Influence of adequate vestibular stimulation on locomotor activity in the guinea pig forelimb muscles. Tilting in relation to the longitudinal axis

1988 ◽  
Vol 19 (4) ◽  
pp. 406-412
Author(s):  
V. V. Marlinskii ◽  
F. I. Tsintsabadze
Keyword(s):  
Locomotor Activity ◽  
Guinea Pig ◽  
Longitudinal Axis ◽  
Vestibular Stimulation ◽  
Forelimb Muscles

Vestibular Signals in the Parasolitary Nucleus

2000 ◽  
Vol 83 (6) ◽  
pp. 3559-3569 ◽  
Author(s):  
N. H. Barmack ◽  
V. Yakhnitsa
Keyword(s):  
Inferior Olive ◽  
Granule Cells ◽  
Vestibular Nucleus ◽  
Semicircular Canals ◽  
Longitudinal Axis ◽  
Vestibular Stimulation ◽  
Primary Afferents ◽  
Climbing Fiber ◽  
Large Sphere ◽  
Optimal Response

Vestibular primary afferents project to secondary vestibular neurons located in the vestibular complex. Vestibular primary afferents also project to the uvula-nodulus of the cerebellum where they terminate on granule cells. In this report we describe the physiological properties of neurons in a “new” vestibular nucleus, the parasolitary nucleus (Psol). This nucleus consists of 2,300 GABAergic neurons that project onto the ipsilateral inferior olive (β-nucleus and dorsomedial cell column) as well as the nucleus reticularis gigantocellularis. These olivary neurons are the exclusive source of vestibularly modulated climbing fiber inputs to the cerebellum. We recorded the activity of Psol neurons during natural vestibular stimulation in anesthetized rabbits. The rabbits were placed in a three-axis rate table at the center of a large sphere, permitting vestibular and optokinetic stimulation. We recorded from 74 neurons in the Psol and from 23 neurons in the regions bordering Psol. The activity of 72/74 Psol neurons and 4/23 non-Psol neurons was modulated by vestibular stimulation in either the pitch or roll planes but not the horizontal plane. Psol neurons responded in phase with ipsilateral side-down head position or velocity during sinusoidal stimulation. Approximately 80% of the recorded Psol neurons responded to static roll-tilt. The optimal response planes of evoked vestibular responses were inferred from measurement of null planes. Optimal response planes usually were aligned with the anatomical orientation of one of the two ipsilateral vertical semicircular canals. The frequency dependence of null plane measurements indicated a convergence of vestibular information from otoliths and semicircular canals. None of the recorded neurons evinced optokinetic sensitivity. These results are consistent with the view that Psol neurons provide the vestibular signals to the inferior olive that eventually reached the cerebellum in the form of modulated climbing fiber discharges. These signals provide information about spatial orientation about the longitudinal axis.

Behavior of Ca2+ waves in multicellular preparations from guinea pig ventricle

2004 ◽  
Vol 287 (6) ◽  
pp. C1646-C1656 ◽  
Author(s):  
Nagomi Kurebayashi ◽  
Haruyo Yamashita ◽  
Yuji Nakazato ◽  
Hiroyuki Daida ◽  
Yasuo Ogawa
Keyword(s):  
Guinea Pig ◽  
Cardiac Arrhythmias ◽  
High Frequency ◽  
Longitudinal Axis ◽  
Krebs Solution ◽  
Papillary Muscles ◽  
Two Dimensional ◽  
Free Medium ◽  
Regular Rhythm ◽  
The One

Ca+ waves have been implicated in Ca2+ overload-induced cardiac arrhythmias. To deepen understanding of the behavior of Ca2+ waves in a multicellular system, consecutive two-dimensional Ca2+ images were obtained with a confocal microscope from surface cells of guinea pig ventricular papillary muscles loaded with fluo 3 or rhod 2. In intact muscles, no Ca2+ waves were detected under the resting condition, whereas they were frequently observed during the rest immediately after high-frequency stimulations where cytoplasmic Ca2+ concentration and Ca2+ stored in the sarcoplasmic reticulum (SR) were gradually decreasing. The intervals of Ca2+ waves increased as they occurred later, their amplitudes and velocities remaining unchanged. A SERCA inhibitor reversibly prolonged the wave intervals. In Na+-free/Ca2+-free medium where neither Ca2+ influx nor Na+/Ca2+ exchange took place, recurrent Ca2+ waves emerged at constant intervals in each cell. These results are consistent with the conclusion that the loading level of the SR is critical for induction of Ca2+ waves. Each cell independently exhibited its own regular rhythm of Ca2+ wave with a distinct interval. These waves propagated in either direction along the longitudinal axis within a muscle cell, but seldom beyond the cell boundary. In contrast, in partially damaged muscles that showed spontaneous Ca2+ waves at rest in normal Krebs solution, their propagation often was unidirectional, decreasing in frequency. In these cases, however, Ca2+ waves rarely moved beyond the cellular boundary. The gradient of the cytoplasmic Ca2+ concentration was suggested to be the cause of the one-way propagation.

Spatial orientation in the lamprey. II. Visual influence on orientation during locomotion and in the attached state

1995 ◽  
Vol 198 (3) ◽  
pp. 675-681
Author(s):  
F Ullén ◽  
T G Deliagina ◽  
G N Orlovsky ◽  
S Grillner
Keyword(s):  
Visual Stimulation ◽  
Video Recording ◽  
Light Response ◽  
Longitudinal Axis ◽  
Vestibular Stimulation ◽  
Dorsal Side ◽  
Transverse Plane ◽  
The Body ◽  
Negative Phototaxis ◽  
Contralateral Eye

The responses of attached lampreys to homogeneous visual stimulation and the role of visual stimuli in orientation during locomotion were investigated. Experiments were performed by video recording the responses of intact and lesioned animals to illumination. The following results were obtained. 1. In lampreys attached with their sucker mouth to the bottom of the aquarium, illumination of one eye evoked several possible motor responses (ordered after mean latency): (a) movement of the illuminated eye downwards, and the contralateral eye upwards; (b) rotation of the body around the longitudinal axis, with the illuminated side tilting downwards; (c) deviation of the caudal part of the anterior dorsal fin in the contralateral direction (away from the light); and (d) flexion of the neck and body towards the side of illumination. 2. Illumination of one eye in attached lampreys often resulted in detachment and subsequent movement in a direction away from the light source (negative phototaxis). This response was not related to the degree of roll tilt before detachment, so the negative phototaxis does not appear to be a consequence of the vestibular stimulation. 3. Negative phototaxis was also seen during locomotion: lampreys turned through 180 ° when they approached a brightly illuminated area. Photostimulation also affected their orientation in the transverse plane during swimming. Illumination of one eye from the side induced a roll movement, so that the illuminated side tilted downwards and the dorsum of the lamprey became turned towards the light. This is similar to the 'dorsal light response' of fish and shows that vision also plays a role in postural control in lampreys. 4. The behaviour of blinded animals differed strikingly from that of intact ones. Whereas intact animals preferentially swam close to the bottom, along horizontal trajectories, blinded animals showed episodes of continuous swimming upwards, near the water surface. During horizontal swimming, their orientation in the transverse plane remained normal, with the dorsal side up.

Responses of Reticulospinal Neurons in Intact Lamprey to Pitch Tilt

2002 ◽  
Vol 88 (3) ◽  
pp. 1136-1146 ◽  
Author(s):  
E. L. Pavlova ◽  
T. G. Deliagina
Keyword(s):  
Spinal Cord ◽  
Conduction Velocity ◽  
Longitudinal Axis ◽  
Maximal Activity ◽  
Vestibular Stimulation ◽  
Dynamic Responses ◽  
Vestibular Reflexes ◽  
Postural Control System ◽  
Roll Control ◽  
Response Group

In the swimming lamprey, a postural control system maintains a definite orientation of the animal's longitudinal axis in relation to the horizon (pitch angle). Operation of this system is based on vestibular reflexes. Important elements of the postural network are the reticulospinal (RS) neurons, which are driven by vestibular input and transmit commands for postural corrections from the brain stem to the spinal cord. Here we describe responses to vestibular stimulation (rotation of the animal in the pitch plane) in RS neurons of intact lampreys. The activity of neurons was recorded from their axons in the spinal cord by chronically implanted arrays of macroelectrodes. From the multielectrode recordings of mass activity, discharges in individual axons were extracted by means of a spike-sorting program, and the axon position in the spinal cord and its conduction velocity were determined. Vestibular stimulation was performed by rotating the animal in steps of 45° throughout 360° or by periodical “trapezoid” tilts between the nose-up and -down positions. Typically, the RS neurons exhibited both dynamic responses (activity during movement) and static responses (activity in a new sustained position). The neurons were classified into two groups according to their pattern of response. Group up neurons responded preferentially to nose-up rotation with maximal activity at 0–135° up. Group down neurons responded preferentially to nose-down rotation with maximal activity at 0–135° down. Neurons of the two groups also differed in the position of their axons in the spinal cord and axonal conduction velocity. An increase in water temperature, which presumably causes a downward turn in swimming lampreys, affected the activity in the up anddown groups differently, so that the ratio upresponses to down responses increased. We suggest that theup and down groups mediate the opposing vestibular reflexes and cause the downward and upward turns of the animal, respectively. The lamprey will stabilize the orientation in the pitch plane at which the effects of up and downgroups are equal to each other. In addition to the main test (rotation in the pitch plane), the animals were also tested by rotation in the transverse (roll) plane. It was found that 22% of RS neurons responding to pitch tilts also responded to roll tilts. The overlap between the pitch and roll populations suggests that the RS pathways are partly shared by the pitch and roll control systems.

Sign in / Sign up

Export Citation Format

Share Document