TEDx talk. Changing memories in the brain. Video. 15.5 min.
Transcript provided.
Looked at mouse hippocampus, trained mouse on simple freezing response (avoidance/fear) response, noted which cells were stimulated, and then stimulated the same cell in a different context and triggered the freezing response. Also incorporated new memory while stimulating an old memory. Association of foot shock between memory of neutral environment - animal froze in an environment where nothing bad had happened.
Remarkable level of detail in this reconstruction from fMRI. Login with UNM NetID and password.
Reports using marijuana to demonstrate a role of glial cells in working memory.
Reconstruction of images based on brain responses to other images:
"The procedure is as follows: [1] Record brain activity while the subject watches several hours of movie trailers. [2] Build dictionaries (regression model) to translate between the shapes, edges and motion in the movies and measured brain activity. A separate dictionary is constructed for each of several thousand points in the brain at which brain activity was measured. (For experts: our success here in building a movie-to-brain activity encoding model was one of the keys of this study) [3] Record brain activity to a new set of movie trailers that will be used to test the quality of the dictionaries and reconstructions. [4] Build a random library of ~18,000,000 seconds of video downloaded at random from YouTube (that have no overlap with the movies subjects saw in the magnet). Put each of these clips through the dictionaries to generate predictions of brain activity. Select the 100 clips whose predicted activity is most similar to the observed brain activity. Average those clips together. This is the reconstruction."
Looked at fMRI responses to thousands of objects, at what parts of the brain were responding to which types of object, and then did a Principal Components Analysis to try to identify how the objects were categorized by place in the brain. Not exactly HOW the brain represents the objects (each point in the analysis represented millions of neurons), but gives some info on the spatial organization and connections between points.