The contribution of single synapses to sensory representation in vivo.
The extent to which synaptic activity can signal a sensory stimulus limits the information available to a neuron. We determined the contribution of individual synapses to sensory representation by recording excitatory postsynaptic currents (EPSCs) in cerebellar granule cells during a time-varying, quantifiable vestibular stimulus. Vestibular-sensitive synapses faithfully reported direction and velocity, rather than position or acceleration of whole-body motion, via bidirectional modulation of EPSC frequency. The lack of short-term synaptic dynamics ensured a highly linear relationship between velocity and charge transfer, and as few as 100 synapses provided resolution approaching psychophysical limits. This indicates that highly accurate stimulus representation can be achieved by small networks and even within single neurons.
Arenz
Alexander
A
Department of Neuroscience, Physiology, and Pharmacology, University College London, University Street, London WC1E 6JJ, UK.
Silver
R Angus
RA
Schaefer
Andreas T
AT
Margrie
Troy W
TW
D000818:Animals; D002531:Cerebellum / Q000166:cytology / Q000502:physiology*; D019706:Excitatory Postsynaptic Potentials; D051379:Mice; D009412:Nerve Fibers / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D018408:Patch-Clamp Techniques; D012399:Rotation; D013569:Synapses / Q000502:physiology*; D014722:Vestibule, Labyrinth / Q000502:physiology*