Original Research ARTICLE

Front. Integr. Neurosci., 30 December 2007 | http://dx.doi.org/10.3389/neuro.07.012.2007

Learning mechanism for column formation in the olfactory bulb

  • 1 Department of Neurobiology, Yale University School of Medicine, USA
  • 2 Institute of Biophysics, National Research Council, Italy

Sensory discrimination requires distributed arrays of processing units. In the olfactory bulb, the processing units for odor discrimination are believed to involve dendrodendritic synaptic interactions between mitral and granule cells. There is increasing anatomical evidence that these cells are organized in columns, and that the columns processing a given odor are arranged in widely distributed arrays. Experimental evidence is lacking on the underlying learning mechanisms for how these columns and arrays are formed. To gain insight into these mechanisms, we have used a simplified realistic circuit model to test the hypothesis that distributed connectivity can self-organize through an activity-dependent dendrodendritic synaptic mechanism. The results point to action potentials propagating in the mitral cell lateral dendrites as playing a critical role in this mechanism. The model predicts that columns emerge from the interaction between the local temporal dynamics of the action potentials and the synapses that they activate during dendritic propagation. The results suggest a novel and robust learning mechanism for the development of distributed processing units in a cortical structure.

Keywords: olfactory bulb, olfactory glomeruli, olfactory maps, dendrodendritic synapses, active dendrites, non-Hebbian learning

Citation: M. Migliore, Carlo Inzirillo and Gordon M. Shepherd (2007). Learning mechanism for column formation in the olfactory bulb. Front. Integr. Neurosci. 1:12. doi: 10.3389/neuro.07/012.2007

Received: 5 November 2007; Paper pending published: 20 November 2007;
Accepted: 5 Decemeber 2007; Published online: 30 December 2007.

Edited by:

Sidney Simon, Duke University Medical Center, USA

Reviewed by:

Bernard W. Balleine, University of California Los Angeles, USA
Sidney Simon, Duke University Medical Center, USA

Copyright: © 2007 Migliore, Inzirillo and Shepherd. This is an open-access article subject to an exclusive license agreement between the authors and the Frontiers Research Foundation, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are credited.

*Correspondence: Gordon M. Shepherd, Department of Neurobiology, Yale University School of Medicine, P. O. Box 208001, New Haven, CT 06520-8001, USA. Tel.: (293)-785-4336. e-mail: gordon.shepherd@yale.edu