Suriya-Arunroj, L. | bioRxiv Science

bioRxiv2026

Different Sources of Expectations Differentially Modulate Communication Between Auditory and Prefrontal Cortices During Auditory Decision-Making

Perceptual decisions can be influenced by expectations that arise from different sources. However, relatively little is known about how and where in the brain these different sources affect decision formation, particularly in the auditory system. To begin to address this question, we recorded local field potentials (LFPs) simultaneously from the auditory cortex (AC) and ventrolateral prefrontal cortex (vlPFC) while monkeys performed an auditory frequency-discrimination task. We manipulated their expectations by presenting either informative cues (LEDs that predicted the target frequency) or uninformative cues (tone sequences that did not predict the target frequency) prior to target onset. Both cues had similar effects on the monkeys accuracy and response times but induced distinct neurophysiological signatures. Coherence, a measure of undirected coupling, between AC and vlPFC increased from cue to target presentation on informative trials but decreased from cue to target presentation on uninformative trials. Phase-slope index (PSI), a measure of directed coupling, between AC and vlPFC was strongest when the target tone contradicted expectations, particularly for ambiguous stimulus conditions when expectations were most valuable. These expectation-dependent changes in the magnitude of functional connectivity also included changes in its spatial organization. Together, these findings provide new insights into how different expectations can dynamically reconfigure functional connectivity between cortical brain areas to support different task demands and behavioral outcomes.

neuroscience↗

bioRxiv2021

Rule-based and stimulus-based cues bias auditory decisions via different computational and physiological mechanisms

Expectations, such as those arising from either learned rules or recent stimulus regularities, can bias subsequent auditory perception in diverse ways. However, it is not well understood if and how these diverse effects depend on the source of the expectations. Further, it is unknown whether different sources of bias use the same or different computational and physiological mechanisms. We examined how rule-based and stimulus-based expectations influenced behavior and pupil- linked arousal, a marker of certain forms of expectation-based processing, of human subjects performing an auditory frequency-discrimination task. Rule-based cues consistently biased choices and response times (RTs) toward the more-probable stimulus. In contrast, stimulus-based cues had a complex combination of effects, including choice and RT biases toward and away from the frequency of recently presented stimuli. These different behavioral patterns also had: 1) distinct computational signatures, including different modulations of key components of a novel form of a drift-diffusion decision model and 2) distinct physiological signatures, including substantial bias- dependent modulations of pupil size in response to rule-based but not stimulus-based cues. These results imply that different sources of expectations can modulate auditory processing via distinct mechanisms: one that uses arousal-linked, rule-based information and another that uses arousal- independent, stimulus-based information to bias the speed and accuracy of auditory perceptual decisions. Author summaryPrior information about upcoming stimuli can bias our perception of those stimuli. Whether different sources of prior information bias perception in similar or distinct ways is not well understood. We compared the influence of two kinds of prior information on tone-frequency discrimination: rule-based cues, in the form of explicit information about the most-likely identity of the upcoming tone; and stimulus-based cues, in the form of sequences of tones presented before the to-be-discriminated tone. Although both types of prior information biased auditory decision- making, they demonstrated distinct behavioral, computational, and physiological signatures. Our results suggest that the brain processes prior information in a form-specific manner rather than utilizing a general-purpose prior. Such form-specific processing has implications for understanding decision biases real-world contexts, in which prior information comes from many different sources and modalities.

neuroscience↗