Auditory event-related potentials during a spatial working memory task.

OBJECTIVE: Sensory cortical activity can be jointly governed by bottom-up (e.g. stimulus features) and top-down (e.g. memory, attention) factors. We tested the hypothesis that auditory sensory cortical activity is affected by encoding and retrieval of spatial information. METHODS: Auditory event-related potentials (ERPs) were recorded during working memory and passive listening conditions. Trials contained three noise bursts (two "items" at different locations, followed by a "probe"). In the working memory task subjects determined if the probe matched an item location. The influence of long-term memory was evaluated by training to one location that was always a non-match. Auditory ERPs were analyzed to items and probes (N100, P200, late positive wave-LPW). RESULTS: Reaction times varied significantly among probes (trained non-match