Identity of neocortical layer 4 neurons is specified through correct positioning into the cortex.

Many cell-intrinsic mechanisms have been shown to regulate neuronal subtype specification in the mammalian neocortex. However, how much cell environment is crucial for subtype determination still remained unclear. Here, we show that knockdown of Protocadherin20 (Pcdh20), which is expressed in post-migratory neurons of layer 4 (L4) lineage, caused the cells to localize in L2/3.

Behavioral transition from attack to parenting in male mice: a crucial role of the vomeronasal system.

Sexually naive male mice show robust aggressive behavior toward pups. However, the proportion of male mice exhibiting pup-directed aggression declines after cohabitation with a pregnant female for 2 weeks after mating. Subsequently, on becoming fathers, they show parental behavior toward pups, similar to maternal behavior by mothers.

Neuromolecular basis of parental behavior in laboratory mice and rats: with special emphasis on technical issues of using mouse genetics.

To support the well-being of the parent-infant relationship, the neuromolecular mechanisms of parental behaviors should be clarified. From neuroanatomical analyses in laboratory rats, the medial preoptic area (MPOA) has been shown to be of critical importance in parental retrieving behavior. More recently, various gene-targeted mouse strains have been found to be defective in different aspects of parental behaviors, contributing to the identification of molecules and signaling pathways required for the behavior.

The cortical subventricular zone-specific molecule Svet1 is part of the nuclear RNA coded by the putative netrin receptor gene Unc5d and is expressed in multipolar migrating cells.

Although Svet1 RNA is a widely used marker for the subventricular zone (SVZ) of the embryonic cerebral cortex, its function remains completely unknown. We report finding that Svet1 contains a high proportion of repetitive sequences and maps in the first intron of the putative Netrin receptor gene Unc5d. The direction of transcription of Svet1 is the same as that of Unc5d.

Identification of molecules preferentially expressed beneath the marginal zone in the developing cerebral cortex.

During cerebral cortical development, the majority of excitatory neurons are born near the ventricle and migrate radially toward the marginal zone (MZ). Since the cells invariably stop migrating beneath the MZ, neurons are aligned in an "inside-out" manner in the cortical plate (CP); that is, the early-born and late-born neurons are ultimately positioned in the deep and superficial layers, respectively. Since dramatic morphological changes occur in cells beneath the MZ, several events critical for proper neuronal maturation and layer formation must take place.