Remember your last birthday party: the guests at the door, the tasty food, the small pile of presents. Those memories are called episodic memories. They are memories of events that happen in a particular place (“where”) and in a particular order (“when”). To form these memories, the brain must stitch together multiple types of information. It merges what you saw, smelled, and heard, and combines this with information about where you were and the sequence of events. That’s a complex task. Scientists believe parts of the temporal lobe play a key role in this process. The temporal lobe is the region of the brain behind your ears and eyes. These areas can be damaged, for instance, in temporal lobe epilepsy. In such cases, people often have trouble forming or recalling episodic memories.
Animal studies offer helpful clues for how the temporal lobe contributes to memory. In rodents, some brain cells change activity in a regular pattern over time, like an internal clock. Others respond only to specific locations. Together, these “when” and “where” signals could tag sensory information so the brain stores a complete episode. Later, during recall, similar patterns of activity appear to be replayed. When this replay is disrupted, animals fail simple memory tasks, which suggests that replay helps support remembering.
In TOTAL RECALL, we will use advanced sensors placed temporarily in patients’ brains as part of their treatment. With those measurements, we will investigate how the human temporal lobe combines the “what,” “where,” and “when” of an experience into a single memory, and how they are reconstructed during recall. We will also study how these processes break down in people with temporal lobe epilepsy and how that breakdown may cause memory problems. Our goal is to identify the brain processes that support episodic memory and the processes that disease triggers which affect memory. We hope to identify targets for improving memory in patients with memory deficits.
