‘Where did I park my car?’ Brain stimulation improves mental time travel

You might remember you ate cereal for breakfast but forget the color of the bowl. Or recall watching your partner put the milk away but can’t remember on which shelf. A new Northwestern Medicine study improved memory of complex, realistic events similar to these by applying transcranial magnetic stimulation (TMS) to the brain network responsible for memory.

Experimental design overview

The study authors used TMS with the goal of altering brain activity and memory for realistic events. Immediately following stimulation, subjects performed a memory task while having their brains scanned using functional magnetic resonance imaging (fMRI). Instead of showing study participants pictures or lists of words — typical practices in laboratory tests that analyze memory — participants in this study watched videos of everyday activities such as such as someone folding laundry or taking out the garbage.

Following stimulation, study participants more accurately answered questions about the content of the video clips, such as identifying the shirt color an actor was wearing or the presence of a tree in the background. Additionally, the study found that brain stimulation led to higher quality reinstatement of memories in the brain, which happens when the brain replays or relives an original event. Following stimulation, a person’s brain activity while watching a video more closely resembled their brain activity when remembering that same video.

Adapted and abridged from Source (Northwestern University. “‘Where did I park my car?’ Brain stimulation improves mental time travel: Study used videos of realistic activities to measure how memory works day to day.” ScienceDaily. ScienceDaily, 4 February 2021.)

Original paper: Hebscher, M., Kragel, J.E., Kahnt, T. and Voss, J.L., 2021. Enhanced reinstatement of naturalistic event memories due to hippocampal-network-targeted stimulation. Current Biology.