Lie detection the 'source'. To use an MRI as a lie detector, an fMRI should be used by placing a magnetic band as a scanner on a subject's head. However, the neurobiological systems that relate to lying are currently poorly understood. The current consensus is that faced with a forced choice paradigm, in which a subject has the choice of telling the truth or spontaneously generating a lie, lying can be distinguished due to increased prefrontal and parietal lobe activity. More specifically, the superior medial and inferolateral prefrontal cortices show net activation in the process of spontaneous lie generation (which involves suppression
Detector (radio) local oscillator, hence the name. By heterodyning, the received signal is mixed (in some type of nonlinear device) with a signal from the local oscillator, to give sum and difference frequencies to the signals being mixed, just as a "first mixer" stage in a superhet would produce an intermediate frequency; the beat frequency in this case, the low frequency modulating signal is recovered and the unwanted high frequencies filtered out from the output of the product detector. Product detector circuits are and so essentially ring modulators or synchronous detectors and closely related to some phase-sensitive detector circuits. They can be