Comparative strength and dendritic organization of thalamocortical and corticocortical synapses onto excitatory layer 4 neurons
| Autor: | Carl E. Schoonover, Verena C. Schilling, Juan-Carlos Tapia, Verena C. Wimmer, Carol A. Mason, Richard Blazeski, Randy M. Bruno, Wanying Zhang |
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| Rok vydání: | 2014 |
| Předmět: |
Dendritic Spines
Thalamus Models Neurological Action Potentials Dendrite Optogenetics Biology Synaptic Transmission law.invention Synapse law Neural Pathways medicine Animals Rats Wistar Cerebral Cortex Neurons Synaptic pharmacology General Neuroscience Dendrites Articles Rats medicine.anatomical_structure Synapses Excitatory postsynaptic potential Soma Electron microscope Neuroscience |
| Zdroj: | The Journal of neuroscience : the official journal of the Society for Neuroscience. 34(20) |
| ISSN: | 1529-2401 |
| Popis: | Thalamus is a potent driver of cortical activity even though cortical synapses onto excitatory layer 4 neurons outnumber thalamic synapses 10 to 1. Previousin vitrostudies have proposed that thalamocortical (TC) synapses are stronger than corticocortical (CC) synapses. Here, we investigated possible anatomical and physiological differences between these inputs in the ratin vivo. We developed a high-throughput light microscopy method, validated by electron microscopy, to completely map the locations of synapses across an entire dendritic tree. This demonstrated that TC synapses are slightly more proximal to the soma than CC synapses, but detailed compartmental modeling predicted that dendritic filtering does not appreciably favor one synaptic class over another. Measurements of synaptic strength in intact animals confirmed that both TC and CC synapses are weak and approximately equivalent. We conclude that thalamic effectiveness does not rely on enhanced TC strength, but rather on coincident activation of converging inputs. |
| Databáze: | OpenAIRE |
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