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System Level Assessment of Motor Control through Patterned Microstimulation in the Superior Colliculus

Katnani, Husam (2012) System Level Assessment of Motor Control through Patterned Microstimulation in the Superior Colliculus. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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We are immersed in an environment full of sensory information, and without much thought or effort we can produce orienting responses to appropriately react to different stimuli. This seemingly simple and reflexive behavior is accomplished by a very complicated set of neural operations, in which motor systems in the brain must control behavior based on populations of sensory information. The oculomotor or saccadic system is particularly well studied in this regard. Within a visual environment consisting of many potential stimuli, we control our gaze with rapid eye movements, or saccades, in order to foveate visual targets of interest. A key sub-cortical structure involved in this process is the superior colliculus (SC). The SC is a structure in the midbrain which receives visual input and in turn projects to lower-level areas in the brainstem that produce saccades. Interestingly, microstimulation of the SC produces eye movements that match the metrics and kinematics of naturally-evoked saccades. As a result, we explore the role of the SC in saccadic motor control by manually introducing distributions of activity through neural stimulation.

Systematic manipulation of microstimulation patterns were used to characterize how ensemble activity in the SC is decoded to generate eye movements. Specifically, we focused on three different facets of saccadic motor control. In the first study, we examine the effective influence of microstimulation parameters on behavior to reveal characteristics of the neural mechanisms underlying saccade generation. In the second study, we experimentally verify the predictions of computational algorithms that are used to describe neural mechanisms for saccade generation. And in the third study, we assess where neural mechanisms for decoding occur within the oculomotor network in order to establish the order of operations necessary for saccade generation. The experiments assess different aspects of saccadic motor control, which collectively, reveal properties and mechanisms that contribute to the comprehensive understanding of signal processing in the oculomotor system.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Katnani, Husamhak41@pitt.eduHAK41
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Thesis AdvisorGandhi, Neerajneg8@pitt.eduNEG8
Committee MemberOlson,
Committee MemberBatista, APB10
Committee MemberWeber, DJW50
Date: 26 September 2012
Date Type: Publication
Defense Date: 10 May 2012
Approval Date: 26 September 2012
Submission Date: 14 May 2012
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 130
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Bioengineering
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: microstimulation, superior colliculus, motor control, vector summation, vector averaging, spatiotemporal, decoding, blink reflex, omnipause neurons
Date Deposited: 26 Sep 2012 14:39
Last Modified: 15 Nov 2016 13:58


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