New Research Shows How Memories Stick Together
Memory plays a crucial role in shaping human experiences, and scientists have long been intrigued by how memories are connected. Research has shown that memories of events occurring close in time are often linked, a process known as memory linking. However, the exact neural mechanisms behind this phenomenon remained unclear.
A recent study by researchers at the University of California, Los Angeles (UCLA), published in Nature Neuroscience, sheds light on this mystery. Their findings suggest that dendritic plasticity—the ability of dendrites, the branch-like extensions of neurons, to change over time—plays a significant role in linking memories.
The Basis of Memory Linking
In 2016, a landmark study revealed that memories formed a few hours apart are stored in the same group of neurons in the hippocampus. This raised an important question: Where within these neurons are memories stored and linked?
Thanks to technological advancements, researchers have now been able to study subcellular mechanisms in greater detail. Working with Yiota Poirazi’s team from the Foundation for Research and Technology in Crete, the UCLA researchers used advanced imaging and modelling techniques to explore how dendritic changes contribute to memory linking.
The Role of Dendritic Plasticity
Previous theories suggested that linked memories should not only share common neurons but also reside in the same dendrites. Inspired by this idea, the researchers conducted experiments on mice using three different imaging techniques. These methods allowed them to observe the involvement of specific neuronal compartments, including the soma (cell body), dendrites, and spines.
Their findings confirmed that when mice formed two memories close in time, the same dendrites and spines were activated. Furthermore, they employed genetic tagging techniques to manipulate these neuronal structures. Remarkably, by forcing independent memories to be stored in the same dendrites within a particular brain region (the retrosplenial cortex), they were able to artificially link these memories.
Experimental Findings
One striking experiment demonstrated the power of dendritic memory linking. Mice that had no prior reason to fear a particular box suddenly developed a fear response simply because its memory was stored in the same dendrites as another memory involving an electric shock.
To further validate their findings, the team collaborated with computational modelers to simulate neuronal activity. These models confirmed that localized dendritic plasticity is essential for memory linking, as it allows synapses to cluster and remain stable over time.
Implications for Memory Disorders
This study provides critical insights into how memories are connected at a cellular level. The researchers propose that similar localized dendritic changes may also play a role in other memory-related processes. While such changes had been observed in previous studies on brain cells, this is the first time their function has been demonstrated in live animals.
Understanding how memories are linked across time has broad implications, especially for neurodegenerative diseases like Alzheimer’s, where memory linking is impaired. By uncovering these mechanisms, scientists hope to develop treatments that can restore or enhance memory linking in affected individuals.
Future Research Directions
The research team plans to build on these findings by exploring the molecular and circuit-level mechanisms underlying dendritic plasticity. Additionally, Poirazi’s lab is extending its computational models to other brain regions to better understand learning and memory functions. They are also applying dendritic mechanisms to artificial neural networks, aiming to make machine learning systems more intelligent and efficient.
Conclusion
This groundbreaking study offers new perspectives on how the brain links memories, emphasizing the role of dendritic plasticity. As research progresses, these insights could lead to innovative approaches for treating memory disorders and enhancing artificial intelligence systems by mimicking the brain’s memory processes.
Source: Inputs from various media Sources
Priya Bairagi
Reviewed by Dr Aarti Nehra (MBBS, MMST)
I’m a pharmacist with a strong background in health sciences. I hold a BSc from Delhi University and a pharmacy degree from PDM University. I write articles and daily health news while interviewing doctors to bring you the latest insights. In my free time, you’ll find me at the gym or lost in a sci-fi novel.
