Biology of the Brain

Choose a scientific article that interests you and read it carefully. Briefly summarize the research and state a question or new experiment you would like to see carried out as a result of this research.

When you submit an article review, remember that you are expected to choose challenging research articles on neurobiology from scientific journals. Articles of a more psychological or social nature will not be acceptable nor will articles from the everyday press.

You must include the full citation for your article and an active link to the article. 


Summation: This study investigated the neurobiology of itching and its modulation by cold treatments. The experimental design used PET scans of blood flow to measure brain activity in 15 healthy volunteers. It was found that an area of the midbrain, the periaqueductal grey, seems to be involved in the modulation of itching. At the same time, several areas of the brain seem to be less active when the itching is modulated than when it is not.

Original Source: This is an original scientific article about research performed at the Tohoku University school of Medicine in Japan.

What was studied: This research investigated what areas of the brain are active during the sensation of itching and what areas are affected when itching is modulated by the administration of cold treatments.

How the study was conducted: 15 healthy young men were exposed to 2 different concentrations of histamine, which is known to elicit the sensation of itching, in a dose dependent manner. Some were also treated with the application of cold on the foot opposite to the one given the histamine treatment. This was done to exclude the possibility of the cold treatment affecting itching on the local level. The study was designed to see how cold treatment affected the sensation of itching through changes in the activity of the brain. Subjects underwent PET scans to determine cerebral blood flow. Blood flow is a known indicator of brain activity. Proper controls were used for all treatments and experimental techniques.

What was concluded: Itching resulted in increased blood flow to many brain areas including left anterior cingulate cortex, left halamus, right posterior parietal cortex, as well as other areas. Concurrent treatment with cold decreased blood flow to these areas and resulted in an increase in blood flow to the periaqueductal area of the midbrain (PAG). It was concluded that the modulation of itching by cold treatment seems to involve increased activity in PAG and decreased activity in other parts of the brain.

New Questions: This article mentions that other studies have shown that an injection of morphine (an opiate receptor agonist) into PAG reduces the sensation of pain. What would happen in a similar study of itching and cold treatment if PAG were injected with morphine? Would it cause the sensation of itching to increase in intensity?

What would be the effect of causing itching in the right foot and cooling the left arm?

Is there some reason the cooling and the itching have to be on contralateral sides of the same site?

My Opinion: Itching doesn’t seem important unless you or someone you know has suffered with it. For some people it can be a serious and chronic condition. Since this research investigated itching and how a treatment such as cold might help, it could lead to improved understanding of itching and better treatments.


Make use of the college resources, good college dictionaries, and your text.

Modulate: (American Heritage dictionary) “To adjust or adapt to a certain proportion; to regulate or temper.”  The article, I reviewed discusses the “modulation” of itching by cold treatment. This means that cold treatment changed (or modulated) activity in those parts of the the brain that had been activated by itching alone and increased activity in an area (PAG) that may be involved in the “modulation of itching.”

PET scan: positron emission tomography. This is a neurological imaging technique that is especially important in measuring brain activity. In this study,  PET scans were performed to determine which areas of the brain were most active when the sensation of itching was induced and which had changed activity levels when cold treatments were added.  See Gale Encyclopedia of Medicine.

PAG: periaqueductal gray. It is an area in the midbrain known to be involved in some pain sensations. In this study, this area of the brain showed increased blood flow when examined with a PET scan. Therefore, PAG seems to have increased activity when cold treatment is used along with itching. The conclusion is that this area of the brain may be involved with the “modulation of  itching.”  See: text page G-19.