Analysis Tools
nervous system
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• ONalphas have an upregulation excitatory synaptic proteins
• however, excitatory snapse number, volume, and shape are normal
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• ON sustained alpha (ONalpha) retinal ganglion cells (RGCs) generate spontaneous excitatory postsynaptic currents (sEPSCs) with elevated peak amplitudes compared to wild-type, without differences in sEPSC kinetics or event frequency, indicating that ONalphas upregulate the strength of excitatory synapses to preserve output
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vision/eye
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• OFF-sustained (OFF-sus) alpha RGCs show abnormally elevated baseline spiking in response to dim light flash applied from darkness and both spike suppression duration and peak spike rate following light onset are reduced, with RGCs showing nearly normal spiking and duration of spike suppression under moderate light conditions and suppress spikes normally under bright conditions, indicating that OFF-sus RGCs show the most severe impairments in their ability to fire properly at dim-light levels
• OFF-sus RGCs shown a normal contrast response curve at moderate-light level and reduced slope at bright-light level, however in the optomotor response assay, mice exhibit normal visual acuity and contrast sensitivity
• inhibitory input to OFF-sus RGCs is reduced at bright-light level; at this bright-light level, the reduced inhibitory conductance has minimal impact on spike output in response to static stimuli
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• dendrites of rod bipolar cells show an approximate 50% attenuated responses to a light flash
• however, excitatory and inhibitory inputs as well as spike outputs remain comparable to wild-type, indicating compensation that preserves ON pathway function
• rod bipolar cells show normal resting membrane potential in current-clamp recordings and input resistance and capacitance remain unaltered for ONalpha RGCs
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