TY - JOUR
T1 - The cortical structure of consolidated memory
T2 - A hypothesis on the role of the cingulate-entorhinal cortical connection
AU - Insel, Nathan
AU - Takehara-Nishiuchi, Kaori
N1 - Funding Information:
This work was supported by NSERC Discovery Grant and CFI Leaders Opportunity Fund (KT).
PY - 2013/11
Y1 - 2013/11
N2 - Daily experiences are represented by networks of neurons distributed across the neocortex, bound together for rapid storage and later retrieval by the hippocampus. While the hippocampus is necessary for retrieving recent episode-based memory associations, over time, consolidation processes take place that enable many of these associations to be expressed independent of the hippocampus. It is generally thought that mechanisms of consolidation involve synaptic weight changes between cortical regions; or, in other words, the formation of "horizontal" cortico-cortical connections. Here, we review anatomical, behavioral, and physiological data which suggest that the connections in and between the entorhinal and cingulate cortices may be uniquely important for the long-term storage of memories that initially depend on the hippocampus. We propose that current theories of consolidation that divide memory into dual systems of hippocampus and neocortex might beimproved by introducing a third, middle layer of entorhinal and cingulate allocortex, the synaptic weights within which are necessary and potentially sufficient for maintaining initially hippocampus-dependent associations over long time periods. This hypothesis makes a number of still untested predictions, and future experiments designed to address these will help to fill gaps in the current understanding of the cortical structure of consolidated memory.
AB - Daily experiences are represented by networks of neurons distributed across the neocortex, bound together for rapid storage and later retrieval by the hippocampus. While the hippocampus is necessary for retrieving recent episode-based memory associations, over time, consolidation processes take place that enable many of these associations to be expressed independent of the hippocampus. It is generally thought that mechanisms of consolidation involve synaptic weight changes between cortical regions; or, in other words, the formation of "horizontal" cortico-cortical connections. Here, we review anatomical, behavioral, and physiological data which suggest that the connections in and between the entorhinal and cingulate cortices may be uniquely important for the long-term storage of memories that initially depend on the hippocampus. We propose that current theories of consolidation that divide memory into dual systems of hippocampus and neocortex might beimproved by introducing a third, middle layer of entorhinal and cingulate allocortex, the synaptic weights within which are necessary and potentially sufficient for maintaining initially hippocampus-dependent associations over long time periods. This hypothesis makes a number of still untested predictions, and future experiments designed to address these will help to fill gaps in the current understanding of the cortical structure of consolidated memory.
KW - Consolidation
KW - Entorhinal cortex
KW - Episodic memory
KW - Hippocampus
KW - Prefrontal cortex
KW - Trace conditioning
UR - http://www.scopus.com/inward/record.url?scp=84888286818&partnerID=8YFLogxK
U2 - 10.1016/j.nlm.2013.07.019
DO - 10.1016/j.nlm.2013.07.019
M3 - Review article
C2 - 23911917
AN - SCOPUS:84888286818
SN - 1074-7427
VL - 106
SP - 343
EP - 350
JO - Neurobiology of Learning and Memory
JF - Neurobiology of Learning and Memory
ER -