Giorgio A. Ascoli, Ph.D., gave a neuroscience lecture titled “Trees of the Brain, Roots of the Mind” at Goodpaster Hall 195 in St. Mary’s College of Maryland (SMCM) on Sept. 17. Giorgio has written five books, 50 book chapters, and over 100 research articles. He is involved in biology and neuroscience programs at George Mason University’s Krasnow Institute for Advanced Study in Fairfax, Va.
Ascoli began his lecture by talking about the basic idea of the brain. He explained that Descartes believed that the mind laid in the heart, but today we know that consciousness lies in the brain. Cells in the brain appear to look like cells you may find in other organs such as the liver, containing the similar structures of the mitochondria, organelles and cell body. But dendrites make neurons different from other cells. Nerve cells in the brain have branch-like limbs that are shaped like trees, and they are immensely diverse. It is the way that neurons communicate information between each other. There are “input trees” and “output trees.” He went on to explain that the swellings on the “branches” or dendrites are specialized for different functions. Their functions can be impacted whether they are in the output or the input.
Ascoli stated that axons are the output of the neurons, while dendrites are the input. Much of the information he talked about is taught in neuroscience or biology classes at SMCM. His presentation stated that “Axons carry output signals from presynaptic neurons to their targets” and they “cover most of the distance between pre- and postsynaptic cells.” Axons span much bigger area than dendrites because they have to transmit the information. He explained that there is a “binary code of spikes traveling unaltered along branching path.” The main idea that Ascoli wanted the audience to take away from this lecture is that “the anatomical distributions of axonal and dendritic trees determines what synapses can be formed.”
Ascoli expanded on the physical description of neurons, explaining that a typical neural branch is 1000 times thinner than a strand of human hair. Also, “the total cable length in a brain is approximately 150 million miles.” That is the length of all the roads in the world combined. It may be surprising to learn that all of these impressive structures function in the human mind.
After describing the structure of neurons, Ascoli stated that there are “spatio-temporal brain patterns of electric activity.” This allows us to have mental states and connections that induce our thoughts. He also told us that “learning is the formation of new synapses in circuits of neurons.” An interesting point to note is that “new synapses only form between two neurons if their axons and dendrites share some of the same space.” Ascoli also Axonal-dendritic overlaps (ADO) are the neural correlate of the capability to learn.
After giving the audience a general overview of the basic functions of a neuron, Ascoli presented his research in the area of Background Information Gating (BIG). He described the phenomenon by comparing it to shopping on amazon for one item, and being referred to similar products. His example was how if you hear a beetle buzzing, you will make the connection that you have heard other insects before. He wants to explore exactly how the brain makes these connections.
If you want to learn more about Ascoli’s research, his lab’s website is krasnow1.gmu.edu/cn3. If you want to see a neuroscience lecture in person, the next of the series is on Oct. 22 at 4:45 in Goodpaster Hall 195 and will be led by Dionna Williams.