A Caltech Library Service

Neural Construction of Conscious Perception


Hesse, Janis Karan (2020) Neural Construction of Conscious Perception. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/07r8-0845.


Out of a myriad of sensory stimulations, our brain constructs a unified, self-consistent reality that we consciously experience. Little is known about how or where in the brain’s processing stream of physical input a conscious percept emerges into awareness. A remarkable property of conscious perception is that even though external input is often ambiguous, the perceptual interpretation of the world that our brain generates is consistent across multiple layers of representation, e.g., figure-ground segmentation and object identity. We thus set out to study how the interaction between different nodes in the brain generates and propagates new conscious percepts. Since the code of object identity is already well-understood, in particular for faces as reviewed in this thesis, we decided to get a handle on segmentation signals first. It turned out that consistent segmentation signals are hard to find, however, we found functionally defined modules in the brain that contained consistent cells from which figure-ground signals can be decoded. We next investigated whether face cells in object recognition areas actually encode the conscious percept of a face or are just passive filters of visual input. To distill conscious perception from other cognitive processes, such as decision making, introspection, and reporting of the percept, which often accompany new conscious percepts, we developed a no-report binocular rivalry paradigm that relies on an active fixation task rather than report, and therefore eliminates these confounding factors. We found that face patches in inferotemporal cortex indeed encode the conscious percept of a face. Using novel high-yield electrodes, we were able to decode what the animal was consciously perceiving at a given time. Preliminary and future experiments of population recordings from multiple nodes of the cortical hierarchy simultaneously promise to go beyond correlates of consciousness and reveal the mechanisms of how and where conscious percepts are constructed.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Consciousness; perception; face patch; segmentation; border-ownership; macaque; visual cortex; object recognition; binocular rivalry; no-report paradigm; Mooney faces
Degree Grantor:California Institute of Technology
Division:Biology and Biological Engineering
Major Option:Computation and Neural Systems
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Tsao, Doris Y.
Thesis Committee:
  • Meister, Markus (chair)
  • Adolphs, Ralph
  • Rutishauser, Ueli
  • Tsao, Doris Y.
Defense Date:28 May 2020
Funding AgencyGrant Number
Howard Hughes Medical Institute (HHMI)UNSPECIFIED
Simons FoundationUNSPECIFIED
Record Number:CaltechTHESIS:05302020-143859367
Persistent URL:
Related URLs:
URLURL TypeDescription adapted for Chapter III adapted for Chapter VI
Hesse, Janis Karan0000-0003-0405-8632
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13743
Deposited By: Janis Karan Hesse
Deposited On:09 Jun 2020 23:14
Last Modified:04 Nov 2021 21:22

Thesis Files

PDF - Final Version
See Usage Policy.


Repository Staff Only: item control page