CBD and Its Potential Impact on the Brain
Today, we explore the science behind cannabidiol and its potential effects on our brains. Is it true that CBD can benefit brain health? If so, how? Find out all you need to know below.
By now, we are all familiar with cannabidiol’s therapeutic promise. As the hype behind medical cannabis continues to grow, the entire world is finally beginning to see many of its benefits to human health. And, amongst all of the body’s vital organs, it is the brain that interacts with cannabis the most.
The endocannabinoid system, for one, transcends through this region of the nervous system. And, once a cannabinoid like CBD enters the body, brain function is one of the first processes affected.
Numerous studies have already explored how cannabidiol affects brain function, most of which have shown promising results and spearheaded further research. But, how exactly does CBD impact the brain and its overall health? This article should explain everything you need to know.
How the Brain Works
The brain’s primary role is to process all of the information sent through the body, then send it back around. It’s like one central computer that controls memory, cognition, and experiences.
- The brain comprises three main sections: the cerebrum, cerebellum, and brain stem. The cerebrum is the largest section, located in the outer part. It is responsible for our ability to walk, think, learn new information, speak, feel, and read.
- The cerebrum has two main hemispheres: the left and the right. The former controls the right side of the body, while the latter controls the left.
Each hemisphere is then divided into four lobes, namely the temporal, frontal, occipital, and parietal. Each has specific functions that control reasoning, decision-making, personality, and sense of smell, among others.
At the back of the brain is the cerebellum, and its primary functions are mostly related to movement. It controls our ability to balance, fine muscle control (i.e. anything that involves hand-eye coordination), equilibrium, and posture maintenance.
Located at the bottom part of the brain is the brain stem. Its main purpose is to connect the cerebrum to the spinal cord. It also controls basic functions like breathing, blood pressure, and eye movement.
Cannabinoid Receptors in the Brain
Before we take a deeper dive into the cannabinoid receptors in our brains, it is important to first understand the endocannabinoid system. In a nutshell, it plays a modulatory role in achieving homeostasis (aka balance) within the brain and central nervous system.
That’s where the two major cannabinoid receptors come in: CB1 and CB2. Both of these receptor types are scattered throughout the body, but each is more concentrated in some areas than others.
Let’s first look at the CB1 receptors. An abundance of these are found in the nervous system, particularly in the brain, brainstem, and cerebellum. There are also CB1 receptors in the eyes, spleen, and the testis. Certain cannabinoids, such as THC, have a high binding affinity for CB1 receptors in the brain, giving rise to the psychotropic effects associated with marijuana.
As for CBD, it doesn’t bind with CB1 in a traditional way. Instead, it interacts with non-cannabinoid receptors  like TRPV1. TRPV1 receptors moderate the body’s response to inflammation and pain. In that regard, CBD potentially has the ability to provide therapeutic relief for pain.
CB2 receptors, meanwhile, are located primarily within immune cells, and take on the role of modulating immune function. It’s through these receptors that the body can help fight inflammation.
CBD displays compelling actions in the human body. But, how exactly does it affect our brains? This article will provide a detailed explanation.
Cbd brain function
Effect of cannabis use in human brain activity
Efeito do uso de maconha na atividade cerebral humana
While Marijuana (Cannabis sativa) has been used recreationally and medicinally for thousands years, over the last decades there has been a steady increase in the consumption of cannabis in many countries, especially among young people. This rising prevalence has caused concern. First, because cannabis use might lead on to the use of other more harmful illegal drugs, such as heroin and cocaine. Second, recent evidence indicates that early and regular cannabis use increases the risk of poor educational performance, early school drop-out, and depression, anxiety and psychosis in later life. 1
Although research on the mental health effects of cannabis has increased dramatically, our knowledge of its effect on the brain is still limited. Cannabis sativa is a plant comprising 400 different identifiable chemical constituents, more than 60 of which are cannabinoids. The two main cannabinoids are delta-9-tetrahydrocannabinol (D9-THC) and cannabidiol (CBD). Cannabinoids exert their effect by interaction with specific endogenous cannabinoid (CB) receptors. The latter involve membrane phospholipids and G-proteins. The CB1 receptor is expressed throughout the central nervous system whereas CB2 expression seems restricted to immune cells. Binding to CB1 receptors has effects on second messenger cascades as well as on ionic membrane conductance. Endocannabinoids may modulate glutamate and GABA synaptic transmission and can have postsynaptic effects on dopamine transmission. The endocannabinoid system has been implicated in a large variety of physiological central functions such as motor behavior, learning and memory, emotion, reward, food intake, neuroprotection, nociception, and some vegetative and peripheral responses. 2
The way that D9-THC and CBD act on the brain remains unclear. D9-THC receptors are densely distributed in the basal ganglia, cerebellum and frontal cortex, suggesting a role for cannabinoid receptors in motor control, and consistent with the effects of cannabis on motor performance. Cannabinoid receptors in paralimbic cerebral cortex (including hippocampus and amygdala) may mediate the effects of cannabis on cognitive and emotional functions in humans. The receptors that mediate the psychological effects of CBD are still unknown. CBD does not bind to the central known cannabinoid receptor, CB1 3 and its effects may be unrelated to THC-type activity.
Neuroimaging techniques, including functional neuroimaging, provide a powerful means of investigating the central actions of cannabis in man, in vivo. To date there have been few neuroimaging studies of the effects of D9-THC. In this issue of Revista Brasileira de Psiquiatria, Crippa et al 4 review neuroimaging research on cannabis. Results from structural neuroimaging studies have so far been inconclusive, perhaps due to methodological problems (few studies, small samples, poly-drug users, and inclusion criteria). Most of the functional imaging studies have used FDG-PET or SPECT, techniques with a relatively poor spatial and temporal resolution, and have examined activity during the “resting state”, making it difficult to link the activity with specific cognitive or emotional processes. These studies have reported changes in anterior cingulate, frontal temporal and cerebellar cortex. There has only been one neuroimaging study of CBD to date, and this indicated that CBD altered resting activity in limbic and paralimbic brain areas. Three studies of cannabis using fMRI have been published. One reported that long-term cannabis users showed greater anterior cingulate and prefrontal activation than controls did when performing a spatial working memory task. Another pilot study in adolescent users of cannabis and nicotine during a working memory task showed reduced hippocampal activation relative to controls. Lastly, a study in young adults of the effects of prenatal exposure to cannabis suggested that it has an impact on the activation of brain areas engaged during a Go/No-Go task.
Crippa et al 4 ‘s review highlights some of the limitations of the research done to date and the need for further investigation . Cannabis misuse, like other psychiatric disorders, involves a complex interaction between biological (genes, protein expression, neuronal circuits) and environmental factors (cannabis, others drugs, family and social background). Functional neuroimaging could be used to characterize the brain areas involved in the different states of the cannabis abuse/dependence disorder (intoxication, withdrawal and craving), as has been done for other substances. 5 It is also possible to use functional imaging to study the modulatory effect of cannabis on brain activation during cognitive tasks engaging cognitive processes that appear to be affected by cannabis use, such as memory and motor function. Neuroimaging can also be used to assess the impact of gene polymorphisms (e.g. COMT) on protein expression and brain function. On the other hand, recent pharmacological research has led to the synthesis of cannabinoid receptor agonist and antagonists, endocannabinoid re-uptake blockers and selective inhibitors of endocannabinoid degradation. Some of them might be new tools for study the cannabinoid receptors, cannabis and endocannabinoid brain activity or future treatments.
Section of Neuroimaging, Institute of Psychiatry, King’s College, London, Great Britain
Pharmacological Research Unit, Institut Municipal d’Investigación Mèdica, Barcelona, Spain
Zerrin Atakan and Philip McGuire
Section of Neuroimaging, Institute of Psychiatry, King’s College, London, Great Britain
1. Arseneault L, Cannon M, Witton J, Murray RM. Causal association between cannabis and psychosis: examination of the evidence. Br J Psychiatry. 2004;184:110-7.
2. Rodriguez de FF, Del A, I, Bermudez-Silva FJ, Bilbao A, Cippitelli A, Navarro M. The endocannabinoid system: physiology and pharmacology. Alcohol Alcohol. 2005;40(1):2-14.
3. Menchoulam R, Hanus L. Cannabidiol: an overview of some chemical and pharmacological aspects. Part I: chemical aspects. Chem Phys Lipids. 2002;121(1-2):35-43.
4. Crippa JA, Lacerda ALT, Amaro E, Busatto G, Zuardi AW, Bressan RA. Brain effects of cannabis: neuroimaging findings. Rev Bras Psiquiatr. 2005;27(1):70-8.
5. Volkow ND, Fowler JS, Wang GJ. The addicted human brain: insights from imaging studies. J Clin Invest. 2003;111(10):1444-51.
Original version accepted in English
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Cbd brain function Effect of cannabis use in human brain activity Efeito do uso de maconha na atividade cerebral humana While Marijuana ( Cannabis sativa ) has been used