Cognitive disorders are a category of mental health disorders that affect learning, memory, perception, and problem solving. They include amnesia, dementia and delirium. A new study has revealed potential new treatments which could help people with cognitive diseases.
For the study, the researchers altered a gene in mice to inhibit the activity of an enzyme called phosphodiesterase-4B (PDE4B), which is present in many organs of the vertebrate body, including the brain. In behavioral tests, the PDE4B-inhibited mice exhibited enhanced cognitive abilities. These rodents tended to learn faster, remember events longer and solve complex exercises better than ordinary mice. However, the PDE4B-inhibited animals also showed less recall of a fearful event after several days than ordinary mice. These findings have not been tested in humans, but PDE4B is also present in humans.
The diminished memory of fear among mice with inhibited PDE4B could be of interest to scientists looking for treatments for pathological fear, also known as Post-Traumatic Stress Disorder (PTSD). The PDE4B-inhibited mice were less anxious. They spent more time in open, brightly-lit spaces than ordinary mice, which preferred dark, enclosed spaces. Ordinary mice are naturally fearful of cats, but the PDE4B-inhibited mice showed a decreased fear response to cat urine, suggesting that one effect of inhibiting PDE4B could also be an increase in risk-taking behavior. Hence, while the PDE4B-inhibited rodents excelled at solving complex exercises, their low levels of anxiety could be counterproductive for a wild mouse.
Lead author Steve Clapcote University of Leeds' said, "Cognitive impairments are currently poorly treated, so I am excited that our work using mice has identified phosphodiesterase-4B as a promising target for potential new treatments."
The study is published in Neuropsychopharmacology.