Enhanced Release Probability without Changes in Synaptic Delay during Analogue–Digital Facilitation
Neuronal timing with millisecond precision is critical for many brain functions such as sensory perception, learning and memory formation. At the level of the chemical synapse, the synaptic delay is determined by the presynaptic release probability (<i>Pr</i>) and the waveform of the pre...
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| Format: | Article |
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MDPI AG
2024-03-01
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| Series: | Cells |
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| Online Access: | https://www.mdpi.com/2073-4409/13/7/573 |
| _version_ | 1797212753131208704 |
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| author | Sami Boudkkazi Dominique Debanne |
| author_facet | Sami Boudkkazi Dominique Debanne |
| author_sort | Sami Boudkkazi |
| collection | DOAJ |
| description | Neuronal timing with millisecond precision is critical for many brain functions such as sensory perception, learning and memory formation. At the level of the chemical synapse, the synaptic delay is determined by the presynaptic release probability (<i>Pr</i>) and the waveform of the presynaptic action potential (AP). For instance, paired-pulse facilitation or presynaptic long-term potentiation are associated with reductions in the synaptic delay, whereas paired-pulse depression or presynaptic long-term depression are associated with an increased synaptic delay. Parallelly, the AP broadening that results from the inactivation of voltage gated potassium (Kv) channels responsible for the repolarization phase of the AP delays the synaptic response, and the inactivation of sodium (Nav) channels by voltage reduces the synaptic latency. However, whether synaptic delay is modulated during depolarization-induced analogue–digital facilitation (d-ADF), a form of context-dependent synaptic facilitation induced by prolonged depolarization of the presynaptic neuron and mediated by the voltage-inactivation of presynaptic Kv1 channels, remains unclear. We show here that despite <i>Pr</i> being elevated during d-ADF at pyramidal L5-L5 cell synapses, the synaptic delay is surprisingly unchanged. This finding suggests that both <i>Pr</i>- and AP-dependent changes in synaptic delay compensate for each other during d-ADF. We conclude that, in contrast to other short- or long-term modulations of presynaptic release, synaptic timing is not affected during d-ADF because of the opposite interaction of <i>Pr</i>- and AP-dependent modulations of synaptic delay. |
| first_indexed | 2024-04-24T10:47:23Z |
| format | Article |
| id | doaj.art-1898d2c5394e46f1a8c7a7db39f0af30 |
| institution | Directory Open Access Journal |
| issn | 2073-4409 |
| language | English |
| last_indexed | 2024-04-24T10:47:23Z |
| publishDate | 2024-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Cells |
| spelling | doaj.art-1898d2c5394e46f1a8c7a7db39f0af302024-04-12T13:16:25ZengMDPI AGCells2073-44092024-03-0113757310.3390/cells13070573Enhanced Release Probability without Changes in Synaptic Delay during Analogue–Digital FacilitationSami Boudkkazi0Dominique Debanne1Physiology Institute, University of Freiburg, 79104 Freiburg, GermanyUnité de Neurobiologie des Canaux Ioniques et de la Synapse (UNIS), Institut National de la Santé et de la Recherche Médicale (INSERM), Aix-Marseille University, 13015 Marseille, FranceNeuronal timing with millisecond precision is critical for many brain functions such as sensory perception, learning and memory formation. At the level of the chemical synapse, the synaptic delay is determined by the presynaptic release probability (<i>Pr</i>) and the waveform of the presynaptic action potential (AP). For instance, paired-pulse facilitation or presynaptic long-term potentiation are associated with reductions in the synaptic delay, whereas paired-pulse depression or presynaptic long-term depression are associated with an increased synaptic delay. Parallelly, the AP broadening that results from the inactivation of voltage gated potassium (Kv) channels responsible for the repolarization phase of the AP delays the synaptic response, and the inactivation of sodium (Nav) channels by voltage reduces the synaptic latency. However, whether synaptic delay is modulated during depolarization-induced analogue–digital facilitation (d-ADF), a form of context-dependent synaptic facilitation induced by prolonged depolarization of the presynaptic neuron and mediated by the voltage-inactivation of presynaptic Kv1 channels, remains unclear. We show here that despite <i>Pr</i> being elevated during d-ADF at pyramidal L5-L5 cell synapses, the synaptic delay is surprisingly unchanged. This finding suggests that both <i>Pr</i>- and AP-dependent changes in synaptic delay compensate for each other during d-ADF. We conclude that, in contrast to other short- or long-term modulations of presynaptic release, synaptic timing is not affected during d-ADF because of the opposite interaction of <i>Pr</i>- and AP-dependent modulations of synaptic delay.https://www.mdpi.com/2073-4409/13/7/573neuronal timingsynaptic transmissionsynaptic latencycontext-dependent facilitationneocortexlocal circuits |
| spellingShingle | Sami Boudkkazi Dominique Debanne Enhanced Release Probability without Changes in Synaptic Delay during Analogue–Digital Facilitation Cells neuronal timing synaptic transmission synaptic latency context-dependent facilitation neocortex local circuits |
| title | Enhanced Release Probability without Changes in Synaptic Delay during Analogue–Digital Facilitation |
| title_full | Enhanced Release Probability without Changes in Synaptic Delay during Analogue–Digital Facilitation |
| title_fullStr | Enhanced Release Probability without Changes in Synaptic Delay during Analogue–Digital Facilitation |
| title_full_unstemmed | Enhanced Release Probability without Changes in Synaptic Delay during Analogue–Digital Facilitation |
| title_short | Enhanced Release Probability without Changes in Synaptic Delay during Analogue–Digital Facilitation |
| title_sort | enhanced release probability without changes in synaptic delay during analogue digital facilitation |
| topic | neuronal timing synaptic transmission synaptic latency context-dependent facilitation neocortex local circuits |
| url | https://www.mdpi.com/2073-4409/13/7/573 |
| work_keys_str_mv | AT samiboudkkazi enhancedreleaseprobabilitywithoutchangesinsynapticdelayduringanaloguedigitalfacilitation AT dominiquedebanne enhancedreleaseprobabilitywithoutchangesinsynapticdelayduringanaloguedigitalfacilitation |