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SUMMARY:Ten Ways To A Better Brain - Simon Laughlin\, Department of Zoolog
 y\, University of Cambridge
DTSTART:20140217T163000Z
DTEND:20140217T180000Z
UID:TALK50016@talks.cam.ac.uk
CONTACT:P.H. Marchington
DESCRIPTION:Sengupta B\, Laughlin SB\, Niven JE (2014) Consequences of Con
 verting Graded to Action Potentials upon Neural Information Coding and Ene
 rgy\nEfficiency. PLoS Comput Biol 10(1): e1003439. doi:10.1371/journal.pcb
 i.1003439\n\nAbstract\nInformation is encoded in neural circuits using bot
 h graded and action potentials\, converting between them within single neu
 rons and successive processing layers. This conversion is accompanied by i
 nformation loss and a drop in energy efficiency. We investigate the biophy
 sical causes of this loss of information and efficiency by comparing spiki
 ng neuron models\, containing stochastic voltage-gated Na+ and K+ channels
 \, with generator potential and graded potential models lacking voltage-ga
 ted Na+ channels. We identify three causes of information loss in the gene
 rator potential that are the by-product of action potential generation: (1
 ) the voltage-gated Na+ channels necessary for action potential generation
  increase intrinsic noise and (2) introduce non-linearities\, and (3) the 
 finite duration of the action potential creates a ‘footprint’ in the g
 enerator potential that obscures incoming signals. These three processes r
 educe information rates by\,50% in generator potentials\, to\, 3 times tha
 t of spike trains. Both generator potentials and graded potentials consume
  almost an order of magnitude less energy per second than spike trains. Be
 cause of the lower information rates of generator potentials they are subs
 tantially less energy efficient than graded potentials. However\, both are
  an order of magnitude more efficient than spike trains due to the higher 
 energy costs and low information content of spikes\, emphasizing that ther
 e is a two-fold cost of converting analogue to digital\; information loss 
 and cost inflation.\n
LOCATION:Hodgkin-Huxley Room\, Department of Physiology Development and Ne
 uroscience
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