Between-systems memory interference model: Difference between revisions

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In studies of contextual fear conditioning, there are many views describing the interaction between HPC and non-HPC systems, or the transition of memories from being hippocampus dependent to independent. The HPC and non-HPC systems may acquire the same memories but if the HPC is intact, the non-HPC systems cannot independently form or retrieve these context memories.<ref name="test" /><ref name="best" /> Therefore, the non-HPC systems appear to act like a back-up system for memories, that are only used when the main system, the HPC, is dysfunctional or absent. On the other hand, the HPC and non-HPC systems also have different functions. For example, the hippocampus is known to be important for context discrimination, while non-hippocampal systems have not shown evidence for this specific function <ref name="test" />

One view for the transfer of memories from HPC-dependent to independent is that the strength of memories changes across the HPC and non-HPC systems, with damage to the HPC. In a study by Lehmann and colleagues (2009)<ref name="test" /> adult male rats were put through contextual fear conditioning using feet shocks. If there was HPC damage and the rats experienced 11 sessions worth of shocks in one session, retrograde amnesia resulted. However, if there was damage in the HPC and shocks were applied over many conditioning sessions, then the memory for the contextual fear conditioning was not affected. So within the numerous conditioning sessions, the memory for contextual fear conditioning may have been formed by the non-HPC memory systems. Specifically memory representations in the non-HPC systems may be strengthened and eventually become independent of the HPC, which normally overshadows/interferes with the non-HPC systems in forming representations of memories in contextual fear conditioning.<ref name="best" /> Conversely another view is that memories become independent of the HPC over time due to a reorganization of stored memories.<ref name="test" /><ref>{{cite journal|last=Squires|first=L.R.|author2=Bayley, P.J.|title=The neuroscience of remote memory|journal=Current Opinion in Neurobiology|year=2007|volume=17|pages=185–196|doi=10.1016/j.conb.2007.02.006|issue=2|pmc=2277361}}</ref> Alternatively others believe memories change characteristics to become independent of the HPC, specifically in becoming less precise, more general and context free memories in non-HPC systems, assuming that the HPC is required for precise, detailed, contextual memories.<ref>{{cite journal|last=Moscovitch|first=M|author2=Nadel, I.|author3=Winocur, G.|author4=Gilboa, A.|author5=Rosenbaum, R.S|title=The cognitive neuroscience of remote episodic, semantic and spatial memory|journal=Current Opinion in Neurobiology|year=2006|volume=16|pages=179–190|doi=10.1016/j.conb.2006.03.013|issue=2|pmid=16564688}}</ref>

== Procedure ==