Cannabinoid Consciousness
How new discoveries pinpointing a possible source for consciousness in the brain may help us understand the important role that natural cannabinoids play in our conscious experience.
Human Consciousness:
A working definition of consciousness is defined by arousal, awareness, sentience, and an ability to experience and feel the world around us. It has been thought that the part of the brain that controls consciousness is the frontal lobe. Other activities controlled by the frontal lobe include problem solving, decision making, emotions and control of purposeful behaviors. However these theories remain almost purely psychological and do not address the actual characteristics of neurons which determine consciousness. In fact, no one actually knows where these consciousness determining neurons are located or what distinguishes them from other neurons. Adding more complexity is that consciousness stems from awareness and awareness arises from short term memory. The consciousness system has two principal functions:
1) Maintenance of waking state (arousal or level of consciousness)
2) Content of experience (awareness or content of consciousness)
It is important to understand the difference between these two. Arousal shows the wakefulness of one person and awareness is the persons ability to perceive the environment. In vegetative state, one is awake but unaware of themselves or their environment.
Our consciousness defines who we are and is foundational to our lived experience, yet we know tragically little about how it actually works. We can seemingly enhance it through the use of stimulants and shut it off by administering anesthetic. Still, despite these abilities we have little understanding of how our consciousness works at a mechanistic level.
Arousal and Awareness:
Scientists studying the brain and consciousness believe that there are two main components of consciousness; arousal and awareness. Arousal is regulated by the brainstem. The brainstem controls the flow of messages between the brain and the rest of the body. In addition to arousal, the brainstem also controls basic body functions such as breathing, swallowing, heart rate, and blood pressure. The brainstem also determines whether a person is awake or a sleep.
Until recently scientists were unsure which part of the brain was responsible for awareness. Now scientists think they may have discovered the part of the brain responsible for working with the brainstem to maintain consciousness. Michael D. Fox, MD, PhD and director of the Laboratory for Brain Network Imaging and Modulation says that, “For the first time, we have found a connection between the brainstem region involved in arousal and regions involved in awareness, two prerequisites for consciousness.” This network of neurons, which plays a central role in human consciousness, was discovered after studying numerous patients who had suffered brain injuries to determine why some would lose consciousness while others did not.
Awareness is also thought to be regulated in widespread areas of the cerebral cortex. The cerebral cortex, the largest area of the brain, is where most thinking functions occur. The cortex consists of four lobes:
- The Frontal Lobe controls emotion, motivation, social functioning, expression of behavior, voluntary movement, and “executive” functions, such as initiation, planning, thought organization, and decision making
- The Temporal Lobe controls memory, receptive language, sequencing, and musical awareness
- The Parietal Lobe controls sensation, academic skills such as reading, hearing, and awareness of spatial relationships
- The Occipital Lobe controls visual perception
To understand better why some brain injury patients were able to maintain consciousness despite their injuries while others fell into a coma, a study analyzed 36 patients who had damaged parts of their brainstem; 12 were in a coma, while 24 were considered to be conscious.
When they looked closely at the brains of those who were in a coma and compared them to the brains of those who were still conscious, they found that 10 of the 12 unconscious patients had damaged a part of the brainstem called the rostral dorsolateral pontine tegmentum. Only one of the conscious patients had similar damage. Apparently this part of the brain is involved with maintaining consciousness and damage to it is likely to result in coma.
Taking this revelation further, researchers began looking at the brains of healthy individuals and were able to pinpoint two areas of the cortex which were linked to the rostral dorsolateral pontine tegmentum. One was in the left, ventral, anterior insula (AI), and the other was in the pregenual anterior cingulate cortex (pACC).
These regions of the brain are now thought to play a role in regulating consciousness via the brainstem. This may help explain why we sometimes experience our own consciousness as being separate from our bodily experience or being outside our own body. The idea of being outside of our own bodies could be explained by showing how consciousness begins in the brain but is mediated by the brainstem which also regulates the flow of information to our brains from our senses. This is pure speculation at this point since we have only just begun to explore and understand the origins of consciousness in our brains but this discovery is sure to help us better understand the mysteries of consciousness that we all experience on a day to day basis.
Cannabinoids and Consciousness:
Natural cannabinoids have a direct impact on our conscious experiences. By consuming natural cannabinoids we are interacting directly with the section of the brain responsible for modulating the regulation of consciousness by controlling the release of neurotransmitters, those special chemical messengers that enable transmission across our nerves. These effects on neurotransmission may help balance our consciousness between the two extremes of mania and coma. Natural cannabinoids are powerful brain-changers. They influence levels of the brain’s most important neurotransmitters, including dopamine, glutamate and serotonin. Serotonin has a direct effect on mood which is related to consciousness. Dopamine is an inhibitory neurotransmitter, meaning that when it finds its way to its receptor sites, it blocks the tendency of that neuron to fire. Dopamine is strongly associated with reward mechanisms in the brain. If it feels good, dopamine neurons are probably involved! Glutamate is an excitatory neurotransmitter and it is the most common neurotransmitter in the central nervous system, as much as half of all neurons in the brain. Glutamate is especially important in regards to memory. Serotonin is an inhibitory neurotransmitter that has been found to be intimately involved in emotion and mood. Too little serotonin has been shown to lead to depression, problems with anger control, obsessive-compulsive disorder, and suicide. Serotonin has a direct effect on mood which is related to consciousness.
Is this the Missing Link?
Our understanding of consciousness remains limited. Beyond the connections between the brain regions, we know little else about how consciousness is regulated or how to explain some of the more curious aspects of consciousness such as curiosity and empathy. Curiosity and empathy are both central to our conscious experience and yet not well explained by a purely biological approach. A great deal more research is needed before doctors can begin targeting these brain regions in order to restore consciousness in unconscious patients. Should that day come it would be a new dawn for patients in comas and vegetative states and an answered prayer for their families and loved ones. This is just another example of how science and technology is combining to reveal great insights about fundamental aspects of the human experience that had long been relegated to philosophers and poets, the only ones contemplating the issue.
