# Thalamocortical Dynamics and Consciousness

> **NIH NIH R01** · MASSACHUSETTS INSTITUTE OF TECHNOLOGY · 2020 · $393,417

## Abstract

Top-down functions (e.g., attention and working memory) go hand-in-hand with consciousness. Yet we
know more about the former, because it is hard to define consciousness in most contexts. There is,
however, a way in. General anesthesia (GA) provides transition through different stages of
consciousness. We aim to determine which aspects of cortical processing are critical for these changes
by using a surgical anesthetic, propofol, in monkeys. Propofol increases cortical-wide delta oscillations
and alpha in frontal cortex. One hypothesis posits that the increased frontal alpha disrupts top-down
cortical feedback from frontal cortex. Another points to the widespread delta oscillations that, unlike
sleep, are decoupled across cortex. This could fragment long-range communication across cortex or, as
some suggest, loss of consciousness (LOC) could be due to frontal-parietal cortex disconnectivity per se.
The thalamus is likely to play a major role. Mounting evidence suggests it controls top-down cortical
processing, perhaps by modulating cortical oscillations. Abnormal thalamic oscillations could entrain
different cortical areas or the changed dynamics could be largely a cortical phenomenon. Previous
primate studies of GA lack the combination of wide scope and single-neuron precision to directly test
these hypotheses. We will use chronic intracranial multiple electrodes in monkeys to record
simultaneously from a wide range of critical brain structures (prefrontal cortex, posterior parietal cortex,
auditory cortex, and thalamus). We will also test if thalamic stimulation can restore consciousness and
wakeful cortical dynamics.

## Key facts

- **NIH application ID:** 9935182
- **Project number:** 5R01MH115592-04
- **Recipient organization:** MASSACHUSETTS INSTITUTE OF TECHNOLOGY
- **Principal Investigator:** EMERY N BROWN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $393,417
- **Award type:** 5
- **Project period:** 2017-09-08 → 2022-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9935182

## Citation

> US National Institutes of Health, RePORTER application 9935182, Thalamocortical Dynamics and Consciousness (5R01MH115592-04). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9935182. Licensed CC0.

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