top of page

Neuroscience Breakthroughs Since Graduate School - Part 3: Consciousness

Updated: Mar 24


Consciousness can be defined as wakefulness, awareness, and self-awareness. Brain imaging studies of people in different levels of consciousness (sleep, vegetative state, coma, neuropsychological disorders) can help reveal the neural correlates of consciousness. The strongest neural correlates of consciousness include attention networks, the default mode network, and the claustrum. The claustrum coordinates the transition between attention networks and the default mode network. Complex functions such as consciousness and attention require coordination amongst multiple brain areas. The location and size of these functional networks can differ between individuals.

Click on our narrator icon to listen to this post.


This post is based on Christopher L. Zerr's invited Physiological Psychology lecture at Truman State University. Ten years before, he sat in the same classroom as Dr. Shaffer lectured. Chris is a Psychological & Brain Sciences Postdoc at Washington University in St. Louis. He is a gifted researcher, dedicated mentor, and amazing colleague!

Christopher L. Zerr


This post covers a small fraction of neuroscience findings for consciousness. The authors focused on the cortex and its role in disorders of consciousness because of the extensive neuroimaging work on these topics. We did not cover auditory and visual awareness studies, a major chunk of consciousness research, to achieve a 16-minute read time.

What is Consciousness?

Consciousness is everything you experience. It is the tune stuck in your head, the sweetness of chocolate mousse, the throbbing pain of a toothache, the fierce love for your child and the bitter knowledge that eventually all feelings will end (Koch, 2018).

William James' Stream of Consciousness

Consciousness, then, does not appear to itself chopped up in bits. Such words as 'chain' or 'train' do not describe it fitly as it presents itself in the first instance. It is nothing jointed; it flows. A 'river' or a 'stream' are the metaphors by which it is most naturally described. In talking of it hereafter let us call it the stream of thought, of consciousness, or of subjective life (James, 1890, 239).

Popular Consciousness Metaphors

Three popular consciousness metaphors are the "tip of the iceberg," a "sea/ocean of consciousness," and a "theater of consciousness."

Tip of the Iceberg

Most brain processes are not conscious. The limited capacity of the contents of consciousness at any given moment is represented by the “tip of the iceberg.” The vast store of largely unconscious knowledge and representations is not available. However, much of it is retrievable from stable knowledge stores.

sea of consciousness