“Our findings show that the brain is far more active and capable during unconsciousness than previously thought,” said Dr. Sameer Sheth, professor and Cullen Foundation Endowed chair of neurosurgery and a McNair Scholar at Baylor. “Even when patients are fully anesthetized, their brains continue to analyze the world around them.”

Recording Brain Activity During Anesthesia

To investigate what the unconscious brain is capable of, Sheth and his colleagues recorded the activity of hundreds of individual neurons in the hippocampus, a brain region involved in memory. The recordings were made while patients undergoing epilepsy surgery were under general anesthesia. These procedures gave researchers a rare opportunity to study this part of the brain directly.

The team used Neuropixels probes, an advanced technology that had never before been used in the hippocampus for this type of research. This allowed them to observe how the brain responded to sounds and language even when patients had no conscious awareness.

The Brain Continued Processing Language

The first experiment exposed patients to a series of repeating tones with occasional unexpected sounds mixed in. The researchers found that neurons in the hippocampus consistently detected these unusual tones. Even more interesting, the brain became better at recognizing them over time, suggesting that learning or neural plasticity was still taking place during anesthesia.

The researchers then increased the complexity of the experiment by playing short stories while continuing to record brain activity. The hippocampus showed clear evidence of processing language in real time. Patterns of neural activity revealed that the brain could distinguish different parts of speech, including nouns, verbs, and adjectives.

The team also made another surprising discovery. Neural signals could be used to predict upcoming words before they were spoken.

“The brain appears to anticipate what comes next in a story, even without conscious awareness,” said Sheth, who is also Director of The Gordon and Mary Cain Pediatric Neurology Research Foundation Laboratories within the Duncan Neurological Research Institute at Texas Children’s Hospital.

“This kind of predictive coding is something we associate with being awake and attentive, yet it’s happening here in an unconscious state,” said Dr. Benjamin Hayden, professor of neurosurgery at Baylor.

Rethinking Consciousness

The findings suggest that important cognitive abilities, including language comprehension and prediction, may not depend on conscious awareness. Instead, consciousness itself may arise from communication across multiple brain regions rather than from activity within a single area such as the hippocampus.

The researchers also noted similarities between the brain’s predictive behavior and artificial intelligence (AI). Just as large language models generate text by anticipating the next word, the hippocampus appeared to make similar predictions during language processing. Understanding these shared principles could help scientists better understand both biological and artificial intelligence.

The work may also contribute to future communication technologies, including speech prosthetics designed for people who have lost the ability to speak.

“Can we use these signals to deploy and run a speech prosthetic for some of the parts of the brain that are damaged by stroke or injury? These are questions that we can now consider in relation to this part of the brain,” said Dr. Vigi Katlowitz, first author and a neurosurgery resident with Baylor.

More Research Is Needed

The researchers caution that the findings should be interpreted carefully. The study examined only one type of general anesthesia, so the results may not apply to other unconscious states such as sleep or coma. In addition, the research focused on a single brain region, and it remains unclear how broadly these processes occur throughout the brain.

“This work pushes us to rethink what it means to be conscious,” said Sheth. “The brain is doing much more behind the scenes than we fully understand.”

A team including scientists from the University of East Anglia (UEA), led by Chinese researcher Dr. Yanfen Zheng, found that naturally occurring soil bacteria can significantly improve plants’ ability to survive in saline conditions.

The study also uncovered a previously unknown way these microbes protect crops such as maize, tomato, and rapeseed from salt stress. The discovery could eventually help farmers grow food on land that has become too salty for conventional agriculture.

Soil salinity threatens global agriculture

Salt buildup in farmland is becoming an increasingly serious problem because of climate change, irrigation practices, and rising sea levels. As salt accumulates in soil, it stunts plant growth, damages roots, and can sharply reduce crop yields.

Prof Jonathan Todd, from UEA’s School of Biological Sciences and the Quadram Institute on the Norwich Research Park, said: “The build-up of salt in farmland is a major and worsening problem — driven by climate change, irrigation and rising sea levels.

“Salt chokes plant growth, damages roots and severely impact entire harvests — putting global food supplies at risk.

“We know that plants rely on communities of microbes around their roots, called the root microbiome, to help them cope with environmental stress. But exactly how these relationships work, and whether they are consistent across crops and soils, has remained largely unclear.

“We found that plants appear to recruit beneficial bacteria in salty soil conditions, which in turn trigger internal changes that strengthen their physical structure and resilience.

“If scientists can harness this natural process, it could mark the beginning of a new era in climate-resilient agriculture.”

Root microbes drawn to salt stressed plants

To better understand these plant and microbe partnerships, the researchers examined root microbiomes from multiple crop species grown in different soil types.

They discovered that a group of naturally occurring bacteria known as pseudomonads consistently gathered around plant roots exposed to salt stress. The same pattern appeared across several crops, including maize, tomato, and rapeseed, suggesting this is a widespread biological response rather than something unique to a single plant.

Genetic analyses also explained why these bacteria perform so well in salty environments.

Prof Todd said: “Compared to other microbes, pseudomonads carry specialized genes that help them tolerate high salt levels, including sodium transport systems and other stress-resistance mechanisms.”

Stronger roots and higher yields

The team then introduced selected pseudomonad strains to soybean plants. In both greenhouse studies and field trials, the bacteria successfully colonized the roots and substantially improved plant growth under salty conditions.

“We found that plants treated with the microbes showed stronger root systems, better development and higher yields compared to untreated plants grown in salty soils,” said Prof Todd.

An unexpected plant defense

The researchers were surprised to discover that the bacteria were not helping plants by reducing salt levels inside their tissues.

“The most surprising thing was finding out how the bacteria helped plants cope.

“For decades, it was thought that plants survive salinity by controlling sodium levels -essentially keeping harmful salt out. But we found no evidence that bacteria influenced sodium transport or ion balance.

“Instead of helping plants manage salt directly, the bacteria stimulated the plant to produce more of a substance called lignin.

“Roots of bacteria-treated plants showed a significant increase in lignin content, with some measurements rising by over 30 percent under salt stress.”

Lignin strengthens plants naturally

Lignin is a strong, woody material that forms part of plant cell walls. It acts like a built in support system, reinforcing plant tissues and helping them withstand environmental stress.

The researchers identified the key genes responsible for increasing lignin production. When those genes were artificially overexpressed, plants performed much better in salty soil.

By contrast, plants that were unable to produce lignin did not benefit from the bacteria, showing that lignin production is essential to the newly discovered protective effect.

Prof Todd said: “We hope this discovery opens up new possibilities for agriculture.

“By harnessing naturally occurring microbes like pseudomonads, bio-based treatments could be developed that help crops grow in saline soils without heavy chemical inputs.

“With vast areas of farmland already affected by salinity and more under threat, microbial solutions could become an essential tool for maintaining crop yields and ensuring food security.”

The findings were published in the journal Science Advances in the paper, “Pseudomonads associated to salt-stressed plants facilitate stress adaption of soybean through enhanced lignin biosynthesis.”

Jeremy Axworthy, a researcher at the Center for Marine Debris Research (CMDR) at Hawaiʻi Pacific University, presented the findings at the spring meeting of the American Chemical Society (ACS).

“This work investigates whether it’s responsible to use recycled plastics in Hawaii’s roads,” shares Axworthy. “By reusing plastic waste that is already in Hawaii, we can reduce the environmental and economic impacts of transporting waste plastics from the islands, incinerating it or dumping it in Hawaii’s overflowing landfills.”

Why Hawaii Is Testing Recycled Plastic Roads

Since 2020, most roads in Hawaii have been built using polymer-modified asphalt (PMA), which is designed to improve strength and durability. Compared with conventional asphalt, PMA is more flexible and better able to resist cracking, rutting, and water damage, making it well suited to Hawaii’s tropical climate.

To make PMA, pellets of styrene-butadiene-styrene (SBS; a type of copolymer) are melted into a sticky petroleum-based asphalt binder. That binder is then mixed with heated aggregates (rocks and sand), coating the material before it is laid as pavement.

Researchers wondered whether some of the virgin polymer could be replaced with discarded plastics. They also wanted to know whether roads made with recycled plastics would perform well and whether they might release microplastics or other chemicals into the environment. Those questions led the Hawaii Department of Transportation (HDOT) to partner with environmental chemist Jennifer Lynch, director of CMDR and leader of the research team.

Recycling Fishing Nets Into Asphalt

HDOT asked Lynch’s team to tackle two key tasks. The first was to supply abandoned fishing nets collected from Hawaii’s waters for use in experimental recycled plastic asphalt.

“Foreign plastic derelict fishing gear is the largest contributor of Hawaii’s marine debris problem,” shares Lynch. “To date, CMDR’s Bounty Project, which pays a financial reward to licensed commercial fishers for marine debris removal, has removed 84 tons of large, derelict fishing gear from the Pacific Ocean.”

The second goal was to determine whether pavement made with recycled plastic released more microplastics than standard SBS-modified asphalt.

“CMDR’s laboratory is equipped with state-of-the-art chemical instrumentation for quantifying and characterizing microplastics in environmental samples,” explains Lynch. “This capability is incredibly unique and impactful, especially when coupled to our marine debris-removal project and our mission to recycle the debris into long-term, locally necessary infrastructure products.”

After a U.S. company processed the recovered plastics into materials suitable for asphalt production, HDOT moved the project into the real world. A local paving company resurfaced sections of a residential street on Oahu using three different asphalt mixtures: one with standard SBS, one containing recycled polyethylene from Honolulu’s residential recycling program, and one made with polyethylene recovered from discarded fishing nets.

About 11 months later, Lynch’s team returned to collect road dust from each section so they could measure any microplastic released into the surrounding environment.

Measuring Microplastic Shedding

The scientists separated different types of polymers from the road dust, including microplastics, larger plastic fragments, and tire rubber. They then used pyrolysis gas chromatography-mass spectrometry (Py-GC-MS) to determine where the materials came from. The analysis identified styrene and butadiene from standard PMA, polyethylene from recycled plastic and fishing net pavements, and isoprene and butadiene rubber from vehicle tires.

Early findings showed that pavement containing recycled polyethylene did not release more polymers than conventional SBS pavement. The same pattern appeared in laboratory performance testing and in simulated stormwater collected from the experimental road sections.

Although researchers detected microplastic-sized particles, only a very small number were identified as polyethylene, regardless of which pavement type they came from. The researchers believe this is because the plastic becomes blended into the asphalt binder. As the road wears over time, the particles that break away are made up of rock, asphalt binder, and polymer together rather than plastic by itself.

The team is also comparing polymer release from the pavement with the amount of tire material found in road dust.

“In our initial Py-GC-MS data,” continues Lynch, “we saw tire wear swamps the signal of polyethylene by orders of magnitude, like gigantic peaks! We had to search the weeds of the chromatogram to find signs of polyethylene.”

A Possible New Future for Plastic Waste

More testing is still needed to evaluate how well these recycled plastic roads hold up over the long term. Even so, the researchers believe the approach could eventually reduce both landfill waste and marine debris across Hawaii.

“Some people think plastic recycling is a hoax — that it doesn’t work; it’s too challenging,” Lynch shares. “But this work demonstrates that recycling can work when society prioritizes sustainability.”

The research was funded by the Hawaii Department of Transportation.

Meeting

ACS Spring 2026

Title

Harvesting ocean plastics to pave hawaiian roads: Evaluation of microplastic and plastic additive release from asphalt incorporating recycled plastic from various waste streams

Abstract

Polymer modified asphalt (PMA) is used to increase strength and durability of roads. In Hawaii, PMA is typically produced using the virgin co-polymer styrene-butadiene-styrene (SBS). Recycled plastics, such as high-density polyethylene (HDPE), may also be added to asphalt serving to sequester plastic waste. In the state of Hawaii, derelict fishing gear (DFG) is a significant problem, yet it is also a source of HDPE that can be used in recycling. However, asphalt performance and the consequences of adding recycled polymers to asphalt are not well understood. In collaboration with the Hawaii Department of Transportation (HDOT) and the University of Hawaii (UH), the Center for Marine Debris Research (CMDR) are testing the feasibility of using recycled HDPE in asphalt by quantifying microplastics and plastic additives release from roads paved with asphalts made from different combinations of virgin and recycled polymers. The specific asphalt combinations being tested are: SBS (Control-PMA), DFG with and without SBS (DFG-PMA and DFG-neat), Local Waste recycled HDPE with and without SBS (LW-PMA and LW-neat), and Commercially Available, post-industrial recycled HDPE with and without SBS (CA-PMA and CA-neat). Microplastic and plastic additive release under laboratory conditions were performed using a Hamburg Wheel Tracker Test (HWTT) with water sample analyses. Field trials were conducted on a residential road on the island of Oahu, Hawaii. Road dust was swept and analyzed for microplastics by direct analysis and solvent extraction to separate bound plastic from asphalt and plastic additives by water extraction. Microplastic samples utilized pyrolysis gas chromatography mass spectrometry for analysis. Plastic additives are subjected to solid phase extraction with analysis by gas chromatography mass spectrometry. Results produced using these novel analytical methods provide guidance on the use of recycled plastics over virgin plastics in roadways. Moreover, results of this study may provide a viable end of life fate for plastic marine debris, leading to cleaner and healthier oceans.