Re-Igniting Consciousness by Manipulating the NCC in the Rodent Model

INSTITUTE: UCLA, Department of Psychology

PROJECT LEADERS: Martin Monti, Julia Crone

PROJECT DURATION: 3 years

LAB WEBSITE: Monti Lab

In the past decades, studies demonstrate that the functional communication of specific brain regions is drastically changed during altered states of consciousness. Most of the affected regions are part of the thalamo-cortical brain circuit known to be involved in maintaining a critical balance in brain function. However, insights mainly come from correlative studies and little has been done to investigate the causal role of this circuit in altering conscious experiences. Thus, this project explores the causal relationship between the activity in specific areas of the thalamo-cortical circuit, its effects on global brain communication, and consciousness. Areas within this circuit have been turned on and off using optogenetics and its effects on specific behavioral aspects of consciousness such as arousal has been recorded. Optogenetics allows to control activation of specific neuronal populations in the brain via a locally induced virus and light, while simultaneously visualizing the effects on brain function in rodents using functional magnetic resonance imaging. 

Findings give insight into the causal information flow of brain circuits underlying arousal, cognition, and conscious awareness with distinguished patterns of brain activation dependent on the specific area and type of stimulation (see Figure 1). For example, excitatory stimulation of the thalamus leads to increased arousal during sleep while excitatory stimulation of the globus pallidus externa (GPe) leads to increased arousal during wakefulness. These insights are crucial for the development of effective treatment strategies in patients with impaired consciousness as well as for the development of intervention programs aimed at intensifying conscious experiences in the healthy population.

Figure 1. Brain responses during stimulation of the thalamo-cortical circuit. Excitatory stimulation (A) and inhibitory stimulation (B) of the thalamus. Excitatory stimulation (C) and inhibitory stimulation (D) of the GPe; hot coloring indicates activatior on>off; cold coloring indicates activation off>on; cross hair indicates tip of optical fiber:

Broader Impact:

Arousal, conscious state, and cognitive function are often confounded when, in the clinic, we try to understand whether the brain of a patient is capable of supporting the re-emergence of consciousness. For example, if a patient were conscious but did not have sufficient residual cognitive function, their level of consciousness might not be apparent to an observer. This project addresses the issue by trying to understand the associations between arousal, conscious state, and cognitive function, and different neural mechanisms.