Zenith Grant Awardee

Doris Y. Tsao

California Institute of Technology

Co-Investigators

Janis K. Hesse, California Institute of Technology

Project Title

Neural construction of conscious perception

Project Summary

How does the brain construct conscious perception? Is there a part of the brain that is the source of all conscious percepts or does the brain act as a whole to generate the reality we experience? After rigorously determining which parts of the brain encode specific conscious percepts, we want to advance the field beyond studying correlates and uncover the mechanisms by which the brain generates new conscious percepts. Through the use of new techniques enabling the recording of hundreds of neurons at the same time, we will ask which part of the brain shows changes in activity first when a new conscious percept is emerges. We will then ask what happens if you stimulate or inactivate this source of conscious percept generation. What will be the effects on behavior and neural processes in other parts of the brain? Throughout these experiments, we will show images that can be interpreted in more than one way, so that the conscious percept changes while physical input is fixed. We believe these experiments will yield critical insights for understanding how the brain constructs an interpretation of an ambiguous world as the reality we consciously perceive.

Technical Abstract

Out of a myriad of sensory stimulations, our brain constructs a unified, self-consistent reality that we consciously experience. Little is known about the neural mechanisms of how conscious perception arises. We believe recent advances in neuroscience make it possible to crack this mystery for the first time. We propose to address two fundamental questions about consciousness. First, where in the brain does a conscious percept first emerge, distinguishing itself from a plentitude of inputs that are subconsciously processed and never reach awareness? Second, once this spark of consciousness is ignited, how do brain regions interact to propagate the conscious percept across the brain and create a consistent interpretation of the world? We will address these questions using large-scale electrophysiological recordings and perturbations across the macaque brain in combination with binocular rivalry, a paradigm where a constant visual input evokes spontaneous switches in conscious percept. Recent conceptual and technological advances such as development of a no-report paradigm for reading out conscious percepts in animals, cracking the code for face identity, and development of ultra-high-yield recording electrodes, put us in a unique position to reveal the mechanisms of consciousness in the brain.