NACS/ISR Special Lecture: Garrett Stanley, "Reading the Neural Code in the Natural Sensory World"
Friday, February 2, 2007
1208 Bio-Psych Building
301 405 6576
Neuroscience and Cognitive Science Program (NACS)
Institute for Systems Research Special Lecture
Reading the Neural Code in the Natural Sensory World
Garrett B. Stanley
Division of Engineering & Applied Sciences
The external world is represented in the brain as spatiotemporal patterns of electrical activity. Sensory signals, such as light, sound, and touch, are transduced at the periphery and subsequently transformed by various stages of neural circuitry, resulting in increasingly abstract representations through the sensory pathways of the brain. It is these representations that ultimately give rise to sensory perception. Deciphering the messages conveyed in the representations is often referred to as reading the neural code. True understanding of the neural code requires knowledge of not only the representation of the external world at a particular stage of the neural pathway, but also knowledge of how this representation is ultimately communicated to downstream brain structures. Our laboratory has focused on various challenges posed by this problem, two of which will be discussed in the context of the mammalian visual and somatosensory pathways. First, a ubiquitous property of neurons throughout the various sensory pathways of the brain is the ability to adapt their response properties to changes in the external environment. Adaptation therefore poses a unique challenge in reading the neural code, as the words to be conveyed downstream constantly change meaning in the non-stationary natural environment. Secondly, in interpreting neural representations, it is necessary to define the relevant temporal and spatial scales. Temporal precision of neural activity exists at the millisecond time scale, even in situations where the natural sensory world is changing over much slower time scales. This level of precision is not absolute, but instead relative to the time scale of the sensory input, and serves a critical role in the synaptic relay to downstream targets. Taken together, an understanding of these complexities and others is critical for ultimately relating spatiotemporal patterns of neural activity to sensory perception, and thus for the development of engineered devices for replacing or augmenting neural function lost to trauma or disease.
Garrett B. Stanley received the B.M.E. degree with highest honors from the Georgia Institute of Technology in 1992, and the M.S. and Ph.D. degrees in mechanical engineering from the University of California at Berkeley in 1995 and 1997, respectively. From 1995 to 1997, he was an American Heart Association Predoctoral Fellow. From 1997 to 1999, he was a Postdoctoral Fellow in the Neuroscience Division of the Department of Molecular and Cell Biology at the University of California at Berkeley, and an NIH Postdoctoral Fellow. In 1999, he joined the faculty of the Division of Engineering and Applied Sciences at Harvard University, where he is currently an Associate Professor of Bioengineering and an active member of the Harvard-MIT Division of Health Sciences and Technology (HST). His research interests include biological signal processing, experimental and theoretical approaches for understanding neural coding in sensory systems, neuronal point processes, parameter estimation, and the development of devices for recording from and stimulating the nervous system.
Cindy Moss and P.S. Krishnaprasad