The long-term objective of this research is to understand how the nervous system translates sensory information into the commands for the initiation and execution of saccadic eye movements. The saccadic system is comparatively well understood because of its simple peripheral mechanics and musculature, because saccade-related brainstem neurons are accessible, and because it is easy to accurately measure eye movements. We know the neuron types,k their discharge patterns, and may of the connections of the neural saccade generator. Our understanding is incomplete, however, so it has been supplemented with reasonable, neurophysiological assumptions to yield working hypotheses, in the form of models,, that simulate a functioning saccade generator. We will perform three sets of experiments to more completely characterize the saccade generation process. The first experiment will test two popular current models. Those two models make distinctly different predictions about the saccades that will result following damage to the oculomotor neural integrator. Therefore we will lesion the putative integrator and record the changes in saccades. This experiment will show that the model that correctly forecasts the resulting saccades most accurate describes the saccade generator. In the second set of experiments we will record from putative inputs to the saccade generator. We will concentrate on saccade-related neurons located in regions of the mesencephalon known to project to the saccade generator. The parameters of the discharge will be quantitatively compared to the saccade and target metrics in order to discover whether these neurons code previously hypothesized saccade signals or new signals that must be incorporated into evolving models of saccade generation. Finally, we will study the connections of mesencephalic saccade-related neurons t neurons in the saccade generator as well as their connections with other saccade-related structures. We will use peri-spike histograms in alert trained animals to assess the functional connections between neurons. The description of discharge characteristics and the demonstration of connections of functionally identified types of neurons will help us to understand how signals originating more centrally produce saccadic eye movements. These studies should further our understanding of how the nervous system transforms visual sensory information to generate saccadic motor responses. In addition, our data and that of other has been, and should continue to be, very useful in the diagnosis and localization of nervous system dysfunction resulting from a wide variety of causes.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY006558-08
Application #
2160475
Study Section
Visual Sciences B Study Section (VISB)
Project Start
1986-09-01
Project End
1995-03-31
Budget Start
1994-04-01
Budget End
1995-03-31
Support Year
8
Fiscal Year
1994
Total Cost
Indirect Cost
Name
University of Washington
Department
Physiology
Type
Schools of Medicine
DUNS #
135646524
City
Seattle
State
WA
Country
United States
Zip Code
98195
Fukushima, Junko; Akao, Teppei; Shichinohe, Natsuko et al. (2011) Neuronal activity in the caudal frontal eye fields of monkeys during memory-based smooth pursuit eye movements: comparison with the supplementary eye fields. Cereb Cortex 21:1910-24
Shichinohe, Natsuko; Akao, Teppei; Kurkin, Sergei et al. (2009) Memory and decision making in the frontal cortex during visual motion processing for smooth pursuit eye movements. Neuron 62:717-32
Kaneko, Chris R S; Fuchs, Albert F (2006) Effect of pharmacological inactivation of nucleus reticularis tegmenti pontis on saccadic eye movements in the monkey. J Neurophysiol 95:3698-711
Fukushima, Junko; Akao, Teppei; Kurkin, Sergei et al. (2006) The vestibular-related frontal cortex and its role in smooth-pursuit eye movements and vestibular-pursuit interactions. J Vestib Res 16:1-22
Kaneko, Chris R S (2006) Saccade-related, long-lead burst neurons in the monkey rostral pons. J Neurophysiol 95:979-94
Sklavos, Sokratis; Porrill, John; Kaneko, Chris R S et al. (2005) Evidence for wide range of time scales in oculomotor plant dynamics: implications for models of eye-movement control. Vision Res 45:1525-42
Takeichi, N; Kaneko, C R S; Fuchs, A F (2005) Discharge of monkey nucleus reticularis tegmenti pontis neurons changes during saccade adaptation. J Neurophysiol 94:1938-51