Changes in neural readout of response magnitude during auditory streaming do not correlate with behavioral choice in the auditory cortex

Abstract

Although previous studies have identified neural mechanisms that may underlie auditory scene analysis, the relationship between these mechanisms and behavior remains elusive. To fill these gaps, we recorded multiunit activity (MUA) from the posterior and anterior auditory fields while monkeys participated in an auditory streaming task. We found that MUA magnitude was reduced as the streaming stimulus unfolded over time, and this reduction depended on the frequency difference between the tone bursts comprising the streaming stimulus. We then examined whether this frequency-dependent reduction in activity could be utilized by downstream neurons to read out "one stream" versus "two streams" and found that, as the frequency difference increased, an ideal observer consistently classified neural activity as "two streams". However, because this classification was not modulated by the monkeys choices, it suggests that this activity may not reflect the segregation of stimuli into perceptually distinct auditory streams but may simply reflect bottom-up processes.