Linking Memories across Time via Neuronal and Dendritic Overlaps in Model Neurons with Active Dendrites.
Memories are believed to be stored in distributed neuronal assemblies through activity-induced changes in synaptic and intrinsic properties. However, the specific mechanisms by which different memories become associated or linked remain a mystery. Here, we develop a simplified, biophysically inspired network model that incorporates multiple plasticity processes and explains linking of information at three different levels: (1) learning of a single associative memory, (2) rescuing of a weak memory when paired with a strong one, and (3) linking of multiple memories across time. By dissecting synaptic from intrinsic plasticity and neuron-wide from dendritically restricted protein capture, the model reveals a simple, unifying principle: linked memories share synaptic clusters within the dendrites of overlapping populations of neurons. The model generates numerous experimentally testable predictions regarding the cellular and sub-cellular properties of memory engrams as well as their spatiotemporal interactions.
Institute of Molecular Biology and Biotechnology (IMBB), Foundation for Research and Technology, Hellas (FORTH), N. Plastira 100, P.O. Box 1385, Heraklion, Crete 70013, Greece; Department of Biology, University of Crete, P.O. Box 2208, Heraklion, Crete 70013, Greece.
George
G
Kastellakis
Integrative Center for Learning and Memory, Departments of Neurobiology, Psychology, and Psychiatry, and Brain Research Institute, UCLA, 2554 Gonda Center, Los Angeles, CA 90095, USA.
Alcino J
AJ
Silva
Institute of Molecular Biology and Biotechnology (IMBB), Foundation for Research and Technology, Hellas (FORTH), N. Plastira 100, P.O. Box 1385, Heraklion, Crete 70013, Greece. Electronic address: poirazi@imbb.forth.gr.
Panayiota
P
Poirazi
D000200:Action Potentials; D003712:Dendrites / Q000502:physiology*; D008568:Memory / Q000502:physiology*; D008959:Models, Neurological; D009415:Nerve Net / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009473:Neuronal Plasticity / Q000502:physiology; D013347:Subcellular Fractions / Q000378:metabolism; D013997:Time Factors
D009419:Nerve Tissue Proteins
computational model; information binding; intrinsic excitability; memory allocation; non-linear dendrites; plasticity; simplified neurons; synaptic clustering; synaptic tagging and capture