Effects of a sound source moving in a vertical plane on postural responses in humans.

The effects of moving sound sources on postural responses were studied. Sound source movement was simulated by sequential switching of loudspeakers located along an arch positioned in the sagittal plane relative to the subject. The total durations of the sound stimulus movement were 1.

The effects of moving sound images on postural responses and the head rotation illusion in humans.

The results of pilot studies on the effects of sound images moving in the horizontal plane on poststimulus responses and the head rotation illusion are presented. These phenomena are demonstrated to occur.

The role of phase changes in sound signals in localization of sound sources.

The auditory system in humans and animals makes virtually no discrimination of phase changes in the structure of monaurally presented sound signals. However, electrophysiological studies have demonstrated marked changes in the responses of the central parts of the auditory system when the phase structure of the signal changes during presentation of the same type of stimulation. We have suggested that this inconsistency is due to the preparative role of phase effects during monaural stimulation for subsequent operations in the auditory system involved in determining the location of a sound source in space.

Changes in evoked potentials during the action of sound signals with different localizing characteristics.

This report presents results of studies of the phenomenon of mismatch negativity (MMN) during exposure to four blocks of sound stimuli each containing identical standards creating an immobile sound image located along the midline of the head and one of a set of deviants, creating a sound image located either by the left ear or moving from the midline of the head towards the left ear or in the opposite direction. All deviants induced mismatch negativity; the minimal amplitude and longest latent period were seen in the mismatch negativity produced by the deviant modeling movement of the sound image from the midline of the head to the left ear. The question of the appearance of mismatch negativity as a criterion for the accurate discrimination of signals with different localizing characteristics is discussed.

Properties of derived cochlear action potentials in forward tonal masking in guinea pigs.

Chronic experiments on guinea pigs were used to study the characteristics of cochlear nerve action potentials and the derived potential in conditions of forward masking. The auditory nerve action potential was recorded from the round window of the cochlea. The derived potential was obtained by subtracting the action potential recorded with masking from the response obtained in silence.