Voltage-dependent K+ channels improve the energy efficiency of signalling in blowfly photoreceptors

Heras, Francisco J H, Anderson, John, Laughlin, Simon B and Niven, Jeremy E (2017) Voltage-dependent K+ channels improve the energy efficiency of signalling in blowfly photoreceptors. Interface, 14 (129). pp. 1-13. ISSN 1742-5689

[img] PDF - Published Version
Available under License All Rights Reserved.

Download (776kB)

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.

Item Type: Article
Keywords: analogue coding, energy-aware bandwidth and gain control, insect graded-potential neuron, membrane impedance, negative feedback, voltage-sensitive potassium conductance, Action Potentials, Animals, Diptera, Electric Conductivity, Energy Metabolism, Insect Proteins, Ion Channel Gating, Membrane Potentials, Models, Biological, Photoreceptor Cells, Invertebrate, Potassium Channels, Voltage-Gated
Schools and Departments: School of Life Sciences > Evolution, Behaviour and Environment
SWORD Depositor: Mx Elements Account
Depositing User: Mx Elements Account
Date Deposited: 23 Jun 2020 14:46
Last Modified: 24 Jun 2020 10:49
URI: http://sro.sussex.ac.uk/id/eprint/92067

View download statistics for this item

📧 Request an update