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)

Clint Eastwood might sound like an unlikely candidate to help investigate the evolution of the brain, but he has lent a helping hand to researchers doing just that. It turns out that brain regions that do the same job in monkeys and humans aren’t always found in the same part of the skull.

Previous studies comparing brains across species tended to assume that human brains were just blown-up versions of monkey brains and that functions are carried out by anatomically similar areas.

To test this idea, Wim Vanduffel of Harvard Medical School in Boston and the Catholic University of Leuven (KUL) in Belgium, and colleagues scanned the brains of 24 people and four rhesus monkeys while they watched The Good, The Bad and The Ugly. They compared the brain responses of each individual to the same sensory stimulation, and identified which brain areas had similar functions.

The majority of the human and monkey brain maps lined up, but some areas with a similar function were in completely different places.

The team say the discovery is crucial to building more accurate models of our evolution. “You can’t assume that because A and B are close together in the monkey brain, they need to be close together in the human brain,” Vanduffel says.

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)

Lesbian and heterosexual women respond differently to specific human odours, a brain-scanning study has found. The homosexual women showed similar brain activity to heterosexual men when they inhaled certain chemicals, which may be pheromones, the researchers say.

The brains of our closest relatives, unlike our own, do not shrink with age.

The findings suggest that humans are more vulnerable than chimpanzees to age-related diseases because we live relatively longer.

Our longer lifespan is probably an adaptation to having bigger brains, the team suggests in their Proceedings of the National Academy of Sciences paper.

Why are we so attracted to prophecies of doom, from religious raptures to environmental collapse? It’s part of our psychology

IN 1919, William Butler Yeats wrote The Second Coming, an allegory of the atmosphere in Europe after the carnage of the first world war.

Things fall apart; the centre cannot hold;Mere anarchy is loosed upon the world,The blood-dimmed tide is loosed, and everywhereThe ceremony of innocence is drowned;The best lack all conviction, while the worstAre full of passionate intensity.

The poem draws heavily on the mythic narrative of the apocalypse - or at least the first half of it, destruction. What usually follows is rebirth and redemption, a second chance, life born anew. The archetype is the Noahian flood myth, the world born again after being washed of its sins.

The latest incarnation of the destruction-redemption myth is brought to you by numerological number-cruncher and evangelical Christian radio host Harold Camping. Originally predicted to unfold on 21 May, the rapture has now been postponed until October after a no-show. It is easy to mock, but such apocalyptic scenarios are not the exclusive property of religion.

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