Spectral and ocellar inputs to honeybee motion-sensitive descending neurons
type: CreativeWork
description: Optomotor reflexes have been observed in many insects and in some cases the neural pathways that mediate these reflexes have been identified physiologically and anatomically. In honeybees Kaiser (1975) established that the spectral sensitivity of optomotor responses in bees almost exactly matched that of the green photoreceptors, suggesting an exclusive input from green photoreceptors. However, physiological studies showed that the motion detectors in the optic lobes have a secondary response peak in the UV region of the spectrum suggesting that there may be more than one type of photoreceptor involved in the optomotor response. Thus in this thesis, I investigate the neural basis of motion and spectral wavelength processing in motion-sensitive descending neurons, which are on the optomotor response pathway, to reveal the neural contributions from other spectral receptor types. In this study, intracellular recording techniques were utilised. The stimuli consisted of a wide-field LED (light emitting diode) display in which green (peak 530 nm) and short-wavelength (peak 380 nm) LEDs were mounted in pairs across a wide visual area. Six types of motion-sensitive descending neurons were recorded and anatomically identified, including two pitch-sensitive neurons (Locth3, DNII2), two roll-sensitive neurons (DNIV2 and DNIV3) and two yaw-sensitive neurons (DNVII1 and DNVII2). The results show that for the vertical sensitive (pitch and roll) neurons, the cells have equal-sized excitatory responses to motion when using short-wavelength or green motion stimulation. However, for the horizontal sensitive (yaw-sensitive) neurons excitatory responses only occurred for the green stimulus in the preferred direction. The short-wavelength stimulus induced clear inhibitory responses for all tested motion directions. The results suggest that besides green photoreceptors, the motion-sensitive descending neurons also receive inputs from the short-wavelength photoreceptors, but only for moti…
abstract: Optomotor reflexes have been observed in many insects and in some cases the neural pathways that mediate these reflexes have been identified physiologically and anatomically. In honeybees Kaiser (1975) established that the spectral sensitivity of optomotor responses in bees almost exactly matched that of the green photoreceptors, suggesting an exclusive input from green photoreceptors. However, physiological studies showed that the motion detectors in the optic lobes have a secondary response peak in the UV region of the spectrum suggesting that there may be more than one type of photoreceptor involved in the optomotor response. Thus in this thesis, I investigate the neural basis of motion and spectral wavelength processing in motion-sensitive descending neurons, which are on the optomotor response pathway, to reveal the neural contributions from other spectral receptor types. In this study, intracellular recording techniques were utilised. The stimuli consisted of a wide-field LED (light emitting diode) display in which green (peak 530 nm) and short-wavelength (peak 380 nm) LEDs were mounted in pairs across a wide visual area. Six types of motion-sensitive descending neurons were recorded and anatomically identified, including two pitch-sensitive neurons (Locth3, DNII2), two roll-sensitive neurons (DNIV2 and DNIV3) and two yaw-sensitive neurons (DNVII1 and DNVII2). The results show that for the vertical sensitive (pitch and roll) neurons, the cells have equal-sized excitatory responses to motion when using short-wavelength or green motion stimulation. However, for the horizontal sensitive (yaw-sensitive) neurons excitatory responses only occurred for the green stimulus in the preferred direction. The short-wavelength stimulus induced clear inhibitory responses for all tested motion directions. The results suggest that besides green photoreceptors, the motion-sensitive descending neurons also receive inputs from the short-wavelength photoreceptors, but only for moti…
author: Hung, Yu-Shan
language: en_AU
date published: 2012
date modified: 2026-07-24T00:54:49Z
provider: Australian National University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Australian National University

PropertyValue
property ID: Handle
value: http://hdl.handle.net/1885/151321