scholarly journals Thermal transients excite neurons through universal intramembrane mechano-electrical effects

2017 ◽  
Author(s):  
Michael Plaksin ◽  
Eitan Kimmel ◽  
Shy Shoham
Keyword(s):  
Neural Control ◽  
Mechanical Effect ◽  
Phospholipid Bilayer ◽  
Thermal Transients ◽  
Cellular Effects ◽  
Ionic Displacement ◽  
Rapid Temperature ◽  
Neural Excitation ◽  
Displacement Currents ◽  
Physical Tools

Modern advances in neurotechnology rely on effectively harnessing physical tools and insights towards remote neural control, thereby creating major new scientific and therapeutic opportunities. Specifically, rapid temperature pulses were shown to increase membrane capacitance, causing capacitive currents that explain neural excitation, but the underlying biophysics is not well understood. Here, we show that an intramembrane thermal-mechanical effect wherein the phospholipid bilayer undergoes axial narrowing and lateral expansion accurately predicts a potentially universal thermal capacitance increase rate of ~0.3%/°C. This capacitance increase and concurrent changes in the surface charge related fields lead to predictable exciting ionic displacement currents. The new theory’s predictions provide an excellent agreement with multiple experimental results and indirect estimates of latent biophysical quantities. Our results further highlight the role of electro-mechanics in neural excitation; they may also help illuminate sub-threshold and novel physical cellular effects, and could potentially lead to advanced new methods for neural control.

Strategies for the Control of Balance During Locomotion

2018 ◽  
Vol 7 (1) ◽  
pp. 18-25 ◽  
Author(s):  
Hendrik Reimann ◽  
Tyler Fettrow ◽  
John J. Jeka
Keyword(s):  
Degrees Of Freedom ◽  
Neural Control ◽  
Control Strategies ◽  
Mechanical Effect ◽  
Space Representation ◽  
Control Mechanisms ◽  
Step Width ◽  
Foot Placement ◽  
The Central Nervous System ◽  
Phase Space Representation

The neural control of balance during locomotion is currently not well understood, even in the light of considerable advances in research on balance during standing. In this paper, we lay out the control problem for this task and present a list of different strategies available to the central nervous system to solve this problem. We discuss the biomechanics of the walking body, using a simplified model that iteratively gains degrees of freedom and complexity. Each addition allows for different control strategies, which we introduce in turn: foot placement shift, ankle strategy, hip strategy, and push-off modulation. The dynamics of the biomechanical system are discussed using the phase space representation, which allows illustrating the mechanical effect of the different control mechanisms. This also enables us to demonstrate the effects of common general stability strategies, such as increasing step width and cadence.

Neural control of canine colon motor function: studies in vitro

1988 ◽  
Vol 66 (3) ◽  
pp. 359-368 ◽  
Author(s):  
T. Gonda ◽  
E. E. Daniel ◽  
F. Kostolanska ◽  
M. Oki ◽  
J. E. T. Fox
Keyword(s):  
Substance P ◽  
Neural Control ◽  
Circular Muscle ◽  
Distal Colon ◽  
Field Stimulation ◽  
Inhibitory Effects ◽  
Release Of Acetylcholine ◽  
Neural Excitation

The responses of strips of the canine colon to stimulation of intrinsic nerves and to the probable mediators of these nerves were studied in vitro. Studies were carried out using longitudinal and circular muscle strips from proximal and distal colon with field stimulation and addition of agents to the bath. Overall, these and other studies in vivo suggested that acetylcholine was an ubiquitous mediator of neural excitation. Norepinephrine had mixed inhibitory and excitatory effects, the latter only in circular muscle. Inhibitory effects of norepinephrine seemed to be both pre- and post-synaptic but no evidence that it was released by field stimulation was obtained. Substance P had excitatory effects chiefly by release of acetylcholine. It, in addition to norepinephrine, at least in circular muscle, deserves evaluation as the mediator of noncholinergic excitation to high frequency field stimulation. Although vasoactive intestinal peptide sometimes had inhibitory effects, these were incomplete and inconsistent. However, further evaluation of its possible role as a nonadrenergic, noncholinergic inhibitory mediator is required to determine if it is involved as one component in the response. Few qualitative differences existed between responses of various regions of the colon to potential neuromediators, although there were some consistent differences between responses of longitudinal and circular muscle. Some differences existed in responses obtained earlier in vivo and in vitro. In particular, inhibitory effects following excitation by substance P on field stimulation were found only in vivo. Nonadrenergic, noncholinergic inhibitory responses to field stimulation were consistently present only in vitro. These differences have not been explained.

Neural Control of Reproduction

1998 ◽  
Vol 48 (3) ◽  
pp. 375-376
Author(s):  
Robert A. Steiner
Keyword(s):  
Neural Control

Central ? Involvement in Neural Control of Blood Glucose in Pigeons

1996 ◽  
Vol 60 (3) ◽  
pp. 889-894
Author(s):  
W Souza
Keyword(s):  
Blood Glucose ◽  
Neural Control

Thermal transients of coated optical fibres exposed to microwave power at 2.45 GHz

1990 ◽  
Vol 137 (3) ◽  
pp. 174
Author(s):  
M.J. Sacco ◽  
L.J. Auchterlonie ◽  
A.J. Harris
Keyword(s):  
Microwave Power ◽  
Optical Fibres ◽  
Thermal Transients

Factors Affecting the lnteraction of Tissue Factor/Factor Vll with Factor X in a Heterogeneous Tubular Reactor

1991 ◽  
Vol 65 (02) ◽  
pp. 139-143 ◽  
Author(s):  
Cynthia H Gemmell ◽  
Vincet T Turitto ◽  
Yale Nemerson
Keyword(s):  
Steady State ◽  
Tissue Factor ◽  
Factor Viia ◽  
Transmembrane Protein ◽  
Strong Association ◽  
Tubular Reactor ◽  
Factor Xa ◽  
Phospholipid Bilayer ◽  
Factor Vii ◽  
Factor X

SummaryA novel reactor recently described for studying phospholipiddependent blood coagulation reactions under flow conditions similar to those occurring in the vasculature has been further charactenzed. The reactor is a capitlary whose inner wall is coated with a stable phospholipid bilayer (or two bilayers) containing tissue factor, a transmembrane protein that is required for the enzymatic activation of factor X by factor VIIa. Perfusion of the capillary at wall shear rates ranging from 25 s−1 to 1,200 s−1 with purified bovine factors X and VIIa led to steady state factor Xa levels at the outlet. Assay were performed using a chromogenic substrate, SpectrozymeTMFXa, or by using a radiometric technique. In the absence of Ca2+ or factor VIIa there was no product formation. No difference was noted in the levels of factor Xa achieved when non-activated factor VII was perfused. Once steady state was achieved further factor Xa production continued in the absence of factor VIIa implying a very strong association of factor VIIa with the tissue factor in the phospholipid membrane. In agreement with static vesicle-type studies the reactor was sensitive to wall tissue factor concentration, temperature and the presence of phosphatidylserine in the bilayer.

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