A global study by an international research team, including Prof. Omri Bronstein of the School of Zoology, Wise Faculty of Life Sciences and the Steinhardt Museum of Natural History at Tel Aviv University - who is leading global efforts to study the wave of sea urchins mass mortalities around the world, presents new and particularly alarming findings: for the first time, evidence of apparent local sea urchin extinction has been found in the Canary Islands.

The study revealed that the genus Diadema (the long-spined black sea urchins many of us are familiar with) is no longer able to produce offspring at this site — a finding that likely indicates local extinction.

The study was carried out by an international consortium including Tel Aviv University scientists in collaboration with researchers from Spain and the Canary Islands. The findings were published in the journal Frontiers in Marine Science.

From Local Die-Offs to Global Spread

Prof. Bronstein describes the sequence of events over recent decades: “In 1983–84, a mass mortality event of Diadema sea urchins was recorded in the Caribbean islands in the western Atlantic Ocean. This die-off triggered a dramatic ecological shift in the region: with the sea urchins — the habitat’s primary algae grazers — gone, vast algal fields spread, blocking sunlight and causing severe, irreversible damage to coral reefs in the region. In 2022, another mortality event struck the Caribbean, and for the first time the pathogen responsible for the lethal disease was identified. This epidemic spread to the Red Sea by 2023, and by 2024 it was also detected in the Western Indian Ocean, off the coast of Reunion.”

The Canary Islands: A Missing Link

In the current study, a formerly undetected mass mortality event was identified in the Canary Islands, off the coast of Morocco in the eastern Atlantic Ocean, which in fact occurred as early as mid-2022. According to the researchers, this event represents the “missing link” in the disease’s geographic spread. The study also revealed a particularly troubling finding, which likely points to the potential local extinction of the species in the Canary Islands. The study was based on extensive observational data collected through local citizen science, alongside scientific surveys, satellite data analysis (remote sensing), and the collection of samples from the seafloor by the research team.

Prof. Bronstein explains: “Sea urchins reproduce by releasing sperm and eggs into the seawater, where fertilization produces millions of embryos that drift as plankton in the water column. After several days to weeks (depending on the species), the larvae settle on the seabed and develop into juvenile urchins — a process known as ‘recruitment.’ In this study, we discovered that for the first time in history, there are no new juvenile urchins being recruited across several Canary Islands, indicating that the recruitment process has halted since the extensive mortality event that took place there. In other words, the die-off of the adult urchins has been so widespread that the species is no longer able to produce a next generation, if no recruitment occurs, the species may disappear from the region’s ecosystem.”

A Warning for Other Marine Ecosystems

The researchers note that sea urchin populations are typically characterized by fluctuations — they often decline and later recover. This time, however, the situation is far more severe and appears to be an extinction event rather than a transitional phase. The researchers warn that the pattern observed in the Canary Islands may also unfold in other regions around the world where unprecedented sea urchin mass mortality events have been recorded in recent years — including the Red Sea coast and the coral reef of the Gulf of Eilat.

Prof. Bronstein concludes: “In this study, we identified a mass mortality event of sea urchins that occurred in mid-2022 in the Canary Islands. In its aftermath, it became clear that the affected species is no longer capable of successfully reproducing in this area — a finding that may lead to local extinction, which is expected to have severe ecological consequences. A likely outcome would be the uncontrolled proliferation of algae, which would affect the entire ecosystem — although at this stage, it is difficult to predict exactly in what way.

 Prof. Omri Bronstein

Prof. Omri Bronstein is a marine biologist whose research focuses on molecular ecology and the processes that lead to the formation of new species. He is a senior faculty member at the School of Zoology in the George S. Wise Faculty of Life Sciences and at the Steinhardt Museum of Natural History, Tel Aviv University.

Can positive anticipation that activates the brain’s reward system strengthen the body’s immune defenses? A new study by Tel Aviv University, the Technion, and Tel Aviv Medical Center (Ichilov), published in the prestigious journal Nature Medicine, provides the first evidence in humans that brain activity associated with the expectation of reward has a measurable effect on the body’s response to a specific vaccine.

Training the Brain’s Reward SystemThe study was conducted through a collaboration between two research groups: the laboratory of Prof. Talma Hendler, from the School of Psychological Sciences and the Gray Faculty of Medical and Health Sciences, together with her former PhD student Dr. Nitzan Lubianiker, at Tel Aviv University and the Sagol Brain Institute at Tel Aviv Medical Center (Ichilov); and the laboratory of Prof. Asya Rolls from The George S. Wise Faculty of Life Sciences, together with her former student Dr. Tamar Koren of the Technion and the Department of Pathology at Tel Aviv Medical Center (Ichilov).

Eighty-five healthy volunteers participated in the experiment. Some underwent special brain training using fMRI neurofeedback technology — a method that enables individuals to learn, in real time, to regulate activity in specific brain regions through reinforcing learning. The aim of the brain training was to increase activity in a key region of the brain’s reward system including  the Ventral Tegmental Area (VTA), which is responsible for dopamine release in the context of mental activity related to the expectation of positive outcomes and motivation to obtain rewards. Participants were instructed to modulate their brain activity using various mental strategies (e.g. thoughts feelings memories) while monitoring positive feedback about the strategy that was saucerful in regulating their brain.

From Brain Activation to Antibodies

Immediately after completing the brain training, all participants received a hepatitis B vaccine. The researchers then tracked the immune response through a series of blood tests, measuring levels of specific antibodies produced following the vaccination.

The results showed that participants who succeeded in significantly increasing activity in the brain’s reward region also demonstrated a greater increase in antibody levels after vaccination. The association was specific to the VTA and was not observed in other brain regions used for control purposes (such as the hippocampus), nor in other reward-system areas linked to different reward-related experiences such as pleasure and satisfaction. In other words, the effect was both anatomically and mentally specific.

Dr. Nitzan Lubianiker, photo credit: Sameer Khan/Fotobuddy

The Role of Positive Anticipation

Furthermore, an in-depth analysis of the mental strategies participants used during training of the VTA (and not other regions) revealed that those who focused on positive anticipation — feelings of excitement, belief in a good outcome, or the expectation of something positive about to happen (such as a favorite food or a long-awaited meeting) — were able to maintain higher VTA brain activity over time, which was also associated with a better immune response. In other words, the researchers identified a link between reward-system brain activity, a mental state of positive anticipation, and the body’s response to an immune challenge.

According to the research team, this is not “positive thinking” in the popular sense or a New Age slogan, but a measurable neurobiological mechanism — related, among other things, to the well-known placebo effect in medicine (a therapeutic response beyond a specific medical intervention). “We show that mental states have a clear brain signature, and that this signature can influence physiological systems such as the immune system,” explain the researchers.

While the study does not propose a substitute for vaccines or medical treatment, it opens the door to new, noninvasive approaches that may one day strengthen immune responses, improve the effectiveness of medical treatments, and even contribute to fields such as immunotherapy and the treatment of chronic immune pathologies. The researchers note that the study’s findings underscore a broader message: the mind–body connection is not merely a theoretical concept, but a real biological process that can be measured, trained, and potentially harnessed to promote better health.

 Prof. Talma Hendler, Photo credit: Tel Aviv Medical Center (Ichilov).

Implications for Medicine and Health

The research team adds that the findings highlight the potential inherent in integrating neuroscience, psychology, and medicine. “Our study shows that the brain is not only a system that responds to the body’s state of health, but also an active player that influences it,” say Prof. Talma Hendler, Prof. Asya Rolls, Dr. Nitzan Lubianiker, and Dr. Tamar Koren. “The ability to consciously activate brain mechanisms associated with positive anticipation opens a new avenue for research and future treatments — as a complement to existing medicine, not as a replacement. In the future, it may be possible to develop simple, noninvasive tools to help strengthen immune responses and enhance the effectiveness of medical treatments by relying on the brain’s natural capacity to influence the body. However, it is important to emphasize that activation of the reward system and its effect on immune response vary between individuals. Therefore, this approach cannot replace existing medical treatments, but may well serve as an additional supportive component.”

The study was led by Elinor Nadir, a PhD student at Tel Aviv University, under the joint supervision of Prof. Yehuda Benayahu of the School of Zoology at Tel Aviv University and Prof. Tamar Lotan of the Department of Marine Biology at the Leon H. Charney School of Marine Sciences at the University of Haifa. The findings were published in the prestigious scientific journal PNAS.

An Orchestra Without a Conductor

The research team discovered that the soft coral Xenia umbellata — one of the most spectacular corals on Red Sea reefs — drives the rhythmic movements of its eight polyp tentacles through a decentralized neural pacemaker system. Rather than relying on a central control center, a network of neurons distributed along the coral’s tentacle enables each one to perform the movement independently, while still achieving precise, collective synchronization.

“It’s a bit like an orchestra without a conductor,” explains Prof. Tamar Lotan of the School of Marine Sciences at the University of Haifa. “Each tentacle acts independently, but they are somehow able to ‘listen’ to each other and move in that perfect harmony that so captivates observers. This is a completely different model from how we understand rhythmic movement in other animals.”

Testing the Limits of Coordination

Corals of the Xeniidae family are known for their hypnotic movements — the cyclic opening and closing of their tentacles. Until now, however, it was unclear how they perform this. To investigate, the researchers conducted cutting experiments on the coral’s tentacles and examined how they regenerated and restored their rhythmic motion. To their surprise, even when the tentacles were cut off and separated from the coral — and even when further divided into smaller fragments — each piece retained its ability to pulse independently.

Ancient Genes, Modern Insights

Subsequently, the researchers conducted advanced genetic analyses and examined gene expression at different stages of tentacle regeneration after separation from the coral. They found that the coral uses the same genes and proteins involved in neural signal transmission in far more complex animals, including acetylcholine receptors and ion channels that regulate rhythmic activity. According to the researchers, this discovery suggests that the origin of rhythmic movements — familiar to us from those underlying breathing, heartbeat, or walking — is far more ancient than previously thought. The corals studied demonstrate how coordinated movement can emerge from a simple, distributed system, long before sophisticated control centers evolved in the brains of advanced animals.

Prof. Benayahu adds: “It is fascinating to reach the conclusion that the same molecular components that activate the pacemaker of the human heart are also at work in a coral that appeared in the oceans hundreds of millions of years ago. The coral we studied allows us to look back in time, to the dawn of the evolution of the nervous system in the animal kingdom. It shows that rhythmic and harmonious movement can be generated even without a brain — through remarkable communication among nerve cells acting together as a smart network. There is no doubt that this study adds an important layer to our understanding of the wonders of the coral reef animal world in general, and of corals in particular, and underscores the paramount need to preserve these extraordinary natural ecosystems.”

This is the central finding of a new study from the School of Psychological Sciences at Tel Aviv University, led by doctoral student Liron Amihai in the lab of Prof. Yaara Yeshurun (together with Elinor Sharvit and Hila Man), in collaboration with Prof. Yael Hanein of TAU’s Fleischman Faculty of Engineering. The study was published in Communications Psychology.

Tracking the Smallest Facial Movements

The study was conducted with dozens of pairs in which one person described two different films to their partner, after which the participants had to choose which film they preferred to watch. Using unique technology, the research team was able to track micro-movements of the face that are not visible to the naked eye.

Research team - Left to right - Prof. Yaara Yeshurun & Liron Amihai

The findings showed that participants consistently preferred the option during which they showed more mimicry of the speaker's positive expressions . They did so even when they were explicitly instructed to choose according to their personal taste and not according to the speaker.

This finding is particularly interesting given that the listeners’ own facial expressions (for example, how much they smiled in general) did not predict their choice, but rather the degree to which they mimicked the speaker.

Even Without Seeing a Face

In another phase of the experiment, participants listened to an actress reading the movie summaries using audio only, without any video. Even though they could not see her face, the researchers found that the participants mimicked her “smile in the voice” and this mimicry again predicted their choice.

The research team: “The study indicates that facial mimicry is not only a social mechanism that helps us connect with other people. It likely also serves as an ‘internal signal’ to the brain that is indexing agreement.”

Illustration of a participant in the study with an EMG electrode measuring her facial expressions activation

More Than Politeness

Liron Amihai explains: “The study showed that we are not just listening to a story — we are actually being ‘swept’ toward the speaker with our facial expressions’ mimicry, and this muscular feedback might influence our decisions. This mimicry often happens automatically, and it can predict which option we will prefer long before we think about it in words. Facial mimicry, therefore, is not merely a polite gesture, but also a part of the decision-making system.”

Liron concludes: “With the help of this technology and these findings, we may be able in the future to build systems that identify emotional preferences naturally — without asking a single question.
In conclusion, the study illustrates that decision-making is not only a matter of thought — but also of feeling, bodily response, and unconscious communication. Facial mimicry emerged as a significant predictor of our preferences. This is a meaningful step toward understanding how we choose, feel, and empathize with others, and it has many implications for the worlds of advertising, marketing, and decision-making processes.”