Abstract

Traditional theories of Spike Time Dependent Plasticity rely on near coincidence between postsynaptic and presynaptic action potentials to produce plasticity. However, recently, the unique dendritic features of the pyramidal neurons, specifically the segregation of their dendritic trees into basal and apical dendrites, have been investigated as a site for branch specific plasticity – the separation of plasticity ‘rules’ across dendritic locales. In this talk, Carl will first introduce the idea of dendrite specific plasticity and present a recent paper by Wright et al. (2025) investigating the differences between apical and basal plasticity rules in L2/3 pyramidal dendrites. Saeyeon will then present the synaptic plasticity mechanisms occurring in the distal tuft dendrites of hippocampal pyramidal neurons (O’Hare et al, 2025). Hippocampal pyramidal neurons support spatial memory by forming place fields, which are known to arise through a recently described mechanism called Behavioral Timescale Synaptic Plasticity (BTSP). According to BTSP , place field formation is driven by plateau potentials in distal dendrites that lead to widespread depolarization across the entire dendritic arbor. However, the relationship between the dendritic and somatic activity in vivo, and the cellular mechanisms that initiate these plateau potentials, remain unclear. Using in vivo recording of both somatic and distal dendritic signals in a single CA1 neuron during a virtual reality-based spatial navigation task in mice, the authors expand on the BTSP model. They demonstrate that the timing and magnitude of dendritic activity predict key properties of the resultant somatic place fields, and that distal tuft dendrites undergo local plasticity during place field formation. Papers Distinct synaptic plasticity rules operate across dendritic compartments in vivo during learning Distal tuft dendrites predict properties of new hippocampal place fields