Chapter 20 A concept for the final common pathway of vocalization and lordosis behavior in the cat

Abstract

Publisher Summary Periaqueductal gray matter (PAG) integrates the autonomic and somatic components of survival and mating behavior. For example, PAG stimulation has been demonstrated to produce simultaneous changes in nociception and blood pressure, vocalization, jumping, arching of the back, micturition, and lordosis. This chapter discusses the projections from the PAG to the nucleus retroambiguus (NRA), especially the projections from the NRA to motoneurons not so much in the framework of vocalization but in the framework of lordosis behavior. NRA neurons also project directly to motoneurons, bypassing the spinal interneurons. The NRA neurons play the role of premotor interneurons, similar to the ones in the spinal intermediate zone. Premotor interneurons usually receive peripheral Ia afferents or input from cortico- and rubrospinal tracts, but this is not the case for the premotor interneurons in the NRA. A probable explanation is that the NRA interneurons have a special function that is, activating a set of motoneuronal cell groups located throughout the lower brainstem and entire spinal cord, totally independent of voluntary input or spinal reflexes. In this context, the NRA receives afferents from other sources such as the PAG and respiration related brainstem nuclei.