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Stop Animal Exploitation NOW!
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"Exposing the truth to wipe out animal experimentation"

Government Grants Promoting Cruelty to Animals

Washington University, St. Louis, MO

GREGORY C. DEANGELIS - Primate Testing - 2006

Grant Number: 5R01EY016178-02
Project Title: Sensory Integration for Heading Perception
PI Information: ASSOCIATE PROFESSOR GREGORY C. DEANGELIS, [email protected] 

Abstract: DESCRIPTION (provided by applicant):
To navigate through our surroundings, we must accurately perceive our direction of self-motion (i.e., heading). Heading perception is an interesting problem in sensory integration, requiring neural circuits that combine visual motion signals (optic flow) with vestibular signals, and perhaps also somatosensory and proprioceptive cues. The multi-sensory nature of heading perception can be appreciated by the experience of section, the powerful illusion of self-motion that accompanies large-field visual motion (e.g., at an IMAX theater). Although the processing of optic flow has been well studied in visual and parietal cortices, little is known about how or where visual and vestibular signals are integrated for heading perception. Areas MSTd and VIP appear to be promising candidates, for these areas are known to be involved in processing optic flow and have also been found to contain vestibular signals regarding head translation. The proposed experiment, which employ a custom-designed virtual reality system, address three specific aims regarding the neural basis of heading perception in trained primates. Aim #1 examines the relative contributions of visual and vestibular cues to heading selectivity in MSTd/VIP. Specifically, we test whether the heading activity of neurons is enhanced by congruent combinations of visual and vestibular cues. Aim #2 tests whether heading signals derived from visual and vestibular cues are coded in a common reference frame (eye-centered, head-centered, or intermediate), as might be expected if these different sensory signals, are combined synergistically to improve heading selectivity. In Aim #3, we test more directly whether MSTd and VIP contribute to heading perception by recording from neurons during performance of a heading discrimination task. Monkeys will perform this task using optic flow alone, vestibular signals alone, or congruent combinations of the two cues. This will allow us to test whether MSTd/VIP neurons can account for the improvement in heading sensitivity seen under cue combination. These experiments will provide a comprehensive examination of whether MSTd/VIP neurons are involved in sensory integration for heading perception. Of clinical relevance, heading perception can be severely impaired in Alzheimer's disease, and this may contribute to spatial disorientation and navigational difficulties. By helping to elucidate the brain areas involved in heading perception, this work may eventually aid in targeting new Alzheimer's therapies to the appropriate brain regions.

Thesaurus Terms:
motion perception, neural information processing, visual perception
cue, psychophysics, sensory discrimination
Macaca fascicularis, Macaca mulatta, behavioral /social science research tag, computer human interaction, computer simulation, saccade, single cell analysis

SAINT LOUIS, MO 631304899
Fiscal Year: 2006
Project Start: 01-AUG-2005
Project End: 31-JUL-2007

The Journal of Neuroscience, January 17, 2007, 27(3):700-712

Spatial Reference Frames of Visual, Vestibular, and Multimodal Heading Signals in the Dorsal Subdivision of the Medial Superior Temporal Area

Christopher R. Fetsch, Sentao Wang, Yong Gu, Gregory C. DeAngelis, * and Dora E. Angelaki *

Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri 63110

Animal preparation.
Subjects were three male rhesus monkeys (Macaca mulata) weighing 47 kg. Under sterile conditions, monkeys were chronically implanted with a circular delrin cap for head stabilization as described previously (Gu et al., 2006a ), as well as one or two scleral search coils for measuring eye position (Robinson, 1963 ; Judge et al., 1980 ). After surgical recovery, monkeys were trained to fixate visual targets for juice rewards using standard operant conditioning techniques. Before recording experiments, a plastic grid (2 x 4 x 0.5 cm) containing staggered rows of holes (0.8 mm spacing) was stereotaxically secured to the inside of the head cap using dental acrylic. The grid was positioned in the horizontal plane and extended from the midline to the area overlying the MSTd bilaterally. Vertical microelectrode penetrations were made via transdural guide tubes inserted in the grid holes. All procedures were approved by the Institutional Animal Care and Use Committee at Washington University and were in accordance with National Institutes of Health guidelines.

Heading stimuli.
During experiments, monkeys were seated comfortably in a primate chair with their head restrained. The chair was secured to a 6-degrees-of-freedom motion platform (MOOG 6DOF2000E; Moog, East Aurora, NY) (see Fig. 1A) that allowed physical translation along any axis in 3D (Gu et al., 2006a ). Visual stimuli and fixation targets were back-projected (Christie Digital Mirage 2000; Christie, Cyrus, CA) onto a tangent screen positioned 30 cm in front of the monkey and subtending 90 x 90 of visual angle. Optic flow was generated using the OpenGL graphics library, allowing the accurate simulation of speed, size, and motion parallax cues experienced during real self-motion. The stimuli depicted movement of the observer through a random cloud of dots plotted in a virtual workspace 100 cm wide, 100 cm tall, and 40 cm deep. Stimuli were viewed binocularly with no disparities added to the display (i.e., no stereo cues were present). The projector, screen, and field coil frame were mounted on the platform and moved along with the animal, and the field coil frame was enclosed such that the animal experienced no visual motion other than the optic flow presented on the screen.  

Please email:  GREGORY C. DEANGELIS, [email protected]  to protest the inhumane use of animals in this experiment. We would also love to know about your efforts with this cause: [email protected]

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Rats, mice, birds, amphibians and other animals have been excluded from coverage by the Animal Welfare Act. Therefore research facility reports do not include these animals. As a result of this situation, a blank report, or one with few animals listed, does not mean that a facility has not performed experiments on non-reportable animals. A blank form does mean that the facility in question has not used covered animals (primates, dogs, cats, rabbits, guinea pigs, hamsters, pigs, sheep, goats, etc.). Rats and mice alone are believed to comprise over 90% of the animals used in experimentation. Therefore the majority of animals used at research facilities are not even counted.

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