1
|
Michalikova M, Remme MW, Schmitz D, Schreiber S, Kempter R. Spikelets in pyramidal neurons: generating mechanisms, distinguishing properties, and functional implications. Rev Neurosci 2019; 31:101-119. [DOI: 10.1515/revneuro-2019-0044] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 05/13/2019] [Indexed: 11/15/2022]
Abstract
Abstract
Spikelets are small spike-like depolarizations that are found in somatic recordings of many neuron types. Spikelets have been assigned important functions, ranging from neuronal synchronization to the regulation of synaptic plasticity, which are specific to the particular mechanism of spikelet generation. As spikelets reflect spiking activity in neuronal compartments that are electrotonically distinct from the soma, four modes of spikelet generation can be envisaged: (1) dendritic spikes or (2) axonal action potentials occurring in a single cell as well as action potentials transmitted via (3) gap junctions or (4) ephaptic coupling in pairs of neurons. In one of the best studied neuron type, cortical pyramidal neurons, the origins and functions of spikelets are still unresolved; all four potential mechanisms have been proposed, but the experimental evidence remains ambiguous. Here we attempt to reconcile the scattered experimental findings in a coherent theoretical framework. We review in detail the various mechanisms that can give rise to spikelets. For each mechanism, we present the biophysical underpinnings as well as the resulting properties of spikelets and compare these predictions to experimental data from pyramidal neurons. We also discuss the functional implications of each mechanism. On the example of pyramidal neurons, we illustrate that several independent spikelet-generating mechanisms fulfilling vastly different functions might be operating in a single cell.
Collapse
Affiliation(s)
- Martina Michalikova
- Institute for Theoretical Biology, Department of Biology , Humboldt-Universität zu Berlin , D-10115 Berlin , Germany
| | - Michiel W.H. Remme
- Institute for Theoretical Biology, Department of Biology , Humboldt-Universität zu Berlin , D-10115 Berlin , Germany
| | - Dietmar Schmitz
- Neuroscience Research Center, Charite-University Medicine , D-10117 Berlin , Germany
- Bernstein Center for Computational Neuroscience Berlin , D-10115 Berlin , Germany
- Einstein Center for Neurosciences Berlin , D-10117 Berlin , Germany
- Berlin Institute of Health , D-10178 Berlin , Germany
- Cluster of Excellence NeuroCure , D-10117 Berlin , Germany
| | - Susanne Schreiber
- Institute for Theoretical Biology, Department of Biology , Humboldt-Universität zu Berlin , D-10115 Berlin , Germany
- Einstein Center for Neurosciences Berlin , D-10117 Berlin , Germany
- Bernstein Center for Computational Neuroscience Berlin , Philippstr. 13, D-10115 Berlin , Germany
| | - Richard Kempter
- Institute for Theoretical Biology, Department of Biology , Humboldt-Universität zu Berlin , D-10115 Berlin , Germany
- Einstein Center for Neurosciences Berlin , D-10117 Berlin , Germany
- Bernstein Center for Computational Neuroscience Berlin , Philippstr. 13, D-10115 Berlin , Germany
| |
Collapse
|