RT Journal Article SR Electronic T1 Periodic Organization of a Major Subtype of Pyramidal Neurons in Neocortical Layer V JF The Journal of Neuroscience JO J. Neurosci. FD Society for Neuroscience SP 18522 OP 18542 DO 10.1523/JNEUROSCI.3117-11.2011 VO 31 IS 50 A1 Hisato Maruoka A1 Kazumasa Kubota A1 Rumi Kurokawa A1 Shun Tsuruno A1 Toshihiko Hosoya YR 2011 UL http://www.jneurosci.org/content/31/50/18522.abstract AB A major question in neocortical research is the extent to which neuronal organization is stereotyped. Previous studies have revealed functional clustering and neuronal interactions among cortical neurons located within tens of micrometers in the tangential orientation (orientation parallel to the pial surface). In the tangential orientation at this scale, however, it is unknown whether the distribution of neuronal subtypes is random or has any stereotypy. We found that the tangential arrangement of subcerebral projection neurons, which are a major pyramidal neuron subtype in mouse layer V, was not random but significantly periodic. This periodicity, which was observed in multiple cortical areas, had a typical wavelength of 30 μm. Under specific visual stimulation, neurons in single repeating units exhibited strongly correlated c-Fos expression. Therefore, subcerebral projection neurons have a periodic arrangement, and neuronal activity leading to c-Fos expression is similar among neurons in the same repeating units. These results suggest that the neocortex has a periodic functional micro-organization composed of a major neuronal subtype in layer V.