The proposed research will continue our studies of pontine and medullary brainstem structures that are part of, or modulate, pathways to ocular motoneurons. Two different project lines will be followed, each of which will employ alert behaving monkeys. Eye position will be accurately measured by an electromagnetic technique and the animal will be trained to track a small moving light spot while subjected to whole body oscillations and full-field movements of the visual world. In one project, the behavior of the saccadic system will be studied by three different approaches designed to distinguish between the traditional Robinson burst generator model and a modified version developed in our lab (Scudder, 1988). First, unit activity will be recorded in the rostral pons to describe both possible visual sensitivity and the motor sensitivity of long lead burst neurons (LLBns): Second, stimulating electrodes placed in various sites of the superior colliculus will be used to activate LLBNs. Second, stimulating electrodes placed in various sites of the superior colliculus will be used to activate LLBNs to ascertain the topographic weighting of the collicular input to the burst generator. Third, simultaneous recordings from collicular burst neurons and LLBNs or LLbns and other elements of the burst generator (e.g., EBNs) will be used to perform cross-correlation analyses to reveal neuronal connections. In the other project, the role of the vestibular nuclei and its apparentally the nucleus prepositus (NPH) in the generation of eye and head movements will be studied in 6 separate projects. First, the visual signals reaching the vestibular nuclei and NPH will be investigated in trained animals to allow the behavioral identification of the various neuronal types. Second, the connections of vestibular nucleus and NPH neurons to the abducens nuclei will be revealed by spike- triggered averages of lateral rectus muscle EMG activity triggered by the action potentials of candidate premotor cells. Third, the degree of canal-canal convergence in these medullary neurons will be investigated by our new multi-axis turntable. Fourth, inputs to subgroups of neurons in the vestibular nuclei and NPH will be identified by physiologically- guided HRP injections. Fifth, lesions of the NPH will be made to confirm its role as the legendary neural integrator. Sixth, the neurons sending descending commands to cervical motoneurons will be identified by antidromic activation and their discharge patterns determined during passive and active head rotations. Studies such as these that demonstrate the pathways and neural structure involved in different types of eye movements make it possible to devise clinical tests to diagnose the site o lesions or strokes that cause specific eye movement disorders in human patients (See Leigh & Zee, The Neurology of Eye Movements: F.A. Davis Co., Philadelphia 1983).

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37EY000745-28
Application #
2710788
Study Section
Special Emphasis Panel (NSS)
Project Start
1976-09-01
Project End
1999-08-31
Budget Start
1998-09-01
Budget End
1999-08-31
Support Year
28
Fiscal Year
1998
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
Kojima, Yoshiko; Fuchs, Albert F; Soetedjo, Robijanto (2015) Adaptation and adaptation transfer characteristics of five different saccade types in the monkey. J Neurophysiol 114:125-37
Knight, T A (2012) Contribution of the frontal eye field to gaze shifts in the head-unrestrained rhesus monkey: neuronal activity. Neuroscience 225:213-36
Kojima, Yoshiko; Soetedjo, Robijanto; Fuchs, Albert F (2011) Effect of inactivation and disinhibition of the oculomotor vermis on saccade adaptation. Brain Res 1401:30-9
Kojima, Yoshiko; Soetedjo, Robijanto; Fuchs, Albert F (2010) Effects of GABA agonist and antagonist injections into the oculomotor vermis on horizontal saccades. Brain Res 1366:93-100
Fuchs, Albert F; Brettler, Sandra; Ling, Leo (2010) Head-free gaze shifts provide further insights into the role of the medial cerebellum in the control of primate saccadic eye movements. J Neurophysiol 103:2158-73
Kojima, Yoshiko; Soetedjo, Robijanto; Fuchs, Albert F (2010) Changes in simple spike activity of some Purkinje cells in the oculomotor vermis during saccade adaptation are appropriate to participate in motor learning. J Neurosci 30:3715-27
Kojima, Yoshiko; Soetedjo, Robijanto; Fuchs, Albert F (2010) Behavior of the oculomotor vermis for five different types of saccade. J Neurophysiol 104:3667-76
Soetedjo, Robijanto; Fuchs, Albert F; Kojima, Yoshiko (2009) Subthreshold activation of the superior colliculus drives saccade motor learning. J Neurosci 29:15213-22
Soetedjo, Robijanto; Kojima, Yoshiko; Fuchs, Albert F (2008) Complex spike activity in the oculomotor vermis of the cerebellum: a vectorial error signal for saccade motor learning? J Neurophysiol 100:1949-66
Ling, Leo; Fuchs, Albert; Siebold, Christoph et al. (2007) Effects of initial eye position on saccade-related behavior of abducens nucleus neurons in the primate. J Neurophysiol 98:3581-99

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