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The response of 835 click-sensitive neurons in the inferior colliculus (IC) to ramp frequency modulated (FM) tones was studied in the anaesthetized rat. More than 70% of the cells were sensitive to the FM sound, and over 25% were "FM specialized". Systematic variations of the stimulus parameters showed that sweep velocity, sweep range, and intensity of the(More)
A method of detecting brainstem auditory evoked potential (BAEP) using adaptive signal enhancement (ASE) is proposed and tested in humans and cats. The ASE in this system estimates the signal component of the primary input, which is correlated with the reference input to the adaptive filter. The reference input is carefully designed to make an optimal and(More)
The paper presents an adaptive Gaussian radial basis function neural network (RBFNN) for rapid estimation of evoked potential (EP). Usually, a recorded EP is severely contaminated by background ongoing activities of the brain. Many approaches have been reported to enhance the signal-to-noise ratio (SNR) of the recorded signal. However, non-linear methods(More)
The response characteristics to linear frequency sweeps were studied in two groups of FM (frequency modulation) sensitive neurons in the rat inferior colliculus. 'FM specialized' cells responded to frequency sweeps but not to pure tones. 'Mixed' cells responded to both frequency sweeps and pure tones. FM specialized cells preferred faster and broader sweeps(More)
1. Sounds reaching the tympanic membranes are first modified by the acoustic properties of the torso, head, and external ear. For certain frequencies in the incident sound there results a complex, direction-dependent spatial distribution of sound pressure at the eardrum such that, within a sound field, localized areas of pressure maxima are flanked by areas(More)
1. Listeners use direction-dependent spectral cues introduced by the torso, head, and pinnae to localize the source of a sound in space. Among the prominent direction-dependent spectral features in the free field-to-eardrum transfer function are narrow regions of low acoustic energy referred to as spectral notches. In this paper, we studied the sensitivity(More)
The present paper describes an adaptive signal enhancer (ASE) method for improving signal-to-noise ratio (SNR) and also for tracking the variation of brain-stem auditory evoked potential (BAEP). The enhancer has two inputs: a primary input which is the original data to be processed, consisting of signal badly corrupted by noise, and a reference input. A(More)
A Chinese woman had a first-episode of psychosis in the second trimester of pregnancy. The sudden onset of psychotic symptoms and fluctuating mental condition with visual hallucinations suggested an organic origin for the psychosis. Antipsychotic medication was started. Ultrasound investigation at 19 weeks of gestation revealed intrauterine growth(More)
We synthesized a set of signals (clicks) for earphone delivery whose waveforms and amplitude spectra, measured at the eardrum, mimic those of sounds arriving from a free-field source. The complete stimulus set represents 1816 sound-source directions, which together surround the head to form a 'virtual acoustic space' for the cat. Virtual-space stimuli were(More)