Document Detail


Dendritic computation of direction selectivity and gain control in visual interneurons.
MedLine Citation:
PMID:  9236213     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The extraction of motion information from time varying retinal images is a fundamental task of visual systems. Accordingly, neurons that selectively respond to visual motion are found in almost all species investigated so far. Despite its general importance, the cellular mechanisms underlying direction selectivity are not yet understood in most systems. Blocking inhibitory input to fly visual interneurons by picrotoxinin (PTX), we demonstrate that their direction selectivity arises largely from interactions between postsynaptic signals elicited by excitatory and inhibitory input elements, which are themselves only weakly tuned to opposite directions of motion. Their joint activation by preferred as well as null direction motion leads to a mixed reversal potential at which the postsynaptic response settles for large field stimuli. Assuming the activation ratio of these opponent inputs to be a function of pattern velocity can explain how the postsynaptic membrane potential saturates with increasing pattern size at different levels for different pattern velocities ("gain control"). Accordingly, we find that after blocking the inhibitory input by PTX, gain control is abolished.
Authors:
S Single; J Haag; A Borst
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of neuroscience : the official journal of the Society for Neuroscience     Volume:  17     ISSN:  0270-6474     ISO Abbreviation:  J. Neurosci.     Publication Date:  1997 Aug 
Date Detail:
Created Date:  1997-08-28     Completed Date:  1997-08-28     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  8102140     Medline TA:  J Neurosci     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  6023-30     Citation Subset:  IM; S    
Affiliation:
Friedrich-Miescher-Laboratory, Max-Planck-Society, D-72076 Tuebingen, Germany.
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MeSH Terms
Descriptor/Qualifier:
Animals
Computer Simulation*
Dendrites / physiology
Diptera / physiology*
Female
Interneurons / physiology*,  ultrastructure
Membrane Potentials / physiology
Models, Neurological*
Motion Perception / physiology*
Neurons, Afferent / physiology
Synaptic Transmission / physiology

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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