Beyond the amyloid hypothesis: proteins that indicate cognitive stability

If you’re wondering where Alzheimer’s research might be headed after the latest large-scale failure of a clinical trial based on the “amyloid hypothesis,” check this Read more

Mother's milk is OK, even for the in-between babies

“Stop feeding him milk right away – just to be safe” was not what a new mother wanted to hear. The call came several days after Tamara Caspary gave birth to fraternal twins, a boy and a girl. She and husband David Katz were in the period of wonder and panic, both recovering and figuring out how to care for them. “A nurse called to ask how my son was doing,” says Caspary, a developmental Read more

Focus on mitochondria in schizophrenia research

Despite advances in genomics in recent years, schizophrenia remains one of the most complex challenges of both genetics and neuroscience. The chromosomal abnormality 22q11 deletion syndrome, also known as DiGeorge syndrome, offers a way in, since it is one of the strongest genetic risk factors for schizophrenia. Out of dozens of genes within the 22q11 deletion, several encode proteins found in mitochondria. A team of Emory scientists, led by cell biologist Victor Faundez, recently analyzed Read more

spinal cord

Happy birthday, spinal cord neurons

Congratulations to JoAnna Anderson, postdoctoral fellow in Francisco Alvarez’ lab, for winning the Best Image contest, part of the Postdoctoral Research Symposium taking place Thursday. We will have explanations of the second and third place images Thursday and Friday.

The brief description of Anderson’s image is: “EdU birthdating of V1 inhibitory interneurons in the postnatal day 5 lumbar spinal cord.” But how did all those colors get in there and what do they mean? Alvarez explains:

The work is about finding the times of neurogenesis of the many inhibitory neurons that pattern motor output in the ventral horn of the spinal cord, so that our muscles contract in a coordinated manner to achieve the desired movements.

For example, when one muscle contracts, the muscle with the opposite action on the same joint will be inhibited. Anderson and her fellow postdoc Andre Rivard have been studying the development of the V1 neurons that carry out this inhibition.

AndersonJoAnnaThe image shows a slice of a 5 day old mouse’s spinal cord, and we can see individual cells. Some of the neurons are producing fluorescent proteins: one of the proteins is red, the other is green, and where both proteins are present, a yellow or orange color can be seen. The red and the green colors are indicators for two genes, Engrailed-1 and FoxP2, respectively, both of which regulate neurons’ development.

In addition, the white spots at the top come from EdU (5-ethynyl-2’-deoxyuridine), a chemical that impersonates a building block of DNA well enough to get incorporated into cells when they are dividing. It is helpful to remember that neurons are cells that have stopped dividing. Giving embryos a pulse of EdU is a way to mark the point at which progenitor cells mature and become neurons.

By repeating the experiment at different dates, the researchers can see that FoxP2 positive green cells are generated after the FoxP2 negative red cells. Both types of cells are derived from the same progenitors, but in different cell cycles. Read more

Posted on by Quinn Eastman in Neuro Leave a comment

Hypoxia is bad, except when it’s good

Randy Trumbower and his colleagues in Emory’s Department of Rehabilitation Medicine recently published a study showing that “daily intermittent hypoxia,” combined with walking exercise, can help patients with incomplete spinal cord injury walk for longer times. What is it about being deprived of oxygen for short periods that has a positive effect?

This research was puzzling at first (at least to your correspondent) because “daily intermittent hypoxia” is a good description of the gasping and snorting interruptions of sleep apnea.

Sleep apnea is a very common condition that increases the risk of high blood pressure, diabetes, heart attack and stroke. On the other side of the coin, many endurance athletes have been harnessing the body’s ability to adapt to low oxygen levels — so-called altitude training — to increase their performance for years.

So we have an apparent clash: hypoxia is bad, except when it’s good. Looking closely, there are some critical differences between sleep apnea and therapeutic hypoxia. The dose makes the poison, right? Read more

Posted on by Quinn Eastman in Neuro Leave a comment