ABSTRACT
The neostriatum is one of the largest subcortical nuclei in the brain and is considered to represent the first stage of neural computation in the basal ganglia. The spiny projection neurones, which constitute the overwhelming majority of cells in this nucleus, are the basic neural substrate for information processing within this nucleus. The spiny cells have been the subject of intensive study during the last twenty years, and many features of their electrophysiological characteristics and anatomical organisation have been elucidated. Physiological data have shed light on the mechanisms underlying the characteristic electrical behaviour of spiny neurones observed in vivo. Specifically, these data have demonstrated how incoming excitatory inputs interact with the intrinsic membrane properties to influence membrane potential state transitions and action potential generation. The combination of both physiological and anatomical data are therefore providing a functional role for synaptic inputs identified in the electron microscope. Although there is a great deal of information on the physiological characteristics of specific types of synaptic inputs to spiny neurones, there are many inputs for which there is as yet no identified physiological function.
