Competition for AP initiation sites in a circuit controlling simple learning (Cruz et al. 2007)

"The spatial and temporal patterns of action potential initiations were studied in a behaving leech preparation to determine the basis of increased firing that accompanies sensitization, a form of non-associative learning requiring the S-interneurons. ... The S-interneurons, one in each ganglion and linked by electrical synapses with both neighbors to form a chain, are interposed between sensory and motor neurons. ... the single site with the largest initiation rate, the S-cell in the stimulated segment, suppressed initiations in adjacent ganglia. Experiments showed this was both because (1) it received the earliest, greatest input and (2) the delayed synaptic input to the adjacent S-cells coincided with the action potential refractory period. A compartmental model of the S-cell and its inputs showed that a simple, intrinsic mechanism of inexcitability after each action potential may account for suppression of impulse initiations. Thus, a non-synaptic competition between neurons alters synaptic integration in the chain. In one mode, inputs to different sites sum independently, whereas in another, synaptic input to a single site precisely specifies the overall pattern of activity."

Model Type: Realistic Network; Neuron or other electrically excitable cell

Region(s) or Organism(s): Leech

Cell Type(s): Leech S cell

Currents: I Na,t; I K,leak

Transmitters: Serotonin

Model Concept(s): Action Potential Initiation; Activity Patterns; Spatio-temporal Activity Patterns

Simulation Environment: NEURON

Implementer(s): Cruz, Ginny [gcruz at]


Cruz GE, Sahley CL, Muller KJ. (2007). Neuronal competition for action potential initiation sites in a circuit controlling simple learning. Neuroscience. 148 [PubMed]

This website requires cookies and limited processing of your personal data in order to function. By continuing to browse or otherwise use this site, you are agreeing to this use. See our Privacy policy and how to cite and terms of use.