The great brain debate - Ted Altschuler
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Did this lesson pique your interest in brain anatomy? PBS has a site The Secret Life of the Brain for you to learn more. Then, explore a 3-dimensional model of the brain. Learn the names for its different lobes, gyri, and sulci. Finally, The Brain From Top to Bottom has information about the brain ranging from simple to complex. Expand your brain and visit the site!
Does probing the brain’s motor cortex sound thought provoking? What exactly does the cortex do? Interested in some of the neuroscientists who pioneered brain studies? Fritsch and Hitzing found they could cause a dog’s muscles to move by applying electrical stimulation to specific parts of the brain’s frontal cortex. David Ferrier’s work contributed something essential to the scientific process, he repeated and confirmed Fritsch and Hitzing's results. He then expanded on their findings by trying the same procedure in different organisms. Wilder Penfield mapped the motor cortex of humans by electrical stimulation while they were in surgery for epilepsy. He produced a map of the motor cortex sometimes called the motor homunculus. Want to probe a human brain yourself? Probe the Brain by PBS allows you to do that! Check out the map of the motor cortex while you are there.
Lesions of the brain, damage created by injury or disease, have been used throughout the history of neuroscience, such as Paul Broca and Carl Wernicke’s work, which was discussed in this lesson. Both scientists made important strides in mapping speech-related brain function. Learn more about Broca’s patient Louis Victor Leborgne, who could only utter one syllable. How did studying this patient revolutionized psychology? Wernicke’s patient could produce speech, but could not understand language. Conditions in which some aspect of speech is damaged are called receptive aphasia and Broca’s aphasia. Both patients had likely experienced strokes, where a blot clot or bleeding occurs in the brain. Since blood is toxic to brain tissue, this tends to compromise brain functions by creating lesions.
Tools measuring different brain phenomena can help us understand different aspects of brain structure and function. Believe it or not, there is a tool called transcranial magnetic stimulation or TMS. It uses electromagnetic energy to disrupt and temporarily change the electrical activity of the brain’s cortex, causing a temporary lesion and disruption to the brain function associated with the location of the lesion.
Electroencephalography or EEG measures the electrical activity of groups of neurons in the brain’s cortex by using electrodes-little discs that are sensitive to electricity. They magnify a small signal and allow doctors to measure changes in electrical activity from the surface of the scalp. EEG measures changes in brain activity on a very fine time scale. This is shown as a graph where each squiggle corresponds to one electrode. For pictures and more information click on PBS: Scanning the Brain.
Magnetic resonance imaging or MRI creates beautiful images of any tissue in the body, including brain tissue, using a large electromagnet. Generally fMRI measures the brain’s grey matter or tissues made up of the cell bodies of neurons and make very fine estimates of where activity is located. Its images are recorded over several seconds, so it gives a picture of activity that occurs over a longer time frame.
Connectome? This is a term for the interconnected network of neurons in your brain. As you have learned, the brain’s many areas work together to accomplish most brain functions – but what does this mean? Brain areas either work in sequence with activity traveling from region to region. This is called anatomical connectivity. The article The brain is full of Manhattan-like grids at National Geographic, gives you a perspective of what this would look like.
What does a diagram of the teenage brain look like? What is going on in there? Frontline: Inside the Teenage Brain has many answers! For more about BRAINS, go to TED-Ed!
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