Research on Consciousness and Unconsciousness

Throughout human history, philosophers, mystics, and spiritual leaders have attempted to define the nature of consciousness. Scientists over many centuries have observed and investigated many different human brain functions, including conscious awareness. New research fields such as cognitive neuroscience emerged to solve the mind-brain “problem” of consciousness: how does brain activity give rise to our self-awareness and our thoughts and emotions?

Neuroscience research grew exponentially in the late 20th century. This expansion led to more and more investigations of the brain networks that underly consciousness. For example, today consciousness researchers are studying what happens to the brain during sleep and anesthesia. Others are investigating the brain networks of patients with disorders of consciousness due to injury and disease, a major research area for the study of unconsciousness.
Coma and Disorders of Consciousness

When a person does not respond to other people or environmental stimuli such as sounds, lights, or physical stimulation, we conclude that the person is likely to be unconscious or unaware. In healthcare, we refer to this as being in a coma or comatose state.

Unconsciousness usually occurs because of a brain injury — traumatic, anoxic (lack of oxygen supply to the brain), or metabolic (a chemical disruption in the body) — or because of certain drugs or excessive alcohol use. A brief period of unconsciousness can occur from a concussion (a mild brain injury) or syncope (fainting) due to dehydration, low blood sugar, or a temporary drop in blood pressure.

Severe injuries to the brain often result in a coma initially and sometimes develop into a more prolonged state of unconsciousness. This prolonged state is often referred to in the general literature as a prolonged coma. Medical terms for this prolonged state of unconsciousness are more precise because people do not stay in a coma indefinitely.