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Marian Diamond, a neuroscientist and professor of neuroanatomy at the University of California at Berkeley, has been researching how the brain works for over 40 years. One area of her research involves the effect of the environment on the growth of brain cells. She has studied how the brain changes physically in response to the environment, for example, by putting rats into impoverished to enriched environments, and studying the changes in the structure of nerve cells in the cerebral cortex. When an interviewer asked Diamond about her use of rats, and about what she has found that applies to humans, she replied: "We work with rats because I have yet to find a human being who's willing to give me a piece of cerebral cortext to study" (D'Arcangelo, 1998).
Diamond's comment highlights the obvious challenges brain researchers face when trying to study the living human brain. However, medical technology used to chart the brain has improved immensely in the last decade or so, and these improvements are helping scientists make amazing new inroads into how the brain works. For example, research on chemicals in the brain has been moving forward rapidly with the use of emerging technology. For example, scientists studying neurotransmitters and their relationship to certain brain functions, use electrodes to stimulate nerve cells and record reactions (Sousa, 2001)
Computerized tomography scans use focused x-ray to produce cross sections of the brain useful for diagnosing strokes and cancer, but don't reveal brain functioning.
Positron-emission tomography can record brain activity and translate the activity into images. This technology is invasive, requiring injection of radioactive material (Sousa, 2001).
Mmagnetic resonance imaging uses radio waves and a magnetic field to align atoms. Different signals are given off by the atoms due to the make-up of the tissue. The signals are interpreted by computer and images of the brain tissue are formed. MRI can record changes in the brain that occur only 50 milliseconds apart and a complete picture of the brain each second. Functional MRI (fMRI) can also measure blood flow in the brain. This equipment can give researchers images of brain activity as the brain responds to stimuli. The fMRI can create little computer-generated movies that show researchers what the brain is doing as activities such as reading and talking.
A new version of electroencephalogram called MEG (magnetoencephalography) has been designed that can make 4,000 brain measurements in a second!
Used collectively, these advances in brain-scanning technology giving scientists views of the brain engaged in activities (Sousa, 2001).
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