Linearization of excitatory synaptic integration at no extra cost
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In many theories of neural computation, linearly summed synaptic activation is a pervasive assumption for the computations performed by individual neurons. Indeed, for certain nominally optimal models, linear summation is required. However, the biophysical mechanisms needed to produce linear summation may add to the energy-cost of neural processing. Thus, the benefits provided by linear summation may be outweighed by the energy-costs. Using voltage-gated conductances in a relatively simple neuron model, this paper quantifies the cost of linearizing dendritically localized synaptic activation. Different combinations of voltage-gated conductances were examined, and many are found to produce linearization; here, four of these models are presented. Comparing the energy-costs to a purely passive model, reveals minimal or even no additional costs in some cases.
KeywordsVoltage-gated conductances Metabolic cost Sodium channel Mixed-cation channel Biophysical model
The authors thank the University of Virginia Department of Neurosurgery for their support.
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Conflict of interests
The authors declare that they have no conflict of interest.
- Carandini, M., Heeger, D.J., & Anthony Movshon, J. (1999). Linearity and gain control in V1 simple cells. In P.S. Ulinski, E.G. Jones, & A. Peters (Eds.) Models of cortical circuits. Cerebral cortex, Vol. 13. Boston: Springer.Google Scholar
- Jagadeesh, B., Wheat, H.S., & Ferster, D. (1993). Linearity of summation of synaptic potentials underlying direction selectivity in simple cells of the cat visual cortex. Science-AAAS-Weekly Paper Edition-including Guide to Scientific Information, 262(5141), 1901–1905.Google Scholar
- Levy, W.B., Colbert, C.M., & Desmond, N.L. (1990). Elemental adaptive processes of neurons and synapses: a statistical/computational perspective Vol. 187. Hillsdale: Erlbaum.Google Scholar
- Magistretti, J., & Alonso, A. (1999). Biophysical properties and slow voltage-dependent inactivation of a sustained sodium current in entorhinal cortex layer-ii principal neurons a whole-cell and single-channel study. The Journal of General Physiology, 114(4), 491–509.CrossRefPubMedPubMedCentralGoogle Scholar