Efforts to study the development and function of the human cerebral cortex in health and disease have been limited by the availability of model systems. Extrapolating from our understanding of rodent cortical development, we have developed a robust, multistep process for human cortical development from pluripotent stem cells: directed differentiation of human embryonic stem (ES) and induced pluripotent stem (iPS) cells to cortical stem and progenitor cells, followed by an extended period of cortical neurogenesis, neuronal terminal differentiation to acquire mature electrophysiological properties, and functional excitatory synaptic network formation. We found that induction of cortical neuroepithelial stem cells from human ES cells and human iPS cells was dependent on retinoid signaling. Furthermore, human ES cell and iPS cell differentiation to cerebral cortex recapitulated in vivo development to generate all classes of cortical projection neurons in a fixed temporal order. This system enables functional studies of human cerebral cortex development and the generation of individual-specific cortical networks ex vivo for disease modeling and therapeutic purposes.

(via fuckyeahneuroscience)

jfs1:

Channelopathy of calcium ion channels induces changes in neural firing, neurotransmitter (dopamine & norepinephrine) over-production, neuron proliferation, and gene expression. The results come from a study using neurons grown from Timothy-syndrome induced pluripotent stem cells (iPS cells) - modeling a psychiatric disease in a Petri dish. 

(Medical Xpress) — Fully mature liver cells from laboratory mice have been transformed directly into functional neurons by researchers at the Stanford University School of Medicine. The switch was accomplished with the introduction of just three genes and did not require the cells to first enter a pluripotent state. It is the first time that cells have been shown to leapfrog from one fundamentally different tissue type to another.

The accomplishment extends previous research by the same group, which showed in 2009 that it is possible to directly transform mouse fibroblasts, or skin cells, into neurons.

“These liver cells unambiguously cross tissue-type boundaries to become fully functional neural cells,” said Marius Wernig, MD, PhD assistant professor of pathology and a member of Stanford’s Institute for Stem Cell Biology and Regenerative Medicine. “Even more surprising, these cells also simultaneously silence their liver-gene expression profile. They are not hybrids; they are completely switching their identities.”

The cells make the change without first becoming a pluripotent type of stem cell — a step long thought to be required for cells to acquire new identities.

(Source: fuckyeahneuroscience)