"... We discovered that the emergence of a direction map in rat barrel cortex occurs long after all known critical periods in the somatosensory system.
This map is remarkably specific, taking a pinwheel-like form centered near the barrel center and aligned to the barrel cortex somatotopy.
We suggest that this map may arise from intracortical mechanisms and demonstrate by simulation that the combination of spike-timing-dependent plasticity at synapses between layer 4 and layer 2/3 and realistic pad stimulation is sufficient to produce such a map.
Kremer Y, Leger JF, Goodman D, Brette R, Bourdieu L (2011) Late emergence of the vibrissa direction selectivity map in the rat barrel cortex. J Neurosci 31:10689-700 [PubMed]