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Responses to head tilt were recorded from vestibular neurons in and around the lateral vestibular nucleus (LVN) of the decerebrate cat. Each animal had all six semicircular canals rendered nonfunctional by a plugging procedure. Each cell was studied by slowly tilting the cat, using one or both of two paradigms. In the first method, sinusoidal tilts (0.05 or(More)
Motion sickness can occur when sensory inputs regarding body position in space are contradictory or are different from those predicted from experience. Signals from the vestibular system are essential for triggering motion sickness. The evolutionary significance of this malady is unclear, although it may simply represent the aberrant activation of(More)
The area postrema (AP) has been implicated as a chemoreceptor trigger zone for vomiting (emesis) for over 40 years. The AP is located on the dorsal surface of the medulla oblongata at the caudal end of the fourth ventricle. It is one of the so-called circumventricular organs that serve as an interface between the brain parenchyma and the cerebrospinal fluid(More)
Control of abdominal musculature by brain stem respiratory neurons was studied in decerebrate unanesthetized cats by determining 1) which brain stem respiratory neurons could be antidromically activated from the lumbar cord, from which the abdominal muscles receive part of their innervation, and 2) if lumbar-projecting respiratory neurons make monosynaptic(More)
The purpose of this study was to determine (1) whether the nucleus retroambigualis (NRA) plays an essential role in periaqueductal gray (PAG)-induced vocalization and (2) which NRA neurons are involved in the projection from the PAG to laryngeal motoneurons. Bilateral injections of the neurotoxin kainic acid into the NRA in decerebrate cats abolished(More)
The responses of central vestibular neurons in the decerebrate cat subjected to whole-body tilt were examined as a function both of stimulus orientation (with respect to the cat's head) and frequency, with the aim of understanding the neural processing responsible for producing the observed response patterns. Responses to whole-body tilt were recorded from(More)
The organization of the central neuronal circuitry that produces vomiting was explored by mapping the distribution of c-fos protein (Fos)-like immunoreactivity (FLI) as a monitor of functional activity. The brainstem and spinal cord were examined in cats administered multiple emetic drugs (cisplatin, lobeline, protoveratrine, naloxone, apomorphine) or(More)
The role of ventral respiratory group (VRG) expiratory (E) neurons in the control of abdominal and internal intercostal (expiratory) muscle activity during vomiting was examined in decerebrate cats by recording from these neurons during fictive vomiting in paralyzed animals and comparing abdominal muscle activity during vomiting before and after sectioning(More)
The lateral tegmental field (LTF), which is comprised of the lateral reticular formation near the obex, is an important integrative area involved in cardiovascular control and the production of emesis. Using neuroanatomical and electrophysiological techniques, we tested the hypothesis that LTF neurons receive vestibular inputs; the neurons studied included(More)
This study was undertaken to better delineate those brain regions that are either essential or non-essential for vomiting. Fictive vomiting, identified by a characteristic pattern of respiratory nerve discharge, was induced by a combination of emetic drugs and electrical stimulation of abdominal vagal afferents in decerebrate, paralyzed cats. Regions(More)