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Titolo:
NONLINEAR MODELS OF THE FIRST SYNAPSE IN THE LIGHT-ADAPTED FLY RETINA
Autore:
JUUSOLA M; WECKSTROM M; UUSITALO RO; KORENBERG MJ; FRENCH AS;
Indirizzi:
DALHOUSIE UNIV,DEPT PHYSIOL & BIOPHYS HALIFAX NS B3H 4H7 CANADA DALHOUSIE UNIV,DEPT PHYSIOL & BIOPHYS HALIFAX NS B3H 4H7 CANADA UNIV OULU,DEPT PHYSIOL OULU FINLAND QUEENS UNIV,DEPT ELECT ENGN KINGSTON ON K7L 3N6 CANADA
Titolo Testata:
Journal of neurophysiology
fascicolo: 6, volume: 74, anno: 1995,
pagine: 2538 - 2547
SICI:
0022-3077(1995)74:6<2538:NMOTFS>2.0.ZU;2-N
Fonte:
ISI
Lingua:
ENG
Soggetto:
INSECT SENSORY NEURON; LARGE MONOPOLAR CELLS; BLOWFLY CALLIPHORA; BIOLOGICAL-SYSTEMS; CASCADE MODELS; COMPOUND EYE; IDENTIFICATION; PHOTORECEPTORS; ENHANCEMENT; BEHAVIOR;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Physical, Chemical & Earth Sciences
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
41
Recensione:
Indirizzi per estratti:
Citazione:
M. Juusola et al., "NONLINEAR MODELS OF THE FIRST SYNAPSE IN THE LIGHT-ADAPTED FLY RETINA", Journal of neurophysiology, 74(6), 1995, pp. 2538-2547

Abstract

1. Randomly modulated light stimuli were used to characterize the nonlinear dynamic properties of the synapse between photoreceptors and large monopolar neurons (LMC) in the fly retina. Membrane potential fluctuations produced by constant variance contrast stimuli were recorded at eight different levels of background light intensity. 2. Representation of the photoreceptor-LMC input-output data in the form of traditional characteristic curves indicated that synaptic gain was reduced bylight adaptation. However, this representation did not include the time-dependent properties of the synaptic function, which are known to be nonlinear. Therefore nonlinear systems analysis was used to characterize the synapse. 3. The responses of photoreceptors and LMCs to random light fluctuations were characterized by second-order Volterra series, with kernel estimation by the parallel cascade method. Photoreceptor responses were approximately linear, but LMC responses were clearly nonlinear. 4. Synaptic input-output relationships were measured by passing the light stimuli to LMCs through the measured photoreceptor characteristics to obtain an estimate of the synaptic input. The resultingnonlinear synaptic functions were well characterized by second-order Volterra series. They could not be modeled by a linear-nonlinear-linear cascade but were better approximated by a nonlinear-linear-nonlinearcascade. 5. These results support two possible structural models of the synapse, the first having two parallel paths for signal flow between the photoreceptor and LMC, and the second having two distinct nonlinear operations, occurring before and after chemical transmission. 6. The two models were each used to calculate the synaptic gain to a briefchange in photoreceptor membrane potential. Both models predicted that synaptic gain is reduced by light adaptation.

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Documento generato il 25/11/20 alle ore 00:41:40