Cannabis and the brain

Cannabis: Good or Bad?  The active ingredient in Marijuana is called THC which is short for delta-9-tetrahydrocannabinol.  This chemical closely resembles another naturally produced chemical in our bodies called cannabinoids, which like THC, bind to areas of the brain called cannabinoid receptors.  These receptors are located in many different areas of the brain including the hypothalamus, cerebral cortex, and the thalamus to name a few.  How the drug works is the THC is artificially responsible for causing increased amounts of the cannabinoid receptor to be stimulated.  This ultimately causes an overflow of feelings we would consider normal or naturally safe.  It’s because of these reasons why marijuana can be so useful in medical practices such as relieving pain/swelling and increasing appetites in cancer patients unable to enjoy food any longer.  However there are also many negative effects on the brain such as disruption of short term memory, altering the minds perception of time, and destroying natural levels of specific chemicals in your brain.  The question is does this drug have more pros then cons or is it as bad for you as your parents would have you believe.  This question cannot be completely yet due to the lack of long term evidence on the brain.  Until the long term effects of consuming THC are known, THC will continue to bind to medical patient’s receptors and illegally to the millions of recreational users throughout the world.

(http://io9.com/5794209/what-cannabis-actually-does-to-your-brain)

Stress: Good or Bad?

Everyone knows the feeling all too well, your cramped for time and you have so many things to do your head is spinning.  We call this mind boggling feeling stress.  Cortisol is the chemical found in the brain which is said to be responsible for managing stress levels.  While short term stress (less then 30 minutes) can be good for the brain and even incresase memory, attention span, and the immune system, long term stress takes our brains to the breaking point.  The article suggests that negative effects on the hippocampus may result from too much stress.  This happens when cortisol can no longer keep up with stress levels.  Long term exposure (greater than 30 minutes) may even result in the shrinking of the hippocampus with associated declines in memory, and cognitive function.  However, the article states that this damage may be reversed if the stressor is eliminated from the picture.    

(http://www.sharpbrains.com/blog/2008/02/05/stress-and-neural-wreckage-part-of-the-brain-plasticity-puzzle/)

lucid dreams

Imagine being able to control your dreams and do whatever you wanted while dreaming.  For some people this is possible and with training it may be possible for a majority of people.  A study conducted (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2737577/pdf/aasm.32.9.1191.pdf) was able to obtain information from subjects able to produce lucid dreams in a lab.  Lucid dreaming can be described as dreaming however, you are aware that you are dreaming.  While dreaming the subject is able to recognize something isn’t right and realizes they are in fact dreaming.  A successful experiment was conducted in which subjects were asked to repeat a specific eye pattern (left horizontal movement, right horizontal movement, back to left, pause, then repeat) once they realized they were dreaming.  Further evidence was produced using electromyographic activity (EMG) in both periods of wakefulness and sleep.  They found that eye movements in REM sleep are significantly less distinct then the pattern the subjects were asked to repeat during lucid dreams.  Lucid dreaming can be thought of as a hybrid between REM sleep and being awake.  Graphical evidence supporting this statement shows the frequency averages of short, medium, and long-range coherences (in Hz) by measuring scalp potential, and current source density.  The graph depicts that lucid dreaming falls somewhere in between wakefulness and sleep.

Furthermore I have heard that it is possible to induce lucid dreaming by mentally preparing yourself before sleep to recognize strange things in dreams.  Im not sure if this is true either but if you lay perfectly still for 30-40 minutes without moving your brain begins to believe you are asleep and you are able to have out of body experiences such as lucid dreams.  

Pair Bonding

Ever wonder what attracts you to your significant other and gives you a special bond with them?  A study done on monogamous voles may have surprising ties with humans.  The study (http://www.nature.com/neuro/journal/v7/n10/pdf/nn1327.pdf) has found that two chemicals found in voles (and in humans) Oxytocin (OT) and Arginine Vasopressin (AV), have found to be very important in pair bonding.  The chemical Oxytocin has been shown to be very important in both males and females however more so to females then males.  Males on the other hand, seem to be more effected by Arginine Vasopressin which leads them to be more aggressive, mark their territory and courtship.  This is interesting because both sexes show the same number of receptors for both Oxytocin and Arginine Vasopressin.  The study has been able to conclude that when Oxytocin is present in both sexes, pair bonding is increased even without mating.  If Oxytocin is blocked for any reason pair bonding is prevented and the animals do not show signs of courtship.  In addition, prenatal exposure of Oxytocin from mother to child is directly correlated with the probability that offspring will exhibit strong pair bonding later in adulthood.  Could this be true in humans as well?  Does a mother who is happily bonded to a father while pregnant give her child a greater chance of being happily bonded to an individual later in life?  Lactating females have been found to release large amounts of OT during nipple stimulation (breast feeding) which is part of the reason they are so close to their offspring.  The article finds that dopamine levels in the prefrontal cortex, nucleus accumbas and ventral palladium have been found to play an important role in pair bonding.  Is there a direct correlation between dopamine and pair bonding?  Evidence suggests that mating and pair bonding are directly correlated due to releases of Oxytocin, Arginine Vasopressin and dopamine.  In addition the specific smell of the partner stimulates the olfactory nerves which in turn, end up releasing dopamine which is why voles prefer to spend time where their partners smell is strongest.  This specific smell has also been shown to eventually release both chemicals associated with pair bonding furthering pair bonding between individuals.  The study has also found that sex releases OT and AV in both males and females with a higher level of AV being released in males and additionally a higher level of OT being released in females.  Although this specific of a study has not been conclusively done on humans, it is hypothesized that humans do in fact have similar correlations with pair bonding.

Neurological reasoning behind thrill seeking behavior

Ever wonder why some people partake in extremely risky behavior such as skydiving, gambling, driving fast, or other dangerous activities?  You may notice that they even seem to be addicted to these activities and go to extreme lengths to find new “fixes”.  A study conducted by the journal of neuroscience (http://teachhealthk-12.uthscsa.edu/curriculum/critical-appraisal/Thrill%20Seeking%20Module%20pdfs/Journal%20Article%20Thrill%20Seeking.pdf) has linked the neurotransmitter dopamine to these thrill seeking behaviors in both rats and humans.  The study was conducted on 34 subjects and found that persons who reported higher occurrences of thrill seeking behavior have fewer total number of dopamine receptors in their brain.  They were also able to conclude that the fewer dopamine receptors is inversely proportional to the amount of the neurotransmitter (dopamine).  As we know dopamine is responsible for that good feeling we get when something good or exciting happens.  The human brain is able to correlate the memory of the exciting event and the good feeling associated with it.  This correlation alone is enough to release dopamine and encourages the individual to recreate the excitement in order to attain the same feeling as before.  This may seem very similar to another group of individuals which we know to be drug abusers.  Drug use as we know is very addicting and it takes more and more of the drug to feel the same effects as the first time the drug was experienced.  This makes people who participate in risky behavior more inclined to drug use.  The feeling behind the event is responsible for the addictive properties in both cases.

The results of the experiment can be found graphically in figure 3 in the experiment.  It shows direct correlation between the dopamine receptor availability and the subjects thrill seeking score.

Visual hallucinations and the Visual Cortex

Thanks to a helpful tip I was able to find a very interesting article all about what hallucinations come from in the brain.  The article titled What Geometric Visual Hallucinations Tell Us about the Visual Cortex. Neural Computation by Bressloff, Cowan, Golubitsky, Thomas and Wiener (http://www.math.utah.edu/~bresslof/publications/01-3.pdf) is extremely useful information on where hallucinations originate within the brain.  Bressloff states that images are generally seen in both eyes and move with them, but maintain their relative positions in the visual field.  This leads him to believe that the above statement is evidence enforcing that hallucinations are generated in the brain.  Sited in the article is information stating that when subjects are instructed to inspect the fine details of their hallucination the fMRI of the V1 area of the brain shows increased activity.  Is it possible that it is coincidence, and does the fMRI show increased activity in areas of the brain responsible for creativity? Is there a possibility that connections between these areas of the brain are linked with areas of the brain responsible for rationalizing thoughts?  Could an error in communication between these areas be responsible for manifesting hallucinations?

What Geometric Visual Hallucinations Tell Us about the Visual Cortex answers this question by with this quote “a nonuniform retino-cortical magnification is generated by the nonuniform packing density of ganglion cells in the retina, whose axons in the optic nerve target neurons in the lateral geniculate nucleus (LGN), and in V1, that are much more uniformly packed.  The article then goes on to prove with using mathematics (which are way over my head) reinforcing that constants are generated in V1.  In addition, this article also gives significant evidence to suggest that iso-orientated patches located on a hypercolumn are the circuits in V1 responsible for detection of oriented edges and formation of contours commonly seen in hallucinations.  This is further evidence suggesting that the V1 area of the brain should in fact show higher levels of activity using fMRI when subjects reporting hallucinations are asked to describe the fine details of their hallucinations.

Meth in Drosophila

The authors of Fruit flies on meth (http://www.sciencedaily.com/releases/2011/04/110420184431.htm) were able to identify the effects of meth on molecular pathways using Drosophila as test subjects.  A barrage of pathways affected by meth such as energy generation, sugar metabolism and hormones have been identified using fly's of all things.  Manfredo Seufferheld (co-author) found evidence that indicates that meth mirrors rapidly growing cancer cells by altering the metabolism of the user.  Both meth and cancer cells use a process known as glycolysis  to provide the energy needed to maintain homeostasis in both humans and flys.  This is different from oxygen respiration which is the process normal cells use while in the presence of oxygen.  This is also known as the Warburg effect.  In this study they were also able to determine that fly's like humans, crave drinks containing large amounts of sugar which is thought to be related to reducing the toxicity of meth.

Although Im no meth expert, a sugary drink seems a bit weak in combating the worlds worst drug and all the negative effects that go along with it.