Reawakening from the Black Hole of Unconsciousness

  In her article “Bringing Back the Unconscious: The Latest Science on Awakenings”, Claudia Wallis examines the mysteries of unconsciousness and the borderline that separates it from wakefulness and awareness. Her discussion begins by introducing the remarkable story of 23-year old George Melendez, who had suffered from a traumatic brain injury that left him “all but dead” due to a tragic car accident. After the medics revived him, the injuries left him in a minimally conscious state. Melendez was awake and occasionally aware of his surroundings but could not respond reliably. Although it was heartbreaking for his mother and stepfather to hear the news from the doctor that there was not much else they could do to save him, the parents never lost hope and continued to care for their son. Four years later, a doctor had prescribed Melendez the common sleep drug zolpidem (Ambien) to help with his consistent thrashing and moaning throughout the night. Extraordinarily, Melendez had woken up. It turned out that he did not suffer from any memory loss except of the car accident. 

 As specified in the article, studies have shown that although Ambien does not have the same effect on every patient suffering from impaired consciousness, it has proved beneficial to an estimated one in every 15. Furthermore, continued research has identified a measurable pattern of brain activity that may indicate which minimally conscious patients can potentially awaken further. A new study team led by neurologist Nicholas Schiff examined the brain activity of three minimally conscious patients that responded positively to Ambien. Prior to treatment with the drug, all three showed the same unusual pattern of brain activity when monitored by the electroencephalogram (EEG), a system used to measure the electrical activity of the brain. It showed a low frequency spike of activity that was synchronized throughout both halves of the brain. This abnormal pattern disappears when the patients were given Ambien. Schiff suspected that the unusual EEG pattern reflected that crucial parts of the cerebral cortex were able to function properly, but the trauma disconnected them from other critical brain circuits that were needed in order to fire normally. He explains that Ambien turns on the level of joint connections between three important brain regions by activating up neurons that are sensitive to the neurotransmitter GABA. Ambien creates a buzz that many would experience when consuming alcohol, which is enough to turn on many brain circuits. 

            Daniel Bor attempts to link consciousness with information processing throughout his book The Ravenous Brain. One of the many topics he discusses questions why human consciousness fluctuates throughout our lives in contrast to other creatures. He relates this idea to his personal experience of general anesthesia when he had to undergo surgery due to a knee injury. Immediately after he regained consciousness, Bor recalled feeling “pleasantly drunk.” Remember, Bor did not suffer from any major traumatic brain injury, and so he was able to regain consciousness easily from the anesthesia. Patients who have suffered from brain damage are not able to regain this consciousness. However, this state of minimal wakefulness was what Melendez was able to reach after an initial dose of Ambien. The manner in which Ambien contributes to the link between consciousness and information processing can be further explained by understanding Bor’s overview of the structure of the brain.

            The creative processing of the human brain reveals a schematic in which three evolutionary versions of the brain are interconnected within our neurological system. The most primitive or “reptilian” brain includes the midbrain and brain stem. It is surrounded by the limbic or “early mammalian” system and is the root to instinct behavior. Finally, the neocortex or “late mammalian” system makes up the outer shell and is responsible for complex mental activity. These “three brains” normally work together and are highly interconnected. Traumatic brain injury results in the severing of these connections. Therefore, these patients suffer from its negative impacts on basic functions of survival and consciousness.

Bor also explains that anesthetic agents increase the production of GABA and dampens neuronal activity throughout the cortex. During this state, neuronal firing is more synchronized with strong spikes that pulse through the cortex in slow rhythms. It can be understood that there exists an association of slow neuronal activity and being heavily unconscious or under the state of minimal consciousness. This was demonstrated in Schiff’s study of the EEG patterns in the patients suffering from brain injuries. 

 It is important to consider that the reason why Ambien may have worked for these patients is that the specific injury had not damaged the neurons in the brain that release GABA. Their minimal state of consciousness resulted when neurons in their brains (assuming that these were the neurons that became damaged due to the injury) were not able to respond to the release of neurotransmitter. However, I wonder how these connections can be reestablished if the neurons themselves are damaged. The drug surely can’t rapidly rebuild a damaged neuron, considering that Melendez was able to eat breakfast by himself the following morning after the Ambien dosage. So the drug may have some other effect on neighboring neurons that do not normally function in the interconnection between the “three brains.” Although Ambien may have given these patients’ their normal, healthy lives back, research must continue to understand the mechanisms of how such an immediate, remarkable “cure” can be reached.

Wallis, Claudia. "Bring Back the Unconscious: The Latest Science on Awkenings." Time. Time, 23 Nov. 2013. Web. 14 Oct. 2014. <http://healthland.time.com/2013/11/22/bringing-back-the-unconscious-the-latest-science-on-awakenings/>.