The vestibular nerve of the chinchilla. V. Relation between afferent discharge properties and peripheral innervation patterns in the utricular macula

1990 ◽  
Vol 63 (4) ◽  
pp. 791-804 ◽  
Author(s):  
J. M. Goldberg ◽  
G. Desmadryl ◽  
R. A. Baird ◽  
C. Fernandez
Keyword(s):  
Lucifer Yellow ◽  
Small Diameter ◽  
Sampling Bias ◽  
Vestibular Nerve ◽  
Strongly Correlated ◽  
Utricular Macula ◽  
Peripheral Innervation ◽  
Physiological Properties ◽  
Innervation Patterns ◽  
Discharge Patterns

1. The relation between the discharge properties of utricular afferents and their peripheral innervation patterns was studied in the chinchilla by the use of intra-axonal labeling techniques. Fifty-three physiologically characterized units were injected with horseradish peroxidase (HRP) or lucifer yellow CH (LY) and their labeled processes were traced to the utricular macula. For most labeled neurons, the discharge regularity, background discharge, and sensitivity to externally applied galvanic currents were determined, as were the gain (g2 Hz) and phase (phi 2 Hz) of the response to 2-Hz sinusoidal linear forces. Terminal fields were reconstructed and fibers were classified as calyx (n = 13) or dimorphic units (n = 40). No bouton units were recovered. Calyx units were confined to the striola. Dimorphic units were located in the striola (n = 8), the juxtastriola (n = 7), or the peripheral extrastriola (n = 25). 2. To determine whether the intra-axonal sample was representative, the physiological properties of labeled utricular units were compared with those of a larger sample of extracellularly recorded units. A comparison was also made between the morphology of intra-axonally labeled units and those labeled by the extracellular injection of HRP into the vestibular nerve. Most of the discrepancies between the intra-axonal and either extracellular sample can be explained by assuming that small-diameter fibers are underrepresented in the former sample. Dimorphic fibers labeled intra-axonally had more bouton endings and larger terminal trees than did those labeled extracellularly. The latter differences may reflect a sampling bias in the extracellular material. 3. Calyx units were irregularly discharging. The discharge regularity of dimorphic units was related to their macular locations. Only 1/8 dimorphic units in the striola was regularly discharging. The ratio increases to 3/7 in the juxtastriola and to 23/25 in the peripheral extrastriola. Among dimorphic units, there is a tendency for irregularly discharging afferents to have fewer bouton endings. The trend is far from perfect because it is possible to pick a subsample of dimorphic units that have similar numbers of boutons and, yet, have discharge patterns that range from regular to irregular. 4. Published morphological polarization maps can be used to predict the excitatory tilt directions of a unit from its macular location. Predictions were confirmed in 39/41 labeled afferents. 5. The galvanic sensitivity (beta *) of an afferent, irrespective of its peripheral innervation pattern or its epithelial location, was strongly correlated with a normalized coefficient of variation (CV*).(ABSTRACT TRUNCATED AT 400 WORDS)

The vestibular nerve of the chinchilla. II. Relation between afferent response properties and peripheral innervation patterns in the semicircular canals

1988 ◽  
Vol 60 (1) ◽  
pp. 182-203 ◽  
Author(s):  
R. A. Baird ◽  
G. Desmadryl ◽  
C. Fernandez ◽  
J. M. Goldberg
Keyword(s):  
Lucifer Yellow ◽  
Discharge Rate ◽  
Small Diameter ◽  
Semicircular Canals ◽  
Preceding Paper ◽  
Vestibular Nerve ◽  
Response Properties ◽  
Peripheral Innervation ◽  
Innervation Patterns ◽  
The One

1. The relation between the response properties of semicircular canal afferents and their peripheral innervation patterns was studied by the use of intra-axonal labeling techniques. Fifty physiologically characterized units were injected with horseradish peroxidase (HRP) or Lucifer yellow CH (LY) and their processes were traced to the crista. The resting discharge, discharge regularity, and responses to both externally applied galvanic currents and sinusoidal head rotations were determined for most neurons. Terminal fields were reconstructed and, as in the preceding paper, the fibers were classified as calyx, bouton, or dimorphic units. 2. To determine if the intra-axonal sample was representative, the physiological properties of the labeled units were compared with those of a sample of extracellularly recorded units. A comparison was also made between the morphology of the intra-axonal units and those labeled by extracellular injection of HRP into the vestibular nerve Most of the discrepancies between the intra-axonal and the two extracellular samples can be explained by assuming that small-diameter fibers are underrepresented in the former sample. 3. A normalized coefficient of variation (CV*), independent of discharge rate, was used to classify units as regular, intermediate, or irregular. The CV* ranged from 0.020 to 0.60. Regular units (CV* less than or equal to 0.10) outnumbered irregular units (CV* greater than or equal to 0.20) by an approximately 3:1 ratio and had higher resting discharges. 4. Calyx units were invariably irregular. The one recovered bouton unit was regular. The discharge regularity of dimorphic units was related to their epithelial location, with those found in the periphery of the crista having a more regular discharge than those located more centrally. Dimorphic units, even those with quite similar morphology, can differ in their discharge regularity. Calyx and dimorphic units, which differ in their morphology, can both be irregular. These observations imply that discharge regularity is not determined by the branching pattern of a fiber or the number and types of hair cells it contacts. 5. The galvanic sensitivity (beta*) of an afferent, irrespective of its peripheral innervation pattern, was strongly correlated with CV*. This is consistent with the notion that discharge regularity and galvanic sensitivity are causally related, both being determined by postspike recovery mechanisms of the afferent nerve terminal.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Palaeoecological differences underlie rare co-occurrence of Miocene European primates

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Daniel DeMiguel ◽  
Laura Domingo ◽  
Israel M. Sánchez ◽  
Isaac Casanovas-Vilar ◽  
Josep M. Robles ◽  
...  
Keyword(s):  
Abiotic Factors ◽  
Sampling Bias ◽  
Tooth Wear ◽  
Primate Species ◽  
Strongly Correlated ◽  
Carbon And Oxygen Isotope ◽  
Gallery Forests ◽  
Miocene Hominoids ◽  
Palaeoenvironmental Changes ◽  
Main Factor

Abstract Background The two main primate groups recorded throughout the European Miocene, hominoids and pliopithecoids, seldom co-occur. Due to both their rarity and insufficiently understood palaeoecology, it is currently unclear whether the infrequent co-occurrence of these groups is due to sampling bias or reflects different ecological preferences. Here we rely on the densely sampled primate-bearing sequence of Abocador de Can Mata (ACM) in Spain to test whether turnovers in primate assemblages are correlated with palaeoenvironmental changes. We reconstruct dietary evolution through time (ca. 12.6–11.4 Ma), and hence climate and habitat, using tooth-wear patterns and carbon and oxygen isotope compositions of enamel of the ubiquitous musk-deer Micromeryx. Results Our results reveal that primate species composition is strongly correlated with distinct environmental phases. Large-bodied hominoids (dryopithecines) are recorded in humid, densely-forested environments on the lowermost portion of the ACM sequence. In contrast, pliopithecoids inhabited less humid, patchy ecosystems, being replaced by dryopithecines and the small-bodied Pliobates toward the top of the series in gallery forests embedded in mosaic environments. Conclusions These results support the view that pliopithecoid primates preferred less humid habitats than hominoids, and reveal that differences in behavioural ecology were the main factor underpinning their rare co-occurrence during the European Miocene. Our findings further support that ACM hominoids, like Miocene apes as a whole, inhabited more seasonal environments than extant apes. Finally, this study highlights the importance of high-resolution, local investigations to complement larger-scale analyses and illustrates that continuous and densely sampled fossiliferous sequences are essential for deciphering the complex interplay between biotic and abiotic factors that shaped past diversity.

Acoustic ocular vestibulat evoked miogenic ptotentials (AC-oVEMP) in assessment of vertigo

2019 ◽  
Vol 8 (2) ◽  
pp. 7-11
Author(s):  
Klaudyna Zwierzyńska ◽  
Magdalena Lachowska ◽  
Jacek Sokołowski ◽  
Emanuel Tataj ◽  
Kazimierz Niemczyk
Keyword(s):  
Diagnostic Tool ◽  
Vestibular Nerve ◽  
Vestibular Evoked Myogenic Potentials ◽  
System Evaluation ◽  
Test Interpretation ◽  
Balance System ◽  
Utricular Macula ◽  
Potential Use

Evaluation of acoustic vestibular evoked myogenic potentials (AC-VEMPs) is one of the tests performed to assess the function of the balance system. Evaluation of acoustic ocular vestibular evoked myogenic potentials (AC-oVEMPs) consists in the measurement of potentials evoked within oculomotor muscles, particularly the inferior oblique muscles (the most superficial muscles) with impulses being transmitted along the superior branch of the vestibular nerve from the utricular macula. Despite the fact that the measurement of oVEMPs was introduced relatively recently, it has found widespread use as a diagnostic tool in otology and neurotology. Despite the growing number of literature reports, the methodology of the test and the methods for the interpretation of its results are still subject to debate. This article is dedicated to various aspects of AC-oVEMP tests, including the methodology of the test, interpretation of its results and potential use in the diagnostics of vertigo.

Auditory Interneurones in the Metathoracic Ganglion of the Grasshopper Chorthippus Biguttulus: I. Morphological and Physiological Characterization

1991 ◽  
Vol 158 (1) ◽  
pp. 391-410 ◽  
Author(s):  
ANDREAS STUMPNER ◽  
BERNHARD RONACHER
Keyword(s):  
White Noise ◽  
Dynamic Range ◽  
Lucifer Yellow ◽  
Physiological Characterization ◽  
Acoustic Stimuli ◽  
Physiological Properties ◽  
Metathoracic Ganglion ◽  
Branching Patterns ◽  
Dependent Inhibition ◽  
Chorthippus Biguttulus

1. Auditory intemeurones originating in the metathoracic ganglion of females of the grasshopper Chorthippus biguttulus can be classified as local (SN), bisegmental (BSN), T-shaped (TN) and ascending neurones (AN). A comparison of branching patterns and physiological properties indicates that auditory interneurones of C. biguttulus are homologous with those described for the locust. 2. Eighteen types of auditory neurones are morphologically characterized on the basis of Lucifer Yellow staining. All of them branch bilaterally in the metathoracic ganglion. Smooth dendrites, from which postsynaptic potentials (PSPs) can be recorded, predominate on the side ipsilateral to the soma. If ‘beaded’ branches exist, they predominate contralaterally. The ascending axon runs contralaterally to the soma, except in T-fibres. 3. Auditory receptors respond tonically. The dynamic range of their intensity-response curve covers 20–25 dB. Local, bisegmental and T-shaped neurones are most sensitive to stimulation ipsilateral to the soma. The responses of SN1 and TNI to white-noise stimuli are similar to those of receptors, while phasic-tonic responses are found in SN4, SN5, SN7 and BSN1. The bisegmental neurones receive side-dependent inhibition that corresponds to a 20–30dB attenuation. One local element (SN6) is predominantly inhibited by acoustic stimuli. 4. Ascending neurones are more sensitive to contralateral stimulation (i.e. on their axon side). Only one of them (AN6) responds tonically to white-noise stimuli at all intensities; others exhibit a tonic discharge only at low or at high intensities.One neurone (AN12) responds with a phasic burst over a wide intensity range. The most directional neurones (AN1, AN2) are excited by contralateral stimuli and (predominantly) inhibited by ipsilateral stimuli. Three ascending neurones (AN13-AN15) are spontaneously active and are inhibited by acoustic stimuli. 5. All auditory intemeurones, except SN5, are more sensitive to pure tones below 10 kHz than to ultrasound.

The vestibular nerve of the chinchilla. I. Peripheral innervation patterns in the horizontal and superior semicircular canals

1988 ◽  
Vol 60 (1) ◽  
pp. 167-181 ◽  
Author(s):  
C. Fernandez ◽  
R. A. Baird ◽  
J. M. Goldberg
Keyword(s):  
Hair Cells ◽  
Afferent Fiber ◽  
Central Zone ◽  
Semicircular Canals ◽  
Peripheral Zone ◽  
Sensory Epithelium ◽  
Vestibular Nerve ◽  
Fiber Types ◽  
Peripheral Innervation ◽  
Numerous Type

1. Afferent fibers supplying the horizontal and superior semicircular canals of the chinchilla were labeled by extracellular injections of horseradish peroxidase (HRP) into the vestibular nerve. The arborizations of labeled fibers within the sensory epithelium were reconstructed from serial sections of the crista. 2. The sensory epithelium of the crista can be divided into central, intermediate, and peripheral zones of approximately equal areas. The three zones can be distinguished in normal material by the density of hair cells and by the morphology of calyx endings. 3. Labeled fibers supply either the canalicular or the utricular side of the crista. Axons seldom bifurcate below the basement membrane and they begin dividing into their terminal arborizations almost immediately upon entering the sensory epithelium. The arborizations are compact, seldom extending more than 50 micron from the parent axon. 4. Both calyx and bouton endings were labeled. Calyces can be simple or complex. Simple calyces innervate individual hair cells, whereas complex calyces supply two to three adjacent hair cells. Complex calyces are commonly found only in the central zone. Simple calyces and boutons are located in all regions of the epithelium. Calyces emerge from the parent axon or one of its thick branches. Boutons, whether en passant or terminal, are always located on thin processes. 5. Fibers were classified as calyx, bouton, or dimorphic. The first type only has calyx endings, the second only has bouton endings, and the third has both kinds of endings. Dimorphic units make up some 70% of the labeled fibers, bouton units some 20%, and calyx units some 10%. The three fiber types differ in the diameters of their parent axons and in the regions of the crista they supply. Axon diameters are largest for calyx units and smallest for bouton units. Calyx units are concentrated in the central zone of the crista, whereas bouton units are largely confined to the peripheral zone. Dimorphic units are seen throughout the sensory epithelium. 6. Calyx units are almost always unbranched and end as simple calyces or, less often, as complex calyces. The terminal arbors of bouton units consist of fine processes containing 15-80 endings. Dimorphic units vary in complexity from fibers with a single calyx and a few boutons to those with one to four calyces and more than 50 boutons. 7. The results emphasize the importance of dimorphic units, which were the most numerous type of afferent fiber labeled in this study and were the only units found to innervate all regions of the sensory epithelium.(ABSTRACT TRUNCATED AT 400 WORDS)

Neuroendocrine bag cells of Aplysia are activated by bag cell peptide-containing neurons in the pleural ganglion

1989 ◽  
Vol 61 (6) ◽  
pp. 1142-1152 ◽  
Author(s):  
R. O. Brown ◽  
S. M. Pulst ◽  
E. Mayeri
Keyword(s):  
Lucifer Yellow ◽  
Cell Activity ◽  
Feedback Mechanism ◽  
Egg Laying ◽  
Electrophysiological Properties ◽  
Physiological Properties ◽  
Positive Feedback Mechanism ◽  
Bag Cells ◽  
Small Clusters

1. The generation of egg-laying behavior in the marine mollusk Aplysia involves a prolonged burst discharge in the neuroendocrine bag cells, which secrete neuropeptides derived from the egg-laying hormone/bag cell peptide (ELH/BCP) precursor protein. 2. Besides the bag cells, which are located in the abdominal ganglion, small clusters of neurons in the cerebral and pleural ganglia also express the ELH/BCP neuropeptides. We made intracellular recordings from 32 of these ELH/BCP cells in right pleural ganglia, in 18 preparations, to characterize their physiological properties and their functional relationship to the bag cells. 3. The identification of these ELH/BCP cells was confirmed by pressure injection of Lucifer yellow and subsequent immunocytochemical processing for alpha-BCP immunoreactivity. 4. The basic electrophysiological properties of the pleural ELH/BCP cells were similar to those of the bag cells. These pleural cells were directly demonstrated to be electrically coupled, and direct intracellular stimulation of individual pleural ELH/BCP cells initiated prolonged, synchronous burst discharges in the entire cluster through a positive feedback mechanism. 5. Burst discharges elicited in the pleural ELH/BCP cells consistently initiated burst discharges in the bag cells. Bag cell burst discharges were less effective in initiating burst discharges in the pleural ELH/BCP cells, indicating that there were reciprocal but asymmetrical connections. 6. The results show that the pleural ELH/BCP cells are functionally coupled to the bag cells. They support the hypothesis that the pleural ELH/BCP cells are part of the descending pathway that initiates bag cell activity and egg-laying behavior, in vivo.

scholarly journals Central and peripheral innervation patterns of defined axial motor units in larval zebrafish

2019 ◽  
Author(s):  
Saul Bello-Rojas ◽  
Ana E. Istrate ◽  
Sandeep Kishore ◽  
David L. McLean
Keyword(s):  
Motor Neurons ◽  
Muscle Fibers ◽  
Motor Units ◽  
Spinal Motor Neurons ◽  
Larval Zebrafish ◽  
Spinal Motor ◽  
Axon Collaterals ◽  
Peripheral Innervation ◽  
Innervation Patterns ◽  
Fast Twitch

AbstractSpinal motor neurons and the peripheral muscle fibers they innervate form discrete motor units that execute movements of varying force and speed. Subsets of spinal motor neurons also exhibit axon collaterals that influence motor output centrally. Here, we have used in vivo imaging to anatomically characterize the central and peripheral innervation patterns of axial motor units in larval zebrafish. Using early born ‘primary’ motor neurons and their division of epaxial and hypaxial muscle into four distinct quadrants as a reference, we define three distinct types of later born ‘secondary’ motor units. The largest are ‘m-type’ units, which innervate deeper fast-twitch muscle fibers via medial nerves. Next in size are ‘ms-type’ secondaries, which innervate superficial fast-twitch and slow fibers via medial and septal nerves, followed by ‘s-type’ units, which exclusively innervate superficial slow muscle fibers via septal nerves. All types of secondaries innervate up to four axial quadrants. Central axon collaterals are found in subsets of primaries based on soma position and predominantly in secondary fast-twitch units (m, ms) with increasing likelihood based on number of quadrants innervated. Collaterals are labeled by synaptophysin-tagged fluorescent proteins, but not PSD95, consistent with their output function. Also, PSD95 dendrite labeling reveals that larger motor units receive more excitatory synaptic input. Collaterals are largely restricted to the neuropil, however perisomatic connections are observed between motor units. These observations suggest that recurrent interactions are dominated by motor neurons recruited during stronger movements and set the stage for functional investigations of recurrent motor circuitry in larval zebrafish.

scholarly journals Physiological and Pharmacological Studies on Cervical Motor Neurons in Slices Prepared from Neonatal and Aged Mice

2021 ◽  
pp. 1-5
Author(s):  
David O. Carpenter ◽  
N Hori ◽  
Z Xu ◽  
N Akaike ◽  
Y Tan ◽  
...  
Keyword(s):  
Amino Acid ◽  
Motor Neurons ◽  
Excitatory Amino Acid ◽  
Lucifer Yellow ◽  
Membrane Resistance ◽  
Aged Mice ◽  
Lucifer Yellow Ch ◽  
Physiological Properties ◽  
Pharmacological Studies ◽  
Delayed Recovery

The effects of age on the physiological properties of cervical motor neurons were examined in slices made from an excised spinal cord graft of ICR mice from the second day after birth to age 350 days. The membrane potential of post-natal day 2 (PD2) to PD350 was about -65 mV and did not change greatly with age, although it was slightly higher at PD2. However, there were significant changes in membrane resistance, which increased with age from about 15 to 30 MΩ. The depolarization induced by the excitatory amino acid agonists, kainic acid, NMDA and AMPA, decreased with aging in spite of the increase in membrane resistance. The motor neurons of the aged mice showed delayed recovery from excitation caused by excitatory amino acid agonists. By injecting Lucifer yellow CH into motor neurons, it was observed that the dendrite trees become thin, and some of the dendrite branches were missing in older animals.

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