A group of researchers in the Department of Biological Sciences led by Professor Seung-Hee Lee have confirmed that somatostatin (SST), a neuropeptide molecule, can enhance visual processing and cognitive faculties. This is a result of its ability to reduce certain excitatory inputs in the cortex.

The research, supported by the National Research Foundation of Korea, was published in Science Advances on April 22. The study was motivated by Professor Lee’s observation that Alzheimer’s disease patients had greatly decreased SST levels in their cerebral cortex and cerebrospinal fluid.

In a 2018 study published in Psychiatry Investigation, the prevalence of dementia among Koreans aged 65 and above was estimated to be about 10%. This proportion will grow as Korea experiences an unprecedented rate of population aging, and the number of people suffering from dementia is expected to double every two decades. The study predicted that by 2025, more than a fifth of the Korean population will be aged 65 years or older, making it a “super-aged” society. By 2050, there will be over three million Koreans suffering from dementia. In addition to the human cost, this also comes with a severe cost to the Korean economy. Currently, the Korean economy is estimated to lose about one percent of GDP due to dementia prevalence, and this loss will also rise sharply in the future.

The Korean government declared a “War Against Dementia” in 2008 and is taking several initiatives to overcome this plight. Alzheimer’s disease, a major cause of dementia, is not well-understood in terms of causes and risk factors. Moreover, not much research has traditionally been carried out in East Asian populations, which adds to the problem given their unique lifestyles and genetic backgrounds. In this scenario, Professor Lee’s discovery is a major achievement, and she is confident that somatostatin treatment will directly aid the recovery of cognitive functions in Alzheimer’s disease patients.

SST-expressing neurons in the cortex inhibit certain excitatory transmissions, leading to the observed effect. Although abundant in the cerebral cortex, it was not previously known whether SST could modulate cognitive processing. The research used specialized electrophysiology and electron microscopy techniques to demonstrate an improvement in the visual processing and cognitive behaviors in mice. SST is a stable and safe neuropeptide naturally present in the brain and can safely be injected into the cortex and cerebrospinal fluid.

In Professor Seung-Hee Lee’s own words, “Our research confirmed the key role of the neuropeptide SST in modulating cortical function and enhancing cognitive ability in the mammalian brain. I hope new drugs can be developed based on the function of somatostatin to treat cognitive disabilities in many patients suffering from neurological disorders.”