Brain signals during vivid, natural movie viewing
The visual system evolved to make sense of a complex natural world combining colours, shapes, motion, textures, luminance, etc., yet the most common approach in visual neuroscience is to isolate the processing mechanism of a single visual feature by measuring the subjects’ response to an artificially generated stimulus. There is rising debate in the field of visual processing that the whole is not quite the sum of its parts – essentially that the interplay of visual processes jointly results in the representation of the stimuli and if these processes are individually activated, these interactions are overlooked. The unique advantage of using naturalistic stimuli is that many processes of the visual system are being activated at any given time, providing the closest image of how the visual system works. Our lab uses vivid natural movies to 1) explore the representation of objects and scenes 2) show that subjects exhibit prototypical fine-scale spatial patterns and 3) compare the injured brain to normal templates of activity.
The challenge to studying the visual system under naturalistic conditions is that the stimulus itself is too complex to parameterize so the brain response is extremely difficult to predict and model. Instead of trying to predict how the brain will react, we may approach the problem by exploring whether different brains react the same way to a naturalistic stimulus. Brains are indeed synchronized over a large area of the cortex when viewing a movie (cite), showing that a naturalistic stimulus can illicit the same temporal patterns in different brains. This leads us to the question: does a naturalistic stimulus produce the same representations of the movie in each subject?