Anesthesia helps us unravel the mystery of consciousness

Conscience is the most complex issue facing philosophy and science. It is a paradox because on the one hand we can not but be aware at all times and not otherwise know how to define it or how to approach it. The study of situations in which anesthesia can bring us to unravel the mystery of the consciousness.

Consciousness

While science is beginning to address the problem of consciousness is the philosophy that has faced with more determination. The philosopher of mind David Chalmers has distinguished between the problem easy and the hard problem of consciousness. The easy problem is very complex. Try to find out how the brain generates consciousness, what are the neural correlates of consciousness, what happens in our brain to be conscious, what areas are involved, why it is imperative to occur and in what sequence.

The difficult problem is that we can not even imagine how neuronal activity, physical phenomena can produce seemingly subjective and intangible. It is clear that consciousness and mental states are brain activity. This brings us to an old philosophical problem posed by Descartes, the so-called mind-body dualism: mental states are the product of neural activity? Or are mental states that produce neural activity? Are they the same thing or are they two different things? They are actually the same thing and, using an analogy, can be seen as two sides of the same coin.

Be aware, be aware of, is its most basic. Have something in mind. Other definitions refer to the previous one. Thus, being aware of oneself (meta-awareness) is to realize what is self and what is foreign.

Several experiments indicate that consciousness is the coordinated activity of a complex neural network that includes many brain areas. The smell of an apple concept invoked other properties of apple flavor, shape, color and finally your name and the situations we have experienced in relation to the block to name a few. All involved brain areas are activated at a time to be aware of an apple. Other stimuli are perceived and stimulate the sensory areas, but do not reach consciousness fade before being aware.

Anesthesia

Dr. Emery Brown is anesthetist. But it is mathematical statistician. The electroencephalogram EEG is routinely used in operations to monitor the patient under anesthesia. Although after one analyzes the data. For areas that fail to communicate during anesthesia, is beginning to use other additional technical functional magnetic resonance imaging, fMRI . The combined statistical analysis of the delivered dose of anesthetic, the patient's behavior, the EEG data and the fMRI opens up new avenues of knowledge. Understanding how to help make anesthesia safer and more effective with fewer side effects. It will also help find new treatments for coma. And it will help to understand consciousness.

Anesthesia has been used for over 150 years, but what causes the brain is a mystery. It is not known to what extent anesthesia induced state resembles sleep or coma caused by an injury. Do you stop or lost parts of communication between the circuits? What distinguishes the anesthesia of meditation or hypnosis? What happens in the brain in the transition from consciousness to the unconscious?

General anesthesia is a reversible coma induced by drugs

We know you can get in and out of anesthesia safely, but still can not say how

Neuroscience has always taken advantage of natural experiments : patients who suffer injury or stroke and lose power. The famous patient HM the hippocampus was removed and left to form new memories that helped us understand better the memory. Paul Broca investigated the brains of patients who could not speak and discovered Broca's area crucial for the generation of language. The anesthesiologists performing these experiments every day leading to loss of pain perception, attention, memory and movement. And the effects are different depending on the doses administered.

We began to realize that parts of the brain do not go out at once. There is a hierarchy, a sequence.

The same happens when drugs fade. Typically, the most basic functions recover faster - breathing again, and then when brainstem areas that control salivation and tear ducts revive the patient's mouth fills with saliva and her eyes water. Swallowing and cough when the areas that control the sensations of the throat become active. Finally move the eyes and then try to respond to the outside world. Later the drowsiness goes away and the more complex functions of the brain recover.

Experience suggests that the senses are not disabled, visual and auditory stimuli to the brain are still coming, but not processed so that they become aware. The brain wave patterns in anesthetized patients are similar to those produced by a seizure or of deep comas. On the other hand, low-dose anesthesia resembles the state of sleepiness prior to sleep. Although it is possible to carry patients to a state of unconsciousness such that the EEG is almost flat, in most cases the EEG alternating bursts of activity with periods of relative inactivity that can last minutes. Some medicines cause a regular slow waves and large areas of the brain, while others generate rapid and regular fluctuations in certain areas. Since usually provides a cocktail of drugs, the effects overlap, but it appears that different parts of the brain stop communicating.

But studying the effects of anesthesia has a problem can be lethal if performed outside the operating room. The EEG is commonly used but the fMRI machine is very large and needs its own room. The solution was to recruit volunteers who had undergone a tracheotomy. In the case of an emergency caused by the anesthetic inside the scanner, can be intubated to keep breathing.

Also being studied in patients with epilepsy who have electrodes implanted in the brain for days. This is done to detect epileptic foci accurately and remove only the origin of the seizures. When they are anesthetized, these electrodes pick up the electrical behavior of the areas in which they are implanted. The electrodes pick up a small area compared to fMRI or EEG, but his record is much more faithful.

Consciousness is a problem that many scientists do not want to address. Instead they prefer to speak of alertness or attention. But studying abnormal states can lead us to understand consciousness: easy problem solving can help us to understand or at least raise the issue difficult.