| Abstract: |
| Periodic behaviors such as breathing, walking, etc. are controlled by central pattern generating (CPG) neural circuits. Variability in rhythmic behaviors can be detrimental, as in heart arrhythmias, or beneficial, as hypothesized as an exploratory strategy in locomotion when dealing with a variable environment, and in feeding strategies when faced with inhomogeneous food.
Thus, what is the behavioral relevance of motor rhythm variability, and what controls it?
Using real-time dynamic clamp interaction between a living CPG neuronal circuit and a computer feedback model, we explored three feedback strategies onto a living CPG circuit, which in vivo is entrained by inhibitory feedback. Strategies were: 1) feedback inhibition duration independent of what the CPG does, 2) inhibit the CPG the longer, the longer it is active, and 3) inhibit the CPG the shorter, the longer it is active.
Any engineer would expect strategy 3) to reduce CPG rhythm variability the most, as it is a negative feedback strategy. That is not what we found - instead strategy 2), which provides positive duration feedback and would therefore be expected to exacerbate variability, was found to actually reduce variability of rhythm period the most out of the three options explored. |
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