Past and future of analog-digital modulation of synaptic transmission

Mickael Zbili (1) , Dominique Debanne (1)

1 UNIS - Inserm U1072 - Unité de Neurobiologie des canaux Ioniques et de la Synapse

Action potentials (APs) are generally produced in response to complex summation of excitatory and inhibitory synaptic inputs. While it is usually considered as a digital event, both the amplitude and width of the AP are significantly impacted by the context of its emission. In particular, the analog variations in subthreshold membrane potential determine the spike waveform and subsequently affect synaptic strength, leading to the so-called analog-digital modulation of synaptic transmission. We review here the numerous evidence suggesting context-dependent modulation of spike waveform, the discovery analog-digital modulation of synaptic transmission in invertebrates and its recent validation in mammals. We discuss the potential roles of analog-digital transmission in the physiology of neural networks. neurotransmitter release and synaptic strength. The first source of spike shape modification is the neuronal firing rate. Repetitive firing may cause inactivation of both voltage-gated sodium channels (Nav) and voltage-gated potassium channels (Kv). Nav inactivation leads to a decrease in spike amplitude during AP trains.

Keywords: axon; ion channels; synaptic transmission; brain circuits; short-term plasticity

Domains: Life Sciences [q-bio]; Neurons and Cognition [q-bio.NC]; Neurobiology

Mickael Zbili, Dominique Debanne. Past and future of analog-digital modulation of synaptic transmission. Frontiers in Cellular Neuroscience, 2019, 13, ⟨10.3389/fncel.2019.00160⟩. ⟨hal-02363629⟩