Fos-defined activity in rat brainstem following centripetal acceleration

Abstract

To identify rat brainstem nuclei involved in the initial, shortterm response to a change in gravito-inertial force, adult Long-Evans rats were rotated in the horizontal plane for 90 min in complete darkness after they were eccentrically positioned off the axis of rotation (off-axis) causing a centripetal acceleration of 2 g. Neural activation was defined by the brainstem distribution of the c-fos primary response gene protein, Fos, using immunohistochemistry.The Fos labeling in off-axis animals was compared with that of control animals who were rotated on the axis of rotation (on-axis) with no centripetal acceleration, or who were restrained but not rotated. In the off-axis animals there was a significant labeling of neurons: in the inferior, medial, and y-group subnuclei of the vestibular complex; in subnuclei of the inferior olive, especially the dorsomedial cell column; in midbrain nuclei, including the interstitial nucleus of Cajal, nucleus of Darkschewitsch, Edinger-Westphal nucleus, and dorsolateral periaqueductal gray; in autonomic centers including the solitary nucleus, area postrema, and locus coeruleus; and in reticular nuclei including the lateral reticular nucleus and the lateral parabrachial nucleus. Also, there was greater Fos expression in the dorsomedial cell column, the principal inferior olive subnuclei, inferior vestibular nucleus, the dorsolateral central gray, and the locus coeruleus in animals who had their heads restrained compared to animals whose heads were not restrained. As one control, the vestibular neuroepithelium was destroyed by injecting sodium arsanilate into the middle ear, bilaterally. This resulted in a complete lack of Fos labeling in the vestibular nuclei and the inferior olive, and a significant reduction in labeling in other nuclei in the off-axis condition, indicating that these nuclei have a significant labyrinth-sensitive component to their Fos labeling. The data indicate that several novel brainstem regions, including the dorsomedial cell column of the inferior olive and the periaqueductal gray, as well as more traditional brainstem nuclei including vestibular and oculomotor related nuclei, respond to otolith activation during a sustained centripetal acceleration.Received Mar. 2, 1992; revised June 5, 1992; accepted June 12, 1992. We thank Jaw-Hem Lee and Huna Nauven for their sutmortine work in our labs. This work is made possible by a griduate student researchepprogram fellowship and NIH Grants DC01086, NS19208, DC001 10, DE06682, and DA06687.Correspondence should be addressed to Alvin J. Normal coordination of body movement and posture depends upon an accurate spatial reference. The otolith organs of the vestibular labyrinth are sensitive to the direction and magnitude of the earth's gravity and could provide a reference for integrating vestibular, visual, and somatosensory information to help control movement. When a sustained change in the gravitoinertial force occurs (e.g., from a novel linear motion, in a microgravity environment, or as a result of inner ear...

Resting Discharge Patterns of Macular Primary Afferents in Otoconia-Deficient Mice

“…The result is an increased level of tonic vestibular discharge and in turn increased levels of activity in central vestibular relays (Fuller et al , 2004Kaufman et al 1992;Murakami et al 2002). Similar changes have been reported during space flight with increases and decreases in gravitational loading (Pompeiano et al 2001a, b).…”

Firing Properties of Head Direction Cells in the Rat Anterior Thalamic Nucleus: Dependence on Vestibular Input

“…On completion of the infusion the ear canal was packed with Gelfoam. Sodium arsanilate treatment produces a degeneration of the neuroepithelium of the vestibular cristae ampullares, maculae utriculi, and the cochlea after systemic (Anniko and Wersäll, 1977) or intratympanic injection (Kaufman et al, 1992). This degeneration is believed to arise from a disruption of osmolality in the vestibular apparatus and leads to the destruction of hair cells (Anniko and Wersäll, 1977).…”

“…However, complete recovery of the spontaneous activity of central vestibular neurons has been reported 7 days after unilateral surgical labyrinthectomy in alert guinea pigs (Ris et al, 1995) and 6 months after bilateral transection of the vestibular nerve in alert rhesus monkeys (Waespe et al, 1992). Despite the potential for compensatory activity of the intact side in the unilateral labyrinthectomy studies (Kaufman et al, 1992;Ris et al, 1995), angular head rotation failed to influence expression of Fos in ipsilateral brainstem vestibular circuits (Kaufman et al, 1992) and did not modulate the firing rates of ipsilateral brainstem vestibular neurons (Ris et al, 1995). These data indicate that although unilateral surgical and arsanilate-induced labyrinthectomies disrupt rotation-induced changes in the activity of brainstem vestibular circuitry, brainstem vestibular nuclei remain intact.…”

“…In addition, the anterior thalamic nuclei in the hemisphere opposite the electrode were assessed under light microscopy for potential gross damage resulting from the sodium arsanilate treatment, and no damage was observed. No attempt was made to histologically examine the consequences of sodium arsanilate treatment on the vestibular nuclei, eighth cranial nerve, or vestibular apparatus, because several previous reports have described such effects (Anniko and Wersäll, 1977;Chen et al, 1986;Kaufman et al, 1992).…”

Hippocampal spatial representations require vestibular input

“…Injections were made using a 25-μl Hamilton syringe. TTX produces a near immediate, but transient, abolition of neural activity within cranial nerve VIII (Beitz et al, 1995), and behavioral changes commensurate with those observed following bilateral labyrinthectomies or transtympanic injection of the vestibular toxin, sodium arsanilate (i.e., head dorsiflexion, a failure of contactrighting, flattened posture with forelimbs and hindlimbs abducted, increased tendency to locomote backwards, and hyperreactivity to handling; Horn et al, 1981;Hunt et al, 1987;Kaufman et al, 1992). The transtympanic TTX injection procedure was also used to examine the anatomical and electrophysiological effects in the cochlear nucleus following VIIIth cranial nerve blockade in the chick (Canady and Rubel, 1992) and gerbil (Pasic and Rubel, 1989).…”