Memory is a funny thing. We’ve all walked into a room, only to forget the reason we entered or lost an item we are sure we saw on the side cabinet. As we age, this typically gets worse, with our working memories declining and everyday tasks becoming more difficult to perform. The anterior thalamus is a key region in the brain involved in memory, particularly spatial, involving our surroundings and how we navigate them.
What do we know about the role of this region?
Neuroscientists have observed that damage to the anterior thalamus in mice leads to impairments in spatial working memory, plus, the age-related decline of this region in humans has also been linked to lower performance in spatial memory tasks.
A team from MIT has recently discovered how brain circuits in the anterior thalamus operate. The study in older mice revealed the circuit is weakened compared to younger specimens, with these regions not being as receptive with age.
Mice in a maze
To explore how spatial working memory works further, mice were trained how to run a T-shaped maze. Once they were familiar with the course, one arm was blocked off, forcing them to choose the other path. The mice then ran the maze again with both arms open, if they chose to run the only previous open route, this showed they remembered their previous decisions.
Utilizing neuronal-optogenetics, the use of light to control molecules in the brain, the anterior thalamus was stimulated or repressed in mice. The maze experiment revealed that when neurons in this region were stimulated, the mice were able to run the circuit with higher rates of success. This suggests that the anterior thalamus is highly important for remembering this type of information in the mind.
Why is this important?
Understanding this region could be key in creating treatments to reverse memory loss without impacting other areas of the brain. “By understanding how the thalamus controls the cortical output, hopefully, we could find more specific and druggable targets in this area, instead of generally modulating the prefrontal cortex, which has many different functions,” says Guoping Feng, senior author of the study.
Next, the group wants to dive deeper into the genetic signatures of neurons that would be the best target for treatment to work toward preventing age-related decline.
Source study: PNAS – Anterior thalamic circuits crucial for working memory
