Long-standing questions about how the brain produces conscious experiences have baffled scientists and philosophers alike. Some sceptics question if science's objective methods will ever be able to comprehend such a subjective event. However, scientists have started to pinpoint the adjustments in brain activity that come along with awareness, and they also have some intriguing hypotheses about how consciousness arose.



How much do we actually understand about awareness in humans?

One of the great mysteries of life is how the brain generates conscious consciousness from the electrical activity of billions of individual nerve cells.

We can all agree that we are conscious—that is, that we have thoughts, perceptions, and feelings—but we are unable to demonstrate this to others. The enigmatic substance that enables us to have such thoughts, perceptions, and feelings is only available to ourselves.

David Chalmers, a philosopher, referred to this impossibility to objective, outside inspection as the "hard problem" of consciousness in the 1990s.

He said that the "neural correlates" of it, or the locations and patterns of brain activity that vary when people have conscious experiences, would be an easier problem for scientists to solve.

There are three levels of consciousness.

They can measure a number of unique dimensions of consciousness. The following are the top three:

• Physiological arousal or waking up

• awareness, or the capacity for conscious mental experiences, such as perceptions, feelings, and thoughts

• sensory organisation, which is the blending of various experiences and more abstract ideas to provide a smooth conscious experience.

Our entire state of consciousness changes moment by moment as a result of the interaction between these three aspects. For instance, while we are fully awake, we are in a state of high awareness, but both wakefulness and awareness decrease as we go to sleep at night.

During REM (rapid eye movement) sleep, when vivid dreams are most likely to happen, awareness and physiological arousal return.

However, most of these sensory sensations are isolated from outside stimuli and from the ideas that, while we are awake, ground us in reality.

Similar to this, typical levels of arousal are present during altered states of consciousness, including those brought on by psychedelic medications or low oxygen levels.

These include auditory, olfactory, and visual hallucinations as well as synesthesia, which is the interplay of normally distinct senses, such as noises that create visual perceptions.

Even lower degrees of awake and awareness than those experienced during non-REM sleep are possible in people who are comatose or under anesthesia.

Patients experience daily cycles of wakefulness and sleep, but without displaying any signs of awareness, in a strange hybrid state of consciousness known as unresponsive wakefulness syndrome, also known as a vegetative state.

They remain alert for extended periods of time, but they don't react behaviorally to outside stimuli.

Some of these patients will regain only a few indicators of awareness, referred to as a "minimally conscious stateTrusted Source," such the capacity to follow a moving object with their eyes or respond to commands.

The consciousness-related neural correlates

Important hints about the neurological correlates of consciousness have been offered by patients in various states of consciousness.

The brain activity that underlies these states has been identified using methods like electroencephalography (EEG) and functional magnetic resonance imaging (fMRI).