Noisy Synaptic Conductance: Bug or a Feature?. Issue 6 (June 2020)

• Record Type: Journal Article
• Authors: Rusakov, Dmitri A.; Savtchenko, Leonid P.; Latham, Peter E.
• Is Part Of: Trends in neurosciences. Volume 43:Issue 6(2020)
• Page Start: 363
• Page End: 372
• Publication Date: 2020-06
• Subjects: synaptic noise -- information transfer -- optimal synapse; Neurology -- Periodicals; Neurophysiology -- Periodicals; Neurobiology -- Periodicals; 612.8
• DOI: 10.1016/j.tins.2020.03.009
• Languages: English
• ISSNs: 0166-2236

Abstract

Abstract : More often than not, action potentials fail to trigger neurotransmitter release. And even when neurotransmitter is released, the resulting change in synaptic conductance is highly variable. Given the energetic cost of generating and propagating action potentials, and the importance of information transmission across synapses, this seems both wasteful and inefficient. However, synaptic noise arising from variable transmission can improve, in certain restricted conditions, information transmission. Under broader conditions, it can improve information transmission per release, a quantity that is relevant given the energetic constraints on computing in the brain. Here we discuss the role, both positive and negative, synaptic noise plays in information transmission and computation in the brain. Highlights: Synaptic transmission is noisy, partially because neurotransmitter release is unreliable but also because synaptic receptor current varies stochastically. When synaptic input is below the cell spike threshold, adding noise may push it above the threshold, thus improving information transmission. Synaptic noise can widen the dynamic range of transmission. Synaptic noise allows synapses to communicate their degree of uncertainty. Noise is a ubiquitous feature of brain activity and is likely to be a critical element in any theory of how the brain works.