scholarly journals Synaptic counts approximate synaptic contact area in Drosophila

2020 ◽  
Author(s):  
Christopher L. Barnes ◽  
Daniel Bonnéry ◽  
Albert Cardona
Keyword(s):  
Surface Area ◽  
Synaptic Contact ◽  
Synaptic Strength ◽  
Circuit Modeling ◽  
Synaptic Connections ◽  
Presynaptic Neuron ◽  
Synaptic Contacts ◽  
Circuit Structure ◽  
The Relationship ◽  
Volume Electron Microscopy

AbstractThe pattern of synaptic connections among neurons defines the circuit structure, which constrains the computations that a circuit can perform. The strength of synaptic connections is costly to measure yet important for accurate circuit modeling. It has been shown that synaptic surface area correlates with synaptic strength, yet in the emerging field of connectomics, most studies rely instead on the counts of synaptic contacts between two neurons. Here we quantified the relationship between synaptic count and synaptic area as measured from volume electron microscopy of the larval Drosophila central nervous system. We found that the total synaptic surface area, summed across all synaptic contacts from one presynaptic neuron to a postsynaptic one, can be accurately predicted solely from the number of synaptic contacts, for a variety of neurotransmitters. Our findings support the use of synaptic counts for approximating synaptic strength when modeling neural circuits.

scholarly journals Excitatory postsynaptic calcium transients at Aplysia sensory-motor neuron synapses allow for quantal examination of synaptic strength over multiple days in culture

2021 ◽  
Author(s):  
Tyler W Dunn ◽  
Wayne S Sossin
Keyword(s):  
Motor Neuron ◽  
Ampa Receptors ◽  
Synaptic Contact ◽  
Synaptic Strength ◽  
Calcium Transients ◽  
Calcium Sensor ◽  
Synaptic Contacts ◽  
Quantal Size ◽  
Sensory Motor ◽  
Postsynaptic Calcium

AbstractThe ability to monitor changes in strength at individual synaptic contacts is required to test the hypothesis that specialized synapses maintain changes in synaptic strength that underlie memory. Measuring excitatory post-synaptic calcium transients through calcium permeable AMPA receptors is one way to monitor synaptic strength at individual synaptic contacts. Using a membrane targeted genetic calcium sensor, we demonstrate that one can measure synaptic events at individual synaptic contacts in Aplysia sensory-motor neuron synapses. These results show that synaptic strength is not evenly distributed between all contacts in these cultures, but dominated by multiquantal sites of synaptic contact. The probability, quantal size and quantal content can be measured over days at individual synaptic contacts using this technique. Surprisingly, most synaptic contacts were not found opposite presynaptic varicosities, but instead at areas of pre- and post-synaptic contact with no visible thickening of membranes. This technique shows promise in being able to address whether specialized synapses maintain synaptic strength underlying memory.

The use of Body Surface Index as a Better Clinical Health indicators Compare to Body Mass Index and Body Surface Area for Clinical Application

2018 ◽  
pp. 131-136
Author(s):  
Shirazu I. ◽  
Theophilus. A. Sackey ◽  
Elvis K. Tiburu ◽  
Mensah Y. B. ◽  
Forson A.
Keyword(s):  
Surface Area ◽  
Body Surface Area ◽  
Clinical Application ◽  
Body Surface ◽  
Body Height ◽  
Health Indicators ◽  
The Body ◽  
Body Parameters ◽  
The Relationship ◽  
Individual Body

The relationship between body height and body weight has been described by using various terms. Notable among them is the body mass index, body surface area, body shape index and body surface index. In clinical setting the first descriptive parameter is the BMI scale, which provides information about whether an individual body weight is proportionate to the body height. Since the development of BMI, two other body parameters have been developed in an attempt to determine the relationship between body height and weight. These are the body surface area (BSA) and body surface index (BSI). Generally, these body parameters are described as clinical health indicators that described how healthy an individual body response to the other internal organs. The aim of the study is to discuss the use of BSI as a better clinical health indicator for preclinical assessment of body-organ/tissue relationship. Hence organ health condition as against other body composition. In addition the study is `also to determine the best body parameter the best predict other parameters for clinical application. The model parameters are presented as; modeled height and weight; modelled BSI and BSA, BSI and BMI and modeled BSA and BMI. The models are presented as clinical application software for comfortable working process and designed as GUI and CAD for use in clinical application.

The relationship between brain structure and general psychopathology in preadolescents

2020 ◽  
Author(s):  
Louise Mewton ◽  
Briana Lees ◽  
Lindsay Squeglia ◽  
Miriam K. Forbes ◽  
Matthew Sunderland ◽  
...  
Keyword(s):  
Mental Disorders ◽  
Surface Area ◽  
Brain Structure ◽  
Parental Education ◽  
Mental Illnesses ◽  
General Psychopathology ◽  
Control Approach ◽  
Cortical Volume ◽  
Subcortical Regions ◽  
The Relationship

Categorical mental disorders are being recognized as suboptimal targets in clinical neuroscience due to poor reliability as well as high rates of heterogeneity within, and comorbidity between, mental disorders. As an alternative to the case-control approach, recent studies have focused on the relationship between neurobiology and latent dimensions of psychopathology. The current study aimed to investigate the relationship between brain structure and psychopathology in the critical preadolescent period when psychopathology is emerging. This study included baseline data from the Adolescent Brain and Cognitive Development (ABCD) Study® (n = 11,721; age range = 9-10 years; male = 52.2%). General psychopathology, externalizing, internalizing, and thought disorder dimensions were based on a higher-order model of psychopathology and estimated using Bayesian plausible values. Outcome variables included global and regional cortical volume, thickness, and surface area. Higher levels of psychopathology across all dimensions were associated with lower volume and surface area globally, as well as widespread and pervasive alterations across the majority of cortical and subcortical regions studied, after adjusting for sex, race/ethnicity, and parental education. The relationships between general psychopathology and brain structure were attenuated when adjusting for cognitive functioning. There was evidence of a relationship between externalizing psychopathology and frontal regions of the cortex that was independent of general psychopathology. The current study identified lower cortical volume and surface area as transdiagnostic biomarkers for general psychopathology in preadolescence. The widespread and pervasive relationships between general psychopathology and brain structure may reflect cognitive dysfunction that is a feature across a range of mental illnesses.

Reverse Optical Trawling for Synaptic Connections In Situ

2009 ◽  
Vol 102 (1) ◽  
pp. 636-643 ◽  
Author(s):  
Takuya Sasaki ◽  
Genki Minamisawa ◽  
Naoya Takahashi ◽  
Norio Matsuki ◽  
Yuji Ikegaya
Keyword(s):  
Network Connectivity ◽  
Synaptic Activity ◽  
Calcium Transients ◽  
Synaptic Connections ◽  
False Positive Error ◽  
Presynaptic Neuron ◽  
Promising Tool ◽  
On Line ◽  
False Positive Error Rate ◽  
Presynaptic Neurons

We introduce a new method to unveil the network connectivity among dozens of neurons in brain slice preparations. While synaptic inputs were whole cell recorded from given postsynaptic neurons, the spatiotemporal firing patterns of presynaptic neuron candidates were monitored en masse with functional multineuron calcium imaging, an optical technique that records action potential–evoked somatic calcium transients with single-cell resolution. By statistically screening the neurons that exhibited calcium transients immediately before the postsynaptic inputs, we identified the presynaptic cells that made synaptic connections onto the patch-clamped neurons. To enhance the detection power, we devised the following points: 1) [K+]e was lowered and [Ca2+]e and [Mg2+]e were elevated, to reduce background synaptic activity and minimize the failure rate of synaptic transmission; and 2) a small fraction of presynaptic neurons was specifically activated by glutamate applied iontophoretically through a glass pipette that was moved to survey the presynaptic network of interest (“trawling”). Then we could theoretically detect 96% of presynaptic neurons activated in the imaged regions with a 1% false-positive error rate. This on-line probing technique would be a promising tool in the study of the wiring topography of neuronal circuits.

scholarly journals General Psychopathology, Cognition, and the Cerebral Cortex in 10-Year-Old Children: Insights From the Adolescent Brain Cognitive Development Study

2022 ◽  
Vol 15 ◽  
Author(s):  
Yash Patel ◽  
Nadine Parker ◽  
Giovanni A. Salum ◽  
Zdenka Pausova ◽  
Tomáš Paus
Keyword(s):  
Cerebral Cortex ◽  
Cognitive Development ◽  
Surface Area ◽  
Cortical Surface ◽  
Strongly Correlated ◽  
General Psychopathology ◽  
Cortical Surface Area ◽  
Neurite Density ◽  
The Relationship ◽  
Strength Of Association

General psychopathology and cognition are likely to have a bidirectional influence on each other. Yet, the relationship between brain structure, psychopathology, and cognition remains unclear. This brief report investigates the association between structural properties of the cerebral cortex [surface area, cortical thickness, intracortical myelination indexed by the T1w/T2w ratio, and neurite density assessed by restriction spectrum imaging (RSI)] with general psychopathology and cognition in a sample of children from the Adolescent Brain Cognitive Development (ABCD) study. Higher levels of psychopathology and lower levels of cognitive ability were associated with a smaller cortical surface area. Inter-regionally—across the cerebral cortex—the strength of association between an area and psychopathology is strongly correlated with the strength of association between an area and cognition. Taken together, structural deviations particularly observed in the cortical surface area influence both psychopathology and cognition.

scholarly journals Mpemba Effect- the Effect of Time

2021 ◽  
Author(s):  
Jianan Wang
Keyword(s):  
Gravitational Field ◽  
Surface Area ◽  
Time Effect ◽  
Light Quantum ◽  
Unit Surface Area ◽  
Heat Flows ◽  
Unit Surface ◽  
Average Wavelength ◽  
Nature Of Time ◽  
The Relationship

This paper draws the following conclusions on the nature of time by analyzing the relationship between time and speed, the relationship between time and gravitational field, the gravitational redshift of the photon, and the black-body radiation theorem: Time on an object is proportional to the amount of energy flowing out (or in) per unit time (observer’s time) per unit surface area of the object. When an object radiates energy outward: t'=μB(T) =μσT 4=μnhν/st Where t’ is the time on the object, μ is a constant, B(T) is the radiosity，the total energy radiated from the unit surface area of the object in unit time (observer’s time), σ is the Stefan-Boltzmann constant, T is the absolute temperature, n is the number of the photons radiated, ν is the average frequency of the photons radiated, s is the surface area of the object and t is the time on the observer. When the object radiates energy outward, the higher the energy density of the space (for example the stronger the gravitational field of the space), the smaller the radiosity B(T) of the object in the space, the longer the average wavelength of the light quantum emitted by the object, the slower the time on the object, the longer the life of the system. When the object radiates energy outward, the faster the object moves relative to the ether, the higher the energy density of the local space in which the object is located, the smaller the radiosity B(T) of the object, the longer the average wavelength of the light quantum radiated by the object, the slower the time on the object, and the longer the life of the system. When the object radiates energy outward, the higher the temperature of the object, the greater the object's radiosity B(T), the shorter the average wavelength of the light quantum radiated by the object, the faster the time on the object, and the shorter the life of the system. Applying the above conclusions about the nature of time, the author analyzes the Mpemba effect and the inverse Mpemba effect, and reaches the following conclusion: the Mpemba effect is the time effect produced when heat flows from objects into space, and the "inverse" Mpemba effect is the time effect produced when heat flows from space into objects.

scholarly journals The perforation of the frustules of planktonic diatoms Pseudosolenia calcar-avis and Proboscia alata (Bacillariophyceae)

2019 ◽  
Vol 2 ◽  
pp. 19-26
Author(s):  
Lyakh A.M.
Keyword(s):  
Surface Area ◽  
Geometric Modeling ◽  
Direct Determination ◽  
Entire Surface ◽  
Planktonic Diatoms ◽  
Centric Diatoms ◽  
Flow Through ◽  
Material Energy ◽  
The Relationship

Physiological and biophysical characteristics of microalgae should strongly depend on the surface area of the cover of organisms, as all the material-energy streams flow through the surface. However, to determine the relationship between the intensity of the flow of substances with the physiology of unicellular, it is necessary to take into account only the area of perforations, since the rest of the shell is impermeable for substances. The direct determination of the area of perforations on the entire surface of the microalgae is very difficult. Therefore, the indirect method of estimating the perforation area using geometric modeling of the perforation distribution (texture) on the surface was used in this study. The object of the research is two types of marine plankton diatoms with large cylindrical frustules. It was assumed that the frustules are covered with a regular triangular texture of the areola. This texture can be divided into regular hexagons, which allows us to estimate the number of areolas as the ratio of the surface area of the frustules to the area of one hexagon. The model takes into account that each areola is covered with a silicon plate perforated by a smaller pore. The multiplication of the number of areolas on the area of a given pore gives the value of the total area of perforations. Calculations showed that the perforation of the frustules of Proboscia alata was 4%, and Pseudosolenia calcar-avis – 6%. These are the first estimates of the perforation of the entire surface of the diatom frustules. The acquired data confirms the hypothesis that frustules of the most centric diatoms are covered by pores by about 5%, and the other surface is impervious to material flows.

Change in event horizon surface area as the source of nonmetricity field

2018 ◽  
Vol 15 (06) ◽  
pp. 1850104
Author(s):  
Yuriy A. Portnov
Keyword(s):  
Black Holes ◽  
Surface Area ◽  
Event Horizon ◽  
Test Body ◽  
Body Motion ◽  
Motion Equations ◽  
Gravitational Source ◽  
Theory Of Gravitation ◽  
The Relationship ◽  
Over Time

This paper concerns the relationship between the nonmetricity 1-form and the change in entropy. Motion equations have been obtained for test bodies in a gravitational field created by a massive body with entropy varying over time. It has been shown that increasing entropy of the gravitational source will bring about an increase in the acceleration of the test body. Applied to the theory of gravitation with nonmetricity, black hole dynamics equations based on foundations laid by S. Hawking and J. Beckenstein, enabled identification of changes in black holes event horizon surface area as a putative source of nonmetricity field. The implication is that changes in event horizon area will affect test body motion. The latter property makes it possible to contemplate a completely new method for discovering short-lived microscopic black holes.

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