Neural mechanisms underlying fundamental vertebrate motor activities can be usefully studies in model systems from other phyla which offer the advantage of a limited number of neurons accessible to intracellular techniques and modern structural analysis. One such activity, generically known as the oculomotor response, comprises complex patterns of behaviour mediated by the visual and vestibular systems: gaze, object scanning and fixation, and the stabilization of the retinal image compensating for complex spatial displacements of the head and body. Oculomotor abnormalities in humans can indicate the onset of central nervous trauma and disease. A greater understanding of the cellular organization of a complex multisensory oculomotor pathway could provide useful leads and suggestions for research on the physiologically less accessible vertebrate counterpart. One such model is provided by the dipteran Calliphora erythrocephala, which has a wide range of sophisticated oculomotor behaviours. In both sexes panoramic motion elicits compensatory head and body movements. Objects is visual space elicit fixation and orientation behaviour. In Calliphora there is a profound sexual dimorphism of the eye: in males there are more receptors, a zone of high visual acuity, and unique sex-specific neurons in the visual centers. Only males are able to sustain fixation, tracking and interception of small rapidly moving objects. This is distinct from behaviour shared by both sexes in which panoramic flow fields are computed by elemental motion- detectors and relayed to giant tectal neurons. Ultimately, mechanosensory information, derived from strategically placed organs for balance tactile perception is integrated with visual information in discrete brain centers from which originate 1) descending pathways to thoracic motor centers controlling head and body musculature and 2) interneurons supplying cerebellarlike higher centers in the midbrain. This research will employ intracellular recordings and stainings, and sophisticated light and electron microscopical strategies to dissect the cellular organization of identified nerve cells, from the receptors to the motor neurons and musculature. The research will focus on the following: 1) retinotopic organization and multimodal response characteristics of visual interneurons; 2) intracellular recordings and synaptic relationships of descending motor neurons; 3) innervation, physiology, and dynamics of effector muscles; 4) skeletal attachment, arthrology, and behaviour. This research proposes to broaden our understanding of neural mechanisms involved in visuo-mechanosensory control of eye movements. A complete description of motor control in this model will contribute a major step towards understanding circuitry for complex oculomotor behaviour and the role of uniquely identified neurons in visual pursuit and interception.

Agency
National Institute of Health (NIH)
Institute
National Center for Research Resources (NCRR)
Type
Research Project (R01)
Project #
5R01RR008688-08
Application #
2283978
Study Section
Special Emphasis Panel (ZRG1-VISB (05))
Project Start
1987-07-01
Project End
1997-09-29
Budget Start
1994-09-30
Budget End
1995-09-29
Support Year
8
Fiscal Year
1994
Total Cost
Indirect Cost
Name
University of Arizona
Department
Biology
Type
Organized Research Units
DUNS #
City
Tucson
State
AZ
Country
United States
Zip Code
85721
Phillips-Portillo, James; Strausfeld, Nicholas J (2012) Representation of the brain's superior protocerebrum of the flesh fly, Neobellieria bullata, in the central body. J Comp Neurol 520:3070-87
Pant, Vivek; Higgins, Charles M (2012) Tracking improves performance of biological collision avoidance models. Biol Cybern 106:307-22
Phillips-Portillo, James (2012) The central complex of the flesh fly, Neobellieria bullata: recordings and morphologies of protocerebral inputs and small-field neurons. J Comp Neurol 520:3088-104
Mu, Laiyong; Ito, Kei; Bacon, Jonathan P et al. (2012) Optic glomeruli and their inputs in Drosophila share an organizational ground pattern with the antennal lobes. J Neurosci 32:6061-71
Rivera-Alvidrez, Zuley; Lin, Ichi; Higgins, Charles M (2011) A neuronally based model of contrast gain adaptation in fly motion vision. Vis Neurosci 28:419-31
Dyhr, Jonathan P; Higgins, Charles M (2010) The spatial frequency tuning of optic-flow-dependent behaviors in the bumblebee Bombus impatiens. J Exp Biol 213:1643-50
Dyhr, Jonathan P; Higgins, Charles M (2010) Non-directional motion detectors can be used to mimic optic flow dependent behaviors. Biol Cybern 103:433-46
Sztarker, Julieta; Strausfeld, Nicholas; Andrew, David et al. (2009) Neural organization of first optic neuropils in the littoral crab Hemigrapsus oregonensis and the semiterrestrial species Chasmagnathus granulatus. J Comp Neurol 513:129-50
Douglass, John K; Strausfeld, Nicholas J (2007) Diverse speed response properties of motion sensitive neurons in the fly's optic lobe. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 193:233-47
Rister, Jens; Pauls, Dennis; Schnell, Bettina et al. (2007) Dissection of the peripheral motion channel in the visual system of Drosophila melanogaster. Neuron 56:155-70

Showing the most recent 10 out of 31 publications