The central auditory brainstem provides an efferent projection known as the medial olivocochlear (MOC) system, which regulates the cochlear amplifier and mediates protection on exposure to loud sound. It arises from neurons of the ventral nucleus of the trapezoid body (VNTB), so control of neuronal excitability in this pathway has profound effects on hearing. The VNTB and the medial nucleus of ...

Experiments were done to characterize the vascular responses to stimulation of aortic and carotid chemoreceptors and to identify the efferent components of the sympathetic system which are activated in different vascular beds. The chemoreceptors were stimulated with nicotine and cyanide in anesthetized and artificially ventilated dogs. The gracilis muscle and hindpaw were isolated and perfused ...

During development, HOX genes play critical roles in the establishment of segmental differences. In the Drosophila central nervous system, these differences are manifested in the number and type of neurons generated by each neuroblast in each segment. HOX genes can act either in neuroblasts or in postmitotic cells, and either early or late in a lineage. Additionally, they can be continuously re...

OBJECTIVES/HYPOTHESIS To explore the innervation areas of the medial vestibular nucleus (MVN) afferent neurons onto vestibular efferent neurons in the brain stem of rats. STUDY DESIGN A morphology study in the central vestibular system. METHODS Two neuronal tracers were used. Lectin PHA-L Conjugates (PHA-L, Invitrogen L - 11270,) was injected into the MVN as an anterograde tracer, and 5% Fl...

BACKGROUND Olivocochlear (OC) neurons make up an efferent, descending auditory system that returns sound representations to the inner ear soon after they have entered the brain. Efferent inputs into the cochlea modulate outer hair cell activity to improve the neural encoding of auditory signals in background noise. Based on this physiological evidence, loss of efferent feedback is expected to d...

To study presumed efferent-mediated responses, we determined if afferents responded to head rotations that stimulated semicircular canals other than the organ being innervated. To minimize stimulation of an afferent's own canal, its plane was placed nearly orthogonal to the rotation plane. Otolith units were tested in a horizontal head position with the ear placed near the rotation axis to mini...

This study investigated the auditory behaviors of transgenic mice with deletions of alpha9 nicotinic acetylcholine receptor subunits. In the normal mammalian cochlea, the mechanical properties of outer hair cells are modified by the release of acetylcholine from olivocochlear efferent terminals. Electrophysiological correlates of this efferent feedback have not been demonstrated in alpha9 knock...

Neuronal death due to ischemic stroke results in permanent deficits in sensory, language, and motor functions. The growth-restrictive environment of the adult central nervous system (CNS) is an obstacle to functional recovery after stroke and other CNS injuries. In this regard, Nogo-A is a potent neurite growth-inhibitory protein known to restrict neuronal plasticity in adults. Previously, we h...