ABSTRACT
It turns out that the nonlinear dynamical behaviour of a Josephson tunnel junction used in Supraconducting Quantum Interference Device (Squid) imaging to measure extremely weak magnetic fields in the femtotesla range (Figure 10) and in cyroelectronics ([7]) can be described in terms of a circle map. Recent advances in Squid design using multiple ultrasensitive magnetic flux detectors arranged in spatial arrays make it possible to record magnetoencephalograms (MEGs) simultaneously from extensive areas of cortex. Notice that the magnetic fields of brain function are an order of 10-4 smaller than magnetic fields produced by the heart ([97]). Band pass filtering and spatial filtering allow to extract perceptual information from the I activity for measurement and display.
