PT  - JOURNAL ARTICLE
AU  - Takeshi Soda
AU  - Ryo Nakashima
AU  - Dai Watanabe
AU  - Kazunori Nakajima
AU  - Ira Pastan
AU  - Shigetada Nakanishi
TI  - Segregation and Coactivation of Developing Neocortical Layer 1 Neurons
AID  - 10.1523/JNEUROSCI.23-15-06272.2003
DP  - 2003 Jul 16
TA  - The Journal of Neuroscience
PG  - 6272--6279
VI  - 23
IP  - 15
4099  - http://www.jneurosci.org/content/23/15/6272.short
4100  - http://www.jneurosci.org/content/23/15/6272.full
SO  - J. Neurosci.2003 Jul 16; 23
AB  - Layer 1 in the developing cerebral cortex is populated by two basic neuronal cell types, Cajal–Retzius (CR) cells and non-CR cells. We generated transgenic mice in which green fluorescent protein (GFP) was driven by the promoter of metabotropic glutamate receptor subtype 2 and expressed specifically in CR cells during cortical development. On the basis of the precise identification of CR cells with GFP fluorescence, we pursued developmental changes and synaptic mechanisms of both CR and non-CR cells during the postnatal period. Immunostaining in combination with GFP fluorescence imaging showed that GFP and reelin, a protein involved in corticogenesis, completely overlap in CR cells at postnatal day 0. At the subsequent postnatal stage, reelin-positive neurons are segregated and categorized into GFP-positive/GABA-negative CR cells and GFP-negative/GABA-positive non-CR cells. Individual and simultaneous whole-cell recordings of CR and non-CR cells in developing cerebral slices revealed that spontaneous and electrically evoked postsynaptic currents (sPSCs and ePSCs) measured in CR and non-CR cells are differentially mediated by GABAA receptors versus GABAA, AMPA, and NMDA receptors, respectively. Furthermore, CR and non-CR cells show synchronized repetitive barrages of sPSCs that reflect a network-driven activity in the developing cerebral cortex. These findings imply that the layer 1 neurons dynamically change and play a distinct and integral role in the postnatal developing neocortex.