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Synaptic scaling and the development of a motor network
Laura D Knogler1, Meijiang Liao, Pierre Drapeau
1Department of Pathology and Cell Biology and Le Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec H3T 1J4, Canada.
Summary
Synaptic scaling adjusts miniature postsynaptic current (mPSC) amplitudes in response to neural activity changes. In zebrafish, this synaptic plasticity did not alter motor patterns or swimming behavior in vivo.
Area of Science:
- Neuroscience
- Developmental Biology
- Synaptic Plasticity
Background:
- Neurons exhibit homeostatic plasticity, adjusting synaptic strength (synaptic scaling) to maintain network activity.
- The in vivo functional consequences of synaptic scaling on neural network behavior remain largely unexplored.
Purpose of the Study:
- To investigate the impact of in vivo synaptic scaling on the neural network controlling locomotion in embryonic zebrafish.
- To determine if synaptic scaling affects motor neuron activity patterns and swimming behavior.
Main Methods:
- Chronic reduction of neural activity using TTX or CNQX, or TNFalpha application in embryonic zebrafish.
- Electrophysiological recordings of spinal neurons to measure miniature postsynaptic current (mPSC) amplitudes.
- Acute induction of mPSC amplitude changes using cyclothiazide or low-dose CNQX.
- Behavioral analysis of swimming patterns and motoneuron activity.
Main Results:
- Glutamatergic mPSCs scaled up by ~25% after activity reduction and down by ~20% after TNFalpha treatment.
- Neither chronic nor acute induction of synaptic scaling altered swimming behavior or synaptic activity patterns.
- Synaptic strength, but not synaptic activity patterning, demonstrated plasticity during development.
Conclusions:
- Synaptic scaling of glutamatergic synapses can be induced in vivo in zebrafish.
- Synaptic patterning is more stable than synaptic strength during early neural network development.
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