Intracellular recordings from different types of medullary respiratory neurons of the cat

1975 ◽  
Vol 38 (5) ◽  
pp. 1162-1171 ◽  
Author(s):  
D. W. Richter ◽  
F. Heyde ◽  
M. Gabriel
Keyword(s):  
Functional Organization ◽  
Silent Period ◽  
Membrane Conductance ◽  
Rhythmic Activity ◽  
Excitatory Input ◽  
Respiratory Neurons ◽  
Inhibitory Input ◽  
Different Types ◽  
Conductance Changes ◽  
Almost All

Respiratory neurons were recorded intracellularly within the lateral region of the lower brain stem of vagotomized and artificially ventilated cats. Bulbospinal, vagal, and antidromically nonresponsive types of neurons were distinguished by means of vagal and intraspinal stimulation. Almost all types of neurons discharged a burst of action potentials during one of the two phases of the central respiratory cycle, as indicated by phrenic nerve activity. The discharge pattern of the different types of neurons were described. The origin of the spntaneous changes of the membrane potential was investigated by measurements of the reversal potentials and membrane conductance changes. The results reveal that both inspiratory and expiratory types of neurons receive an excitatory input during their discharge period, and a reciprocal inhibitory input during their silent period. In addition, one type of neuron was described which receives inhibitory inputs during both inspiration and expiration. Recurrent inhibition, as indicated by hyperpolarizing postsynaptic potentials and membrane conductance changes following the antidromic action potential seems to exist only within the network of the vagal neurons. Suggestions are made about the functional organization of the neuronal network of the medullary respiratory system and the mechanism generating its rhythmic activity.

Membrane Conductance Changes Associated with the Response of Motion Sensitive Insect Visual Neurons

1990 ◽  
Vol 45 (11-12) ◽  
pp. 1222-1224 ◽  
Author(s):  
Cole Gilbert
Keyword(s):  
Direct Evidence ◽  
Membrane Conductance ◽  
Inhibitory Input ◽  
Intracellular Recordings ◽  
Transmembrane Conductance ◽  
Visual Neurons ◽  
Impedance Measurements ◽  
Lobula Plate ◽  
Conductance Changes

Abstract Intracellular recordings and impedance measurements from directionally-selective visual interneurons of the lobula plate of flies show that during motion, transmembrane conductance increases during both depolarizing responses to preferred directions and hyperpolarizing re­sponses to anti-preferred directions. This provides direct evidence that these interneurons are postsynaptic to two separate populations of excitatory and inhibitory input elements.

scholarly journals Actions of a Pair of Identified Cerebral-Buccal Interneurons (CBI-8/9) in Aplysia That Contain the Peptide Myomodulin

1999 ◽  
Vol 81 (2) ◽  
pp. 507-520 ◽  
Author(s):  
Yuanpei Xin ◽  
Itay Hurwitz ◽  
Ray Perrins ◽  
Colin G. Evans ◽  
Vera Alexeeva ◽  
...  
Keyword(s):  
Cerebral Ganglion ◽  
Rhythmic Activity ◽  
Excitatory Input ◽  
Small Population ◽  
Inhibitory Input ◽  
Functional Roles ◽  
Buccal Mass ◽  
Strong Contraction ◽  
A Cell ◽  
To Receive

Actions of a pair of identified cerebral-buccal interneurons (CBI-8/9) in Aplysia that contain the peptide myomodulin. A combination of biocytin back-fills of the cerebral-buccal connectives and immunocytochemistry of the cerebral ganglion demonstrated that of the 13 bilateral pairs of cerebral-buccal interneurons in the cerebral ganglion, a subpopulation of 3 are immunopositive for the peptide myomodulin. The present paper describes the properties of two of these cells, which we have termed CBI-8 and CBI-9. CBI-8 and CBI-9 were found to be dye coupled and electrically coupled. The cells have virtually identical properties, and consequently we consider them to be “twin” pairs and refer to them as CBI-8/9. CBI-8/9 were identified by electrophysiological criteria and then labeled with dye. Labeled cells were found to be immunopositive for myomodulin, and, using high pressure liquid chromatography, the cells were shown to contain authentic myomodulin. CBI-8/9 were found to receive synaptic input after mechanical stimulation of the tentacles. They also received excitatory input from C-PR, a neuron involved in neck lengthening, and received a slow inhibitory input from CC5, a cell involved in neck shortening, suggesting that CBI-8/9 may be active during forward movements of the head or buccal mass. Firing of CBI-8 or CBI-9 resulted in the activation of a relatively small number of buccal neurons as evidenced by extracellular recordings from buccal nerves. Firing also produced local movements of the buccal mass, in particular a strong contraction of the I7 muscle, which mediates radula opening. CBI-8/9 were found to produce a slow depolarization and rhythmic activity of B48, the motor neuron for the I7 muscle. The data provide continuing evidence that the small population of cerebral buccal interneurons is composed of neurons that are highly diverse in their functional roles. CBI-8/9 may function as a type of premotor neuron, or perhaps as a peptidergic modulatory neuron, the functions of which are dependent on the coactivity of other neurons.

scholarly journals Cortical-Like Functional Organization of the Pheromone-Processing Circuits in the Medial Amygdala

2008 ◽  
Vol 99 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Xiling Bian ◽  
Yuchio Yanagawa ◽  
Wei R. Chen ◽  
Minmin Luo
Keyword(s):  
Functional Organization ◽  
Piriform Cortex ◽  
Pyramidal Cells ◽  
Ventromedial Hypothalamus ◽  
Excitatory Input ◽  
Gabaergic Neurons ◽  
Inhibitory Input ◽  
Medial Amygdala ◽  
Cellular Mechanisms ◽  
Homogeneous Population

The medial amygdala (MeA) is a critical center for processing pheromonal signals that regulate social and reproductive behaviors, but the fundamental cellular mechanisms underlying signal processing in the MeA have remained largely unknown. Some studies suggest that the MeA belongs to the striatum and provides inhibitory output to hypothalamic areas including the ventromedial hypothalamus (VMH). By combining tract tracing, genetic labeling of GABAergic neurons, and immunostaining against markers for glutamatergic synapses, we found that a majority of MeA neurons projecting to the VMH are glutamatergic. Whole cell patch-clamp recordings revealed that VMH-projecting neurons form a homogeneous population in terms of morphological and intrinsic properties. Nearly all cells possess Ih and IT and in some cases they can give rise to postinhibitory rebound spikes. Morphological analysis of neurobiotin-filled cells revealed neurons with long dendritic arbors that extend to the MeA external layer and within the amygdala. Thus the VMH-projecting neurons in the MeA differ from the medium spiny neurons, the principal neurons of striatum, in terms of intrinsic physiological properties and morphology. In contrast, they resemble a subset of pyramidal cells in deep piriform cortex. Similar to pyramidal cells in piriform cortex, the VMH-projecting neurons in the MeA received direct excitatory input from their upstream sensory areas and inhibitory input from local GABAergic neurons. We conclude that pheromonal signals relayed to the VMH are processed by unique cortical, but not striatal, circuitry in the MeA.

Types of refractive errors and methods for their diagnosis

2020 ◽  
pp. 30-36
Author(s):  
Olga Lemzyakova
Keyword(s):  
Optical System ◽  
Contact Lenses ◽  
Vision Impairment ◽  
Refractive Errors ◽  
Vision Correction ◽  
Light Rays ◽  
Different Types ◽  
Almost All ◽  
Degrees Of Severity ◽  
The Brain

Refraction of the eye means its ability to bend (refract) light in its own optical system. In a normal state, which is called emmetropia, light rays passing through the optical system of the eye focus on the retina, from where the impulse is transmitted to the visual cortex of the brain and is analyzed there. A person sees equally well both in the distance and near in this situation. However, very often, refractive errors develop as a result of various types of influences. Myopia, or short-sightedness, occurs when the light rays are focused in front of the retina as a result of passing through the optical system of the eye. In this case, a person will clearly distinguish close objects and have difficulties in seeing distant objects. On the opposite side is development of farsightedness (hypermetropia), in which the focusing of light rays occurs behind the retina — such a person sees distant objects clearly, but outlines of closer objects are out of focus. Near vision impairment in old age is a natural process called presbyopia, it develops due to the lens thickening. Both myopia and hypermetropia can have different degrees of severity. The variant, when different refractive errors are observed in different eyes, is called anisometropia. In the same case, if different types of refraction are observed in the same eye, it is astigmatism, and most often it is a congenital pathology. Almost all of the above mentioned refractive errors require correction with spectacles or use of contact lenses. Recently, people are increasingly resorting to the methods of surgical vision correction.

Immunoglobulin E mediated membrane conductance changes in rat basophilic leukemia cells

1988 ◽  
Vol 66 (3) ◽  
pp. 328-331 ◽  
Author(s):  
Carlos Barajas-López ◽  
Jan D. Huizinga
Keyword(s):  
Immunoglobulin E ◽  
Calcium Influx ◽  
Membrane Conductance ◽  
Membrane Resistance ◽  
Leukemia Cells ◽  
Rat Basophilic Leukemia Cells ◽  
Conductance Changes ◽  
Electrophysiological Effects ◽  
Basophilic Leukemia ◽  
Stimulation Of

Electrophysiological effects of anaphylactic stimulation of rat basophilic leukemia cells (RBL-2H3) were studied using conventional microelectrodes. Stimulation of passively sensitized cells by anti-immunoglobulin E resulted in hyperpolarization followed by depolarization. These changes in membrane polarization were associated with a decrease in input membrane resistance. No effect of anaphylactic stimulation was seen in Ca2+-free solution or when Ca2+ influx was blocked by Co2+, but it was mimicked by the Ca2+ ionophore A-23187. This suggests that the changes in ionic conductances were associated with calcium influx. These results support the hypothesis that membrane conductance changes are involved in the stimulus-secretion process of the RBL-2H3 cells.

XXVI.—The Field of the Essay

PMLA ◽  
1921 ◽  
Vol 36 (4) ◽  
pp. 551-564 ◽  
Author(s):  
Charles E. Whitmore
Keyword(s):  
Subject Matter ◽  
Actual Practice ◽  
Different Types ◽  
Almost All ◽  
Moderate Length

Of all the literary terms in common use, the word “essay” has perhaps the widest field and the most indeterminate content. Since the form to which it applies has taken on a fresh character in the hands of almost all its chief exponents, it has become in practice the designation for any piece of prose of moderate length, and has consequently embraced a bewilderingly various subject-matter. Moreover, the essayists themselves are by no means all of a piece. Bacon and Lamb, for instance, have little in common; and the type of ‘essayist’ represented by Macaulay and Carlyle has little in common with either. As a result of this wide extension, studies of the essay either include so much as to be very indefinite, or else are based on partial views, the upshot, in either case, becoming sufficiently vague. At the same time, the word “essay” goes on being used, and collections, of curiously assorted content, go on being made; and it therefore seems worth while to pass in review the different types represented in actual practice, in order to see just how much continuity is discernible among them.

scholarly journals Intrinsic Dynamics in Neuronal Networks. I. Theory

2000 ◽  
Vol 83 (2) ◽  
pp. 808-827 ◽  
Author(s):  
P. E. Latham ◽  
B. J. Richmond ◽  
P. G. Nelson ◽  
S. Nirenberg
Keyword(s):  
Firing Rate ◽  
Firing Pattern ◽  
Neuronal Networks ◽  
Network Connectivity ◽  
Excitatory Input ◽  
High Rate ◽  
Inhibitory Neurons ◽  
Inhibitory Input ◽  
Dynamic Interactions ◽  
Firing Patterns

Many networks in the mammalian nervous system remain active in the absence of stimuli. This activity falls into two main patterns: steady firing at low rates and rhythmic bursting. How are these firing patterns generated? Specifically, how do dynamic interactions between excitatory and inhibitory neurons produce these firing patterns, and how do networks switch from one firing pattern to the other? We investigated these questions theoretically by examining the intrinsic dynamics of large networks of neurons. Using both a semianalytic model based on mean firing rate dynamics and simulations with large neuronal networks, we found that the dynamics, and thus the firing patterns, are controlled largely by one parameter, the fraction of endogenously active cells. When no endogenously active cells are present, networks are either silent or fire at a high rate; as the number of endogenously active cells increases, there is a transition to bursting; and, with a further increase, there is a second transition to steady firing at a low rate. A secondary role is played by network connectivity, which determines whether activity occurs at a constant mean firing rate or oscillates around that mean. These conclusions require only conventional assumptions: excitatory input to a neuron increases its firing rate, inhibitory input decreases it, and neurons exhibit spike-frequency adaptation. These conclusions also lead to two experimentally testable predictions: 1) isolated networks that fire at low rates must contain endogenously active cells and 2) a reduction in the fraction of endogenously active cells in such networks must lead to bursting.

Chromosomal instability in different species of agricultural animals (review)

2021 ◽  
pp. 19-26
Author(s):  
V. A. Andreeva
Keyword(s):  
Chromosomal Instability ◽  
Animal Species ◽  
Western Siberia ◽  
Reproductive Function ◽  
Farm Animals ◽  
Chromosomal Disorders ◽  
Important Indicator ◽  
Karyotypic Analysis ◽  
Different Types ◽  
Almost All

The purpose of the work was to analyze the frequency of chromosomal instability in different species of agricultural animals in Western Siberia on the basis of literature data. The analysis of the literature on the topic of somatic chromosomal instability in agricultural animals has been carried out. Despite the stability of the chromosome set, deviations from it are quite common. It is noteworthy that chromosomal instability is characteristic of almost all individuals in the population and serves as an important indicator for assessing the natural mutability of chromosomes. It has been found if an aberration appeared in one tissue, it is very likely to occur in others. It has been noted that somatic chromosomal instability occurs in animals with reduced reproductive function, as well as those suffering from any pathology. For example, in calves with parakeratosis the increase in the frequency of chromatid and isochromatid breaks has been found. Analysis of the frequency of aberrations in sires, which differ in the level of perinatal mortality of offspring revealed the increased percentage of offspring mortality in fathers with the large number of chromosomal disorders. Therefore, low fertilization, spontaneous abortions and stillbirths may be indications for karyotypic analysis. It has been revealed that the lability of the karyotype is inherent in all animal species, regardless of the species, sex and age, as well as the morphofunctional state. The data on some types of somatic chromosomal instability in different types of farm animals in Western Siberia has been presented. Such indicators as the frequency of polyploidy, the number of cells with fragments of chromosomes, as well as single and paired fragments of chromosomes has been given. Different types of chromosomal instability varied depending on the animal species and climate zone. The presented data can be accepted as a physiological norm and used in veterinary medicine and animal science.

Binaural processing of sound pressure level in the inferior colliculus

1987 ◽  
Vol 57 (4) ◽  
pp. 1130-1147 ◽  
Author(s):  
M. N. Semple ◽  
L. M. Kitzes
Keyword(s):  
Inferior Colliculus ◽  
Sound Pressure ◽  
Spatial Information ◽  
Discharge Rate ◽  
Excitatory Input ◽  
Central Nucleus ◽  
Intensity Difference ◽  
Inhibitory Input ◽  
Directional Information ◽  
Discharge Rates

The central auditory system could encode information about the location of a high-frequency sound source by comparing the sound pressure levels at the ears. Two potential computations are the interaural intensity difference (IID) and the average binaural intensity (ABI). In this study of the central nucleus of the inferior colliculus (ICC) of the anesthetized gerbil, we demonstrate that responses of 85% of the 97 single units in our sample were jointly influenced by IID and ABI. For a given ABI, discharge rate of most units is a sigmoidal function of IID, and peak rates occur at IIDs favoring the contralateral ear. Most commonly, successive increments of ABI cause successive shifts of the IID functions toward IIDs favoring the ipsilateral ear. Neurons displaying this behavior include many that would conventionally be classified EI (receiving predominantly excitatory input arising from one ear and inhibitory input from the other), many that would be classified EE (receiving predominantly excitatory input arising from each ear), and all that are responsive only to contralateral stimulation. The IID sensitivity of a very few EI neurons is unaffected by ABI, except near threshold. Such units could provide directional information that is independent of source intensity. A few EE neurons are very sensitive to ABI, but are minimally sensitive to IID. Nevertheless, our data indicate that responses of most EE units in ICC are strongly dominated by excitation of contralateral origin. For some units, discharge rate is nonmonotonically related to IID and is maximal when the stimuli at the two ears are of comparable sound pressure. This preference for zero IID is common for all binaural levels. Many EI neurons respond nonmonotonically to ABI. Discharge rates are greater for IIDs representative of contralateral space and are maximal at a single best ABI. For a subset of these neurons, the influence arising from the ipsilateral ear is comprised of a mixture of excitation and inhibition. As a consequence, discharge rates are nonmonotonically related not only to ABI but also to IID. This dual nonmonotonicity creates a clear focus of peak response at a particular ABI/IID combination. Because of their mixed monaural influences, such units would be ascribed to different classes of the conventional (EE/EI) binaural classification scheme depending on the binaural level presented. Several response classes were identified in this study, and each might contribute differently to the encoding of spatial information.(ABSTRACT TRUNCATED AT 400 WORDS)

Parameter Space Analysis Suggests Multi-Site Plasticity Contributes to Motor Pattern Initiation in Tritonia

2007 ◽  
Vol 98 (4) ◽  
pp. 2382-2398 ◽  
Author(s):  
Robert J. Calin-Jageman ◽  
Mark J. Tunstall ◽  
Brett D. Mensh ◽  
Paul S. Katz ◽  
William N. Frost
Keyword(s):  
Parameter Space ◽  
Large Scale ◽  
Time Course ◽  
Scale Parameter ◽  
Motor Pattern ◽  
Rhythmic Activity ◽  
Excitatory Input ◽  
Space Analysis ◽  
Gastropod Mollusk ◽  
Detailed Simulation

This research examines the mechanisms that initiate rhythmic activity in the episodic central pattern generator (CPG) underlying escape swimming in the gastropod mollusk Tritonia diomedea. Activation of the network is triggered by extrinsic excitatory input but also accompanied by intrinsic neuromodulation and the recruitment of additional excitation into the circuit. To examine how these factors influence circuit activation, a detailed simulation of the unmodulated CPG network was constructed from an extensive set of physiological measurements. In this model, extrinsic input alone is insufficient to initiate rhythmic activity, confirming that additional processes are involved in circuit activation. However, incorporating known neuromodulatory and polysynaptic effects into the model still failed to enable rhythmic activity, suggesting that additional circuit features are also required. To delineate the additional activation requirements, a large-scale parameter-space analysis was conducted (∼2 × 106 configurations). The results suggest that initiation of the swim motor pattern requires substantial reconfiguration at multiple sites within the network, especially to recruit ventral swim interneuron-B (VSI) activity and increase coupling between the dorsal swim interneurons (DSIs) and cerebral neuron 2 (C2) coupling. Within the parameter space examined, we observed a tendency for rhythmic activity to be spontaneous and self-sustaining. This suggests that initiation of episodic rhythmic activity may involve temporarily restructuring a nonrhythmic network into a persistent oscillator. In particular, the time course of neuromodulatory effects may control both activation and termination of rhythmic bursting.

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