Your Brain On Cannabis: Part Three

Welcome to the final part of this three part series on the effects of cannabis on the brain, and today we look at marijuana as medicine.

There are several well-documented beneficial effects of marijuana including the amelioration of nausea and vomiting, stimulation of hunger in chemotherapy and AIDS patients, lowered intraocular eye pressure (shown to be effective for treating glaucoma), as well as general analgesic effects (pain reliever).

The first treatment to emerge from understanding cannabinoids is the drug rimonabant, recently approved in Europe to treat obesity and related metabolic conditions. The drug works by binding to receptors in the brain and body organs to block cannabinoid action. Studies have shown that an overactivated cannabinoid system in brain areas like the hypothalamus -which is involved in appetite increases food intake and fat accumulation. Rimonabant and similar compounds reduce cannabinoid overstimulation to help normalize appetite, body weight and fat, and also cholesterol levels. Drugs that decrease cannabinoid action also may cause anxiety or depression-side effects scientists are working to combat.

Research is underway to determine if rimonabant also will help smokers and heavy drinkers quit. Scientists believe that rimonabant could work in these conditions by reducing levels of the chemical dopamine in the brain’s motivation centers, which nicotine and other addictive drugs trigger.

In 2011, an oromucosal spray for Multiple Sclerosis patients became licensed for use as a medicine in Canada and parts of Europe, allowing it to be routinely prescribed by doctors. This drug reduces the pain, tremor, and muscle spasms associated with this disease.

Synthesized cannabinoids are also sold as prescription drugs, including Marinol (dronabinol) in the United States and Germany and Cesamet (nabilone) in Canada, Mexico, the United States and the United Kingdom. Canada, Spain, The Netherlands, Austria and fourteen states in the US have legalized some form of cannabis for medicinal use.

I regularly visit schools to explain how addictive drugs including cannabis affect the brain.

Click to arrange a speaking engagement.

For those interested in the topic of marijuana abuse more information can be found at: http://drugabuse.gov/ResearchReports/Marijuana/marijuana3.html


Weekly Neuroscience Update

A new study reveals for the first time that activating the brain’s visual cortex with a small amount of electrical stimulation actually improves our sense of smell. The finding revises our understanding of the complex biology of the senses in the brain.

By training birds to ‘get rhythm’, scientists uncover evidence that our capacity to move in time with music may be connected with our ability to learn speech.

Daily doses of a drug used to treat Parkinson’s disease significantly improved function in severely brain-injured people thought to be beyond the reach of treatment. Scientists have reported on the first rigorous evidence to date that any therapy reliably helps such patients.

Remembering where we left our keys requires at least three different regions of the brain to work together, a study published in the Journal of Neuroscience says.

If you’re a left brain thinker, chances are you use your right hand to hold your cell phone up to your right ear, according to a new study from Henry Ford Hospital in Detroit.

People who experience a traumatic brain injury show a marked decline in the ability to make appropriate financial decisions in the immediate aftermath and a continued impairment on complex financial skills six months later, according to new research from the University of Alabama at Birmingham.

For the first time, a team led by Carnegie Mellon University neuroscientists has identified how different neural regions communicate to determine what to visually pay attention to and what to ignore. This finding is a major discovery for visual cognition and will guide future research into visual and attention deficit disorders.

Finally this week, Ireland’s neurological charities have come together to launch a new patient information and services website in time for National Brain Awareness Week which takes place next week (05 – 11 March).

Ode To The Brain

Through the powerful words of scientists Carl Sagan, Robert Winston, Vilayanur Ramachandran, Jill Bolte Taylor, Bill Nye, and Oliver Sacks, this wonderful video covers different aspects of the brain including its evolution, neuron networks, folding, and more.

Some of my favourite quotes from the video:

It’s amazing to consider that I’m holding in my hands the place where someone once felt, thought, and loved… [Robert Winston]

Here is this mass of jelly you can hold in the palm of your hands
And it can contemplate the vastness of interstellar space [Vilayanur Ramachandran]

No longer at the mercy of the reptile brain we can change ourselves. Think of the possibilities [Bill Nye]

Think of your brain as a newspaper, think of all the information it can store, but it doesn’t take up too much room, because it’s folded [Oliver Sacks]

It is the most mysterious part of the human body, and  yet it dominates the way we live our adult lives. It is the brain [Robert Winston]

Your Brain On Cannabis: Part Two

This a follow on post from last month’s Your Brain On Cannabis, which has become one of the most widely read posts on Inside the Brain.

The effects of marijuana on your brain

The drug acts in areas of the brain involved in memory and emotion by interacting with two receptors – the so-called CB1 and CB2 cannabinoid receptors – to cause a profound effect on recent memory. Long term memories are not affected. One brain region called the hippocampus has receptors for endogenous “marijuana” (anandamide). Hippocampal damage is associated with failure to make new memories and if the CB1 and CB2 receptors are stimulated activity decreases in this brain region.  Interestingly, with repeated use, tolerance to loss of memory develops but this is often associated with a further increase in drug intake.

Learning and marijuana don’t mix

Marijuana also changes the way sensory information is processed in the brain and is associated with poor performance in school and increased delinquency. There is impairment in the ability to learn. Listening and repetition learning is also compromised. Heavy marijuana use is associated with deficits in mathematical skill and verbal expression. Taken together these effects can lead to catastrophic social and psychological consequences particularly for the young abuser – not to mention the lost employee productivity, public health care costs, accidents and crashes and loss of income – Americans spent $10.6 billion on marijuana purchases in 1999.

Marijuana is addictive

Marijuana addicts experience withdrawal and an animal model for dependence has been developed by scientists to understand how this happens. Withdrawal has been described after 21 days of heavy use and starts 10 hours after stopping and includes insomnia, nausea, anorexia, agitation, restlessness, irritability, depression and shaking (tremor). The symptoms peak within 48 hours and gradually wear off by the fifth day of abstinence.

The war on marijuana starts with spreading the word

During the 1970s in the US it was decided that a liberal approach be adopted to marijuana use and 11 states decriminalized marijuana, 30,000 head shops were allowed to spring up and “responsible-use” messages were promoted. The drinking age was lowered to 18 years and the sale of cigarettes and alcohol to teens was tolerated. By 1979 35% of adolescents, 65%of high school seniors and 70%of young adults had tried an illicit drug. These facts and the increase in drug-related crime prompted universal outrage and the laws were tightened up. As a result – from 1979 to 1992 marijuana use has dropped by 2/3 among adolescents, and young adults and daily marijuana use has dropped by 500%. However, it has taken over 20 years to undo the damage in the US.

In tackling the marijuana problem head-on  – the following common myths need to be debunked (i) marijuana is harmless, (ii) marijuana is not addictive (iii) youth experimentation is inevitable and (iv) the criminalization of marijuana use is what leads to crime, not the drug itself.

In the final part of this series on the effects of cannabis on your brain, we will take a look at the possible medicinal uses of marijuana.


This is your brain on improv

Musician and researcher Charles Limb wondered how the brain works during musical improvisation — so he put jazz musicians and rappers in an fMRI to find out. What he and his team found has deep implications for our understanding of creativity of all kinds.

Weekly Neuroscience News

Scientists identify link between size of brain region and conformity.

Although there are several drugs and experimental conditions that can block cognitive function and impair learning and memory, researchers have recently shown that some drugs can actually improve cognitive function. The new multi-national study, published in the 21 February issue of the open-access journal PLoS Biology, reveals that these findings may implicate scientists’ understanding of cognitive disorders like Alzheimer’s disease.

New connections between brain cells emerge in clusters in the brain according to a study published in Nature on February 19 (advance online publication). Led by researchers at the University of California, Santa Cruz, the study reveals details of how brain circuits are rewired during the formation of new motor memories.

A new study shows that depression is linked to hyperconnectivity of brain regions.

A study in the February issue of Neurosurgery reveals that deep brain stimulation (DBS), commonly used to treat individuals with movement disorders or chronic pain, also affects respiratory function.

The Neuroscience of Illusion

 

In this illusion, created by Edward Adelson at MIT, squares A and B are the same shade of gray.

This illusion occurs because our brain does not directly perceive the true colors and brightness of objects in the world, but instead compares the color and brightness of a given item with others in its vicinity.

For instance, the same gray square will look lighter when surrounded by black than when it is surrounded by white. Another example: when you read printed text on a page under indoor lighting, the amount of light reflected by the white space on the page is lower than the amount of light that would be reflected by the black letters in direct sunlight.

Your brain doesn’t really care about actual light levels, though, and instead interprets the letters as black because they remain darker than the rest of the page, no matter the lighting conditions. In other words, every newspaper is also a visual illusion!

Neuroscience News

Bilingualism is good for the brain

The human brain has room for an uncounted number of languages as well as a sort of executive control system to keep them active but separate. This ability, a form of mental exercise, seems to be beneficial for the brain.

Researchers from the University of Wisconsin, Madison have presented innovative magnetic resonance imaging (MRI) techniques that can measure changes in the microstructure of the white matter likely to affect brain function and the ability of different regions of the brain to communicate.

Memory strengthened by stimulating key site in brain.

Researchers have created a living 3-D model of a brain tumor and its surrounding blood vessels. In experiments, the scientists report that iron-oxide nanoparticles carrying the agent tumstatin were taken by blood vessels, meaning they should block blood vessel growth. The living-tissue model could be used to test the effectiveness of nanoparticles in fighting other diseases. Results appear in Theranostics.

New model of neuro-electric activity could help scientists better understand coma states.

Scientists at Emory University School of Medicine have identified a new group of compounds that may protect brain cells from inflammation linked to seizures and neurodegenerative diseases.

Researchers at the University of Warwick and Indiana University have identified parallels between animals looking for food in the wild and humans searching for items within their memory – suggesting that people with the best ‘memory foraging’ strategies are better at recalling items.

Researchers at the Salk Institute have discovered a startling feature of early brain development that helps to explain how complex neuron wiring patterns are programmed using just a handful of critical genes. The findings, published in Cell, may help scientists develop new therapies for neurological disorders, such as amyotrophic lateral sclerosis (ALS), and provide insight into certain cancers.

The charitable brain

What motivates us to donate to charity? It seems that neuroscience might have some of the answers.

Michael Rosen reports on a new study from researchers at Texas Tech University into charitable giving behavior.

Researchers used brain scans to look at what motivates individuals to make a charitable bequest commitment as well as what de-motivates them. This is the first time that Magnetic Resonance Imaging has been used to examine charitable bequest decision making.

The three key findings of the report are:

  • Bequest giving and current giving stimulate different parts of the brain. This suggests that different motivators and de-motivators are at work.
  • Making a charitable bequest decision involves the internal visualization system, specifically those parts of the brain engaged for recalling autobiographical events, including the recent death of a loved one.
  • Charitable bequest decision making engages parts of the brain associated with, what researchers call, “management of death salience.” In other words, and not surprisingly, charitable bequest decision making involves reminders of one’s mortality.

You can read Michael Rosen’s article in full here