Sister neurons in the developing neocortex

It has been proposed that during development clonally related neurons migrate along the same radial glial fibre, forming clusters of functionally similar cells. However, this has not been shown experimentally. Two groups now demonstrate electrical coupling between sister neurons in the developing cerebral cortex that shapes subsequent functional relationships. Song-Hai Shi and colleagues report that in neocortical tissue from postnatal mice, long-range connections between sister neurons are maintained through electrical couplings that precede the formation of chemical synapses between them. Any blockade of gap junctions during development disrupts the eventual synaptic connectivity of sister cells and prevents their synchronous firing. Yang Dan and colleagues show that, in the mouse visual cortex, sister neurons in the same radial clone have similar orientation preferences. Disrupting gap-junction coupling shortly after birth diminishes the functional similarity between sister neurons, suggesting that the development of functional organization from ontogenetically related neurons requires this form of neural communication.