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Physiology and Structure of Motion Sensitive Neurons in the Dragonfly Visual System
Author(s) -
Shapiro Benjamin Goodman
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.760.2
Subject(s) - dragonfly , neuroscience , octopamine (neurotransmitter) , escape response , biology , optogenetics , odonata , ecology , biochemistry , receptor , serotonin
Aeshnid dragonflies are among the largest North American insects and also among the fastest and most accurate predators. During prey pursuit, they quickly respond to deviations in their flying‐prey trajectory and alter their flight paths to intercept their quarry. Remarkably, a deviation in the prey's path results in a dragonfly turn in only 30 ms, much faster than the visual latencies in most animals. Visual neurons, called target‐selective descending neurons (TSDNs) are hypothesized to mediate the dragonfly's fast response to flying prey. Once stimulated, these neurons send signals down the nerve cord to the wing‐motor circuitry controlling flight, allowing for a flight path correction. In laboratory experiments with restrained dragonflies, TSDN activity is relatively weaker and slower than expected from the behavior. We are testing the idea that this neural “lethargy” is due to the lack of neuromodulators such as octopamine in the restrained dragonfly's brain. We are investigating this hypothesis by comparing TSDN visual responses before and after injection of the octopamine mimic, chlordimeform. Our results show dramatic increases in TSDN spike activity after chlordimeform injection, suggesting that TSDN activity is augmented in the behaving animal by the neuromodulator, octopamine. Further, utilizing intracellular recording techniques, we aim to identify the individual neurons which mediate responses to specific types of stimuli, such as approaching objects. Once a cell is identified, we will inject a dye through the recording microelectrode, which will travel within the cell in question up into the brain. This will allow us to obtain a structural representation of the neuron, which can then be linked back to its specific function in the visual processing cascade. Support or Funding Information Funded in part by a Student Research Grant from Union College. Special thanks to Prof. Robert Olberg, Biology Department, Union College