Spatiotemporal sequences of neuronal activity encode odor information in the olfactory bulb

A.U. Nicol¹, A Segonds-Pichon¹, K.M. Kendrick¹ and M.S. Magnusson²

¹Babraham Institute, Cambridge, UK,
²Human Behaviour Laboratory, University of Iceland, Reykjavik, Iceland

Spontaneously recurring complex sequences of neuronal activity were recently demonstrated in action potential (spike) generation amongst simultaneously sampled multiple neurons and in postsynaptic potentials. Using Theme™ (PatternVision Ltd, Iceland) developed for detecting non-randomly recurring real-time sequential patterns (T-patterns) in behavior and interactions, we have inquired whether such patterns exist in the olfactory bulb (OB) and if so whether they have functional significance. In accordance with the Animals (Scientific Procedures) Act 1986 (UK), an electrode array (5x6 or 6x8 electrodes, 350µ or 250µ separation respectively, sampling area 2.2mm2) was positioned in the OB (mitral layer) in 8 anaesthetised rats. Spikes were sampled in equivalent periods preceding and during 10s odour presentations (amyl acetate, cineole) at various concentrations. Breathing was recorded as markers of peak inhale and peak exhale. Long t-patterns were identified. Often these patterns spanned the entire array. A considerable proportion incorporated breathing, and these patterns are the focus here. The incidence and length of breathing-related sequences varied with ventilatory phase and odour quality. Thus, in the OB, precise sequences of neuronal discharge encode olfactory information.

Paper presented at Measuring Behavior 2005 , 5^th International Conference on Methods and Techniques in Behavioral Research, 30 August - 2 September 2005, Wageningen, The Netherlands.

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