in configural processing.

2017 ◽  
Vol 131 (1) ◽  
pp. 46-54 ◽  
Author(s):  
Travis P. Todd ◽  
Nicole E. DeAngeli ◽  
Matthew Y. Jiang ◽  
David J. Bucci
Keyword(s):  
Fear Conditioning ◽  
Retrograde Amnesia ◽  
Retrosplenial Cortex ◽  
Contextual Fear Conditioning ◽  
Configural Processing ◽  
Contextual Fear

scholarly journals Network supporting contextual fear learning after dorsal hippocampal damage has increased dependence on retrosplenial cortex

2017 ◽  
Author(s):  
Cesar A.O. Coelho ◽  
Tatiana L. Ferreira ◽  
Juliana C.K. Soares ◽  
João R. Sato ◽  
Maria Gabriela M. Oliveira
Keyword(s):  
Fear Conditioning ◽  
Correlation Coefficients ◽  
Brain Regions ◽  
Memory System ◽  
Retrosplenial Cortex ◽  
Contextual Fear Conditioning ◽  
Fear Learning ◽  
Hippocampal Damage ◽  
Contextual Fear ◽  
Dorsal Hippocampal

ABSTRACTHippocampal damage results in profound retrograde, but no anterograde amnesia in contextual fear conditioning (CFC). Although the content learned in the latter have been discussed, the compensating regions were seldom proposed and never empirically addressed. Here, we employed network analysis of pCREB expression quantified from brain slices of rats with dorsal hippocampal lesion (dHPC) after undergoing CFC session. Using inter-regional correlations of pCREB-positive nuclei between brain regions, we modelled functional networks using different thresholds. The dHPC network showed small-world topology, equivalent to SHAM (control) network. However, diverging hubs were identified in each network. In a direct comparison, hubs in both networks showed consistently higher centrality values compared to the other network. Further, the distribution of correlation coefficients was different between the groups, with most significantly stronger correlation coefficients belonging to the SHAM network. These results suggest that dHPC network engaged in CFC learning is partially different, and engage alternative hubs. We next tested if pre-training lesions of dHPC and one of the new dHPC network hubs (perirhinal, Per; or disgranular retrosplenial, RSC, cortices) would impair CFC. Only dHPC-RSC, but not dHPC-Per, impaired CFC. Interestingly, only RSC showed a consistently higher centrality in the dHPC network, suggesting that the increased centrality reflects an increased functional dependence on RSC. Our results provide evidence that, without hippocampus, the RSC, an anatomically central region in the medial temporal lobe memory system might support CFC learning and memory.AUTHOR SUMMARYWhen determined cognitive performances are not affected by brain lesions of regions generally involved in that performance, the interpretation is that the remaining regions can compensate the damaged one. In contextual fear conditioning, a memory model largely used in laboratory rodents, hippocampal lesions produce amnesia for events occurred before, but not after the lesion, although the hippocampus is known to be important for new learning. Addressing compensation in animal models has always been challenging as it requires large-scale brain mapping. Here, we quantified 30 brain regions and used mathematical tools to model how a brain network can compensate hippocampal loss and learn contextual fear. We described that the damaged network preserved general interactivity characteristics, although different brain regions were identified as highly important for the network (e.g. highly connected). Further, we empirically validated our network model by performing double lesions of the hippocampus and the alternative hubs observed in the network models. We verified that double lesion of the hippocampus and retrosplenial cortex, one of the hubs, impaired contextual fear learning. We provide evidence that without hippocampus, the remaining network relies on alternative important regions from the memory system to coordinate contextual fear learning.

Role of dorsal and ventral hippocampal muscarinic receptor activity in acquisition and retention of contextual fear conditioning.

2020 ◽  
Vol 134 (5) ◽  
pp. 460-470
Author(s):  
Claudia C. Pinizzotto ◽  
Nicholas A. Heroux ◽  
Colin J. Horgan ◽  
Mark E. Stanton
Keyword(s):  
Fear Conditioning ◽  
Muscarinic Receptor ◽  
Contextual Fear Conditioning ◽  
Receptor Activity ◽  
Contextual Fear

scholarly journals Hippocampus-retrosplenial cortex interaction is increased during phasic REM and contributes to memory consolidation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniel Gomes de Almeida-Filho ◽  
Bruna Del Vechio Koike ◽  
Francesca Billwiller ◽  
Kelly Soares Farias ◽  
Igor Rafael Praxedes de Sales ◽  
...  
Keyword(s):  
Rem Sleep ◽  
Memory Consolidation ◽  
Retrosplenial Cortex ◽  
Contextual Fear Conditioning ◽  
Oscillatory Activity ◽  
Theta Oscillation ◽  
Contextual Fear ◽  
Before And After ◽  
Freely Behaving ◽  
Phasic Rem Sleep

AbstractHippocampal (HPC) theta oscillation during post-training rapid eye movement (REM) sleep supports spatial learning. Theta also modulates neuronal and oscillatory activity in the retrosplenial cortex (RSC) during REM sleep. To investigate the relevance of theta-driven interaction between these two regions to memory consolidation, we computed the Granger causality within theta range on electrophysiological data recorded in freely behaving rats during REM sleep, both before and after contextual fear conditioning. We found a training-induced modulation of causality between HPC and RSC that was correlated with memory retrieval 24 h later. Retrieval was proportional to the change in the relative influence RSC exerted upon HPC theta oscillation. Importantly, causality peaked during theta acceleration, in synchrony with phasic REM sleep. Altogether, these results support a role for phasic REM sleep in hippocampo-cortical memory consolidation and suggest that causality modulation between RSC and HPC during REM sleep plays a functional role in that phenomenon.

scholarly journals Dysbindin-1 loss compromises NMDAR-dependent synaptic plasticity and contextual fear conditioning

Hippocampus ◽  
2013 ◽  
Vol 24 (2) ◽  
pp. 204-213 ◽  
Author(s):  
W. Bailey Glen ◽  
Bryant Horowitz ◽  
Gregory C. Carlson ◽  
Tyrone D. Cannon ◽  
Konrad Talbot ◽  
...  
Keyword(s):  
Synaptic Plasticity ◽  
Fear Conditioning ◽  
Contextual Fear Conditioning ◽  
Contextual Fear
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