The brain is one of the most complex organs in the human body. It acts as the control center and manages the body’s physiological systems via complex networks and pathways. As commonly shown in research, and even in popular media, the brain’s functions tend to decline with age. But what is the reason behind this? How is age linked to the deterioration of brain functions like memory?
A research study led by Lars Nyberg, a Umea University Professor in Neuroscience and Director at Umea Centre for Functional Brain Imaging (UFBI), has shown a positive link between a dopamine receptor in the brain and episodic memory (episodic memory is defined as “a person’s unique memory of a specific event“). Dopamine is a neurotransmitter that is usually associated with motor functions in the body, but it is also related to memory and brain functions via the D1 and D2 receptor systems.
The D1 dopamine receptor system has already been positively correlated to frontal lobe functions, but the D2 receptor system’s function has yet to be explained. Professor Lars Nyberg and his team conducted this study by using PET scans (Positron Emission Tomography: the use of a radioactive tracer to image the body and show how organs/ tissues are working), MRIs (Magnetic Resonance Imaging: the use of magnetic field and radio waves to image the body), memory tests, and more to study the patients. Using PET cameras, the researchers compared the differences in the D2 receptor systems activity of 181 healthy participants, all between the ages of 64 and 68. All of the participants also had MRIs (to measure the sizes of different parts of the brain) conducted, along with long-term episodic memory, working memory and processing speed tests to compare the PET camera data to.
Professor Nyberg’s team’s research was able to show a positive link between the D2 receptor system and episodic memory through the comparisons of the PET camera data and the various memory tests, as well as a link between the D2 receptor system and the hippocampus–the memory center of the brain (through the comparisons of the PET camera data and the MRI scans). This likely points to the conclusion that the D2 dopamine receptor system is linked to episodic memory via the hippocampus.
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Professor Lars Nyberg stated that episodic memory is often reduced with age. His research has shown us that impairment of the dopamine system is an important factor to keep in mind when discussing the deterioration of certain brain functions due to aging. This research also opens the door for other neuroscientists to find possible links between dopamine and other higher brain functions, or even how certain neurotransmitters respond to aging over time, and how that affects other higher brain functions.
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