Deep cortical layers are activated directly by thalamus

Christine M. Constantinople, Randy M. Bruno

Research output: Contribution to journalArticle

Abstract

The thalamocortical (TC) projection to layer 4 (L4) is thought to be the main route by which sensory organs communicate with cortex. Sensory information is believed to then propagate through the cortical column along the L4→L2/3→L5/6 pathway. Here, we show that sensory-evoked responses of L5/6 neurons in rats derive instead from direct TC synapses. Many L5/6 neurons exhibited sensory-evoked postsynaptic potentials with the same latencies as L4. Paired in vivo recordings from L5/6 neurons and thalamic neurons revealed substantial convergence of direct TC synapses onto diverse types of infragranular neurons, particularly in L5B. Pharmacological inactivation of L4 had no effect on sensory-evoked synaptic input to L5/6 neurons. L4 is thus not an obligatory distribution hub for cortical activity, and thalamus activates two separate, independent "strata" of cortex in parallel.

Original languageEnglish (US)
Pages (from-to)1591-1594
Number of pages4
JournalScience
Volume340
Issue number6140
DOIs
StatePublished - 2013

ASJC Scopus subject areas

  • General

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    Constantinople, C. M., & Bruno, R. M. (2013). Deep cortical layers are activated directly by thalamus. Science, 340(6140), 1591-1594. https://doi.org/10.1126/science.1236425