A new study reveals how distinct parts of the brain, each underlying a different type of memory, can influence where we place our attention in new situations.
“We’ve long understood there are different types of memories, but what these findings reveal are how different kinds of memories can drive our attention in the future,” said study leader Elizabeth Goldfarb, a doctoral candidate in the Department of Psychology at New York University (NYU).
The study focused on two basic types of memories: episodic memories and habitual, or rigid, memories. Episodic memories are our recollections of the contextual details of life events, such as remembering the layout and location of objects in a familiar room.
Habitual memories, on the other hand, are reflexive in nature and are triggered frequently in our daily lives. For example, if you take a right turn at a certain stop sign as you are driving to work everyday, you might habitually take a right instead of a left even when you are not going to work.
Prior research shows that these different types of memories depend on different brain systems. The hippocampus is important for episodic memories and the striatum for habitual memories. Less understood, however, are the neurological processes by which these memories can direct one’s attention during novel situations.
For the study, the researchers conducted a series of experiments in which both episodic and habitual memories could influence future attention. During these tasks, researchers observed participants’ brain activity with functional magnetic resonance imaging (fMRI).
The researchers explored episodic memories with a series of experiments based on “contextual cueing.” In this case, participants looked for target (a rotated “T”), mixed among other distracting visuals, on a computer screen, then pressed a button once they found it, indicating the T’s direction.
The participants were not aware that some of these computer screens were repeating themselves, allowing their memory of that familiar context to guide their attention to the target — much like a memory upon walking into a familiar room. Not surprisingly, the results showed that context-guided attention was linked to activity in the brain’s hippocampus.
Habitual memories were studied with a series of experiments that used a “stimulus-response” mechanism. In this case, the shapes on the screen (the “T” and distracting visuals) were presented in a different color. This color served as the “stimulus,” comparable to the stop sign in the previous example.
Over time, participants learned that, when they saw this color, they should look in a particular part of the screen for the “T” and make the appropriate response. In these activities, the brain’s striatum was more active, revealing its role in guiding attention.
“Even though subjects had no idea that they were forming these memories, the fact that they performed better when contextual or habitual cues were present shows us that their attention was driven by memory,” said Goldfarb. “What we found here is that each of these types of memory can inform your future behavior.”
The findings are published in the journal Neuron.
Source: New York University