The first cortical circuits: Subplate neurons lead the way and shape cortical organization

The cerebral cortex is essential for our sensory experiences and conscious thought. Its neural connections, in particular sensory areas of the cerebral cortex, are shaped and sculpted by our early sensory experiences. Onset of these first sensory experiences of the world mark an important developmental event, enabling our worldy interactions to shape the makeup of our cerebral cortex. These long-lasting effects of early sensory experience are particularly striking in human communication, since early exposure to the mother's language is required to detect all nuances in the underlying sounds. Early interactions with the world are mediated by a key set of neurons, subplate neurons, which remain part of the developing cerebral cortex until most of them disappear at later stages of development. They play a crucial role in the developing mammalian brain. Here I review the circuitry and functional roles of cortical subplate neurons, focusing on their purpose in the development of primary sensory cortices.