Wednesday, March 10, 2010


In high school we are taught that brain cells do not repair themselves once they are damaged no matter what, but now that I am taking upper level biology courses I have found this is not the case. Recently, I have begun learning that adults can grow new neurons and repair themselves in certain areas of the brain. Regulated by growth factors, neurogenesis develops new brain cells from multi-potent neural stem cells which divide in the brain into neurons or glia. These cells move away from the multi-potent cells to mature and those that survive make connections with neurons and are able to begin sending signals. This process has been shown to occur in both the hippocampus and the olfactory bulb. Neurogenesis offers hope to those suffering from many neurological disorders including Parkinson’s, Alzheimers, and Huntingtons through the use of drugs that stimulate areas of the brain to replace its own cells.

recent study on adult neurogenesis involved the possibility of preventing cocaine addiction and relapse by increasing neurogenesis in the hippocampus. Researchers used lab rats to test their hypothesis by demonstrating that decreasing neurogenesis by blocking new growth of certain nerve cells increases vulnerability for cocaine addiction and relapse. Those involved aimed to decrease the neurogenesis in the brain and believe it could potentially help those being medically treated with potentially addictive medications, as well as those who are recovering from addiction. The hippocampus is the center of memory and learning, and it makes sense that altering the part of the brain that forms drug-context relationships could help to prevent relapse by helping to forget associations previously made while using the drug. They tested their theory by first manipulating the grow of the neural cells through advanced radiation delivery techniques in order to prevent growth in the hippocampus. Researchers found that rats where more likely to self administer cocaine with a lever than those who did not receive radiation. A second test with the rats involved them first self administering cocaine with the lever, and a round of radiation while not ingesting the drug. Rats that were radiated, with decreased neurogenesis, took longer to realize when there was no longer cocaine attached to the lever. Because the addicted rats continued to push the lever even though there was no physical satisfaction or stimulation of receiving the drug, it supports the notion that decreased neurogenesis fueled the process of addiction rather than the actual drug changing the brain.

Do you think that manipulating a single part of the brain can really have a large impact on improving or curing addiction to drugs? Addiction is more than just a memory formed one region of the brain, the hippocampus. Addiction is physical and takes a toll on your body. Also, many drugs affect pleasure regions in the brain so one would think the neuron growth would need to be reduced in multiple places in order for this to be plausible.

Posted by Asia Barnes (7)


  1. I have read a similar article to this one before, but it did not include a study on cocaine and neurogenesis. I find it quite informative to know that there is a correlation between the rate of neurogenesis and the prevention of cocaine addiction and relapse through drug context relationship. I would think that other drug addictions can be preventable to use methods similar to the one used in the article. This exemplifies psychological biology, which is one of the areas that truly grasps my interest in biology.

    Posted by Vinh Tran

  2. I too have always been taught that new brain cells can not be made, so if one dies, another does not replace it. Last semester i thought i heard my teacher give an example of certain brain cells that divide again but i thought i had just mistaken what he had said. My only question with the article is what do they do with the old neurons that were dependent on or signaling for addiction (if this is what happens). I can't understand how just making new neurons stops a person from being addicted to a drug but am interested to know. I agree with you that if a drug affects many areas of the brain then neurogenesis would also have to be performed on those areas as well.

    Posted by Kayla Perry

  3. Recently in my physiology class we had an extra credit assignment due about neurogenesis and what can help to facilitate this process. It was interesting to find that cannaboid compounds are chemicals that can help to stimulate neurogenesis in the brain. Firstly it's very interesting and promising to know that some damage done to the brain is not entirely irreverible. The study about neurogenesis helping to cure addiction is something that I wouldn't have really expected. I feel as though these disease such as Parkinson's or alzheimers would be the first thing to come to mind when we talk about disrupted neuron functions. Obviously there is a lot more to addiction than decreased neurogenesis, but anything that might be able to help ease cravings and reduce the possibility of relapse are great advances. I'm not sure i understand just how this works...are they suggesting that old neurons present during drug use are programmed to send certain "addicted" or alternate signals than cells that were not present? In this case are the rats being radiated getting rid of their old pathways related to cocaine use and growing all together new neurons whereas the other rats just have faulty wiring in their hippocampus?

    -Tom Roper