Understanding the neural mechanisms for perceiving long-range motion

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Understanding the brain is one of the major scientific undertakings of the past and current century. The visual system is one of the largest and most important parts of the brain. A core function of the visual system is to process and interpret motion. Motion is a critical cue in the environment because it underlies our abilities to interact with the world. When objects are in a cluttered environment they can move behind and around other objects. These movements cause objects to disappear from view for large intervals of space and time before reappearing later. Humans are able to easily perceive motion along these complex paths. However, our current understanding of the brain cannot explain how this is accomplished. The proposed research will allow us to develop new models of how the brain processes motion, one of the most important roles of vision for a mobile animal such as ourselves. Over the last 4-5 decades, a beautiful architecture has been worked out showing how the brain progressively processes moving stimuli to create a cohesive and correct impression of motion in the world. The details of this architecture has improved our knowledge of how groups of neurons our organized and communicate. The wider neuroscientific community has utilized the impacts of these conceptual advances. The understanding of the brains response to motion enables researchers to build more complicated experiments that probe other functions of the brain. For example, because we know how motion is integrated across brain regions it has become an important stimulus used to study how the brain creates decisions about the world. This makes motion a fundamentally important topic underpinning our efforts for a complete understanding of the brain. But this detailed and elegant work is insufficient as it can only explain motion processing over small regions of space: our current models can misinterpret an objects true motion. We are missing an understanding of how motion is integrated when there are missing segments in the motion of an object. This is an important feature of real objects moving through the natural environment. It happens when objects move behind surfaces. The missing segments make it difficult to interpret what is happening. Our current understanding of the brain doesn't explain how this works. Humans, however, are able to perceive motion from a wide variety of stimuli that can move in complex environments. The neural mechanisms responsible for this ability have yet to be identified and characterized. The proposed project will provide a missing piece of our understanding of the brain by determining a better and more general understanding of how the brain processes moving objects. This will be accomplished by combining multiple state-of-the-art neuroimaging methods. In the past, brain imaging tools have been able to study either brain function across space (the classic 'brain areas' identified by fMRI), or across time (EEG recordings from the scalp). My work will allow these tools to be combined in powerful new ways. These tools will be used to create a complete picture of the set of brain areas, and how they interact to process motion.