37 research outputs found

    Visually-guided Attention Enhances Target Identification in a Complex Auditory Scene

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    In auditory scenes containing many similar sound sources, sorting of acoustic information into streams becomes difficult, which can lead to disruptions in the identification of behaviorally relevant targets. This study investigated the benefit of providing simple visual cues for when and/or where a target would occur in a complex acoustic mixture. Importantly, the visual cues provided no information about the target content. In separate experiments, human subjects either identified learned birdsongs in the presence of a chorus of unlearned songs or recalled strings of spoken digits in the presence of speech maskers. A visual cue indicating which loudspeaker (from an array of five) would contain the target improved accuracy for both kinds of stimuli. A cue indicating which time segment (out of a possible five) would contain the target also improved accuracy, but much more for birdsong than for speech. These results suggest that in real world situations, information about where a target of interest is located can enhance its identification, while information about when to listen can also be helpful when targets are unfamiliar or extremely similar to their competitors

    Auditory cortex spatial sensitivity sharpens during task performance.

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    Activity in the primary auditory cortex (A1) is essential for normal sound localization behavior, but previous studies of the spatial sensitivity of neurons in A1 have found broad spatial tuning. We tested the hypothesis that spatial tuning sharpens when an animal engages in an auditory task. Cats performed a task that required evaluation of the locations of sounds and one that required active listening, but in which sound location was irrelevant. Some 26-44% of the units recorded in A1 showed substantially sharpened spatial tuning during the behavioral tasks as compared with idle conditions, with the greatest sharpening occurring during the location-relevant task. Spatial sharpening occurred on a scale of tens of seconds and could be replicated multiple times in ∼1.5-h test sessions. Sharpening resulted primarily from increased suppression of responses to sounds at least-preferred locations. That and an observed increase in latencies suggest an important role of inhibitory mechanisms
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