scholarly journals Precision of auditory responses deteriorates on the way to frontal cortical areas

2019 ◽  
Author(s):  
Luciana López-Jury ◽  
Adrian Mannel ◽  
Francisco Garcia-Rosales ◽  
Julio C. Hechavarria
Keyword(s):  
Neuronal Model ◽  
Sound Processing ◽  
Complex Behaviour ◽  
Response Properties ◽  
Auditory Responses ◽  
Low Threshold ◽  
Pure Tones ◽  
Synaptic Dynamics ◽  
Auditory Field

AbstractFrontal areas of the mammalian cortex are thought to be important for cognitive control and complex behaviour. These areas have been studied mostly in humans, non-human primates and rodents. In this article, we present a quantitative characterization of response properties of a frontal auditory area responsive to sound in the bat brain, the frontal auditory field (FAF). Bats are highly vocal animals and they constitute an important experimental model for studying the auditory system. At present, little is known about neuronal sound processing in the bat FAF. We combined electrophysiology experiments and computational simulations to compare the response properties of auditory neurons found in the bat FAF and auditory cortex (AC) to simple sounds (pure tones). Anatomical studies have shown that the latter provide feedforward inputs to the former. Our results show that bat FAF neurons are responsive to sounds, however, when compared to AC neurons, they presented sparser, less precise spiking and longer-lasting responses. Based on the results of an integrate-and-fire neuronal model, we speculate that slow, low-threshold, synaptic dynamics could contribute to the changes in activity pattern that occur as information travels through cortico-cortical projections from the AC to the FAF.

scholarly journals Characterization of Direct Perturbations on Voltage-Gated Sodium Current by Esaxerenone, a Nonsteroidal Mineralocorticoid Receptor Blocker

Biomedicines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 549
Author(s):  
Wei-Ting Chang ◽  
Sheng-Nan Wu
Keyword(s):  
Mineralocorticoid Receptor ◽  
Sodium Current ◽  
Ionic Currents ◽  
Antagonistic Effect ◽  
Gh3 Cells ◽  
Excitable Cells ◽  
Voltage Gated ◽  
Ic50 Value ◽  
Low Threshold

Esaxerenone (ESAX; CS-3150, Minnebro®) is known to be a newly non-steroidal mineralocorticoid receptor (MR) antagonist. However, its modulatory actions on different types of ionic currents in electrically excitable cells remain largely unanswered. The present investigations were undertaken to explore the possible perturbations of ESAX on the transient, late and persistent components of voltage-gated Na+ current (INa) identified from pituitary GH3 or MMQ cells. GH3-cell exposure to ESAX depressed the transient and late components of INa with varying potencies. The IC50 value of ESAX required for its differential reduction in peak or late INa in GH3 cells was estimated to be 13.2 or 3.2 μM, respectively. The steady-state activation curve of peak INa remained unchanged during exposure to ESAX; however, recovery of peak INa block was prolonged in the presence 3 μM ESAX. In continued presence of aldosterone (10 μM), further addition of 3 μM ESAX remained effective at inhibiting INa. ESAX (3 μM) potently reversed Tef-induced augmentation of INa. By using isosceles-triangular ramp pulse with varying durations, the amplitude of persistent INa measured at high or low threshold was enhanced by the presence of tefluthrin (Tef), in combination with the appearance of the figure-of-eight hysteretic loop; moreover, hysteretic strength of the current was attenuated by subsequent addition of ESAX. Likewise, in MMQ lactotrophs, the addition of ESAX also effectively decreased the peak amplitude of INa along with the increased current inactivation rate. Taken together, the present results provide a noticeable yet unidentified finding disclosing that, apart from its antagonistic effect on MR receptor, ESAX may directly and concertedly modify the amplitude, gating properties and hysteresis of INa in electrically excitable cells.

scholarly journals Characterization of ligand response properties of the CRP protein from Pseudomonas putida

2012 ◽  
Vol 57 (30) ◽  
pp. 3878-3885 ◽  
Author(s):  
Feng Jiang ◽  
ZheXian Tian ◽  
YiPing Wang
Keyword(s):  
Pseudomonas Putida ◽  
Response Properties

scholarly journals Conventional Nanoindentation in Self-Assembled Monolayers Deposited on Gold and Silver Substrates

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Leila Costelle ◽  
Liina Lind ◽  
Pasi Jalkanen ◽  
Minna T. Räisänen ◽  
Roman Nowak ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Self Assembled Monolayers ◽  
Energy Calculation ◽  
Complex Behaviour ◽  
Assembled Monolayers ◽  
Efficient Data ◽  
Self Assembled ◽  
Efficient Data Analysis ◽  
Insight Into

Self-assembled monolayers (SAMs) are promising materials for micromechanical applications. However, characterization of mechanical properties of monolayers is challenging for standard nanoindentation, and new efficient analysis techniques are needed. Hereby, a conventional nanoindentation method has been combined in a unique way with efficient data analysis based on consumed energy calculation and load-displacement data. The procedure has been applied on SAMs of 4,4′-biphenyldithiol (BPDT) on Au, 1-tetradecanethiol (TDT), and 1-hexadecanethiol (HDT) on Au and Ag substrates being the first study where SAMs of the same thiols on different substrates are analyzed by nanoindentation providing a new insight into the substrate effects. Unlike TDT and HDT SAMs, which are found to strongly enhance the homogeneity and stiffness of the underlying substrate, the BPDT covered Au substrate appears softer in mechanical response. In the case of TDT and HDT SAMs on Ag the structures are softer showing also faster relaxation than the corresponding structures on Au substrate. The proposed procedure enables a fast and efficient way of assessing the complex behaviour of SAM modified substrates. As a consequence, the results are relevant to practical issues dependent on layer activity and toughness.

Enhanced Cellular Activity on Conducting Polymer

2021 ◽  
pp. 734-773
Author(s):  
Rajiv Borah ◽  
Ashok Kumar
Keyword(s):  
Tissue Engineering ◽  
Conducting Polymer ◽  
Neural Tissue ◽  
Neuronal Model ◽  
Neural Tissue Engineering ◽  
Electrically Conductive ◽  
Pc12 Cell Line ◽  
Nih 3T3

This chapter includes detailed review of the research undertaken with conducting polymer (CP) based composites with chitosan (Ch) for tissue engineering till date. The beneficial role of electrically conductive biomaterials has been discussed with the possible strategies to overcome the shortcomings of CP alone through blending with Ch due to its excellent biocompatibility, biodegradability, and bioactivity. Additionally, this embodiment deals with the optimization and characterization of electrically conductive, biocompatible and biodegradable Polyaniline: Chitosan (PAni:Ch) nanocomposites as cell culture substrates for MDA-MB-231 and NIH 3T3 fibroblast in order to examine the combined effect of nanofiber structure and surface modification on cell-biomaterial interactions. The nanocomposites were further checked as a conductive scaffold for electrical stimulation of a neuronal model PC12 cell line in order to explore the potential of the materials in neural tissue engineering.

scholarly journals Physiological characterization of a rare subpopulation of doublet-spiking neurons in the ferret lateral geniculate nucleus

2020 ◽  
Vol 124 (2) ◽  
pp. 432-442
Author(s):  
Allison J. Murphy ◽  
J. Michael Hasse ◽  
Farran Briggs
Keyword(s):  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Visual Response ◽  
Retinal Ganglion ◽  
Visual Responses ◽  
Response Properties ◽  
Physiological Characterization ◽  
Visual Thalamus ◽  
Spike Shape

Interest in visual system homologies across species has recently increased. Across species, retinas contain diverse retinal ganglion cells including cells with unusual visual response properties. It is unclear whether rare retinal ganglion cells in carnivores project to and drive similarly unique visual responses in the visual thalamus. We discovered a rare subpopulation of thalamic neurons defined by unique spike shape and visual response properties, suggesting that nonstandard visual computations are common to many species.

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