08. Neuroscience

7 of the Most Exciting Neuroscience Discoveries of 2021

December 21, 2021

Year on year, the pace of neuroscience discoveries is both exciting and relentless. From lab grown mini-brains, to artificial intelligence uncovering evolutionary secrets of the human brain, enjoy these 7 of the most amazing breakthroughs of 2021.

Treating Severe Depression with Adaptive Deep Brain Stimulation

A research team at the University of California San Francisco have successfully developed a method using deep brain stimulation (DBS) to adaptively treat depressive symptoms only when they appear. Deep brain stimulation involves implanting electrodes within the brain to deliver electrical currents to alter brain activity.

Previous studies have had limited success for treating depression with DBS because devices could only deliver constant electrical stimulation in one area of the brain. However depression can affect various areas of the brain, and the neural signatures of depression can rise and fall unpredictably.

With the aim of essentially creating a pacemaker for the brain, the scientists decoded a new neural biomarker. This specific pattern of brain activity effectively predicts the onset of symptoms. With this knowledge the team customized a new DBS technology that only activates when and where it recognizes that pattern.

The type of automatic on-demand therapy is impressive because it's functional responses are unique to both the patient’s brain and the neural circuit causing the illness. In it’s first trial, this custom DBS method was tested with a patient suffering from severe depression and passed with flying colors.  Almost immediately, the patient’s symptoms were alleviated, and this continued to be the case long term.

In the COVID era, where anxiety and mental health problems are becoming rife, this approach could prove an invaluable drug-free therapy for hundreds of millions of people.

Beyond Human Hearing

Similar to light waves, humans can only perceive a relatively small spectrum of the sound waves that travel around us. Typically we can only pick up on frequencies between 20 Hz and 20,000 Hz, beyond this is considered ultrasonic. This is the frequency range that animals like bats operate in, and also what is put to use in ultra sound medical scans.

A new method utilizing sophisticated technology has been pioneered by scientists at Aalto University, and has led to a device that basically gives humans bat-level hearing. This includes not only the ability to hear frequencies well beyond 20,000 Hz, but also to discern the direction and distance of the sound sources. For biologists for example, it allows people to track otherwise stealthy bats in flight, and locate their positions.

It works by recording ultrasound via a spherical microphone array, which detects ultrasonic sounds and uses a computer to translate the pitch to audible frequencies. It then plays the converted sound waves through headphones in real-time. Being able to perceive normally inaudible sounds could have valuable industrial applications, for example being able to hear and locate otherwise silent gas leaks.

Imagecredit: Ville Pulkki/Aalto University

AI Independently Learns to Smell in the Same Way Humans Do

Although neuroscience is a relatively young and fast-growing domain of science, artificial intelligence (AI) is both much newer and growing faster. The potential of combining these two fields of science has been revealed by researchers at MIT.

Using machine learning, they have discovered that artificial neural networks can self-learn how to smell in just a few minutes, actually mimicking the olfactory circuits in mammalian brains. This is profound because the algorithm put to work had no knowledge of the millions of years evolution required to develop smell biologically.

Yet amazingly, the artificial neural network replicated the biological activity of smell so closely that it revealed the brain’s olfactory network is mathematically optimized for its function.

This precise mimicking of the natural structure of circuits in the brain by independent machine learning may herald a new era, whereby AI teaches us the inner secrets of biological evolution. Sense of smell is the starting point in 2021, but who knows where this could lead…

Imagecredit: MIT

Neuroprosthesis Converts Thoughts into Sentences in Severely Paralyzed Patient

Researchers at UC San Francisco developed a new kind of a speech neuroprosthesis for patients with paralyses that prevents them for speaking. The method was demonstrated successfully on a man with a severely damaged brain stem, causing whole body paralysis.

Somewhat remarkably it works by detecting speech-related brain signals that control the vocal cords. When we speak, the vocal cords require complex motor-function instructions in order to articulate the wide variety of sounds we use when conversing. Even when unable to move, these signals can still get sent from the brain.

Using brain recordings from epilepsy patients, the scientists developed a method for real-time decoding of instructions to vocal muscles, into words. From these neural patterns, they were able to reliably discern 50 different common words whenever the patient was thinking them.  

All that was required was for the patient to wear a high-density electrode array to capture and record neural activity, which recorded signals from the speech motor cortex. This allowed up 18 words per minute to be translated with 93% accuracy. The advantage for the patient was that he simply had to act like he was really speaking and he could communicate hundreds of different sentences from the 50 words vocabulary.

Although this breakthrough seems limited to paralyzed patients, we undergo paralysis every night when we dream (unless we sleep walk). If evolved sufficiently, this approach could, for example, pave the way to translating our very thoughts while sleeping!

Human Mini-Brains Developed with Complex Neural Activity

Technically termed ‘brain organoids’, mini-brains can be grown from induced pluripotent stem cells. These stem cells can be taken from a person’s skin or blood, and the the potential to be morph into any type of cells. The benefit is that cell structures normally very difficult to access, can in principle, be grown and isolated for study. This is especially relevant for the brain, however previous mini-brains had limited functional structures.

This year’s breakthrough by scientists at UCLA has catapulted the structural complexity by growing aggregates of organoids to form complex three-dimensional brain structures. The researchers took stem cells from patients with Rett syndrome (a condition with seizures), and were able to grow mini-brains with functional activity similar to parts of human brains. This meant they were able to safely and successfully observe patterns of electrical activity that resemble the onset of seizures.

This research shows for the first time that some aspects of brain function can be isolated and studied in the lab down to the level of individual living cells. The key advantage is that these mini-brains can be grown to replicate aspects of both normal and diseased brain functions, as well as to test drugs and treatments with no risks to human or animals.

The scale of the human brain is enormous, so there are still clear limitations in terms of the complexity of brain structures that can be studied, but clearly this emerging neuroscience domain has sci-fi like potential.

Image credit: UCLA Broad Stem Cell Research Center/Nature Neuroscience

‘Neurograins’ Used to Develop Next-Generation Brain-Computer Interface

With the exponential growth in growth in computing power in recent decades, microchips have been getting increasingly smaller each year. Tech focused neuroscientists at Brown University have now developed a wireless computer so small it can be easily missed by the human eye. Dubbed ‘neurograins’ - because they are about the size of a grain of salt - they were developed to track and monitor brain activity.  

These ultra-tiny computers are able to record electrical activity from nearby neurons, and transmit their data wirelessly. The goal was to develop a new type of brain-computer interface (BCI) system, where a network of the mini-sensors can collectively track meaningful aspects of brain activity, and send the information to a nearby hub.

In a proof-of-concept experiment, the researchers deployed a network to successfully record a rodent’s neural activity with much greater accuracy than ever achieved before. This recording of brain signals in unprecedented detail it’s still in it’s early stages, but the technological breakthrough holds much promise for being able to convert brain waves into useful real-world actions without any physical effort.

Image credit: Jihun Lee

Restoring Functional Vision for Completely Blind People

This year a new type of microelectrode array has been used to create a form of artificial vision via a visual prosthesis. University of Utah scientists at the John A. Moran Eye Center built the device to record and stimulate neuronal activity within the visual cortex.

Implanted within the eye, the array receives visual information through glasses containing a small video camera, with the data processed by specialized software. The device then activates retinal neurons to produce phosphenes, as if they are receiving points of light. In turn allowing basic images of lines and shapes to be percieved by the mind.

Trialed with a completely blind patient, this method proved to be effective, and involved no complications from the surgery or the neuronal stimulation. In this first test, only a single array was used. However, the next goal is to use 7 to 10 arrays to deliver more detailed images that will allow blind people to actually navigate the world visually.

Image credit: John A. Moran Eye Center/University of Utah

New Injectable Molecular Therapy Repairs Severe Spinal Cord Injuries

A new class of ‘dancing molecules’ has been applied by researchers at Northwestern University to repair tissue in severe spinal cord injuries and successfully reverse paralysis. The dancing part involves manipulating the motion of these molecules to that they can wiggle their way into normally impossible to reach cellular receptors, in order to prompt them to get into gear repairing nerve tissues.

These seemingly magic molecules work by setting-off cascading signals, triggering axons to regenerate and helping neurons to survive after injury by encouraging a variety of new cell types to be born. This is in turn supports the regrowth of lost blood vessels necessary for cellular healing.

Tested in mice, just a single injection of the molecular therapy led to the paralyzed mice being able to walk again in under four weeks. Somewhat conveniently, 12 weeks later (well after recovery is complete), the materials biodegrade into nutrients for the cells without any side effects, effectively disappearing from the body naturally.

Dancing molecules triggering nerve tissue repair. Illustration by Mark Seniw.

VR Delivers Therapy to Overcome Fear of Heights

Virtual Reality (VR) has been used by psychophysicists for decades to investigate how we perceive sensory information. This year researchers from the University of Basel, the oldest university in Switzerland, developed a virtual reality application to actually treat height phobias.

Called Easyheights, the smartphone compatible software provides exposure therapy using 360° images of real locations. Wearing a VR headset, users stand on a platform that starts one meter above the ground, and then progressively rises as the users acclimatizes to each stage of height. It works by increasing sensory exposure to height with without increasingly the level of fear.

A clinical trial demonstrated the efficacy of this immersive form of treatment, producing significant reductions in phobia in real height situations. The benefits were experienced with just four hours of home-based training. This discovery shows how combining neuroscience knowledge with today’s technologies, can clinically improve peoples’ quality of life in ways that are easily accessible.

Image credit: Bentz et al., NPJ Digital Medicine 2021

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