title: Interplay between short- and long-term plasticity in cell-assembly formation.
abstract: Various hippocampal and neocortical synapses of mammalian brain show both short-term plasticity and long-term plasticity, which are considered to underlie learning and memory by the brain. According to Hebb's postulate, synaptic plasticity encodes memory traces of past experiences into cell assemblies in cortical circuits. However, it remains unclear how the various forms of long-term and short-term synaptic plasticity cooperatively create and reorganize such cell assemblies. Here, we investigate the mechanism in which the three forms of synaptic plasticity known in cortical circuits, i.e., spike-timing-dependent plasticity (STDP), short-term depression (STD) and homeostatic plasticity, cooperatively generate, retain and reorganize cell assemblies in a recurrent neuronal network model. We show that multiple cell assemblies generated by external stimuli can survive noisy spontaneous network activity for an adequate range of the strength of STD. Furthermore, our model predicts that a symmetric temporal window of STDP, such as observed in dopaminergic modulations on hippocampal neurons, is crucial for the retention and integration of multiple cell assemblies. These results may have implications for the understanding of cortical memory processes.
authors.affiliation: Department of Complexity Science and Engineering, The University of Tokyo, Kashiwa, Chiba, Japan; Research Fellow of Japan Society for the Promotion of Science, Chiyoda, Tokyo, Japan; Lab for Neural Circuit Theory, RIKEN Brain Science Institute, Wako, Saitama, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Hiratani
authors.affiliation: Department of Complexity Science and Engineering, The University of Tokyo, Kashiwa, Chiba, Japan; Lab for Neural Circuit Theory, RIKEN Brain Science Institute, Wako, Saitama, Japan; Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Fukai
mesh_terms: D000200:Action Potentials; D000465:Algorithms; D059290:Dopaminergic Neurons / Q000502:physiology; D006624:Hippocampus / Q000502:physiology; D006801:Humans; D017774:Long-Term Potentiation; D008959:Models, Neurological; D009473:Neuronal Plasticity