Eyes on 6G safety as Chinese scientists find terahertz radiation boosts brain cell growth in mice
- Discovery can help assess new communication technology and also develop therapies to treat brain diseases, Beijing researchers say
- Separate study by team from Xian Jiaotong University finds terahertz radiation can make young mice ‘smarter’ but same effect not found in old mice
Scientists who observed the accelerated growth of mouse neurons after the rodents were exposed to brief, low-dose radiation from terahertz waves say their findings have implications for future communication devices.
After a three-minute exposure to 100-microwatt pulse radiation with wide frequencies ranging from 0.3 to 3 terahertz, the mouse neurons grow nearly 150 per cent faster than normal in a Petri dish, according to the researchers.
The total length of connections between these neurons also doubled in just three days.
Despite the superfast growth compared with a control, molecular analysis suggested the exposed brain cells remained healthy, according to the scientists.
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The discovery could help evaluate the safety of new communication technology and also develop therapies to treat brain diseases, according to the researchers.
“The safety of terahertz radiation protocol is a top concern,” Li Xiaoli, the lead scientist of the study write in a paper published in the peer-reviewed journal Acta Physica Sinica last month.
Li and his colleagues from the State Key Laboratory of Cognitive Neuroscience and Learning at Beijing Normal University said the negative health effects of future communication technology could be avoided by reducing the strength and duration of radiation exposure.
Their results also suggested “terahertz waves of certain frequencies and energies can be developed as a novel neuromodulation technology” to treat or intervene in diseases such as neurodevelopmental disorders.
“Abnormal neuron development and the resulting abnormal neural network structure can lead to the occurrence of various psychiatric and neurological diseases, such as Alzheimer’s disease, autism and Parkinson’s disease,” they said.
Radio waves in higher frequencies can transmit more information, but they also carry more energy.
The terahertz waves have a considerably higher frequency than the millimetre waves used in 5G that is capped with a 20 Gbps top speed.
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Some terahertz devices have already been used in airport body scanners with the energy waves effectively able to penetrate cloth and produce a clear image of a body with concealed items.
According to a study by researchers at the Russian Academy of Sciences in 2009, exposure to strong terahertz radiation for several hours a day, with power reaching a few watts, could increase temperature in brain cells, disturb their development and cause dehydration that reduces cell size and other damage.
But a lower dose of terahertz radiation could increase the production and activity of certain proteins – such as GluA1, GluN1 and SY-38 – that are known to stimulate neuron growth, according to Li’s team.
In these proteins there are lots of hydrogen bonds that vibrate constantly. The frequency of these vibrations happens to fall in the terahertz band.
Terahertz waves “can directly couple with proteins and effectively cause them to resonate in a non-linear manner,” Li’s team said in the paper.
This could “affect the shape of the proteins, and therefore the structure and function of neurons”, they said.
But the internal structure of proteins can vary significantly from one to another. Only certain proteins would respond to relatively weak terahertz radiation, according to the researchers.
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They said more investigation was needed to understand the protein changes induced by different exposure intensities.
The exposed brain cells would not grow forever, according to the paper. Two days after the initial radiation the growth rate tended to slow significantly.
In a separate study, professor Liu Jianxin with the Institute of Brain Science at Xian Jiaotong University, Shaanxi province, found that terahertz radiation could make young mice smarter.
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Exposure with 90-milliwatt terahertz radiation for 20 minutes a day over three weeks significantly increased the number of new brain cells in young mice, according to their paper published in the domestic peer-reviewed Journal of Terahertz Science and Electronic Information Technology in June.
These new brain cells could help the mice find an escape route more quickly when their lives came under threat, according to the researchers.
But old mice given the same treatment did not show any improvement in the experiment.
The reasons were not clear, the researchers said.
