Search results
Results from the WOW.Com Content Network
From the point of view of control theory, the voltage clamp experiment can be described in terms of the application of a high-gain output feedback control law [13] to the neuronal membrane. [14] Mathematically, the membrane voltage can be modeled by a conductance-based model with an input given by the applied current I a p p ( t ...
Perceptual control theory (PCT) is a model of behavior based on the properties of negative feedback control loops. A control loop maintains a sensed variable at or near a reference value by means of the effects of its outputs upon that variable, as mediated by physical properties of the environment.
Attenuation is a second mechanism of negative feedback in the trp operon. While the TrpR repressor decreases transcription by a factor of 70, attenuation can further decrease it by a factor of 10, thus allowing accumulated repression of about 700-fold. Attenuation is made possible by the fact that in prokaryotes (which have no nucleus), the ...
The ERP is plotted with negative voltages upward, a common, but not universal, practice in ERP research. An event-related potential (ERP) is the measured brain response that is the direct result of a specific sensory, cognitive, or motor event. [1] More formally, it is any stereotyped electrophysiological response to a stimulus.
This signaling network illustrates the simultaneous positive and negative feedback loops whose exquisite sensitivity helps create a bistable switch. Bistability can only arise in biological and chemical systems if three necessary conditions are fulfilled: positive feedback , a mechanism to filter out small stimuli and a mechanism to prevent ...
In the process of depolarization, the negative internal charge of the cell temporarily becomes more positive (less negative). This shift from a negative to a more positive membrane potential occurs during several processes, including an action potential. During an action potential, the depolarization is so large that the potential difference ...
In biology, most biochemical processes strive to maintain equilibrium (homeostasis), a steady state that exists more as an ideal and less as an achievable condition. Environmental factors, internal or external stimuli, continually disrupt homeostasis; an organism's present condition is a state of constant flux moving about a homeostatic point ...
There is a positive feedback loop that results from a simultaneous input of signals from PF-CF and increases DAG and Ca 2+ in Purkinje dendritic spines. Calcium and DAG activate conventional PKC (cPKC), which then activates MAPKKK and the rest of the MAPK cascade. Activated MAPK and Ca 2+ activate PLA2, AA and cPKC creating a positive feedback ...