It has been known for sometime that brain tissue show marked low-frequency dielectric dispersion and large permittivity (>106) in a frequency range of 10–100 Hz. We have shown that these properties can be due to electrically long neurites by solving equations that describe a model with a bundle of finite length cylindrical neurites subjected to oscillating extracellular electric fields. We also provide a notion of the apparent extracellular space and a generalized formulation for the EEG inverse problem that takes permittivity into account.
We formulate error and disturbance in quantum measurement in terms of the classical Fisher information and the quantum Fisher information. The error formulated here characterizes the accuracy of the estimate of the expectation value of an observable. The disturbance characterizes the irreversibility of the measurement process. We show that the product of the error and disturbance is bounded from below by the commutator of the observables. We also find the attainable bound of the product.