Carl Sagan, Cannabis, and the Right Brain Hemisphere, Part II

Sadly, Sagan died in 1996, too early to witness the revolutionary discovery of the endocannabinoid system. Since then, we have learned about the amazing range of its physiological and cognitive functions. So, can we actually find evidence for or against Sagan’s hypothesis for instance looking at the distribution of endocannabinoid recepors?


Sadly, Sagan died in 1996, too early to witness the revolutionary discovery of the endocannabinoid system. Since then, we have learned about the amazing range of its physiological and cognitive functions. So, can we actually find evidence for or against Sagan’s hypothesis for instance looking at the distribution of endocannabinoid recepors (especially the CB-1 receptor, on which the exogenous THC acts)?

Sagan’s Thesis and the Endocannabinoid System

As far as I can see, there does not seem to be extensive research what concerns lateralization and the role of endocannabinoid signaling for higher cognitive functions. One often cited study found an increased blood flow in parts of the right hemisphere during a high[1], but another study states that relatively high concentrations of cannabinoid receptors were consistently seen in cortical regions of the left (dominant) hemisphere, known to be associated with verbal language functions.“[2]

“The left and the right brain hemisphere. They are anatomically similar, but different, and ongoing cognitive science is still being done to find out which cognitive functions are dominated by one side or the other.”
“The left and the right brain hemisphere. They are anatomically similar, but different, and ongoing cognitive science is still being done to find out which cognitive functions are dominated by one side or the other.”

It seems much too early to draw conclusions from brain imaging studies to evaluate Sagan’s hypothesis. Marsicano and Kuhner remind us that „sometimes the endocannabinoid system appears to be functionally important in regions or cell types where the density of CB1 receptor is relatively low {e.g. control of pain perceptions in the brainstem}.”[3] As far as I can see, we haven’t yet begun to understand how the endocannbinoids are involved in affecting different higher cognitive functions based in the left or right brain hemisphere.

Recent Neuroscience and Reports about the Marijuana High

However, some more support for Sagan’s thesis seems to come from two other sources. First, Sagan’s description of the cognitive enhancements during a marijuana high have been described in detail by many more cannabis users. [4] The most impressive collection of recent anecdotal reports and essays about those enhancements comes from Sagan’s best friend Lester Grinspoon and can be found on his website marijuana-uses.com.

Second, if we look at what recent neuroscience has to say about differences in the cognitive functions and processing styles in the two brain hemispheres, Sagan still seems to have a point. From what we know now, the right hemisphere plays an important role for the cognitive processes named by Carl Sagan as enhanced during a high, as well as for many other enhancements described by other marijuana users. In his book The Master and his Emissary. The Divided Brain and the Making of the Modern World, (2009), psychiatrist Ian McGilchrist gives a survey of the current scientific knowledge about the different styles of cognition in the left and the right brain hemisphere emerging from stroke cases in one hemisphere, split brain patient cases, and newer brain imaging studies. According to McGilchrist, the right hemisphere is predominately involved in our ability to remember personal events (episodic memory), for associations between widely different concepts and ideas, complex pattern recognition, creative problem solving, insights, the appreciation of humor, the understanding of metaphors, self-awareness, the empathic understanding of others, the processing of words describing the mind, and the interpretation of emotional expression in faces, in intonation and verbal implications. Also, the right hemisphere seems to be crucially involved in the interpretation of non-verbal communication and the perception of music. For the sake of brevity, I will leave it at this incomplete list, but actually, McGilchrist describes more cognitive functions as right hemisphere based; functions which also have been consistently reported to be enhanced during a high.

The Effect of Marijuana on Attention

In general, then, it seems that research of the last forty years in the neurosciences lend some more support Sagan’s thesis that marijuana leads to an enhancement of right hemisphere-based cognitive abilities. One interesting puzzle, though, is one of the fundamental effects of marijuana on attention. During a marijuana high, we seem to ‘hyperfocus’. High users often get completely absorbed by the taste of ice-cream, by an intense stream of memories or ideas, or by the sensation of a kiss.

“Romeo and Juliet”, painting by Frank Dicksee
“Romeo and Juliet”, painting by Frank Dicksee

In other words, a high seems to cause a strong selective focus on whatever we attend to.  According to McGilchrist, however, focussed attention is not a cognitive function performed primarily in the right hemisphere. Quite on the contrary, he summarizes the current research as saying that “(…) the right hemisphere is responsible for every type of attention except focused attention.”[5]

Evaluating Sagan’s Hypothesis

So, when it comes to attention, at least one of the typical cognitive changes during a high does not seem to come from an enhancement of processes in the right hemisphere. Generally, then, while Sagan seems to have been basically on the right track with his hypothesis, not all of the cognitive enhanced functions during a high seem to be predominately based in right hemisphere activities. We will have to wait for more research to be done in this field to see how exactly cannabis affects cognitive activities in the left and right brain hemisphere.

What about Sagan’s hypothesis that a high could suppress left hemisphere function and, thus, ‘bring out the stars’ and allow for an enhanced right hemisphere activity? As far as I can see, we are far from being able to tell whether the mind enhancements during a high observed by so many users come from a direct enhancement of certain cognitive functions, or whether they come from a suppression of some left hemisphere activities. According to McGilchrist, the left and the right hemisphere are in a constant battle for control. In order to help us to survive, we and other animals need two conflicting systems of attention. He explains this point with the example of birds: to pick up seeds for food, a bird needs to narrowly focus on the seeds on the ground to motor control and coordinate food intake (left hemisphere function); but in order to survive, the bird has to get distracted by a predator like a fox or a falcon in the fringe of its perception.

 

Laggar_Falcon_in_FlightSo there must be another type of attention drawing it to unusual new sensations (right hemisphere). Only the interplay of these competing attention systems located in the two brain hemispheres allows birds and other animals like us to survive.

Clearly, then, an enhancement of cognitive processes in one hemisphere could come from the suppression or weakening of cognitive functions in the other hemisphere. We still have to await further research to come to a better understanding on how consumed cannabinoids affect the endocannabinoid system and, generally, its role in higher cognition. Yet, almost forty years after Sagan’s hypothesis, I think we can still say that he was on an interesting track. As far as I can see, we will only come to a better understanding of the nature of the high and its effects on attention, memory, pattern recognition, creativity, empathy, or insights, if we are beginning to research how endocannabinoids and consumed marijuana affects various cognitive processes in the left and the right brain hemisphere.

 

[1] Roy Mathew et al. (1997) , „Marijuana intoxication and brain activation in marijuana smokers“, Life Sci. 1997;60(23):2075-89.

[2] Glass, M., Dragunov, M., Faull, RL (1997) „Cannabinoid receptors in the human brain: a detailed anatomical and quantitative autoradiographic study in the fetal, neonatal and adult human brain.“ Neuroscience. 1997 Mar; 77(2): p. 299-318.

[3] Marsicano, G., and Kuner, R. (2008), „Distribution of CB1 Cannabinoid Receptors in the Nervous System“, in: Attila Köfalfi (ed.) (2008),  „Cannabinoids and the Brain“,  Springer Science and Business Media, New York, p. 164.

[4] Compare Sebastián Marincolo (2010), „High. Insights on Marijuana“, Dogear Publishing Indianapolis, Indiana.

[5] McGilchrist, Ian (2009), „The Master and His Emissary, The Divided Brain and the Making of he Modern World“, Yale University Press, New Haven and London, p. 39.

Comment Section

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JB Haze

Lovely. Such fond memories of Carl's wonderful Cosmos series from childhood. I briefly discuss Carl's use of the herb in a new book (Cannabis Regeneration) from Green Candy Press - forthcoming: Sept 2015. Carl was proof that you could explore both the inner-self and the universe with enthusiasm, vigour, passion, and an open mind.

02/07/2015

Ole K

Wauw that was very satisfying experience, i have just come from a private meditation session where i also vaporized some cannabis, and wanted so share my experience and express my gratitude to this article.

First of all, im a former regularly user of cannabis, who used to have a moderate level/amount of intake, when i used/vaporized cannabis. (Meaning, i dont vape much when i do it, compared to most other users i know of).
Now, i only use cannabis once in a while, (about 2 to 3 times a month). I have then started a practice where i sometimes vaporize some cannabis and meditate for a couple of hours thereafter.
This night i had some insights, which led me to formulate a question which then led me to find this blog-article.
And it was just so awesome to find out how much i resonated with the information regarding cannabis usage and the effect on our consciousness and attention-focus in (in between) the left and right hemisphere.
Amongst other things of what i experienced, is the experience/feeling of being awake and asleep at the same time, like being conscious in the sub- or unconsciousness. Like with lucid dremaing where you "wake up" and become consciouss inside the dream.
I also felt like being one with the now and with everything, and very aware/awake, and at total peace. It was a truly amazing experience.

Thanks alot, Sebastián Marincolo for bringing this information to the net. It was very confirming and satisfying to me.

08/10/2016

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