Magnetoencephalography (MEG) is a technique for measuring changes in the magnetic field of the brain caused by external stimuli such as touching the body or viewing images of food. Such a change in the field occurs due to electrical activity (current) in the brain. During the process, magnetic sensors are placed on the skin to measure the magnetic field at that location. Typical field strengths are a few femtoteslas (1 femtotesla=1 fT=10−15 T) . An adult brain is about 140 mm wide and divided into two sections (called "hemispheres" although the brain is not truly spherical), which are each about 70 mm wide. Model the current in one hemisphere as a circular current loop 65.0 mm in diameter. A sensor is placed so that it is along the axis of the loop, 2.10 cm from the center. Suppose a magnetic field of 5.55 fT is measured by the sensor. According to the model, what is the current ? in the hemisphere of the brain being measured?What is the magnetic field ?B at the center of the same hemisphere?
Magnetoencephalography (MEG) is a technique for measuring changes in the magnetic field of the brain caused...
Magnetoencephalography (MEG) is a technique for measuring changes in the magnetic field of the brain caused by external stimuli such as touching the body or viewing images of food. Such a change in the field occurs due to electrical activity (current) in the brain. During the process, magnetic sensors are placed on the skin to measure the magnetic field at that location.... Magnetoencephalography (MEG) is a technique for measuring changes in the magnetic field of the brain caused by external...
Typical field strengths are a few femoteslas (1fT=10^-15T). An adult brain is about 140mm wide, divided into two sections (called hemispheres) each about 70mm wide. We can model the current in one hemisphere as a circular loop, 65mm in diameter, just inside the brain. The sensor is placed so that it is along the axis of the loop 2.30cm from the center. A reasonable magnetic field is 4.35fT at the sensor. According to this model, what is the current in...
Neurons in our bodies carry weak currents that produce detectable magnetic fields. A technique called magnetoencephalography, or MEG, is used to study electrical activity in the brain using this concept. This technique is capable of detecting magnetic fields as weak as 0.8x10−15 T. Model the neuron as a long wire carrying a current and find the current it must carry to produce a field of this magnitude at a distance of 3.8 cm from the neuron.
Neurons in our bodies carry weak currents that produce detectable magnetic fields. A technique called magnetoencephalography, or MEG, is used to study electrical activity in the brain using this concept. This technique is capable of detecting magnetic fields as weak as 1.0 10-15 T. Model the neuron as a long wire carrying a current and find the current it must carry to produce a field of this magnitude at a distance of 4.4 cm from the neuron.
The magnetic field of the brain has been measured to be approximately 3.0x10-12 T. A simple estimate of the related currents can be obtained by assuming that the magnetic field is due to a single current loop with a diameter of 16 cm (the width of a typical head). What current is needed to produce such a field at the center of the loop?
The magnetic field of the brain has been measured to be approximately 3.0 ×10−12T. Although the currents that cause this field are quite complicated, we can get a rough estimate of their size by modeling them as a single circular current loop 16 cm (the width of a typical head) in diameter. What current is needed to produce such a field at the center of the loop?