Q&A: Memory, brain function, and behavior—exploring the intricate connection through fear memories

In a world challenged by mental health problems such as anxiety, depression, and PTSD, a unique perspective arises from new research led by Dr. Steve Ramirez, a neuroscientist from Boston University together with a collaborative team. Their study, which was recently featured in the Journal of Neuroscience, delves into the intricate interplay of fear memories, brain function, and behavioral responses. The research, headed by Kaitlyn Dorst and Ryan Senne, serves as a foundational element of Dorst's PhD. The study offers significant insights intounderstanding memory formation; it also enhances our comprehension of varying behavioral responses in different situations, potentially benefiting the field of mental health. This Q&A features Dr. Ramirez explaining the motivation, challenges, and key discoveries of their research.

The study was primarily focused on fear memories, a category of memory that's extensively studied in rodents, provides measurable behavioral outcomes. When an animal experiences fear, its behavior changes, these alterations can be marked as an indication of fear. For instance, fear-induced behaviors in animals include freezing on the spot—a common indication of fear in rodents. Moreover, fear forms a vital element of various pathological states in the brain, particularly PTSD, generalized anxiety, and to some extent, depression. There's a direct connection between a fear memory and its potential to transform into a pathological state like PTSD.

The term 'engram' denotes the physical manifestation of memory—a definition that remains elusive. While we are in the dark about what memory entirely looks like in the brain, and we do not fully understand the appearance of an 'engram', we have made substantial progress in visualizing the physical substrates of memories in the brain. We've observed that there are cells throughout the brain involved in forming a memory, like a 'fear memory', and that certain areas of the brain are particularly active during memory formation.

During their research, Dr. Ramirez and his team discovered that fear behaviors are responsive to the environment. When in a smaller environment, rodents default to freezing when their fear memory was artificially activated. However, in larger environments, the rodents do not freeze when the same fear memory is activated again. Instead, they engage in other behaviors. The study suggests that the brain processes a lot of information before turning a thought or a memory into action and that this process varies for each individual.

Moving forward, the aim is to continue exploring potential targets in the brain that could help moderate fear responses. Dr. Ramirez hopes that their research inspires others to delve deeper into understanding the complex mechanics of memory formation and the subsequent action.