Weird Animal Brain: Octopus

The octopus almost reaches alien status when it comes to its brain and nervous system.  And yet, the differences can help us understand more about the human brain as well as unique solutions nature has come up with for difficult problems like camouflage.  Octopuses can see polarized light, but cannot see color.  However, their skin changes both color and texture to camouflage with the surroundings.Continue reading

Brain Cigarette Knowing Neurons

The Strange Relationship between Nicotine and Parkinson’s Disease

According to the World Health Organization, smoking is responsible for approximately 6 million deaths in the world every year or one fatality every six seconds.  71% of all lung cancers and 42% of all chronic obstructive pulmonary diseases are attributable to tobacco use.  Oddly enough, not everything related to smoking is bad news: smokers seem to be protected against Parkinson’s disease.  Continue reading

The Departure of Skill Memories from Motor Cortex: Deeper Directions for Neuroscience

You probably have certain skills that I don’t.  Each of us, having spent enough time practicing something new, can become an expert.  A simple, ubiquitous example is driving a car with a manual transmission.  The precise sequence and timing of controlling the clutch, giving gas, and shifting the gears are challenging to coordinate when initially learning to drive a stick shift.  But eventually, the precision with which we can perform these sequences of movements is impressive.  Specifically, the errors we make when learning, indicated by gear grinding and stalling, are reduced with repeated practice.  Skill learning is relatively easy to train both in humans and in animals.  It therefore serves as a great way to study how the brain forms memories and uses those memories in the future.Continue reading

Smooth Move: How GABAergic Interneurons Regulate Skilled Motor Behavior

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

Zebrafish

What Zebrafish Teach Us About Touch

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

(Transneuronal) Attack of the Mutant Huntingtin! Knowing Neurons

(Transneuronal) Attack of the Mutant Huntingtin!

Huntington’s disease (HD) is an incredibly debilitating neurodegenerative disorder. Currently, there is no treatment that effectively reverses the progression of the disease or delays its onset. Huntington’s is a particularly difficult diagnosis because it is an autosomal dominant degenerative disease, meaning that any child of an affected parent has a 50% chance of inheriting the disease. Most children who inherit the disease have inevitably watched their parents battle with it.Continue reading

Forming Memories, One Neuron at a Time

On Monday, Knowing Neurons highlighted a recent research article that described a new miniature microscope that was small enough to sit on a mouse’s head and light enough to allow it to move freely!  This technology represents a great advancement for the field of neuroscience in general and place cell research, specifically!  For the first time, researchers at Stanford are able to literally watch neurons turn on and off in the hippocampus of a mouse, while it explores an open arena (video), all in real time. This technology adds a new twist on a classic way of studying how the brain maps out the world around us.Continue reading

You Are Here: Mapping The World With Neurons

“You are here.”  It’s the phrase that you’ll find on almost any map, punctuated with the ubiquitous oversized arrow.  It is the salient mark in a sea of confusing lines, shapes and labels that provides orientation and a sense of direction.  Since the release of Google Maps and smart phones, many of us have become accustomed to having a boundless map in the palms of our hands, one that constantly updates according to our position in the world, complete with a large arrow.  But in the absence of a map, directory, or an oversized arrow, how do you find your way?  Where is the internal map in your brain and how does it store information about the world in a sea of connected neurons?  Neuroscientists have been asking these questions for nearly thirty years now, and we only have a vague idea of how the brain forms internal representations of the outside world.Continue reading