Wide-Field Feedback Neurons Dynamically Tune Early Visual Processing
authors: John C. Tuthill, Aljoscha Nern, Gerald M. Rubin, Michael B. Reiser
doi: 10.1016/j.neuron.2014.04.023
CITATION
Tuthill, J. C., Nern, A., Rubin, G. M., & Reiser, M. B. (2014). Wide-Field Feedback Neurons Dynamically Tune Early Visual Processing. Neuron, 82(4), 887–895. https://doi.org/10.1016/j.neuron.2014.04.023
ABSTRACT
fleeting notes
matching cellular response to distribution of input signals is important
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but the structure and relevance of sensory input depends on behavior
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wide field neurons provide feedback to the most peripheral layer of fly visual system - the lamina
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lamina wide-field neurons respond to low frequency luminance fluctuations
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gain and frequency tuning changes during flight
- mimicked by octopamine
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lamina wide field neurons are gated by behavior to enhance coding of low frequency signals
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reducing low frequency input is an exmaple of predictive coding - trying to reduce redundant information
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increased gain in LPTCs is triggered by octopamine release
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octopamine mediated behavioral state modulation extends to the lamina
lawf2 (wide-field) neurons provide cholinergic feedback from medulla to the lamina
- modulate signal encoding at the input to the motion detection pathway
wide field neurons depolarized after light onset and fired small numbers of spikes
- but had a long latency meaning they responded more strongly to low frequency flickers
wide field neurons have large receptive fields, not direction selective
visual response properties are modulated by behavior
- during flight light flashes evoked higher spike rates and decreased latency of first stimulus evoked spike
- octopamine drives change in cell activity
octopamine alters response latency and excitability of wide field neurons and frequency sensitivity
current injection evoked higher spike rates when octopamine was present and these changes may be due to direct neuromodulation of the wide field neurons
- octopamine directly increases widefield neuron excitability
the wide field neurons are important for feedback about low frequency motion during flight to suppress behavioral responses
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silencing wide field neurons causes flies to steer towards slower stimuli (opposite of what they typically do)
highlights
“An important strategy for efficient neural coding is to match the range of cellular responses to the distribution of relevant input signals”Page
“the structure and relevance of sensory signals depend on behavioral state”Page
“behavior modifies neural activity at the earliest stages of fly vision”Page
“wide-field neurons that provide feedback to the most peripheral layer of the Drosophila visual system, the lamina”Page