Head-direction cells are neurons that signal a rat's directional heading in the horizontal plane. Head-direction cells in the anterior thalamus are anticipatory, so that their firing rate is better correlated with the rat's future head direction than with the present or past head direction. We recorded single-unit activity from head-direction cells in the anterior thalamus of freely moving rats...

We report on low-noise heterodyne mixing with NbN/A1N/NbN tunnel junctions in the submillimeter-wave region for the first time. The receiver consists of the quasi-optical NbN SIS mixer with an integrated tuning circuit in which a radial short stub tuner is incorporated to resonate out the junction capacitance for RF matching and a balanced IF circuit for broadband IF matching. The prepared NbN ...

The oculomotor neural integrator is a brainstem nucleus that stores the short term memory of eye position during gaze holding. This neural integrator is believed to perform temporal integration of transient eye velocity input using positive feedback. Such models of integration are known to suffer from a fine-tuning problem [9] since changes in the amount of feedback by less than 10% can de-tune...

A design approach for a tunable active filter of constant bandwidth and center-frequency gain is described. The approach is based on a feedback configuration with a complex pole pair in the forward transfer function, and a complex zero pair in the feedback transfer function. Center frequency tuning is achieved with the variation of only one element, a potentiomenter, which controls the feedback...

Receptive field properties of visual cortical neurons depend on the spatiotemporal context within which the stimuli are presented. We have examined the temporal context dependence of cortical orientation tuning using dynamic visual stimuli with rapidly changing orientations. We found that tuning to the orientation of the test stimulus depended on a briefly presented preceding stimulus, with the...

We have developed a low-noise 850 GHz superconductor–insulator–superconductor quasiparticle mixer with NbTiN thin-film microstrip tuning circuits and hybrid Nb/AlN/NbTiN tunnel junctions. The mixer uses a quasioptical configuration with a planar twin-slot antenna feeding a two-junction tuning circuit. At 798 GHz, we measured an uncorrected double-sideband receiver noise temperature of TRX5260 K...

This paper presents a new concept of fine frequency tuning in a differential LC oscillator by injecting quadrature phase shifted current into the tank that can replace the use of a conventional varactor, eliminating all limitations associated with it, such as specific bias voltage requirement, limited Q-factor, technology/process uncertainties, model accuracy etc. Wide tuning range of 8-14 GHz ...

A test-chip for exploring the possibility of implementing RFID on a new 0.5-μm gate-array technology, with 20-μm Si substrates, is presented. It comprises of 4 transmitter circuits based on two ring oscillators and two cross-coupled oscillators. The design strategy adopted ensures simplicity in circuit design and a wide tuning range to account for the uncertainty implicated by the new technolog...

We present results on the development of a novel micromachined parallel-plate tunable capacitor with a wide tuning range. Different from conventional two-parallel-plate tunable capacitors, this novel tunable capacitor consists of one suspended top plate and two fixed bottom plates. One of the two fixed plates and the top plate form a variable capacitor, where as the other fixed plate and the to...