Voltage-dependent K+ channels improve the energy efficiency of signalling in blowfly photoreceptors. Issue 129 (30th April 2017)

• Record Type: Journal Article
• Authors: Heras, Francisco J. H.; Anderson, John; Laughlin, Simon B.; Niven, Jeremy E.
• Is Part Of: Journal of the Royal Society interface. Volume 14:Issue 129(2017)
• Publication Date: 2017-04-30
• Subjects: voltage-sensitive potassium conductance -- energy-aware bandwidth and gain control -- negative feedback -- membrane impedance -- insect graded-potential neuron -- analogue coding; Physical sciences -- Research -- Periodicals; Life sciences -- Research -- Periodicals; Interdisciplinary research -- Periodicals; 570.5
• DOI: 10.1098/rsif.2016.0938
• Languages: English
• ISSNs: 1742-5689

Abstract

Abstract : Voltage-dependent conductances in many spiking neurons are tuned to reduce action potential energy consumption, so improving the energy efficiency of spike coding. However, the contribution of voltage-dependent conductances to the energy efficiency of analogue coding, by graded potentials in dendrites and non-spiking neurons, remains unclear. We investigate the contribution of voltage-dependent conductances to the energy efficiency of analogue coding by modelling blowfly R1-6 photoreceptor membrane. Two voltage-dependent delayed rectifier K + conductances (DRs) shape the membrane's voltage response and contribute to light adaptation. They make two types of energy saving. By reducing membrane resistance upon depolarization they convert the cheap, low bandwidth membrane needed in dim light to the expensive high bandwidth membrane needed in bright light. This investment of energy in bandwidth according to functional requirements can halve daily energy consumption. Second, DRs produce negative feedback that reduces membrane impedance and increases bandwidth. This negative feedback allows an active membrane with DRs to consume at least 30% less energy than a passive membrane with the same capacitance and bandwidth. Voltage-dependent conductances in other non-spiking neurons, and in dendrites, might be organized to make similar savings.