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Visual Computations in the Superior Colliculus


Lee, Kyu Hyun (2020) Visual Computations in the Superior Colliculus. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/zn2j-m319.


This thesis presents two projects related to large-scale extracellular recordings of neural signals. The first project asks how the brain sifts the onslaught of sensory information to identify the few bits that are relevant for guiding behavior. This question is studied in the context of the looming reaction, an innate defensive behavior against an approaching aerial predator. Interestingly, the mouse responds very selectively to the looming stimulus regardless of changes in orthogonal features, such as its position. The neural basis of this phenomenon is investigated with extracellular recordings in the superior colliculus, a midbrain visual area known to mediate the looming reaction. A detailed analysis of the difference between the superficial and deeper layers of the superior colliculus highlights a core function of visual processing: to discard information intelligently.

The second project presents electrode pooling, a novel method to increase the yield of extracellular recordings with the modern silicon electrode array. The fundamental constraint of wire volume in these devices is identified, and a solution that makes use of the switching circuitry and the sparseness of the neural signal in the time axis is described. Specifically, the method proposes to intelligently choose many recording sites that carry signal and connect them to a single wire via manipulating the switches. This pooled recording is subsequently un-mixed by a spike-sorting algorithm. The method is implemented in a state-of-the-art silicon neural probe, and its effect on signal and noise is analyzed by theory and experiment. Recommendations on the design of silicon devices are made to facilitate the incorporation of this method in the future.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:superior colliculus, sensory processing, selectivity, invariance, habituation, electrode, pooling, electrophysiology, silicon probe
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Biochemistry and Molecular Biophysics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Meister, Markus
Thesis Committee:
  • Tsao, Doris Y. (chair)
  • Anderson, David J.
  • Rutishauser, Ueli
  • Meister, Markus
Defense Date:26 May 2020
Non-Caltech Author Email:kyuhyun9056 (AT)
Record Number:CaltechTHESIS:06012020-165101402
Persistent URL:
Related URLs:
URLURL TypeDescription adapted for Chapter 2 DOIArticle adapted for Chapter 3
Lee, Kyu Hyun0000-0001-6483-9444
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13765
Deposited By: Kyu Hyun Lee
Deposited On:03 Jun 2020 17:47
Last Modified:11 Jun 2020 23:08

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