Deep cortical layers are activated directly by thalamus

  • Constantinople C
  • Bruno R
  • 591

    Readers

    Mendeley users who have this article in their library.
  • 155

    Citations

    Citations of this article.

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.

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Authors

  • Christine M. Constantinople

  • Randy M. Bruno

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free