Extensive migration of young neurons into the infant human frontal lobe

Abstract

The first few months after birth, when a child begins to interact with the environment, are critical to human brain development. The human frontal lobe is important for social behavior and executive function; it has increased in size and complexity relative to other species, but the processes that have contributed to this expansion are unknown. Our studies of postmortem infant human brains revealed a collection of neurons that migrate and integrate widely into the frontal lobe during infancy. Chains of young neurons move tangentially close to the walls of the lateral ventricles and along blood vessels. These cells then individually disperse long distances to reach cortical tissue, where they differentiate and contribute to inhibitory circuits. Late-arriving interneurons could contribute to developmental plasticity, and the disruption of their postnatal migration or differentiation may underlie neurodevelopmental disorders.

Secretagogin is Expressed by Developing Neocortical GABAergic Neurons in Humans but not Mice and Increases Neurite Arbor Size and Complexity

“…9). These findings are consistent with the idea that the CGE/LGE contribute substantially to late-arriving interneurons in the human frontal lobe (Paredes et al 2016). Across the human lifespan (Kang et al 2011), analysis of 11 neocortical areas revealed that SCGN expression peaks in the late mid-fetal period (GW21-GW26) and declines monotonically thereafter (Fig.…”

“…At birth, SCGN was widely expressed in migratory streams of young doublecortin (DCX) + neurons in the frontal lobe, including neurons comprising the Arc, a newly described caplike structure surrounding the anterior body of the lateral ventricle (Paredes et al 2016) (Supplementary Fig. 9).…”

What is CAR doing in the middle of the adult neurogenic road?

“…13,14 By contrast, in rodents the second major site of postnatal neuronal differentiation is the OB. In the SVZ, pre-determined neuronal stem cells (NSCs) generate large amounts of NPCs.…”

Sculpting Cerebral Cortex with Serotonin in Rodent and Primate

“…However, a substantial proportion of them is likely to be generated in the pallium from the VZ and the SVZ [12,[94][95][96] (Figure 3C). Recently, migration of subclasses of human cortical interneurons has been reported to continue after birth [97].…”

“…These interneurons expressed a combination of transcription factors and a substantial fraction of them expressed COUP-TFII or SP8 (22 or 28% respectively) that are mainly specific of 5-HT 3A + interneurons suggesting that 5-HT could also modulate the migration and positioning of these neurons in human [97]. Interestingly, in the primate cortex, it was shown that 5-HT 3A is expressed by a subset of small GABA+, substance P+ or calbindin+ neurons and by medium-size CR+ neurons [190].…”