Localized and Long-Lasting Adaptation in Dragonfly Target-Detecting Neurons
Matthew B Schwarz1, David C O'Carroll2, Bernard J E Evans3
1School of Biomedicine, The University of Adelaide, Adelaide, South Australia 5001, Australia matthew.schwarz@adelaide.edu.au steven.wiederman@adelaide.edu.au.
Eneuro
|September 10, 2024
Summary
Dragonfly visual neurons, known as small target motion detectors (STMDs), adapt to repeated stimuli. This adaptation is localized and depends on recent target history, crucial for pursuit behaviors.
Area of Science:
- Neuroethology
- Insect vision
- Sensory processing
Background:
- Dragonfly optic lobe neurons, specifically small target motion detector (STMD) neurons, are vital for detecting and pursuing small, moving objects.
- Previous studies noted adaptation in STMD neurons with repetitive stimuli, but its characteristics remained unquantified due to experimental limitations.
Purpose of the Study:
- To quantify the spatial and temporal properties of STMD adaptation in dragonflies.
- To understand the role of STMD adaptation in the context of closed-loop behaviors like prey pursuit.
Main Methods:
- Extracellular recordings were used to monitor STMD neuron activity in dragonflies over several hours.
- Stimuli involved repetitive presentation of targets at short intervals to induce and measure adaptation.
Main Results:
- STMD adaptation varied across individual neurons, with repeated stimuli causing faster adaptation and a habituation-like effect.
- Responses recovered quickly post-stimulus, with recovery rate decreasing nonlinearly over time.
- Adaptation was highly localized (∼2.5° displacement) and target-tuned, not triggered by general motion or flicker.
Conclusions:
- STMD adaptation is a localized, history-dependent phenomenon crucial for efficient visual processing during prolonged target fixation.
- This adaptation likely optimizes closed-loop behaviors by modulating neural responses based on recent visual experience.
