Auditory adaptation time course in the Yangtze finless porpoises, Neophocaena asiaeorientalis asiaeorientalis

Bioacoustics ◽  
2019 ◽  
Vol 30 (1) ◽  
pp. 30-40 ◽  
Author(s):  
Vladimir V. Popov ◽  
Zhi-Tao Wang ◽  
Dmitry I. Nechaev ◽  
Ding Wang ◽  
Alexander Ya Supin ◽  
...  
Keyword(s):  
Time Course ◽  
Adaptation Time ◽  
Auditory Adaptation ◽  
Neophocaena Asiaeorientalis Asiaeorientalis

scholarly journals Time-course of adaptations for electroretinography and pupillography

2021 ◽  
Vol 9 (4) ◽  
Author(s):  
Ken Asakawa
Keyword(s):  
Dark Adaptation ◽  
Time Course ◽  
Light Adaptation ◽  
Light Condition ◽  
Pupillary Response ◽  
Implicit Time ◽  
Scotopic Vision ◽  
Adaptation Time ◽  
Practical Applications ◽  
Rod Response

Cones are primarily involved in photopic vision and light adaptation. Rods are responsible for scotopic vision and dark adaptation. The typical time-courses of light and dark adaptations have been known for century. However, information regarding the minimal adaptation time for electroretinography (ERG) and pupillography would be helpful for practical applications and clinical efficiency. Therefore, we investigated the relationship between adaptation time and the parameters of ERG and pupillography. Forty-six eyes of 23 healthy women (mean age, 21.7 years) were enrolled. ERG and pupillography were tested for right and left eyes, respectively. ERG with a skin electrode was used to determine amplitude (µV) and implicit time (msec) by the records of rod-, flash-, cone-, and flicker-responses with white light (0.01–30 cd·s/m2). Infrared pupillography was used to record the pupillary response to 1-sec stimulation of red light (100 cd/m2). Cone- and flicker- (rod-, flash-, and pupil) responses were recorded after light (dark) adaptation at 1, 5, 10, 15, and 20 min. Amplitude was significantly different between 1 min and ≥5 or ≥10 min after adaptation in b-wave of cone- or rod-response, respectively. Implicit time differed significantly between 1 min and ≥5 min after adaptation with b-wave of cone- and rod-response. There were significant differences between 1 min and ≥10 or ≥5 min after dark adaptation in parameter of minimum pupil diameter or constriction rate, respectively. Consequently, light-adapted ERGs can be recorded, even in 5 min of light adaptation time without special light condition, whereas dark-adapted ERGs and pupillary response results can be obtained in 10 min or longer of dark adaptation time in complete darkness.

scholarly journals Hair-Cell Versus Afferent Adaptation in the Semicircular Canals

2005 ◽  
Vol 93 (1) ◽  
pp. 424-436 ◽  
Author(s):  
R. D. Rabbitt ◽  
R. Boyle ◽  
G. R. Holstein ◽  
S. M. Highstein
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Semicircular Canal ◽  
Time Course ◽  
Dynamic Range ◽  
Cell Voltage ◽  
Frequency Dependent ◽  
Adaptation Time ◽  
Phase Lead ◽  
Flat Gain

The time course and extent of adaptation in semicircular canal hair cells was compared to adaptation in primary afferent neurons for physiological stimuli in vivo to study the origins of the neural code transmitted to the brain. The oyster toadfish, Opsanus tau, was used as the experimental model. Afferent firing-rate adaptation followed a double-exponential time course in response to step cupula displacements. The dominant adaptation time constant varied considerably among afferent fibers and spanned six orders of magnitude for the population (∼1 ms to >1,000 s). For sinusoidal stimuli (0.1–20 Hz), the rapidly adapting afferents exhibited a 90° phase lead and frequency-dependent gain, whereas slowly adapting afferents exhibited a flat gain and no phase lead. Hair-cell voltage and current modulations were similar to the slowly adapting afferents and exhibited a relatively flat gain with very little phase lead over the physiological bandwidth and dynamic range tested. Semicircular canal microphonics also showed responses consistent with the slowly adapting subset of afferents and with hair cells. The relatively broad diversity of afferent adaptation time constants and frequency-dependent discharge modulations relative to hair-cell voltage implicate a subsequent site of adaptation that plays a major role in further shaping the temporal characteristics of semicircular canal afferent neural signals.

Logarithmic time course of sensory adaptation in electrosensory afferent nerve fibers in a weakly electric fish

1996 ◽  
Vol 76 (3) ◽  
pp. 2020-2032 ◽  
Author(s):  
Z. Xu ◽  
J. R. Payne ◽  
M. E. Nelson
Keyword(s):  
Firing Rate ◽  
Lateral Line ◽  
Time Course ◽  
Electric Fish ◽  
Weakly Electric Fish ◽  
Sensory Adaptation ◽  
Adaptation Time ◽  
Firing Rates ◽  
P Type ◽  
Weakly Electric

1. We recorded single unit activity from individual primary electrosensory afferent axons in the posterior branch of the anterior lateral line nerve of gymnotid weakly electric fish, Apteronotus leptorhynchus. We analyzed the responses of P-type (probability-coding) afferent fibers to externally applied amplitude step changes in the quasi-sinusoidal transdermal potential established by the fish's own electric organ discharge (EOD). 2. In response to AM step increases in transdermal potential, the firing rate of P-type afferents exhibited an abrupt increase followed by an initially rapid and subsequently more gradual decay back toward the baseline level. Afferent responses continued to adapt slowly throughout the duration of prolonged step stimuli lasting > 100 s. The time course of sensory adaptation was similar for all units tested. 3. We introduce a new functional form for describing the time course of sensory adaptation in which the change in firing rate delta r decays logarithmically with time: delta r(t) = A/[B In (t) + 1]. This logarithmic form accurately describes the adaptation time course of P-type afferents over five decades in time, from milliseconds to hundreds of seconds, with only two free parameters. Using a nonlinear least-squares fitting technique, we obtained a mean value of the parameter B, which characterizes the adaptation time course, of 0.149 +/- 0.028 (mean +/- SD, n = 49). 4. We compare logarithmic fits with traditional multiexponential and power law forms and demonstrate that the logarithmic form yields a better characterization of P-type afferent responses. This analysis helps explain the variability in previously reported adaptation time constants, which have ranged from 0.2 to 3.4 s, in gymnotid P-type afferents. 5. We tested the linearity of P-type afferent responses using positive and negative AM steps of varying amplitudes. Aside from nonlinearities associated with rectification (firing rates cannot be negative) and saturation (firing rates cannot exceed the EOD frequency), we found that P-type afferent responses scaled linearly with stimulus amplitude. 6. Based on the observed linearity, we predict the frequency domain response characteristics of P-type afferents and find that the predicted gain and phase are in good agreement with experimental measurements using sinusoidal AM stimuli over a range of AM frequencies from 1 to 100 Hz. Thus the logarithmic parameterization of the step appears to accurately capture the response dynamics of P-type afferents over a wide range of behaviorally relevant AM frequencies. 7. We conclude that the temporal filtering properties of pyramidal cells in the medullary electrosensory nucleus, the electrosensory lateral line lobe (ELL), need to be reevaluated in light of the logarithmic adaptation time course in the periphery, and we discuss implications for the role of P-type afferents in driving a feedback gain control mechanism that regulated ELL pyramidal cell responsiveness.

Ultrastructural Changes of the Symbiotic Chlorella-Like Alga Isolated from Hydra Viridis

1982 ◽  
Vol 40 ◽  
pp. 320-321
Author(s):  
K.W. Lee ◽  
R.H. Meints ◽  
D. Kuczmarski ◽  
J.L. Van Etten
Keyword(s):  
Time Course ◽  
Reciprocal Cross ◽  
Ultrastructural Level ◽  
Ultrastructural Changes ◽  
Symbiotic Relationship ◽  
Cell Recognition ◽  
Green Hydra ◽  
Different Strains ◽  
Hydra Viridis

The physiological, biochemical, and ultrastructural aspects of the symbiotic relationship between the Chlorella-like algae and the hydra have been intensively investigated. Reciprocal cross-transfer of the Chlorellalike algae between different strains of green hydra provide a system for the study of cell recognition. However, our attempts to culture the algae free of the host hydra of the Florida strain, Hydra viridis, have been consistently unsuccessful. We were, therefore, prompted to examine the isolated algae at the ultrastructural level on a time course.

Destruction of Actin Filaments by Osmium Tetroxide

1977 ◽  
Vol 35 ◽  
pp. 466-467
Author(s):  
P. Maupin-Szamier ◽  
T. D. Pollard
Keyword(s):  
Actin Filaments ◽  
Time Course ◽  
Osmium Tetroxide ◽  
Rabbit Muscle ◽  
Muscle Actin ◽  
Sodium Phosphate Buffer ◽  
Transmission Electron ◽  
The Difference ◽  
Rates Of Decay ◽  
Short Time

We have studied the destruction of rabbit muscle actin filaments by osmium tetroxide (OSO4) to develop methods which will preserve the structure of actin filaments during preparation for transmission electron microscopy.Negatively stained F-actin, which appears as smooth, gently curved filaments in control samples (Fig. 1a), acquire an angular, distorted profile and break into progressively shorter pieces after exposure to OSO4 (Fig. 1b,c). We followed the time course of the reaction with viscometry since it is a simple, quantitative method to assess filament integrity. The difference in rates of decay in viscosity of polymerized actin solutions after the addition of four concentrations of OSO4 is illustrated in Fig. 2. Viscometry indicated that the rate of actin filament destruction is also dependent upon temperature, buffer type, buffer concentration, and pH, and requires the continued presence of OSO4. The conditions most favorable to filament preservation are fixation in a low concentration of OSO4 for a short time at 0°C in 100mM sodium phosphate buffer, pH 6.0.

The time course of calcium deposition in shells of the barnacle (Balanus amphititre amphititre) during cyprid-juvenile metamorphosis

1994 ◽  
Vol 52 ◽  
pp. 178-179
Author(s):  
Nancy R. Wallace ◽  
Craig C. Freudenrich ◽  
Karl Wilbur ◽  
Peter Ingram ◽  
Ann LeFurgey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Time Course ◽  
Vertical Plane ◽  
Mantle Cavity ◽  
Qualitative Assessment ◽  
Calcium Deposition ◽  
Free Swimming ◽  
Freeze Dried ◽  
Scanning Electron

The morphology of balanomorph barnacles during metamorphosis from the cyprid larval stage to the juvenile has been examined by light microscopy and scanning electron microscopy (SEM). The free-swimming cyprid attaches to a substrate, rotates 90° in the vertical plane, molts, and assumes the adult shape. The resulting metamorph is clad in soft cuticle and has an adult-like appearance with a mantle cavity, thorax with cirri, and incipient shell plates. At some time during the development from cyprid to juvenile, the barnacle begins to mineralize its shell, but it is not known whether calcification occurs before, during, or after ecdysis. To examine this issue, electron probe x-ray microanalysis (EPXMA) was used to detect calcium in cyprids and juveniles at various times during metamorphosis.Laboratory-raised, free-swimming cyprid larvae were allowed to settle on plastic coverslips in culture dishes of seawater. The cyprids were observed with a dissecting microscope, cryopreserved in liquid nitrogen-cooled liquid propane at various times (0-24 h) during metamorphosis, freeze dried, rotary carbon-coated, and examined with scanning electron microscopy (SEM). EPXMA dot maps were obtained in parallel for qualitative assessment of calcium and other elements in the carapace, wall, and opercular plates.

Arabidopsis 4-COUMAROYL-COA LIGASE 8 contributes to the biosynthesis of the benzenoid ring of coenzyme Q in peroxisomes

2019 ◽  
Vol 476 (22) ◽  
pp. 3521-3532
Author(s):  
Eric Soubeyrand ◽  
Megan Kelly ◽  
Shea A. Keene ◽  
Ann C. Bernert ◽  
Scott Latimer ◽  
...  
Keyword(s):  
Oxidative Metabolism ◽  
Time Course ◽  
Reverse Genetics ◽  
De Novo ◽  
Coenzyme Q ◽  
Control Level ◽  
Wild Type ◽  
Fluorescent Reporters ◽  
Coa Ligase ◽  
Peroxisomal Targeting

Plants have evolved the ability to derive the benzenoid moiety of the respiratory cofactor and antioxidant, ubiquinone (coenzyme Q), either from the β-oxidative metabolism of p-coumarate or from the peroxidative cleavage of kaempferol. Here, isotopic feeding assays, gene co-expression analysis and reverse genetics identified Arabidopsis 4-COUMARATE-COA LIGASE 8 (4-CL8; At5g38120) as a contributor to the β-oxidation of p-coumarate for ubiquinone biosynthesis. The enzyme is part of the same clade (V) of acyl-activating enzymes than At4g19010, a p-coumarate CoA ligase known to play a central role in the conversion of p-coumarate into 4-hydroxybenzoate. A 4-cl8 T-DNA knockout displayed a 20% decrease in ubiquinone content compared with wild-type plants, while 4-CL8 overexpression boosted ubiquinone content up to 150% of the control level. Similarly, the isotopic enrichment of ubiquinone's ring was decreased by 28% in the 4-cl8 knockout as compared with wild-type controls when Phe-[Ring-13C6] was fed to the plants. This metabolic blockage could be bypassed via the exogenous supply of 4-hydroxybenzoate, the product of p-coumarate β-oxidation. Arabidopsis 4-CL8 displays a canonical peroxisomal targeting sequence type 1, and confocal microscopy experiments using fused fluorescent reporters demonstrated that this enzyme is imported into peroxisomes. Time course feeding assays using Phe-[Ring-13C6] in a series of Arabidopsis single and double knockouts blocked in the β-oxidative metabolism of p-coumarate (4-cl8; at4g19010; at4g19010 × 4-cl8), flavonol biosynthesis (flavanone-3-hydroxylase), or both (at4g19010 × flavanone-3-hydroxylase) indicated that continuous high light treatments (500 µE m−2 s−1; 24 h) markedly stimulated the de novo biosynthesis of ubiquinone independently of kaempferol catabolism.

Short-term volume and turgor regulation in yeast

2008 ◽  
Vol 45 ◽  
pp. 147-160 ◽  
Author(s):  
Jörg Schaber ◽  
Edda Klipp
Keyword(s):  
Dynamic Model ◽  
Volume Change ◽  
Volume Regulation ◽  
Time Course ◽  
Osmotic Shock ◽  
Intracellular Concentration ◽  
Short Term ◽  
Hydrodynamic Property ◽  
Turgor Regulation ◽  
Thermodynamic Framework

Volume is a highly regulated property of cells, because it critically affects intracellular concentration. In the present chapter, we focus on the short-term volume regulation in yeast as a consequence of a shift in extracellular osmotic conditions. We review a basic thermodynamic framework to model volume and solute flows. In addition, we try to select a model for turgor, which is an important hydrodynamic property, especially in walled cells. Finally, we demonstrate the validity of the presented approach by fitting the dynamic model to a time course of volume change upon osmotic shock in yeast.

Preliminary Evaluation of a Weibull Function for Fitting Slow-Component Eye Velocity over the Time Course of Caloric-Induced Nystagmus

1989 ◽  
Vol 32 (3) ◽  
pp. 681-687 ◽  
Author(s):  
C. Formby ◽  
B. Albritton ◽  
I. M. Rivera
Keyword(s):  
Time Course ◽  
Slow Component ◽  
Weibull Function ◽  
Preliminary Evaluation ◽  
Mathematical Function ◽  
Before And After ◽  
Best Fitting ◽  
Eye Velocity ◽  
Fitting Parameters ◽  
Weibull Equation

We describe preliminary attempts to fit a mathematical function to the slow-component eye velocity (SCV) over the time course of caloric-induced nystagmus. Initially, we consider a Weibull equation with three parameters. These parameters are estimated by a least-squares procedure to fit digitized SCV data. We present examples of SCV data and fitted curves to show how adjustments in the parameters of the model affect the fitted curve. The best fitting parameters are presented for curves fit to 120 warm caloric responses. The fitting parameters and the efficacy of the fitted curves are compared before and after the SCV data were smoothed to reduce response variability. We also consider a more flexible four-parameter Weibull equation that, for 98% of the smoothed caloric responses, yields fits that describe the data more precisely than a line through the mean. Finally, we consider advantages and problems in fitting the Weibull function to caloric data.

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