Research
Background
When we encounter a perturbation in the environment or our body—reaching to grasp an object underwater, for example—there are significant challenges the brain must overcome. Light is bent by water, so we see the underwater hand in a different location from where we feel it proprioceptively. While initially movement errors occur in a situation like this, a healthy person quickly learns to compensate. This compensation can take different forms: the brain can ignore the proprioceptive estimate of the hand’s location and focus solely on vision (sensory reweighting); the brain can shift the proprioceptive estimate closer to the visual estimate or vice versa (sensory realignment); or the brain can compensate for any movement errors by altering the motor commands to the arm or the internal model of the arm’s dynamics (motor adaptation). Together, these processes make up the arsenal of potential methods available to the brain to compensate for the many sensorimotor changes we experience (Block & Bastian 2011). Failure to compensate for a perturbation can result in movement difficulties, yet little is known about the functional relationships or neural bases of these processes. In addition to providing direction in rehabilitation of patient groups with sensorimotor deficits, this knowledge would help answer fundamental questions about how sensory and motor processes interact in the brain.
When we encounter a perturbation in the environment or our body—reaching to grasp an object underwater, for example—there are significant challenges the brain must overcome. Light is bent by water, so we see the underwater hand in a different location from where we feel it proprioceptively. While initially movement errors occur in a situation like this, a healthy person quickly learns to compensate. This compensation can take different forms: the brain can ignore the proprioceptive estimate of the hand’s location and focus solely on vision (sensory reweighting); the brain can shift the proprioceptive estimate closer to the visual estimate or vice versa (sensory realignment); or the brain can compensate for any movement errors by altering the motor commands to the arm or the internal model of the arm’s dynamics (motor adaptation). Together, these processes make up the arsenal of potential methods available to the brain to compensate for the many sensorimotor changes we experience (Block & Bastian 2011). Failure to compensate for a perturbation can result in movement difficulties, yet little is known about the functional relationships or neural bases of these processes. In addition to providing direction in rehabilitation of patient groups with sensorimotor deficits, this knowledge would help answer fundamental questions about how sensory and motor processes interact in the brain.