Environmental Effect of High-voltage Towers on the Cerebellum and Cognitive Impairments in the Monkey.

High-voltage power lines create a harmful environment for people who live or work near them. Previous research and epidemiological studies have shown that the extremely low-frequency (ELF) electromagnetic fields around these lines significantly harm the brains and cognitive functions of animals and humans. To study the direct physiological effects of exposure to high voltage (HV), researchers exposed a male rhesus monkey to an artificially generated voltage of 3 kV/m in a laboratory setting.

In this experiment, 2 adult rhesus monkeys were used: 1 as the test subject and 1 as the control. The test monkey was exposed to a simulated high-voltage field of 3 kV/m for 4 hours per day for 1 month. This corresponds to the field strength at a distance of approximately 20 meters from a 275 kV transmission line. Behavioral tests were performed before and after exposure using a specially developed and custom made device. Two tests were administered: a visual learning test and a visual memory test. Blood levels of adrenocorticotropic hormone (ACTH) were analyzed before and after exposure. Expression of the glucocorticoid receptor (GR) gene was also examined. Changes in the anatomy of the cerebellum were examined using magnetic resonance imaging (MRI). All tests were performed before and after the study period and compared with the results for the control monkey.

The results of the behavioral study showed that the exposed monkey performed worse on visual learning tests in an HV field than before the test. Meanwhile, there were no significant changes in the control group. The exposed monkey demonstrated reduced visual memory performance in the HV field compared to its previous state. ACTH levels increased in the exposed monkey, while the control group showed no significant change. Notably, these hormone levels decreased and returned to baseline within 1 month after the recovery period. The expression of the glucocorticoid receptor gene decreased significantly in the exposed monkey, but it also returned to baseline during the 1-month recovery period. Magnetic resonance imaging (MRI) scans of the cerebellum revealed no significant changes in volume. However, bleeding was detected on the left side of the exposed monkey's cerebellum, but only after the 1-month exposure period.

The study results show that the monkey exposed to HV fields exhibited significant cognitive and behavioral changes. Before the test, the monkey was intelligent, alert, lively, and energetic. However, significant changes occurred after the testing period. It became inattentive, lethargic, inactive, listless, and depressed, and lost approximately 1 kg of weight. The monkey showed elevated ACTH levels after the test. ACTH regulates cortisol, a hormone that plays an important role in cognitive functions, such as memory and learning, in the central nervous system. Increased ACTH levels reduce cortisol secretion, and abnormal cortisol secretion can lead to mental disorders. Conversely, cortisol plays an essential role in the expression of the glucocorticoid receptor (GR) gene. GRs and N-methyl-D-aspartate (NMDA) receptors, which play an important role in memory and learning processes, are distributed throughout the central nervous system. The highest concentrations of these receptor genes are found in the hippocampus, prefrontal cortex, amygdala, and cerebellum. According to the results of this study, high-voltage transmission lines pose a serious threat to the cognitive abilities of residents in the surrounding area, necessitating further research.

Editor's note:

This was a well-conducted semifield study because it used a realistic high-voltage simulation. The behavioral findings were physiologically confirmed and plausibly explained. However, using only 1 test animal instead of 10 or 30 yielded weaker statistical results. However, when monkeys are used as realistic test animals, which is expensive and raises ethical questions, even a single test animal (with a control) is significant. (AT)