New evidence challenges the long-held view that motor cortex lacks a fourth layer, and reveals that its circuitry resembles that of other cortical regions more than previously thought.

Layer 4 neuronal identity is specified by Protocadherin20 positioning the neurons into layer 4 so that they receive a positional cue from thalamocortical axons.

Neocortical synapses in layer 4 of the human temporal lobe neocortex were quantitatively characterized, at the subcellular level, using high-end, high-resolution electron microscopy and 3D-volume reconstructions.

Touch information is represented with minimal noise in the somatosensory cortex during tactile exploration.

The binocular matching of thalamic inputs to layer 4 cortical neurons initiates before that of intracortical inputs.

Layers 1 and 3b/4 of auditory cortex receive surprisingly heterogeneous but tonotopically matching input from the thalamus.