Present address: Neurological Institute of New York, 710 West 168th Street, Columbia University Medical Center, New York, NY 10032-3784, USA.
The influence of single bursts versus single spikes at excitatory dendrodendritic synapses
Article first published online: 25 JAN 2012
© 2012 The Authors. European Journal of Neuroscience © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd
European Journal of Neuroscience
Volume 35, Issue 3, pages 389–401, February 2012
How to Cite
Masurkar, A. V. and Chen, W. R. (2012), The influence of single bursts versus single spikes at excitatory dendrodendritic synapses. European Journal of Neuroscience, 35: 389–401. doi: 10.1111/j.1460-9568.2011.07978.x
- Issue published online: 31 JAN 2012
- Article first published online: 25 JAN 2012
- Received 27 September 2011, revised 21 November 2011, accepted 30 November 2011
The synchronization of neuronal activity is thought to enhance information processing. There is much evidence supporting rhythmically bursting external tufted cells (ETCs) of the rodent olfactory bulb glomeruli coordinating the activation of glomerular interneurons and mitral cells via dendrodendritic excitation. However, as bursting has variable significance at axodendritic cortical synapses, it is not clear if ETC bursting imparts a specific functional advantage over the preliminary spike in dendrodendritic synaptic networks. To answer this question, we investigated the influence of single ETC bursts and spikes with the in vitro rat olfactory bulb preparation at different levels of processing, via calcium imaging of presynaptic ETC dendrites, dual electrical recording of ETC –interneuron synaptic pairs, and multicellular calcium imaging of ETC-induced population activity. Our findings supported single ETC bursts, versus single spikes, driving robust presynaptic calcium signaling, which in turn was associated with profound extension of the initial monosynaptic spike-driven dendrodendritic excitatory postsynaptic potential. This extension could be driven by either the spike-dependent or spike-independent components of the burst. At the population level, burst-induced excitation was more widespread and reliable compared with single spikes. This further supports the ETC network, in part due to a functional advantage of bursting at excitatory dendrodendritic synapses, coordinating synchronous activity at behaviorally relevant frequencies related to odor processing in vivo.