Stem cells have two characteristic and essential properties:
- Self-renewal. They can divide to give rise to another stem cell.
- Potency. They are capable of differentiating into specialized cells.
Stem cells have two characteristic and essential properties:
In early 2014, the American free-solo rock climber Alex Honnold climbed 2,500 feet of limestone without ropes. The demanding route called El Sendero Luminoso in El Potrero Chico, Mexico required 3 hours of intense concentration and precise movements. One wrong move and the young climber would have fallen thousands of feet with catastrophic consequences. In the video featured below, you see Honnold’s skilled movements and elegant displays of strength and precision. His ability to dramatically support his body weight with his fingertips and scale the wall like a spider monkey is due to the elaborate neural transformations that are directing each motor act. The ability to perform an action like a climb is dependent on sensory feedback and refinement of local inhibitory microcircuits. Goal-directed reaching behavior depends on a hardwired control systems that underlies our capacity to smoothly execute movement.Continue reading
There’s always one person snoring through the talk you’re trying to listen to at SfN. That person might even be you at some point during this meeting! Whether you are sleepy because of the time change, or because you finished your poster at 3AM, or because you were up late catching up with friends and colleagues, sleep is an essential behavior that is regulated by two independent processes: (1) a circadian clock that regulates the timing of sleep, and (2) a homeostatic mechanism that influences the amount and depth of sleep. Surprisingly, despite significant progress in our understanding of the molecular clock, the mechanisms by which the circadian clock regulates the timing of sleep is poorly understood.Continue reading
Unlike the sense of vision, which is perceived only by light-sensitive photoreceptors in our eyes, the mechanoreceptors that respond to light touch are located in sensory neurons all over the body. Our sense of touch starts in the skin, where sensory neurons with elaborate dendrites just below the skin’s surface provide dense coverage over the entire area of the body. When we touch something, the mechanical pressure created by the contact between an object and our skin opens mechanoreceptors that cause the sensory neuron to fire an action potential and activate downstream neurons. We are constantly coming into physical contact with objects and people in our environment, and as a result a large number sensory neurons are being activated over many different areas of our body at any given moment! How does the nervous system handle all of this incoming tactile information?Continue reading
If you think about it, the surface of the human body, the skin, is actually one huge sheet of tactile receptors. The dozens of types of receptors that innervate the skin help us connect with our surroundings. But the properties of these neurons – how they are organized in the skin, where the project into the spinal cord and brainstem, and how this organization gives rise to the sense of touch – are actually poorly understood! I spoke with David Ginty, Ph.D., who is Professor of Neurobiology at Harvard Medical School and an investigator with the Howard Hughes Medical Institute, to find out about the newest ways his lab is studying sensory biology.Continue reading
Imagine that you’re driving down a road undeterred, no red lights or stop signs to slow you down. While that may seem like a very exciting idea, it is obviously very dangerous, since our roads are not all parallel, but interconnected in a number of different ways. For traffic to go smoothly in all directions, we have stop signs, red lights, speed bumps and police cars to make sure no accidents occur. Continue reading
It is easy to assume that if a car has a gas pedal, it needs to have brakes, and similarly, if our brain has excitatory neurons, it needs inhibition too. For a long time, the field of neuroscience had thought of inhibitory interneurons as the “brakes” of the brain, providing suppression to neuronal activity. However, in my conversation with Dr. Gordon J. Fishell, I learned that interneurons are far more fascinating cell types than merely being inhibitory! Their multifarious morphology can be attributed to a palette of functions in brain developmental and regulation.Continue reading
Snap! Crackle! Pop!
Those are the sounds that Professors David Hubel and Torsten Wiesel heard in the early 1950s when they recorded from neurons in the visual cortex of a cat, as they moved a bright line across its retina. During their recordings, they noticed a few interesting things: (1) the neurons fired only when the line was in a particular place on the retina, (2) the activity of these neurons changed depending on the orientation of the line, and (3) sometimes the neurons fired only when the line was moving in a particular direction.Continue reading
When we see the world, there is a huge amount of processing that occurs in the neural circuits of the retina, thalamus, and cortex before we can even begin to comprehend our environment. And all of this computation happens very quickly! In this interview with Dr. Botond Roska, Senior Group Leader at the Friedrich Miescher Institute for Biomedical Research in Basel, Switzerland, we discuss his research on the elements of the visual system that compute visual information as well as how this knowledge can be used to help blind patients. Dr. Roska was inspired by the work and scientific approach of David Hubel (more about this on Wednesday!), and continues to follow his example: “Listen to the experiment, and not your colleagues,” says Dr. Roska. But what would he be, if not a neuroscientist? Find out in my conversation with Dr. Roska, who also shares his story of transition from musician, to medicine, to mathematics and to neuroscience!Continue reading
Take your wildest guess. How many neurons make up the human brain? You’re not guessing wild enough if you said anything less than a trillion. The circuitry of the human brain consists of a quadrillion (1015) synapses. These neural circuits aren’t necessarily hard-wired and have the capacity to be re-wired in response to experience. In our interview with Dr. Kelsey C. Martin, Professor of Psychiatry and Biological Chemistry at University of California, Los Angeles, we discuss the long-lasting forms of plasticity that enable memories to be formed. During the course of our conversation, Dr. Martin shares stories from her time in the Peace Corps. and discusses what it was like to study memory formation as a post-doc in the lab of the Nobel Prize winning scientist, Eric Kandel. In this highly anticipated interview from Knowing Neurons, we sit down with Dr. Martin to get advice on what it takes to become a Principal Investigator, to discuss her upcoming Presidential lecture at SFN, and to find out exactly what this English major turned M.D./Ph.D. is currently reading.Continue reading
This is an exciting time for neuroscience! The Nobel Prize for Physiology and Medicine was just awarded to three neuroscientists “for their discoveries of cells that constitute a positioning system in the brain.” John O’Keefe is best known for his work on place cells in the hippocampus, and May-Britt Moser and Edvard I. Moser study grid cells in the entorhinal cortex. Together, these cells provide an internal map of the external environment. In a way, they act as a GPS in the brain that can even navigate our 3D world!Continue reading