The concept of posture control has morphed over the past century from a reflex, hierarchically controlled, innate behavior to a complex and adaptable motor act highly influenced by cognitive processes as well as confidence and attentiveness of the performer. In addition, multisensory control of posture has been recognized as a process of fusion and integration rather than summation and inhibition. Advances in computational modeling and imaging have revealed that higher cortical centers are involved in production of what were previously believed to be stereotypical, triggered reactions. Emerging evidence now supports the idea that postural behaviors are regulated by distributed control in the neuraxis and shaped by dynamic interactions of sensorimotor processes in a task- and context-dependent manner.

Rapid corrective actions, termed automatic postural responses, are essential to counter the destabilizing effect of mechanical perturbations during natural behaviors. Previous research has demonstrated that automatic postural responses of the limbs and body share a number of capabilities in adapting to the prevailing circumstances and these abilities reflect contributions from multiple supraspinal pathways, including brainstem nuclei, basal ganglia, and primary motor cortex. However, we do not know the context-dependent contribution from specific generators, whether different neural pathways have a common role across different effectors, and how sensory and central deficits in one pathway are accommodated by those remaining. Bridging these gaps is essential to integrate the diverse set of studies, develop general theories of motor control, and explicate how the nervous system addresses the partially distinct behavioral demands of co-evolved effector system. The considerable flexibility and multiple interacting pathways of automatic postural responses also make it ideal for understanding how powerful formal theories, like optimal feedback control, are achieved by a distributed hierarchical neural network.

This is the most comprehensive and up-to-date account of the control of vertebrate head movements and its biomechanical and neural basis. It covers the entire spectrum of research on head-neck movements, ranging from the global description and analysis of a particular behavior to its underlying mechanisms at the level of neurotransmitter release and membrane biophysics.