During the course of evolution, animals have adapted to the particular demands of their local environments in ways that increased their chances of survival and reproduction. This is also true of diverse aspects of the sensory systems that enable species to perceive their surroundings. In the case of the visual system, these adaptations have shaped features such as the positioning of the eyes and the relative acuity of different regions of the retina.

However, our knowledge of the functional evolution of visual systems in mammals has remained relatively sparse. “In the past 10 or 15 years, the mouse has become the favored model for the investigation of the processing of visual information,” says Professor Laura Busse of the Department of Biology II at Ludwig-Maximilians-Universitaet (LMU) in Munich. “That’s a somewhat surprising development, given that it was previously thought that these rodents primarily sensed the world using their whisker system and smell.” However, color vision in mammals is known to have an effect on the ability to find food, evade predators, and choose mating partners.

“It occurred to us that we don’t really know how mice perceive their natural environment visually,” says Busse, who is a member of the transregional Collaborative Research Center (CRC) 1233 on “Robust Vision.” Here, the term “robust” refers the fact that animals (including humans) are able to draw inferences from limited amounts of visual information, even in environments that are constantly changing. Busse decided to close this gap by studying the visual input and the processing of neuronal signals in mice,” In collaboration with Professor Thomas Euler of Tuebingen University, the Coordinating University of the CRC.

A camera that captures the mouse’s view

Mice are dichromate — in other words, they have two types of cone cells (the photoreceptors that are responsible for color vision) in their retinas. These cells detect electromagnetic radiation in the green and ultraviolet regions of the spectrum, centered on wavelengths of 510 nanometers (nm) and 350 nm, respectively. “We wanted to know what range of color information is available to mice in their natural habitats, and whether the prevalence of these colors can explain the functional characteristics of the neural circuits in the mouse retina,” Busse explains.

Together, the teams in Munich and Tuebingen set out to develop an low-cost, open-source camera which, unlike conventional cameras, was specifically designed to cover the spectral regions in the green and ultraviolet to which the mice retina is sensitive. To facilitate its use in the field, the hand-held camera is equipped with a gimbal, which automatically orients the picture frame, thus avoiding sudden, unintentional shifts in perspective.

The researchers used this camera to image the environment as it would appear to a mouse, at different times of the day, in fields that showed clear signs of their presence. “We knew that the upper hemisphere of the mouse retina, with which they can see the sky, is especially sensitive to UV light,” says Busse. “The lower half of the mouse retina, which is normally oriented towards the ground, shows a higher sensitivity in the green region. The team confirmed that these two spectral ranges closely match the color statistics of the natural environments that are favored by mouse populations. This adaptation could be a result of evolutionary processes — and for example help the animal to perceive birds of prey in the sky — and take evasive action. Experiments using artificial neural nets that mimic the processing characteristics of cone cells in the mouse retina confirm this conjecture.

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Materials provided by Ludwig-Maximilians-Universität München. Note: Content may be edited for style and length.

“Despite the headlines, there is no scientific evidence that shows that smartphones and digital technology harm our biological cognitive abilities,” says the UC professor of philosophy and psychology who recently co-authored a paper stating such in Nature Human Behaviour.

In the paper, Chemero and colleagues at the University of Toronto’s Rotman School of Management expound on the evolution of the digital age, explaining how smart technology supplements thinking, thus helping us to excel.

“What smartphones and digital technology seem to do instead is to change the ways in which we engage our biological cognitive abilities,” Chemero says, adding “these changes are actually cognitively beneficial.”

For example, he says, your smart phone knows the way to the baseball stadium so that you don’t have to dig out a map or ask for directions, which frees up brain energy to think about something else. The same holds true in a professional setting: “We’re not solving complex mathematical problems with pen and paper or memorizing phone numbers in 2021.”

Computers, tablets and smart phones, he says, function as an auxiliary, serving as tools which are good at memorization, calculation and storing information and presenting information when you need it.

Additionally, smart technology augments decision making skills that we would be hard pressed to accomplish on our own, says the paper’s lead author Lorenzo Cecutti, a PhD candidate at the University of Toronto. Using GPS technology on our phones, he says, can not only help us get there, but lets us choose a route based on traffic conditions. “That would be a challenging task when driving round in a new city.”

Chemero adds: “You put all this technology) together with a naked human brain and you get something that’s smarter…and the result is that we, supplemented by our technology, are actually capable of accomplishing much more complex tasks than we could with our un-supplemented biological abilities.”

While there may be other consequences to smart technology, “making us stupid is not one of them,” says Chemero.

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Materials provided by University of Cincinnati. Original written by Angela Koenig. Note: Content may be edited for style and length.

“Given the increasing use of brain stimulation in human brain study and treatment of neurological diseases, this research can make a big impact on physicians and their patients,” said Xiaoming Jin, PhD, associate professor of anatomy, cell biology and physiology.

When someone experiences a brain injury, nerve injury, or neurodegeneration, such as in epilepsy and TBI, there is damage to the brain which can lead to loss and damage of nerve or neurons and development of hyperexcitability that underlies some neurological disorders such as neuropathic pain and epilepsy.

“The conventional treatment is mainly to try to directly inhibit such hyperexcitability,” Jin said, “but we found the initial damage of the brain or nerve system was caused by a loss of brain tissue, which causes the nervous system to compensate for loss of function by working harder, so we need to stimulate activity instead of inhibit it.”

The technique, described in a newly published paper in Neurotherapeutics, uses a new type of magnetoelectric nanoparticles that can be delivered to a specific part of the brain using a magnetic field. After, a magnetic wave can be emitted to stimulate neural activity in that particular part of the brain. The method is noninvasive, good for stimulating deep brain function and is more efficient than traditional methods of brain stimulation, without the need for genetic manipulation.

“This is the only new type of nanoparticle that allows us to effectively stimulate the brain without doing any invasive procedures,” Jin said. “We can inject the nanoparticle as a solution into the vein and then bring it to any part of the body. When you apply a magnet on the head, you can localize and deliver the nanoparticle to the targeted brain region.”

The team has been working on the technique for five years in collaboration with the University of Miami and hopes to begin studying the method in humans in the next couple of years. The study has received funding from the Defense Advanced Research Projects Agency (DARPA) of the United States Department of Defense, National Science Foundation, as well as the Indiana Clinical and Translational Sciences Institute (CTSI), which helped provide funding for a medical neuroscience graduate student, Tyler Nguyen, to participate in the research. Read the full published paper in Neurotherapeutics.

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Materials provided by Indiana University School of Medicine. Original written by Christina Griffiths. Note: Content may be edited for style and length.

The study in Ecology Letters documents how the Anolis lizard species in the Caribbean, and the Draco lizard species in Southeast Asia, have solved the challenge of communicating with one another to defend territories and attract mates.

It found males from both species perform elaborate head bob and push up displays, and rapidly extend and retract their often large and conspicuously coloured dewlap, or throat fan, specifically in habitats with lots of wind-blown vegetation or low light.

The lizards occupy the same range of rainforest and grassland habitats, and therefore face the same problems when it comes to communicating to a potential mate or enemy in visually ‘noisy’ environments.

Remarkably, they have evolved the same strategy to cope with the same selection problems, lead author Dr Terry Ord from the Evolution & Ecology Research Centre at the UNSW School of Biological, Earth and Environmental Sciences says.

According to his research, this scenario of two unrelated lizards displaying similar behaviour shows that natural selection directs evolution towards the same common set of adaptive outcomes over and over again.

“The surprise is that lizards in both groups have evolved remarkably similar displays for communication, but they also tailor the production of those displays according to the prevailing conditions experienced at the time of display,” Dr Ord says.

“That is, increasing the speed or the length of time they spend displaying the movements as the viewing conditions deteriorate.

“Really there should be essentially innumerable ways these lizards could have adapted their displays to remain effective, and there is strong evolutionary predictions that would lead us to expect this as well.”

Dr Ord says what this study shows is that natural selection driving similarities between different species.

Formally, this is known as convergent evolution — the independent origin of similar adaptations, he says.

“It seemed that these types of convergent, common adaptations are outcomes that would only really occur among species that are closely-related in some capacity,” he says.

“The reason for this is a bit complicated and it rests on the fact that adaptations build on characteristics that a species already possesses.”

“So, the longer species have evolved independently of each other, the less likely they would evolve the same adaptive solutions if they were exposed to the same change in the environment.”

But what this study highlights, he says, is what many evolutionary ecologists have argued — that natural selection is an extremely powerful process that can override the “baggage” of past history to produce the same adaptations.

“So if arm-waving is the most effective solution to some change in the environment, then natural selection would ultimately lead to its evolution rather than a more subtle (less effective) modification to an existing vocal call,” he says.

“Evolutionary biologists are excited about convergent evolution because it gives us multiple examples of the same adaptation evolving time and time again in very different animals.?

“So it tells us what the challenges are faced by these animals and how they have solved it in terms of evolutionary adaptation.”

The study documents this independent evolution of common communication strategies amongst groups that have evolved separately from each other for hundreds of millions of years.

Dr Ord says the striking similarities in communication strategies for maintaining an effective communication system in noisy conditions has evolved in various forms in many insects, fish, frogs, birds and mammals.

“For example, increasing the volume of calls when there’s lots of acoustic background noise, or extending the length of those calls or even vibrational signals by spiders and such,” Dr Ord says .

“The fact that many other groups of animals have also evolved thesesame adaptive strategies is even more extraordinary.”

Their new study, published online on July 1, 2021 in Cell Reports Medicine, shows that both CD4+ “helper” T cells and CD8+ “killer” T cells can still recognize mutated forms of the virus. This reactivity is key to the body’s complex immune response to the virus, which allows the body to kill infected cells and stop severe infections.

“This study suggests that the impact of mutations found in the variants of concern is limited,” says LJI Professor Alessandro Sette, Dr.Bio.Sci., study senior author and member of the LJI Center for Infectious Disease and Vaccine Research. “We can presume that T cells would still be available as a line of defense against viral infection.”

The researchers emphasize that the study only addresses how the body’s T cells respond to Variants of Concern (VOCs). The researchers emphasize that several of these variants, are linked to lower levels of virus-fighting antibodies.

The current study includes data on four of the most prevalent VOCs. Ongoing studies have been expanded to a larger panel of variants, including the Delta (B.1.617.2) variant, which became prevalent after this study had been initiated. The team has also established relationships with more than 20 different laboratories around the world to help monitor T cell reactivity to VOCs.

“These variants are still a concern, but our study shows that even if there is a decrease in antibodies, as other studies have shown, the T cells remain largely unaffected,” says LJI Instructor Alba Grifoni, Ph.D. “The vaccines still work.”

The Johnson & Johnson/Janssen COVID-19 vaccine was not part of this study because it was not available at the time the study was launched.

For the new study, the researchers analyzed T cells from three different groups: people who had recovered from COVID-19, people who had received either the Moderna or Pfizer-BioNTech vaccines, and people never exposed to SARS-CoV-2 (from samples taken before the pandemic).

Both the recovered subjects and the vaccinated subjects were likely to have T cells that recognized the “ancestral lineage” of SARS-CoV-2. This was the original strain that emerged at the beginning of the pandemic; however, the virus has mutated since December 2019, and several variants have been identified as VOCs.

The question was whether people with T cells trained to recognize the ancestral strain would also recognize the new variants. The researchers tested T cell responses from the donor groups against four prominent VOCs: Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1) and Epsilon (B.1.427/B.1.429).

The researchers found that both vaccinated individuals and the recovered patients had cross-reactive T cells that could target these variants. That is good news for anyone who has received one of the two mRNA vaccines and for anyone who has recovered from any variant of the virus.

“With this study, the underlying message is optimistic,” adds Tarke. “At least, as far as the T cell response goes, your immune system is still able to recognize these new variants and your T cells will be able to respond.”

Similar results reporting largely unaffected T cell reactivity has now been presented through independent studies published in Nature and Science Immunology.

Study co-author and LJI Professor Shane Crotty, Ph.D., says this research highlights the importance of enlisting T cells in fighting SARS-CoV-2.

“COVID vaccines do a fantastic job of making antibodies that stop SARS-CoV-2 infections, but some of the vaccines do less well at stopping infections from variants,” Crotty says. “You can think of T cells as a backup system: if the virus gets past the antibodies — if you have vaccine T cells the T cells can probably still stop the variant coronavirus infection before you get pneumonia.”

Researchers are now looking for ways to take advantage of how flexible the T cells response appears to be. With T cells already working hard to recognize SARS-CoV-2 variants, Grifoni says future “booster” shots could increase immunity by prompting the body to produce more antibodies against the variants and/or by adding additional parts of the virus recognized by T cells.

“T cell epitopes are well conserved among SARS-CoV-2 variants, so incorporating T cell targets into future COVID vaccines could be a clever way to make sure future variants can’t escape the vaccines,” adds Crotty.

There is also the possibility that current SARS-CoV-2 research may one day lead to a universal, “pan-coronavirus” vaccine. This kind of vaccine would train the body to recognize the structural details, such as elements of the spike protein, that all coronaviruses have in common.

“This research shows that a pan-coronavirus vaccine is feasible,” says Grifoni.

The group is now studying a much larger group of 12 different Variants of Concern (VOCs) and Variants of Interest (VOIs), including the Delta variant (B.1.617.2), Eta (B.1.525), Iota (B.1.526), Kappa (B.1.617.1), Lambda (C37) and the variants B.1.526.1, B.1.617.3, R1 and B.1.1.519.

Sette says he’d also like to study T cells from people who have been infected with the variants and see how those T cells react to the ancestral strain of the virus.

The study, “Impact of SARS-CoV-2 variants on the total CD4+ and CD8+ T cell reactivity in infected or vaccinated individuals” was supported by The National Institutes of Health’s National Institute of Allergy and Infectious Diseases (AI142742, 75N9301900065, 75N93019C00001 and SARS-CoV-2 Assessment of Viral Evolution program (SAVE) ), the National Institutes of Health (grants U01 CA260541-01, AI036214), UC San Diego T32s (AI007036, AI007384), the Jonathan and Mary Tu Foundation, and a Clinical and Experimental Immunology Course at the University of Genoa, Italy.

Additional study authors include John Sidney, Nils Methot, Esther Dawen Yu, Yun Zhang, Jennifer M. Dan, Paul Rubiro, Aaron Sutherland, Eric Wang, Ricardo da Silva Antunes, April Frazier, Sydney I. Ramirez, Bjoern Peters, Richard Scheuermann, Stephen A. Rawlings, Davey M. Smith and Daniela Weiskopf.

LJI findings guide COVID-19 vaccine efforts

This study was previously published online as a pre-print in March 2021. The findings were then highlighted by National Institutes of Allergy and Infectious Diseases Director Anthony Fauci, M.D., in a March 31 White House press briefing.

“We’re learning more and more that these CD4+ and CD8+ T cells are very important in that they cross-react against certain viral variants,” Fauci said.

In the time since the paper was first published, the researchers nearly tripled their patient cohort and performed an additional method of stringent statistical analysis. “We’ve also added an unexposed donor cohort,” says study first author Alison Tarke, a Ph.D. student of the University of Genoa, guested in the Sette Lab at LJI.