Grant: Discovery Grants Program - Individual

If we reach for our morning cup of coffee, but we miss to the right, we can easily adjust our next movement leftward to pickup the cup. Although this seems effortless, it requires the integration of different sensory signals and the coordination of multiple brain regions. One way to examine this type of motor learning in the laboratory is to use prism adaptation. During prism adaptation, a person wears goggles that shift their vision in one direction, for example, to the right. While wearing the goggles the person is asked to reach towards an object. However, their reach will miss to the right of the object because of the visual shift induced by the goggles. To compensate for their rightward error, the person must learn to adjust their movements leftward (similar to the coffee drinker). Previous research in our lab has shown that rightward prism adaptation can be used to help patients with right brain damage attend to objects on their left side more easily. Similarly, leftward shifting prisms, which result in a rightward adjustment in movements, can shift attention rightwards in healthy adults. This suggests that the mechanisms underlying motor control and attention are closely linked. The long-term objective of this research program is to better understand the cognitive and neural mechanisms that allow the attention and motor systems to interact. Thus, prism adaptation represents an ideal paradigm to investigate this interaction. The work proposed here will help scientists better understand the basic mechanisms underlying how the motor and attention systems interact by focusing on three objectives: 1) We will explore how different sensory error signals that are generated during prism adaptation can be optimally integrated to better adjust future movements. 2) We will examine how optimizing the integration of these different sensory error signals can increase the effects of prisms on visual attention. 3) We will determine how different sensory error signals are processed in the cerebellum - a brain region known to be critical for motor learning - by studying patients with cerebellar brain damage. In addition, we will examine how altering levels of neural activity in the cerebellum in healthy adults using non-invasive brain stimulation, can disrupt the integration of these sensory error signals. This research has many important applications and thus, will benefit Canadians in several ways. First, the knowledge obtained from these studies will help scientists better understand the basic mechanisms underlying motor learning, and how it can influence attention. Second, this work can be applied to designing more efficient methods to rehabilitate attention problems in patients with brain damage. Finally, this work can also be applied to engineering more efficient control systems for prosthetic limbs, or robots, which can learn to utilize sensory feedback signals from movement errors in order to optimize future movements.