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Michael Wong

 

 

http://physics.ust.hk/phkywong/

 

Tuesday 15th January 2013

Time: 3.30pm

 

4th Floor Seminar Room

Alexandra House, 17 Queen Square, London, WC1N 3AR

 

 

Synaptic Depression Compensates Delays in Neural Systems

 

 

Department of Physics, The Hong Kong University of Science and Technology, Hong Kong, China.

 

A neural system processes continuous dynamic information, such as position and direction, by generating its own internal state to track the changes in external inputs. To achieve real-time tracking, it is critical to compensate the transmission and processing delays in the system. Here we show that dynamical synapses with short-term depression can enhance the mobility of the network states such that an effectively constant anticipation time or zero-lag between the tracking state and the stimulus is achieved. The anticipation time covers the range of 101 ms and decreases mildly with stimulus speed, in agreement with head-direction experiments in rodents. The parameter regions for delayed, perfect, and anticipative tracking correspond to static, ready-to-move, and spontaneously moving network states respectively, demonstrating the correlation between tracking performance and the system intrinsic behaviors. When the stimulus moves with the natural speed of the network state, the delay becomes effectively independent of the stimulus amplitude.

This work was done in collaboration with C. C. Alan Fung (HKUST) and Si Wu (Beijing Normal University), and was supported by the Research Grants Council of Hong Kong (grant numbers 604008 and 605010) and the National Foundation of Natural Science of China (No.91132702, No.31221003).