Yet, little is known about how the time-varying firing rate of sensory neurons control the specific motor sequences Epigenetic pathway inhibitors underlying ongoing, complex motor behaviors. Collision avoidance and

escape behaviors provide a favorable model to study this question. They are critical for survival and are implemented by specialized neural circuits in several species (Wang and Frost, 1992, Graziano et al., 1994, Wicklein and Strausfeld, 2000, Yamamoto et al., 2003, Preuss et al., 2006, Oliva et al., 2007 and Fotowat et al., 2009). In locusts, the third neuropil in each of the two optic lobes contains an identified neuron, the lobula giant movement detector (LGMD) that responds specifically to objects approaching on a collision course in its associated visual hemifield, or their 2D projection: looming stimuli (Hatsopoulos et al., 1995, Schlotterer, 1977, Rind and Simmons, this website 1992, Judge and

Rind, 1997 and Peron and Gabbiani, 2009). Each LGMD synapses in the brain onto the descending contralateral movement detector (DCMD) neuron, such that their spikes are in one-to-one correspondence (Rind, 1984 and Killmann and Schurmann, 1985). In response to looming stimuli, the firing rate of these neurons gradually increases, peaks, and rapidly decreases before expected collision (Gabbiani et al., 1999). Similar response profiles have now been described in neurons of wide-ranging species (pigeon: Sun and Frost, 1998; frog: Nakagawa and Hongjian,

2010; fish: Preuss et al., 2006; fruit fly: Fotowat et al., 2009). In locusts, this response profile is robust to a broad spectrum of stimulus changes, suggesting that it may play an important role in the generation of escape behaviors (Gabbiani et al., 2001). From the brain, each DCMD axon projects through the contralateral nerve cord to motor centers involved in jump and flight steering (O’Shea et al., 1974 and Simmons, 1980). In particular, the DCMDs make both direct and indirect synaptic contacts with the fast extensor tibia (FETi) motoneuron of the hindleg and indirect connections to the flexor tibia motoneurons (Burrows and Rowell, 1973, Pearson et al., 1980 and Pearson and Robertson, 1981). The involvement of DCMD activity in jump escape behaviors has been studied, but its role remains Etomidate unclear (Fotowat and Gabbiani, 2007, Burrows, 1996 and Santer et al., 2005). Up to now, it was impossible to record simultaneously from the DCMD and motoneurons during freely executed, visually guided jump escape behaviors. Consequently, it was not possible to observe how sensory and motor activities are related on a trial-by-trial basis. To achieve this goal, we built a telemetry system capable of wireless transmission of neural and muscle recordings. This system was sufficiently small that locusts could carry it as a backpack and still respond to looming stimuli by jumping.