Behavioural correlates of combinatorial versus temporal features of odour codes.
Most sensory stimuli evoke spiking responses that are distributed across neurons and are temporally structured. Whether the temporal structure of ensemble activity is modulated to facilitate different neural computations is not known. Here, we investigated this issue in the insect olfactory system. We found that an odourant can generate synchronous or asynchronous spiking activity across a neural ensemble in the antennal lobe circuit depending on its relative novelty with respect to a preceding stimulus. Regardless of variations in temporal spiking patterns, the activated combinations of neurons robustly represented stimulus identity. Consistent with this interpretation, locusts reliably recognized both solitary and sequential introductions of trained odourants in a quantitative behavioural assay. However, predictable behavioural responses across locusts were observed only to novel stimuli that evoked synchronized spiking patterns across neural ensembles. Hence, our results indicate that the combinatorial ensemble response encodes for stimulus identity, whereas the temporal structure of the ensemble response selectively emphasizes novel stimuli.
Department of Biomedical Engineering, Washington University in St Louis, St Louis, Missouri 63130, USA.
Debajit
D
Saha
Department of Biomedical Engineering, Washington University in St Louis, St Louis, Missouri 63130, USA.
Chao
C
Li
Department of Biomedical Engineering, Washington University in St Louis, St Louis, Missouri 63130, USA.
Steven
S
Peterson
Department of Biomedical Engineering, Washington University in St Louis, St Louis, Missouri 63130, USA.
William
W
Padovano
Department of Biomedical Engineering, Washington University in St Louis, St Louis, Missouri 63130, USA.
Nalin
N
Katta
Department of Biomedical Engineering, Washington University in St Louis, St Louis, Missouri 63130, USA.
Baranidharan
000000027866155X
B
Raman
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D006110:Grasshoppers / Q000502:physiology*; D024521:Mushroom Bodies / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D055696:Olfactory Perception / Q000502:physiology*; D011897:Random Allocation; D012903:Smell / Q000502:physiology*