Researchers are using virtual reality to learn more about the role the hippocampus plays in spatial and episodic memory and gain new insight into how different brain areas assemble memories in context.
In a study published last week in Nature Communications, University of California, Davis graduate student Halle Dimsdale-Zucker and colleagues used a virtual reality environment to train subjects, then showed that different areas of the hippocampus are activated for different types of memories.
For the study, Dimsdale-Zucker built houses in a 3-D virtual environment. The subjects watched a series of videos in which they went into one house then another. In each video, different objects were positioned within the houses. The subjects therefore memorized the objects in two contexts: which video (episodic memory) and which house (spatial memory). In the second phase of the study, the subjects were asked to try to remember the objects while they were scanned by fMRI.
Being asked about the objects spontaneously reactivated contextual information, Dimsdale-Zucker said. Different regions of the hippocampus were activated for different kinds of information: One area, CA1, was associated with representing shared information about contexts (e.g., objects that were in the same video); another, distinct area was linked to representing differences in context.
Another interesting finding was that in this study, the hippocampus was involved in episodic memories linking both time and space, she said. Conventional thinking has been that the hippocampus codes primarily for spatial memories, for example those involved in navigation.
Virtual reality makes it possible to carry out controlled laboratory experiments with episodic memory, Dimsdale-Zucker said. A better understanding of how memories are formed, stored, and recalled could eventually lead to better diagnosis and treatment for memory problems in aging or degenerative disorders.
Image: UC Davis neuroscientists are using virtual reality to investigate how memories are organized. Graduate student Halle Dimsdale-Zucker showed subjects movies created with virtual sketching software and asked them questions about objects inside the houses. She was able to show that different regions of the hippocampus play different roles in remembering items in context.