Cerebellum learning: Myths and revelations in the blink of an eye
Abstract: Our current understanding about the function of the cerebellum is based on textbook accounts of its remarkable anatomical architecture, which is thought to be specialized for performing supervised learning: specific error-related climbing fiber inputs are used to teach sensorimotor associations to small ensembles of Purkinje cells located in functionally distinct modules that operate independently of each other in a purely feedforward manner. Here, we test whether the basic operation of the cerebellum complies with this basic architecture in mice that learned a simple sensorimotor association during eyeblink conditioning. By recording Purkinje cells in different modules and testing whether their responses rely on recurrent circuits, our results reveal three operational principles about the functional organization of the cerebellum that stand in stark contrast to the conventional view: (1) Antagonistic organization, (2) Recurrent network dynamics, and (3) Intermodular communication. We propose that the neural architecture of the cerebellum implements these three operational principles to achieve optimal performance and solve a number of problems in motor control.
Vivian L Smith Associate Professor in Neuroscience, Baylor College of Medicine
Dr. Javier Medina was born in Madrid, but grew up in sunny Malaga on the Mediterranean coast of Spain. After finishing high school, he was awarded a full-tuition scholarship to study in the United States. He graduated summa cum laude from Drexel University (Philadelphia) in 1993, with dual degrees in Physics and in Computer Science. He then moved to The University of Texas (Houston), where he spent the next 7 years learning about the brain and doing a PhD in Neuroscience in the laboratory of Dr. Michael Mauk. His thesis work and subsequent post-doctoral studies in the laboratory of Dr. Steve Lisberger at The University of California (San Francisco) have a common goal that continues to drive much of Dr. Medina’s research program today: to achieve a full mechanistic understanding of how the brain learns to control our movements with high precision. In 2008 Dr. Medina became an Assistant Professor in the Psychology Department at The University of Pennsylvania (Philadelphia) and in 2014, he was given tenure and promoted to the rank of Associate Professor. In 2015, Dr. Medina moved his laboratory to Baylor College of Medicine (Houston), where he is currently the Vivian L Smith Associate Professor in Neuroscience. Dr. Medina’s laboratory is currently using computational approaches and tools from pharmacology, in vivo neurophysiology and optogenetics to examine the mechanisms of cerebellar learning in mice.
About the Wu Tsai Neuro Seminar Series
The Wu Tsai Neurosciences Institute seminar series brings together the Stanford neuroscience community to discuss cutting-edge brain research, including imaging, neuro-engineering, computational approaches, theory, translational neuroscience, human neuroscience and basic neurobiology.
Unless otherwise noted, seminars are held Thursdays at 12:00 noon PT.