Top Ten Neuroscience Breakthroughs of 2018
Neuroscience research is progressing at a rapid rate. Advancements in tools and new techniques are enabling neuroscientists to forge inroads towards an understanding of the brain. This year, tens if-not hundreds of thousands of research papers, reviews and book chapters were published in the academic press in the field of neuroscience research. We have compiled a list of ten highlights (and one giant milestone!) from the past year, in chronological order.

1. RAIDERS OF THE LOST ARC – NOVEL INTERCELLULAR SIGNALLING MECHANISM DESCRIBED

In January 2018, two groups published their findings in Cell detailing a new way by which neurons communicate. Jason Shepherd’s group from the University of Utah and Vivian Budnik and Travis Thomson from the University of Massachusetts showed in mice1 and drosophila2, respectively, how Arc proteins are retroviral-like in their appearance and their ability to carry genetic material across a synapse.
However, the purpose of this intercellular communication still remained elusive until later in 2018, when Mriganka Sur’s group at MIT implicated Arc’s role in the dynamic structural plasticity his group observed when they imaged dendrites in the visual cortex. Performing in vivo imaging and optogenetic stimulation combined with ex vivo validation with 3D electron microscopy, the group showed that as one synapse strengthens in response to repeated signalling, the strength of its silent neighboring synapses weaken. This process is dependent on the correct function of Arc.3
Learn more: In Vivo imaging of dendrites

1. Pastuzyn, E. D., Day, C. E., Kearns, R. B., Kyrke-Smith, M., Taibi, A. V., McCormick, J., … & Briggs, J. A. (2018). The neuronal gene Arc encodes a repurposed retrotransposon Gag protein that mediates intercellular RNA transfer. Cell, 172(1), 275-288.
2. Ashley, J., Cordy, B., Lucia, D., Fradkin, L. G., Budnik, V., & Thomson, T. (2018). Retrovirus-like Gag protein Arc1 binds RNA and traffics across synaptic boutons. Cell, 172(1), 262-274.
3. El-Boustani, S., Ip, J., Breton-Provencher, V., Knott, G., Okuno, H., Bito, H., & Sur, M. (2018). Locally coordinated synaptic plasticity of visual cortex neurons in vivo. Science, 360(6395), 1349-1354. doi: 10.1126/science.aao0862

2. NON-INVASIVE OPTOGENETICS – SCIENTISTS ACTIVATE CHANNEL RHODOPSINS FROM OUTSIDE THE BRAIN

In February 2018, Tom McHugh’s lab at the Riken Brain Science Institute in Japan succeeded in activating blue-light-selective channel rhodopsin proteins deep inside the rodent brain, remotely. The team achieved this by injecting upconverting nanoparticles in their brain region of interest. The scientists then activated the upconverting nanoparticles non-invasively with infrared light from outside the head. The upconverting nanoparticles are excited by long wavelength light and emit light in the blue-light spectrum, activating the nearby channel rhodopsin proteins, and therefore the neurons of interest. This removes the need for intrusive implantation of light-guides and optic fibres.
Learn: How to set up optogenetics in your lab
Chen, S., Weitemier, A. Z., Zeng, X., He, L., Wang, X., Tao, Y., … & McHugh, T.J.  (2018). Near-infrared deep brain stimulation via upconversion nanoparticle–mediated optogenetics. Science, 359(6376), 679-684.

3. A NEURAL LAW OF EFFECT – OUR BRAINS OUR HARDWIRED FOR REWARD

In February 2018, Rui Costa’s group from Columbia University published their findings supporting a neural correlate for Thorndike’s law of effect, which states that actions that lead to reinforcements tend to be repeated more often. Using a closed-loop self-stimulation system involving electrode arrays positioned in the motor cortex and a light guide in to the ventral tegmental area (VTA). Ingeniously, they paired neuronal activity in the motor cortex to musical tones. When the motor cortex activity coordinated to play a certain pattern of tones, dopamine release was induced in the VTA by optogenetic activation. They found that, over time, the motor neurons would synchronise their activity to repeat the tones and generate more dopamine release, more frequently.
Learn how: A new type of customizable electrode array avoids damaging the brain tissue it records from
Athalye, V. R., Santos, F. J., Carmena, J. M., & Costa, R. M. (2018). Evidence for a neural law of effect. Science, 359(6379), 1024-1029.

4. BRAIN REGULATION OF PARENTING BEHAVIOR- MAPPING PARENTAL CIRCUITRY

2018 was a massive year for Johnny Kohl as he picked up the Eppendorf and Science Prize for Neurobiology and The Gruber prize for his outstanding work elucidating the neural circuitry of parenting behaviour.
During his postdoc in Catherine Dulac’s lab at Harvard University, Johnny explored the organization of circuits containing galanin-expressing neurons in the medial preoptic nucleus. He used optogenetic tools to map how projections from and to these cells form circuits that contribute to different aspects of parenting behaviour, such as grooming.
Some background reading: Fundamentals of deep tissue imaging
Kohl, J., Babayan, B. M., Rubinstein, N. D., Autry, A. E., Marin-Rodriguez, B., Kapoor, V., … & Dulac, C. (2018). Functional circuit architecture underlying parental behaviour. Nature, 556(7701), 326.

5. UN-PICKING PICK’S DISEASE – HOMING IN ON THE CAUSE OF FRONTOTEMPORAL DEMENTIA

Building on their pioneering work in 2017 to solve the structure of the misfolded human Tau protein that underlies Alzheimer’s disease, the scientists, led by Sjors Scheres and Michel Goedert from the Medical Research Council’s Laboratory of Molecular Biology in the UK, solved the structure of the tau protein isoform that causes frontotemporal dementia or Pick’s disease. The scientists used Cryo-electron microscopy to image the whole misfolded protein at atomic resolution. This level of detail will enable chemists to design compounds to interact with the protein to better diagnose or even treat the disease.
Falcon, B., Zhang, W., Murzin, A. G., Murshudov, G., Garringer, H. J., Vidal, R., … & Goedert, M. (2018). Structures of filaments from Pick’s disease reveal a novel tau protein fold. Nature 561, 137–140

NEUROSCIENCE MILESTONE ACHIEVED: THE LARGEST COMPLETE BRAIN VOLUME TO BE IMAGED AT THE SYNAPTIC LEVEL

In July this year, the results of a mammoth collaborative effort involving 23 scientists and taking more than six years to complete were published in Cell. Led by Davi Bock of Janelia Research Campus, the group achieved the 3D volume of the entire fruit fly (Drosophila melanogaster) brain. The poppy-seed sized brain contains around 100 thousand neurons thought to be connected by 40-50 million synapses. The volume was reconstructed from 21 million electron micrographs taken from 7,062 sections of brain and is the largest complete brain to be imaged at the synaptic level.

Credit, YouTube
Zheng, Z., Lauritzen, J. S., Perlman, E., Robinson, C. G., Nichols, M., Milkie, D., … & Calle-Schuler, S. A. (2018). A complete electron microscopy volume of the brain of adult Drosophila melanogaster. Cell174(3), 730-743.

6. NEW BRAIN CELL TYPE DISCOVERED – AND IT’S BEAUTIFUL

In August 2018, Scientists at the Allen Institute for Brain Science and the University of Szeged, published the morphophysiological and transcriptional characterisation of a newly discovered human cortical GABAergic neuron, called the Rosehip neuron.

A reconstruction of a newly discovered type of human neuron. The researchers who identified the new cell type dubbed it a ‘rosehip neuron’ for its compact, budlike shape. Image courtesy of Boldog, et al.; Nature Neuroscience.
The technology behind the science: CleverArm micromanipulators enable micrometer precision placement of microelectrodes
Boldog, E., Bakken, T. E., Hodge, R. D., Novotny, M., Aevermann, B. D., Baka, J., … & Faragó, N. (2018). Transcriptomic and morphophysiological evidence for a specialized human cortical GABAergic cell type. Nature neuroscience, 21(9), 1185.

7. THE BRAIN BOUNCES BACK FROM INJURY – STUDY CHALLENGES DOGMA AND CONVENTIONAL MEDICAL WISDOM

In September 2018, Randy Bruno’s group from the Zuckerman Institute at Columbia University provided some of the most compelling evidence against a cortex-centric top-down view of sensory information flow, processing and storage in the brain.
In their experiments, mice undertook a whisking task before the sensory cortex was optogenetically silenced or removed. During the silencing and immediately following the lesion, the mice were unable to complete the whisking task. However, the group found that within two days, the mice could recover their ability to perform the whisking task, meaning more areas than just the sensory cortex are involved in processing sensory information.
Their findings also fly in the face of coventional treatment for patients following stroke, suggesting that movement is better than prolonged rest for recovering the use of affected limbs.
Did you know, we can provide all the equipment and training needed to implement stereotaxic surgeries in your lab? Contact us
Hong, Y. K., Lacefield, C. O., Rodgers, C. C., & Bruno, R. M. (2018). Sensation, movement and learning in the absence of barrel cortex. Nature, 561(7724), 542.

8. PATCHING HUMAN DENDRITES – TO UNDERSTAND THE ELECTROPHYSIOGICAL PROPERTIES OF WHAT MAKES US HUMAN

In October 2018, MIT neuroscientists in Mark Harnett’s group performed patch clamp electrophysiology on human neurons in tissue resected during routine operations. Going one step further, they patched the dendrites of the human neurons to explore how electrical signals propagated along them. They then directly compared their findings with those made from rodent neurons. This is the first study to directly compare electrical transmission in human and rodent neurons.
Get: Complete electrophysiological and imaging rig
Beaulieu-Laroche, L., Toloza, E. H., van der Goes, M. S., Lafourcade, M., Barnagian, D., Williams, Z. M., … & Harnett, M. T. (2018). Enhanced Dendritic Compartmentalization in Human Cortical Neurons. Cell, 175(3), 643-651.

9. BRAIN CARTOGRAPHER FINDS NEW BRAIN REGION – THE ENDORESTIFORM NUCLEUS

In November 2018, Scientia Professor George Paxinos AO, University of New South Wales and Neuroscience Research Australia (NeuRA) found a previously unknown region of the human brain -that he suspected existed 30 years ago.
The Endorestiform nucleus is found in the brainstem, more specifically in the inferior cerebellar peduncle, an area that integrates sensory and motor information to refine our control of posture, balance and fine motor movements.

Scientia Professor George Paxinos AO describes the hidden region of the brain, which he has named the endorestiform nucleus. He tells us where it’s located and its possible function. He also discusses 3D mapping and why this discovery might set us apart from other primates. Credit: Neuroscience Research Australia, YouTube.

10. PARALYSED WALK AGAIN – LIFE CHANGING TECH IMPLANTS

In November 2018, Swiss neuroscientists and neurologists published the findings of their Stimulation Movement Overground (STIMO) study. By implanting specially designed electrodes and using precisely timed electrical stimulation, the scientists enabled paralysed patients to walk unaided.
“All the patients could walk using body weight support within one week. I knew immediately that we were on the right path,” Jocelyne Bloch, CHUV Neurosurgeon
Read the full story on the NeuroTech Today blog.
Wagner, F. B., Mignardot, J.-B., Goff-Mignardot, C. G. L., Demesmaeker, R., Komi, S., Capogrosso, M., … Courtine, G. (2018). Targeted neurotechnology restores walking in humans with spinal cord injury. Nature, 563(7729), 65. https://doi.org/10.1038/s41586-018-0649-2
Formento, E., Minassian, K., Wagner, F., Mignardot, J. B., Goff-Mignardot, C. G. L., Rowald, A., … Courtine, G. (2018). Electrical spinal cord stimulation must preserve proprioception to enable locomotion in humans with spinal cord injury. Nature Neuroscience, 1. https://doi.org/10.1038/s41593-018-0262-6
Read more about these and other neuroscience research stories on the NeuroTech Today Blog

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