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The Synapse Between LE Sensory Neurons and Gill Motoneurons Makes Only a Small Contribution to the Aplysia Gill‐withdrawal Reflex
Author(s) -
Hickie Christopher,
Cohen Lawrence B.,
Balaban Pavel M.
Publication year - 1997
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.1997.tb01411.x
Subject(s) - aplysia , neuroscience , reflex , synapse , sensory system , withdrawal reflex , biology , anatomy , psychology
The monosynaptic connection between the mechano‐sensory neurons in the LE cluster and gill motoneurons has been extensively studied and used as a model for the gill‐withdrawal reflex and its behavioural plasticity. In an attempt to evaluate the contribution of this synapse to the behaviour, we used voltage‐sensitive dye recording to determine the number of activated LE neurons and the number of spikes made by each neuron in response to a light touch. In five preparations, light touch activated a median of five sensory cells with a median of 1.6 spikes per cell. From a comparison of the sizes of the motoneuron synaptic potentials elicited by LE spikes and elicited by a light siphon touch, we estimate that the LE sensory neurons contribute ˜5% of the motoneuron synaptic potential in response to this touch. This result casts doubt on the validity of using this synaptic connection as a model for gill‐withdrawal behaviour. Siphon nerve recordings reveal the existence of short‐latency, low‐threshold neurons that may provide much of the sensory input in response to a light touch.