"Identified neurons and the networks they compose produce stereotypical, albeit individually unique, activity
across members of a species. We propose, for a motor circuit driven by a central pattern generator (CPG), that
the uniqueness derives mainly from differences in synaptic strength rather than from differences in intrinsic
membrane conductances. We studied a dataset of recordings from six leech (Hirudo sp.) heartbeat control
networks, containing complete spiking activity patterns from inhibitory premotor interneurons, motor output spike
patterns, and synaptic strength patterns to investigate the source of uniqueness. We used a conductance-based
multicompartmental motor neuron model to construct a bilateral motor circuit model, and controlled it by playing
recorded input spike trains from premotor interneurons to generate output inhibitory synaptic patterns similar to
experimental measurements. By generating different synaptic conductance parameter sets of this circuit model,
we found that relative premotor synaptic strengths impinging onto motor neurons must be different across
individuals to produce animal-specific output burst phasing. Obtaining unique outputs from each individual’s
circuit model did not require different intrinsic ionic conductance parameters. Furthermore, changing intrinsic conductances failed to compensate for modified synaptic strength patterns. ..."
Reference:
1 .
Günay C, Doloc-Mihu A, Lamb DG, Calabrese RL (2019) Synaptic Strengths Dominate Phasing of Motor Circuit: Intrinsic Conductances of Neuron Types Need Not Vary across Animals. eNeuro [PubMed]
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