Students, faculty and researchers gathered in Gerstenzang Science Library for the John Lisman ’66 Memorial Lecture delivered by Dr. David Fitzpatrick, the CEO and scientific director of the Max Planck Florida Institute for Neuroscience April 10. Formerly the Jay Pepose ’75 Award was changed in 2017 to memorialize the renowned Brandeis neuroscientist Prof. John Lisman who passed away in Oct., 2017.
Fitzpatrick is a pioneer in the research of the cerebral cortex, the most complicated part of the brain, also known as grey matter. His research interests include the neural basis of visual perception, functional organization of cortical circuits, the imaging of neural activity and development of cortical networks.
Fitzpatrick graduated from Pennsylvania State University with a Bachelors of Science in 1974 and earned his Ph.D. from Duke University in 1982. He had been the James B. Duke Professor of Neurobiology at the Duke University School of Medicine and the Director of the Duke Institute for Brain Sciences until 2011.
The lecture was titled “Functional Synaptic Architecture in Primary Visual Cortex.” Fitzpatrick pointed out that humans’ understanding of the brain is still very basic. Aiming to have a general picture of the neural network as a whole, neuroscientists are striving to understand how single neurons interact with each other. Fitzpatrick focuses on the neurons of cerebral cortex, which is responsible for a wide range of human behaviors including sensing, vision and cognition by receiving and processing many signals they receive. One of Fitzpatrick’s major goals is to understand the way neurons integrate these signals.
For a long time, the general scientific consensus was that there is an overall map of a neuron’s dendrites in response to simulations, or in other words, a region is responsible for a specific type of stimulation. However, researchers found out that such mapping doesn’t exist. The responses to even a single stimulus was scattered across the dendrites. Inputs close to the cell body (soma) weren’t different from those far away.
Neuroscientists in Fitzpatrick Lab noticed a pattern that within an individual dendrite, spines that respond to a stimulus are often neighbors. After systematic research, they concluded that the neighboring spines within 5 microns are most likely to be co-activated, which shows that the synaptic inputs in the visual cortex are organized locally instead of globally. The research finding promotes the understanding of how a neuron deals with stimuli, representing a big step in understanding how the mechanism of a neural network.
