Functional analysis of middle temporal visual area and its associated behavior

Our lab's long-term goal is to elucidate the circuitry of the visual cortex, to develop quantitative computational models of neuronal function in the visual cortex, and to establish how these models may relate to visual perception and visually guided behavior. Central to this goal is the analysis of functional architecture, which is crucial to an understanding of how the brain works. In my thesis research, I applied behavioral and microstimulation techniques to demonstrate the causal connections between neural activity and behavior. Understanding these relationships is one of the fundamental issues needed to be addressed in Neurobiology. Specifically, I focused on the functional analysis of the middle temporal visual area (MT) and the behavior associated with it. MT is an extrastriate area that is primarily involved in visual motion processing. A very important function within MT is a segregation of center-surround interactions which plays a critical role in processing visual motion cues. There are two types of motion center-surround interactions in MT neurons: surrounds may reinforce (at wide-field sites) or suppress (at local-motion sites) the centers' directional responses. They are important in representing the initial stages of a functional segregation between wide-field and local-contrast motion processing. To further study the computational model used by the brain to readout sensory information, I conducted microstimulation experiments in MT by changing stimulation amplitudes (from 10/LA to 160tA) and frequencies (from 25Hz to 500Hz). Microstimulation can introduce an additional velocity signal into MT and the pursuit and saccadic systems usually compute a vector average of the visually evoked and microstimulation-induced velocity signals.

Department dc:contributor.department

Harvard University--MIT Division of Health Sciences and Technology.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2002

Author dc:creator

• Zhao, Ruilin, 1972-

Advisor dc:contributor.advisor

• Richard T. Born.

• Harvard University--MIT Division of Health Sciences and Technology.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/8084

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/8084