1. Take home point: Action potentials in a distributed neural network can be precisely timed via distributed oscillatory fields events. When you remove those oscillations you desynchronize distributed activity and this results in a specific impairment, the loss of fine odor discrimination.

2. Methods 1 Parallel recordings of mushroom body local field potentials and antennal lobe PNs Stimulate with a panel of odors/repeats and blanks Apply PCT and repeat stimulation Analysis includes Visual inspection of raw data Sliding window Correlograms (auto and cross) Power spectral density analysis

3. A. Autocorrelograms reveal odor- driven oscillations B-D. Crosscorrelograms reveal odor-driven phase locking of action potentials to odor-driven oscillations E. Two cells transiently synchronize spikes and sub threshold events Results: LFP correlates spiking activity

4. Results: GABA blockers abolish odor-driven oscillations odor-driven oscillations lost pre vs during PCT Loss of power in the oscillatory range that is present during odor response pre vs during PCT Autocorrelograms reveal odor- driven oscillations are lost during PCT

5. Spike trains appear unaffected by PCT Two cells and two repeats of three odors show consistent odor- dependent responses One cell in response to one odor (4 repeats) before vs during PCT Responses are unaffected. One cell 3 odors and PCT: same story plus cell maintains odor- dependent responses during PCT Parallel LFP recordings show PCT-dependent loss of power

6. Methods 2 Groups of honeybees conditioned Apply either PCT or saline vehicle in separate groups Tested in a stimulus generalization paradigm Analysis includes Statistical comparison of groups using t-tests

8. Conclusions: Output cells phase lock to local field potentials only transiently during odor-driven response This provides a temporal sequence of synchronized spikes across a distributed population. TOS is mediated by GABA, blocking GABA only disrupts this synchronizing mechanism This loss of synchronization only affects discrimination of closely related odors Thus the temporal aspect of encoding of odors disambiguates closely related odor representations.