Dendritic spine density in multisensory versus primary sensory cortex
Article first published online: 26 APR 2012
Copyright © 2012 Wiley Periodicals, Inc.
Volume 66, Issue 8, pages 714–724, August 2012
How to Cite
Clemo, H. R. and Meredith, M. A. (2012), Dendritic spine density in multisensory versus primary sensory cortex. Synapse, 66: 714–724. doi: 10.1002/syn.21560
- Issue published online: 2 JUN 2012
- Article first published online: 26 APR 2012
- Accepted manuscript online: 4 APR 2012 06:42AM EST
- Manuscript Accepted: 23 MAR 2012
- Manuscript Revised: 22 MAR 2012
- Manuscript Received: 21 OCT 2011
- NIH. Grant Number: NS064675
- multisensory integration;
- association cortex;
In sensory areas, neuronal dendritic spines receive sensory-specific inputs whose net activity drives neuronal spiking responses to effective external stimuli. Previous studies indicate that neurons in primary sensory cortical areas, which largely receive inputs from a single sensory modality, exhibit an average of 0.5–1.4 dendritic spines/μm, depending on species. In higher-order, associational cortices, inputs converge from multiple sensory sources onto individual, multisensory neurons. This raises the question: when inputs from two different modalities converge onto individual neurons, how are the dendritic spines apportioned to subserve the generation of robust spiking responses to each modality? As inputs arrive from two different sensory sources, it might be expected that neurons in multisensory areas exhibit approximately double the spine density of neurons in areas that receive just one sensory input. The present study examined this possibility in Golgi-stained neurons from ferret primary auditory (A1) and somatosensory (S1) cortices, as well as from regions in which inputs from two different sensory modalities converge: the lateral rostral suprasylvian sulcus (LRSS) and the rostral posterior parietal (PPr) areas. Dendritic spine density (spines/μm) was measured for pyramidal neurons in layers 2–3 and layers 5–6 for each cortical area from three animals using light microscopy. Primary sensory regions A1 and S1 showed remarkably similar average spine densities (A1 = 1.27 spines/μm ± 0.3 s.d.; S1 = 1.14 spines/μm ± 0.3), but average spine densities from the multisensory areas were lower (LRSS = 0.98 ± 0.3; PPr = 1.04 ± 0.3). Thus, for a given cortical area, dendritic spine density appears to be determined by factors other than the levels of sensory modality convergence. Synapse, 2012. © 2012 Wiley Periodicals, Inc.