PBIO SEMINAR SERIES

Reading the Neural Code: Representations and Transformations in the Natural Sensory World

Wednesday - April 04, 2007
06-07 Seminar Series
T-435

Garrett Stanley
Associate Professor Harvard
Speaker's website

Host: Eb Fetz

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 one particular stage of the neural pathway, but ultimately how sensory information is communicated from the periphery to successive downstream brain structures. Our laboratory has focused on various challenges posed by this problem, two of which will be discussed. First, 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. Secondly, sensory information is often obtained in an active manner, in which the observer’s own motion strongly influences the sensory signals received at the periphery, yet somehow result in a stable representation of the external environment. Taken together, an understanding of these complexities and others is critical for understanding how information about the outside world is acquired and communicated to downstream brain structures, in relating spatiotemporal patterns of neural activity to sensory perception, and for the development of engineered devices for replacing or augmenting sensory function lost to trauma or disease.