Thursday, October 30, 2008

Just a shade shy of true wickedness...

What can I say? Halloween makes me think of two things... candy and evil... haha... I heard a song say "I’m just a shade shy of true wickedness" and that made me think about whether we are just a gene shy of true wickedness... in other words is there an "evil gene" that could make humans murderous or overly aggressive or violent. The short answer is no... but there certainly seems to be a tremendous amount of effort attempting to discover a potential genetic basis for social behaviors like aggression or a predisposition to criminal behavior. It is a little scary to think that a monster could be lurking in the human gene pool. But given the complexity of the human behavior and interactions of genes, it seems unlikely that a mutation in a single gene sequence (say adenine to cytosine) during development is going to turn normal humans into serial killers... although it might be a cool movie. During my somewhat futile search for the evil gene I did come across some interesting stuff:
  • In the book Hard-Wired (here), author William Clark points out that in the laboratory, rats and mice have been selectively bred for many generations to create strains that are docile or fearful or aggressive with these traits being passed on to each generation each time they breed.
  • Creating transgenic knockout mice, scientists showed that disrupting a single gene encoding the vassopressin 1B receptor created mice with "reduced levels of social forms of aggression"(here). Genetically introducing a related receptor (vassopressin 1A receptor) into the brain of promiscuous rodents (mating with many partners) transformed them into monogamous (one mating partner), pair-bonding animals (here). Does this mean will will be getting an actual"chill" pill in the future or a monogamy pill for all the cheaters out there? Interesting...
  • A few years ago, scientists created so called "daredevil mice" by altering one single gene that is highly expressed in the amygdala of the brain. These transgenic mice were more fearless and displayed risk taking behavior not normally seen in mice.
  • According to an expert commentary in the Journal of the American Academy of Psychiatry and the Law (here), "any attempt to study violent or deviant behavior under the rubric of evil will be fraught with bias and moralistic judgments. Embracing the term evil as though it were a legitimate scientific concept will contribute to the stigma of mental illness, diminish the credibility of forensic psychiatry, and corrupt forensic treatment efforts." Well okay then... deviant behavior gene.
  • People that carve scary or "evil"pumpkins are 3.5X more likely to commit crimes such as shoplifting, illegal parking, and littering... just kidding. That isn't true. Just my hypothesis.
Take home message? There seems to be no evil gene... maybe we shouldn't even use the term evil in the scientific realm. But certainly, studies of rodents and other species prove overwhelmingly that genes influence social behaviors... and there is likely a cohort or group of genes that influence and/or predispose humans to deviant or bad behaviors. Who knows, someday they might even have a genetic test that will determine if you have an increased risk to commit murder!?


Happy Halloween! Be good.







~~~~~BIO25~~~~~

Wednesday, October 29, 2008

Brain Strain...

If you watch lots of sports like me then you are also hearing injury news about players. Unfortunately, most of the reports are often inaccurate and vague in terms of the anatomy and the actual structures that have been injured. One distinction to keep in mind is sprain versus strain.

According to the National Institute of Arthritis and Musculoskeletal and Skin Disease:

Sprain is a stretch and/or tear of a ligament. One or more ligaments can be injured at the same time. The severity of the injury will depend on the extent of injury (whether a tear is partial or complete) and the number of ligaments involved. Common examples would be an ankle sprain involving the stabilizing ligaments of the ankle or injury to the ligaments of the knee or shoulder.

Strain is an injury to either a muscle or a tendon. Depending on the severity of the injury, a strain may be a simple overstretch of the muscle or tendon, or it can result from a partial or complete tear. Common examples would be the injury of hamstring muscles (biceps femoris, semitendinosus, semimembranosus) or muscle od the back. So injury of the calcaneal tendon (Achilles) would be a strain.

Over at Stephania Bell's ESPN blog she points out that an injury to the acromioclavicular (AC) joint, since it is stabilized by ligaments around the joint, can be called a sprain. Although, injury at the AC joint tends to separate the acromion process of the scapula from its articulation with the clavicle... and so we would often just call the injury a "shoulder" separation. She implies that, perhaps, when the team would like to downplay an injury they might say shoulder sprain rather than the more serious sounding shoulder separation. Recall in class to make the distinction between shoulder separation, at the AC joint, and shoulder dislocation which occurs at the glenohumeral joint (humerus with scapula). Stephania discusses a term called shoulder sublaxation which refers to the humerus slipping only partially off the glenoid surface, but not completely dislocating out of the glenoid fossa... so there is an additional shoulder injury to think about... shoulder sublaxation. You are practically an orthopedic surgeon or physical therapist if you are still reading this... ha!

Go read the super cool anatomical NFL injury blog at ESPN (Click Here).





~~~~~BIO25~~~~~

Friday, October 17, 2008

Hooray for cheap anatomy and physiology textbooks!

I wanted to proudly display my "new" but used and very cheaply purchased A&P textbook... courtesy of Half.com by eBay. This was purchased and delivered for under $20... the book is in great shape and hardly looks used at all. The publishing date is 2004, luckily not much has changed in the content of A&P books since 2004 so it would be perfect for any anatomy or physiology class. It did take about a week and a half to arrive but if you are not in a hurry... it even had the CDROM, unopened in the back of the book. This is a great alternative to the $125-$210 new textbooks available online and at the Bookstore.









~~~~BIO25~~~~

Tuesday, October 14, 2008

Misty's dancing career and leg go pop!

Superstar athlete and 2-time Olympic beach volleyball gold medalist Misty May-Treanor injured her leg on the reality TV series Dancing With The Stars. She was forced to drop out of the dancing competition and had to undergo surgery to repair her injured leg. During training / rehearsal for the show Misty ruptured her calcaneal (Achilles) tendon. She reportedly heard a "pop" which is common of people tearing their calcaneal tendon... others often describe "feeling" something hit the back of their leg... caused by the sudden rupture of the body's largest and possibly strongest tendon. [Click images for a larger view]



The rupture of the calcaneal tendon could be a somewhat serious injury to a volleyball player like Misty given the tremendous force and stress on the tendon during jumping and leaping. The Achilles is formed by the tendinous contributions of the gastrocnemius and soleus muscles (i.e., the calf muscles) which are used in plantarflexion of the foot at the ankle... which is part of the motion of jumping. Of course, most athletes make a full recovery from this type of injury and the occurrence of re-rupturing the tendon does not appear to be high. Check out eMedicine for a detailed description of Achilles tendon rupture (LINK). Hopefully Misty will be back to volleyball as good as new when she returns to the beach, and perhaps the AVP beach volleyball tour will comeback to Sacramento... haha... probably not... look at the empty stands... regardless, check out May-Treanor's vertical leap at the net. She is going to need those Achilles tendons healed and healthy.




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~~~~BIO25~~~~

Sunday, October 5, 2008

This is your brain on drugs... errr.... music

All of us would probably agree that the music we listen to depends on our mood or even shapes our mood. A slow song might help you mellow out or fall asleep... loud rock songs or hip-hop might motivate your workout routine at the gym. Songs evoke strong emotions and memories from our past.

But what I really wanted to know is "why does listening to your favorite song make you feel so good?" Like many people, it seems I am always finding a new favorite song, listening to it almost obsessively for awhile, and then eventually it is on to a new one. It occurred to me that this seems a lot like reward-seeking behavior or pleasure-seeking behavior such as eating your favorite food, smoking cigarettes, shopping, taking drugs, hiking to the top of a mountain, gambling, etc. You might wonder, as I did, is music making us feel good just like all these other rewarding stimuli?

Well, it turns out that neuroscientists and psychologists have recently been studying music as a model to discover the brain circuitry involved in pleasure and reward. Here are some interesting things I came across on the subject of music listening, pleasure, and the brain:

  • In humans, music increases activity in a network of brain structures involved in reward and pleasure processing including the nucleus accumbens and the ventral tegmental area (1). These brain structures are also known to be active in response to other very pleasurable stimuli, such as food, sex, and drugs of abuse (2).
  • It is believed that pleasurable music activates dopamine pathways in brain regions such as the nucleus accumbens, thus increasing the levels of dopamine in the brain. Dopamine is a neurotransmitter used by neurons to signal to each other. Interestingly, cocaine exposure increases dopamine levels specifically in the nucleus accumbens of rats (3) and music too has been shown to increase dopamine levels in the rat brain within the nucleus accumbens (4,5). What does all this mean? Drugs and music (both seemingly pleasurable stimuli) induce the same neurochemical changes in the same exact brain regions, at least in rats. This is likely to be similar in the human brain.
  • Increased dopamine levels in the brain are associated with compulsive eating, falling in love, sexual pleasure, drug abuse, alcohol consumption, and many other euphoria-inducing stimuli.
What is the take home message? Well, this just might help explain why listening to music* is one of the most rewarding and pleasurable human experiences. It certainly helps me understand why I like listening to my favorite songs over and over again... it is basically a sonic addiction.





*remember music is cheaper than drugs and healthier than cigarettes. Some free music and dopamine release courtesy of SubPop records. Sorry, no hip-hop :)

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~~~~~ BIO25~~~~~~