PREFRONTAL AND POSTERIOR CORTICAL ACTIVATION DURING AUDITORY WORKING-MEMORY

The present study investigated brain mechanisms underlying auditory me mory. In a modified Stemberg memory scanning task, 11 subjects indicat ed whether a probe sound was part of a previously presented 4-item mem ory set by a button press. Behaviorally, subjects responded fastest an d most accurately to probes that matched the last memory set items and slowest and least accurately to negative probes and to positive probe s to the first two memory set items. Electrophysiologically, probes to the last memory set items' elicited the largest amplitude and earlies t latency P3 components while other probes elicited smaller amplitude, prolonged P3s as well as a negativity around 400 ms. These results su ggest that subjects utilized a trace strength/self-terminating search model to perform the memory scanning task. Subjects only generated the P3 component during the matching phase of the auditory memory task wh ile a sustained frontal negativity was elicited during both the encodi ng and matching phase. Taken together these findings provide evidence of differential activation of distributed neural activity during non-l inguistic auditory memory.