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Admission to this internship program is by application only and is at the discretion of the individual research scientists - space is limited. The program is open to all undergraduates at Rutgers and NJIT. Specific course of skill prerequisites will vary by instructor.
For more information, contact Connie Sadaka
at 973-353-1080 x 3294 |
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Research Opportunities: Ralph Siegel
Research Overview -
The primate cortex is a highly organized organ which ultimately is responsible for all the cognitive functions of the mind. It is a reality generating engine and works by combining multiple inputs from the sensorium within the context of the present situation to generate motor behavior. One critical problem in brain function is a description of the process whereby we perceive the surrounding visual world in order to guide motor action. We use a multidisciplinary approach to understand the physiology, psychophysics, theory and neurology underlying visual perception. The ultimate goal of this work is an understanding of the visual perceptual process and application of this knowledge to assist persons who have suffered neurological damage.
In particular, we have been exploring the different ways in which the visual space immediately around us is represented in the cortex. Visual movement is one critical pieces of incoming visual input that contributes to this process. In the psychophysical studies, we train animals to perform tasks that utilize different complex movement cues. Precisely the same tests are performed on human subjects and comparison between different species indicates that they have quite similar perceptual experiences (Siegel and Andersen, 1988). Modulation of the different parameters of the stimuli have suggested a number of constraints on the cortical processing that underlies this perception.
We next have directly examined the process whereby the incoming visual motion becomes a visual perception by recording from single cells in the brain during the performance of the perceptual task. In the inferior parietal lobule and the temporal lobe, neurons have been found which respond preferentially when the animal is indicating the perception of a particular motion. Analysis of the properties of these neurons indicates that there are complex non-linear interactions among different regions of the visual field that underlie the visual perception.
Two different theoretical models have been proposed for this perceptual process. In the first, the functional architecture of the cortical regions involved in motion analysis has been imitated (Siegel, 1988). This model is taught to perform the same task as the human subjects and has a similar behavior and sensitivity to the parameters of the stimulus as both primates. The properties of this model indicate how the non-linear interactions observed in the actual neural recordings underlie the perceptual process. The second model for this perceptual process rests on the application of non-linear dynamical system theory, more commonly known as chaos theory (Siegel, 1990). In these studies we study the dynamical properties of populations of neurons. We have shown that the behavior of such a model is similar to other non-linear natural systems (e.g. convection currents of a fluid, the orbit of planetary bodies) in that it has Universal behavior.
Lastly, we are involved in working with patients with neurological damage using results of the above and related studies. These studies are helping fulfill the goal of using the results of Neuroscience to best understand, and alleviate, the difficulties that patients undergo with neurological insult.
More Information -
Webpage:
Ralph Siegel |
