The control of movement is accomplished by the coordinated activity of many different brain nuclei, which are discrete collections of brain cells or neurons. One system of brain nuclei that make important contributions to the function of movement in general is the basal ganglia. Recently it has been shown that the basal ganglia help to control eye movements as well as other types of movements. Signals from the basal ganglia are known to project to lower brainstem structures that control the detailed execution of saccadic eye movements, which are rapid, ballistic-like eye movements that are made in order to rapidly change the direction of gaze. Another pathway by which the basal ganglia can influence eye movements is via a projection to nuclei of the thalamus. Such signals are then propagated to selected parts of the neocortex where more complex aspects of eye movements are regulated. In this award to Dr. Thomas Gardiner, signals transmitted to the thalamus from the basal ganglia will be studied to understand the type of controls that the basal ganglia has over eye movements via pathways from the thalamus to the neocortex. Recordings of activity will be made from neurons in thalamic regions which receive basal ganglia input in relation to the performance of both saccadic eye movements, as described above, and pursuit eye movements, which are the smooth, slow movements that allow visual tracking of moving objects. This work will contribute important knowledge about how the central nervous system controls eye movements.
