Neuroscientists at MIT have created the most detailed functional map of the brain by monitoring neural activity as participants watched movies. The discovery provides insights into how different brain networks are activated by complex stimuli, paving the way for future research on brain function and cognitive disorders.
In a new study, neuroscientists have produced the most detailed functional brain map to date by scanning the brains of participants while they watched a variety of movie clips. The study, published in the Cell Press journal Neuron, utilized data from 176 young adults who viewed 60 minutes of film segments from both independent and Hollywood productions, such as “Inception,” “The Social Network” and “Home Alone.”
The researchers discovered that different brain networks are activated during scenes featuring people, inanimate objects, action and dialogue. Moreover, the study highlighted how the brain’s executive networks, which aid in planning and problem-solving, prioritize information differently depending on the complexity of the movie scene.
“Our work is the first attempt to get a layout of different areas and networks of the brain during naturalistic conditions,” first author Reza Rajimehr, a research scientist at MIT’s McGovern Institute for Brain Research, said in a news release.
Unlike prior research that mainly focused on brain network studies conducted with participants at rest, this study presented dynamic and engaging stimuli to provide a better understanding of how complex audio-visual information is processed.
“With resting-state fMRI, there is no stimulus — people are just thinking internally, so you don’t know what has activated these networks,” added Rajimehr. “But with our movie stimulus, we can go back and figure out how different brain networks are responding to different aspects of the movie.”
By leveraging an fMRI dataset from the Human Connectome Project, the research team averaged brain activity across all participants and applied machine learning techniques to identify specific brain networks within the cerebral cortex. The analysis revealed 24 distinct networks linked to recognizing human faces and bodies, movement, places and landmarks, speech and social interactions.
Additionally, the study demonstrated an inverse relationship between executive control domains and brain regions with more specialized functions. During more challenging or ambiguous movie scenes, there was heightened activity in executive control regions. Conversely, more easily understood scenes triggered brain regions associated with specific functions, such as language processing.
“Executive control domains are usually active in difficult tasks when the cognitive load is high,” Rajimehr added. “It looks like when the movie scenes are quite easily comprehendible — for example, if there’s a clear conversation going on — the language areas are active, but in situations where there is a complex scene involving context, semantics and ambiguity in the meaning of the scene, more cognitive effort is required, and so the brain switches over to using general executive control domains.”
This study’s findings have the potential to significantly impact future neuroscience research, including investigations into how brain network functions differ across individuals, ages or even in those with developmental or psychiatric disorders.
“In future studies, we can look at the maps of individual subjects, which would allow us to relate the individualized map of each subject to the behavioral profile of that subject,” Rajimehr added. “Now, we’re studying in more depth how specific content in each movie frame drives these networks — for example, the semantic and social context, or the relationship between people and the background scene.”
This research represents a significant advancement in understanding brain function under naturalistic conditions and sets the stage for future insights into the complexities of cognitive processing.