John Tuthill, Ph.D.

Research

The Tuthill lab will investigate how animals sense the position of their legs and use this spatial information to coordinate their locomotion. To precisely control movement of the limbs, motor circuits must receive and integrate feedback about where our arms and legs are located and how they are moving through space. This feedback is provided by mechanically sensitive proprioceptor neurons embedded throughout the body. Fruit flies, for example, have 135 proprioceptor neurons in the femur of each leg. Feedback from these neurons helps the fly to expertly negotiate unpredictable terrain. By recording the activity of these proprioceptors during controlled leg movements, we found different neuronal subtypes that encode joint position, movement, and direction. Now, we aim to combine genetic and optical methods to monitor and manipulate the activity of leg proprioceptors in walking flies. This work will determine how sensory feedback fine-tunes leg motor control as flies walk on a treadmill, and how perturbation of the proprioceptive system alters the flies’ gait. We will also investigate how proprioception enables adaptive motor plasticity as a fly learns to avoid an obstacle during walking. Because deficits in sensory feedback can lead to a loss of fine motor control, the work could guide therapeutic efforts for sensorimotor disorders or rehabilitation after nerve injury.