学术报告
题目：Specifying functional cortical circuits: roles of experience and cell lineage
报告人：Ye Li
Howard Hughes Medical Institute,
University of California, Berkeley,
时间：15:10-16:10 PM, May 22, 2014 (Thu.)
地点：Rm. 411, New Life Sciences Building
In order to interpret what we see, the visual system must encode multiple spatial and temporal cues in visual scenes. The neural representation of such cues arises from the highly selective response properties of individual neurons in the visual pathway. Especially in the primary visual cortex (V1), neurons are tuned to different features of stimuli, such as position in visual space, orientation, and direction of motion, with specific patterns of cortical circuits. My general research interests are in understanding how cortical circuits are constructed to specify brain functions to enable human perception and behavior. Visual system provides us an wonderful framework to study this questions. In this talk, I will present “a tale of two stories”. Using optical intrinsic imaging and two-photon calcium imaging, my graduate work demonstrated that visual experience has a strong influence on the development of orientation/direction selectivity of ferret V1 neurons. In my postdoc training, my colleagues and I have recently showed that cell lineage also plays an important role in specifying cortical circuits for orientation preference of mouse V1 neurons. Unlike in ferrets, cats and primates, the orientation preferences of V1 neurons in rodents are not organized into functional columns. Instead, the neuron with different orientation preferences are intermixed in a pattern of “salt and pepper”. Using a GFP-expressing retrovirus to label isolated ontogenetic columns formed by clonally related sister neurons and two-photon calcium imaging to simultaneously monitor the activity of hundreds of V1 neurons at single-cell resolution, I found that sister neurons shared similar orientation preference whereas nearby non-sister neurons showed no such relationship. These results suggested that despite the lack of a macroscopic orientation columns, the ontogenetic columns specified by cell lineage constitutes the functional processing unit in the cortex. At last, I will talk about my latest studies, aiming to extend the concept of functional units to other cortical areas. Particularly, I hope it will help us better understand the functional organization of frontal lobe for cognitive control. I have been developing techniques of chronic two-photon imaging and electrophysiological recordings in head-fixed behaving animals, which can allow me to explore the clonal-functional relationship of prefrontal cortical neurons in awake mice while performing goal-directed tasks. Together, thanks to a new generation of genetic tools and various imaging technologies, we are in the new era of discovering how endogenous factors interact with environment factors to specify neuronal circuits for normal brain function. It will also likely have a profound impact on diagnosing and treating neurological disorders with malfunctioning circuitry.
欢迎各位老师和同学积极参加！