CaMKII Measures the Passage of Time to Coordinate Motivational State

Summary

Date: 
November 8, 2017 - 1:00pm
Location: 
Northwest Building, Room 243
About the Speaker
Name: 
Stephen Thornquist
Speaker Title: 
PhD Candidate, Crickmore Lab

Proposed models for neuronal measurement of interval time rely predominantly on electrical activity, which occurs on the timescale of milliseconds. It is not clear if additional mechanisms are needed to time intervals of more than a few seconds. We show that an initial increase, and subsequent relaxation, of calcium-independent CaMKII activity controls the timing of two functionally linked but mechanistically separate events in male Drosophila: a dramatic decrease in the motivation to continue mating that occurs 5-7 minutes after a mating begins, and the simultaneous transfer of sperm. We localize this timing function to four male-specific neurons whose electrical activity is used only to report the culmination of CaMKII’s activity decay—not for the measurement of the time interval. This decisive neuronal computation is therefore invisible to standard measurements of neuronal activity. Broad conservation, ubiquitous expression, and tunable duration of activity suggest that CaMKII may be used to time a wide variety of behavioral and cognitive processes.