Asian Scientist Magazine (Sep. 05, 2022) — Depression affects 280 million people globally. It influences an individual’s emotions, cognition and behaviour negatively especially during intense and recurrent depressive episodes. The affected individuals suffer from loss of energy and interest in activities they once enjoyed, and find it difficult to make decisions. In severe cases, they might even attempt or die by suicide. Although various antidepressants are available in the market, scientists have been increasingly looking for alternate non-invasive interventions. One such option, getting considerable attention, is ultrasound waves.
A team of researchers from Tokyo University of Science have discovered that ultrasound exposure has potential antidepressant effects on rodents. Their findings were published in NeuroReport.
Currently, there is a keen interest in studying how ultrasound waves can affect human brain functioning such as decision making. Ultrasound waves are sound waves outside of the range of human hearing. They have the potential to control neurons in a non-invasive manner. However, there are gaps in our understanding about how these waves can influence emotions like depression or neural pathways that give rise to different types of emotions.
The study used rodents to examine the effect ultrasound exposure has on brain activities. The researchers used olfactory bulbectomized (OB) rodents which lack olfactory lobes. Lack of olfactory lobes causes changes in the rodents’ brain which mirror the biological mechanism behind depression in humans—where there are significant changes in the neurotransmitters which lead to feelings of depression.
To understand how ultrasound can influence emotions, the team exposed both normal and OB rats to ultrasound waves for 24 hours. They then evaluated the degree of hyperemotionality—behaviours and actions suggesting distress and agitation under emotionally stimulating scenarios such as getting attacked. The researchers measured blood plasma corticosterone levels and tracked anxiety-like behaviours in these rats. Corticosterone are stress hormones. Large amounts of corticosterone are associated with the development of depression.
The team discovered that OB rats with ultrasound exposure were less hyper emotional and had lower stress levels. Ultrasound exposure also increased the likelihood of OB rats moving into the enclosed arms of the elevated plus maze (EPM) which is indicative of anxiety-like behaviour.
Professor Akiyoshi Saitoh, from the Department of Pharmacy in Tokyo University of Science, said that this study can be useful as it “suggests that OB rats may be a useful animal model for investigating the effects of ultrasound exposure and mechanisms of influence”
These results are promising and point at the potential ultrasound offers in treatment of depression.
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Source: Tokyo University of Science ; Image: Shelly Liew
The paper can be found at: High-frequency ultrasound exposure improves depressive-like behavior in an olfactory bulbectomized rat model of depression
