The Journal of Neuroscience, 0000, 20:RC85:1-7
RAPID COMMUNICATION
Short-Term Synaptic Enhancement Modulates Ingestion Motor
Programs of Aplysia
José Antonio D.
Sánchez and
Mark D.
Kirk
Division of Biological Sciences, University of Missouri-Columbia,
Columbia, Missouri 65211
Activity-dependent synaptic plasticity regulates the flow of
information in neuronal networks and has important implications for the
expression of behavior. We find a functional role for short-term
synaptic enhancement (STE) such as facilitation, augmentation, and
post-tetanic potentiation at central synapses in the sea slug Aplysia californica. Consummatory feeding in
Aplysia such as rhythmic biting is controlled by
command-like cerebral-buccal interneurons (CBIs) that drive rhythmic
motor output in the buccal ganglia. CBI interneuron-2 (CBI-2) makes
monosynaptic connections onto buccal neurons, including premotor
neurons B31/32 and B34 and motor neurons B61/62. Stimulating CBI-2 at a
physiological firing frequency of 10 Hz for 30 sec causes these
synapses to increase their EPSP amplitude by ~200%. This STE
persists for nearly 2 min, during which time there is an increased
cycle frequency of rhythmic ingestion buccal motor programs (iBMPs)
elicited by CBI-2. This increase does not occur if the contralateral
CBI-2 is trained and the test is performed with the ipsilateral CBI-2;
therefore, the effect on motor programs only occurs in CBI-2 pathways
in which STE is elicited. Furthermore, we find that STE elicited at
CBI-2 buccal synapses permits iBMPs to be initiated at lower firing
frequencies. Thus, STE of CBI-2 synapses appears to contribute to the
initiation or modulation, or both, of buccal motor programs for
rhythmic ingestion in Aplysia.
Key words:
facilitation; augmentation; post-tetanic potentiation; synaptic plasticity; synaptic modulation; buccal ganglia; Aplysia
californica
Copyright © 0000 Society for Neuroscience 0270-6474/00/$05.00/0
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