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SUMMARY:LCN Seminar: Non-invasive characterization of individual neurons w
 ith Continuous dynamic photo-stimulation
DTSTART:20130930T140000
DTSTAMP:20260427T225213Z
UID:ed1b652ddd958d5d942ddc82eb005bd4526d119982b8fa961b007742
CATEGORIES:Conferences - Seminars
DESCRIPTION:Ahmed EL HADY\, Max Planck Institute for Dynamics and Self Org
 anization\, Goettingen\, Germany\nUnderstanding information encoding by in
 dividual central neurons requires characterization of their input-output f
 unctions under near-natural input conditions\, e.g. in the fluctuation dri
 ven regime\, characteristic of cortical circuits. Controlling the input an
 d registering on the order of 10.000 - 100.000 spikes as output\, one can 
 compute transfer metrics which are critical for collective network dynamic
 s\, such as dynamic gain\, correlation gain or spike frequency vs current 
 (FI-) curves. So far now such data are exclusively obtained in sharp elect
 rode or patch-clamp recordings\, where the input to the cell body and ther
 efore to the spike trigger zone in the axon initial segment is directly co
 ntrolled. Due to the limited number of spikes obtained in invasive recordi
 ngs\, characterization of individual neurons is often not possible\, dynam
 ic gain curves\, for instance\, are averaged over tens of neurons.\nWe rec
 ently developed an alternative\, non-invasive method for neuronal characte
 rization. Spikes are recorded by an array of extracellular electrodes. Wel
 l-defined\, fluctuating stimuli are delivered via light-activated channelr
 hodopsins to pharmacologically isolated neurons. Careful characterization 
 of channelrhodopsin’s transfer function warrants precise control over th
 e waveform of the induced conductance. The setup delivers orders of magnit
 ude more data than previously possible in the field of input-output charac
 terization.\nNeuronal responses were stable\, measurement of intracellular
  pH showed only minor acidification under continuous stimulation. Comparis
 on of our results with dynamic gain measurements and FI-curves obtain with
  traditional methods establishes the equivalence of the non-invasive\, hig
 h-throughput method.
LOCATION:SV 2715 http://plan.epfl.ch/?room=sv2715
STATUS:CONFIRMED
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