Cortex is driven by weak but synchronously active thalamocortical synapses.

Randy M Bruno; Bert Sakmann

doi:10.1126/science.1124593

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Cortex is driven by weak but synchronously active thalamocortical synapses.

Randy M Bruno·Bert Sakmann

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Abstract

Sensory stimuli reach the brain via the thalamocortical projection, a group of axons thought to be among the most powerful in the neocortex. Surprisingly, these axons account for only approximately 15% of synapses onto cortical neurons. The thalamocortical pathway might thus achieve its effectiveness via high-efficacy thalamocortical synapses or via amplification within cortical layer 4. In rat somatosensory cortex, we measured in vivo the excitatory postsynaptic potential evoked by a single synaptic connection and found that thalamocortical synapses have low efficacy. Convergent inputs, however, are both numerous and synchronous, and intracortical amplification is not required. Our results suggest a mechanism of cortical activation by which thalamic input alone can drive cortex.

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Action Potentials Animals Axons Dendrites Electric Stimulation Excitatory Postsynaptic Potentials Membrane Potentials Neural Pathways Neurons Rats Rats, Wistar Somatosensory Cortex Synapses Synaptic Transmission Thalamus Vibrissae Journal Article Research Support, Non-U.S. Gov't

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Randy M Bruno, Bert Sakmann. 2006-06-16. Cortex is driven by weak but synchronously active thalamocortical synapses.. https://doi.org/10.1126/science.1124593

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