2018 was when neuroscience made the impossible possible. Here are four neuroscience findings from 2018 that still blow our minds as we kick off the New Year.
Electrical implant restores walking in paralyzed patients
2018 was, without doubt, a breakthrough year for restoring mobility in paralyzed patients.
The technology is several years in the making, with initial positive results in monkeys. It works by implanting a neuroprosthesis into the spinal cord to bypass the site of injury by artificially stimulating remaining nerves.
In September, the Mayo Clinic reported the extraordinary case of Jered Chinnock, who was paralyzed at the waist in 2013. After getting the implant, he walked half the length of a football field. Another report showed that electrical stimulation in four cases was able to help some paralyzed patients go home and get around with only a walker.
Less than a month later, yet another team reported that electrical stimulation using a wireless implant helped three paralyzed patients walk with the aid of crutches or a walker. After a few months of training, the patients could more easily move around even when the stimulation was off, suggesting that the regime had helped remaining healthy nerves rework their connections to adapt and heal.
Electrical stimulation isn’t the only treatment in the works. Another study found that human stem cells, when implanted into monkeys, could synapse with the recipient’s own neurons and restore natural movement after spinal cord injury. These therapies—although expensive and in their infancy—lay a promising road ahead for returning mobility to paralyzed patients.
CRISPR barcodes map brain development in exquisite detail
The developing mammalian brain consists of an intricately-choreographed dance of newborn neurons, with each adopting its specific identity and migrating to its home base in the brain. Scientists have long hoped to examine the process in detail, which could help uncover secrets of brain development—and how it goes wrong.
Perhaps unsurprisingly, tracing the history of every single one of the billions of developing cells in the brain has been impossible—until CRISPR came along.
Last August, a team used CRISPR to generate a unique genetic barcode for every single cell in the mouse brain. By reading the barcodes, scientists were able to retrace a cell’s entire history in the developing brain. Like genetic sleuths, the scientists reconstructed entire cellular family trees to show how cells relate to one another.
A new type of neuron in the cortex that’s potentially uniquely human
Perhaps shockingly, even today neuroscientists are still uncovering new cellular components that make up our mighty brains. Last year saw the discovery of giant neurons within the claustrum, a thin sheet of cells that some believe is the seat of consciousness.
This year, the Allen Institute in Seattle is back at it with another finding: rosehip neurons, each containing dense bundles of processes around the cell’s center that make it look like a rose after shedding its petals.
These neurons make up nearly 15 percent of neurons in the outermost layer of the brain that supports high-level cognitive functions. Remarkably, rosehip neurons have never before been seen in mice or other well-studied lab animals. Although the team can’t yet fully conclude that they’re specific to humans, their scarcity within the animal kingdom is intriguing.
The next step is figuring out the functions of these rose-like neurons—in particular, are they partly why our brains are special?—and whether they are linked to neuropsychiatric disorders.
Gut-brain connection grows stronger with direct anatomical link
One of the hottest research trends in neuroscience is the link between the brain and the gut—often dubbed the “little brain.”
The human gut is lined with over 100 million nerve cells that allow it to talk to the brain, letting us know when we’re hungry or when we’ve over-indulged. But it’s not all digestion: scientists are increasingly realizing that the gut could contribute to anxiety, depression, or more controversially, cognition.
Last year scientists found a new set of informational highways that directly link the gut to the brain. Within the gut, enteroendocrine cells pump out hormones that kick off digestion and suppress hunger. These cells have little foot-like protrusions that look remarkably like synapses—the structure that neurons use to talk to each other using chemicals.
With the help of a glow-in-the-dark rabies virus, which can jump from synapse to synapse, the team found that enteroendocrine cells directly link to neurons in the vagus nerve—a giant nerve that runs from the brain to vital organs such as the heart and lungs. What’s more, they chat with their partners using classical neurotransmitters including glutamate and serotonin, which work much faster than hormones.
Another study found that the gut directly links to the brain’s reward centers through the vagus nerve. Using lasers to zap sensory neurons in the gut of mice, the scientists found increased levels of mood-boosting dopamine in their brains.
These new connections could explain why vagus nerve stimulation is potentially helpful for those with severe depression. More relevant to the holiday season, it also could explain why eating makes us feel warm and fuzzy.
Uncovering the gut-brain connection is gaining steam as a research field. Eventually, the findings could lead to new treatments for disorders linked to a malfunctioning gut—for example, obesity, eating disorders, depression, or even autism.
ref:. singularityhub.com | discoverieshub.com
