Scanner Background Noise
Scanner Background Noise - Related Videos
01:18
Thermodynamic Background
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2026
The law of mass action states that "the rate of a chemical reaction is directly proportional to the product of the molar concentrations of the reactants." It means that the more 'active mass' or 'concentration' of the reactants present, the faster the reaction will proceed.In a chemical reaction, there are forward and reverse reactions. The forward reaction is the process where the reactants combine to form products. The reverse reaction is the process where the products break down to form the...
08:25
Using Flatbed Scanners to Collect High-resolution Time-lapsed Images of the Arabidopsis Root Gravitropic Response
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Cited by 6 •
2014
This protocol describes a process for rapid collection of images of Arabidopsis seedlings responding to a gravity stimulus using commercially-available flatbed scanners. The method allows for inexpensive, high-volume capture of high-resolution images amenable for downstream analysis algorithms.
15:04
Rejection of Fluorescence Background in Resonance and Spontaneous Raman Microspectroscopy
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Cited by 5 •
2011
We discuss the construction and operation of a complex nonlinear optical system that uses ultrafast all-optical switching to isolate Raman from fluorescence signals. Using this system we are able to successfully separate Raman and fluorescence signals utilizing pulse energies and average powers that remain biologically safe.
07:01
Frequency Mixing Magnetic Detection Scanner for Imaging Magnetic Particles in Planar Samples
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Cited by 5 •
2016
A scanner for imaging magnetic particles in planar samples was developed using the planar frequency mixing magnetic detection technique. The magnetic intermodulation product response from the nonlinear nonhysteretic magnetization of the particles is recorded upon a two-frequency excitation. It can be used to take 2D images of thin biological samples.
02:27
Background and Environment Affect Phenotype
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2021
Although the genetic makeup of an organism plays a major role in determining the phenotype, there are also several environmental factors, such as temperature, oxygen availability, presence of mutagens, that can alter an organism’s phenotype. An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
FAQs
Rapidly switching gradient coils interact with the main magnetic field and create mechanical vibrations. The resulting acoustic pattern changes with the imaging sequence, so different sequences can expose participants to different rhythmic sound profiles. This variation matters when comparing scans or interpreting biological responses, because the auditory stimulus is not necessarily constant across acquisitions.
Noise can stimulate auditory pathways, which may change brain activity and behavior during an MRI session. In functional MRI, those responses can overlap with or modify the biological signal researchers intend to measure. Without accounting for the acoustic environment, an apparent task-related or condition-related difference may partly reflect unequal scanner sound rather than the process under study.
Matching acoustic exposure helps separate effects of scanner sound from effects associated with the experimental condition. Because noise timing and intensity depend on the sequence, two conditions that differ in sequence-related sound may also differ in auditory stimulation. Noise-matched protocols therefore improve interpretability and reduce a potential confound in comparisons of brain activity.
They reduce participant exposure to scanner noise and support hearing safety and comfort. Their use also helps limit noise-driven changes in behavior or brain activity, although researchers still need suitable control conditions and noise-matched protocols when measuring biological responses. Attenuation therefore supports participant protection while experimental controls address remaining effects on the data.
First, account for the sequence-specific timing and intensity of the sound. Next, use hearing protection or sound-attenuating equipment, then include control conditions that represent the acoustic exposure. For comparisons involving functional MRI, noise-matched protocols help ensure that differences in measured brain activity are not simply differences in scanner sound.
It is especially important in neuroscience and other studies using functional MRI, where brain activity and behavior are key measurements. The issue becomes more consequential when experimental conditions use different imaging sequences or acoustic profiles. Addressing it helps researchers interpret auditory, behavioral, and functional imaging results more reliably while also supporting participant comfort and hearing safety.