Auditory Decisions Research Articles

Modality independent or modality specific? Common computations underlie confidence judgements in visual and auditory decisions.

The mechanisms that enable humans to evaluate their confidence across a range of different decisions remain poorly understood. To bridge this gap in understanding, we used computational modelling to investigate the processes that underlie confidence judgements for perceptual decisions and the extent to which these computations are the same in the visual and auditory modalities. Participants completed two versions of a categorisation task with visual or auditory stimuli and made confidence judgements about their category decisions. In each modality, we varied both evidence strength, (i.e., the strength of the evidence for a particular category) and sensory uncertainty (i.e., the intensity of the sensory signal). We evaluated several classes of computational models which formalise the mapping of evidence strength and sensory uncertainty to confidence in different ways: 1) unscaled evidence strength models, 2) scaled evidence strength models, and 3) Bayesian models. Our model comparison results showed that across tasks and modalities, participants take evidence strength and sensory uncertainty into account in a way that is consistent with the scaled evidence strength class. Notably, the Bayesian class provided a relatively poor account of the data across modalities, particularly in the more complex categorisation task. Our findings suggest that a common process is used for evaluating confidence in perceptual decisions across domains, but that the parameter settings governing the process are tuned differently in each modality. Overall, our results highlight the impact of sensory uncertainty on confidence and the unity of metacognitive processing across sensory modalities.

Nigrostriatal dopamine pathway regulates auditory discrimination behavior

The auditory striatum, the tail portion of dorsal striatum in basal ganglia, is implicated in perceptual decision-making, transforming auditory stimuli to action outcomes. Despite its known connections to diverse neurological conditions, the dopaminergic modulation of sensory striatal neuronal activity and its behavioral influences remain unknown. We demonstrated that the optogenetic inhibition of dopaminergic projections from the substantia nigra pars compacta to the auditory striatum specifically impairs mouse choice performance but not movement in an auditory frequency discrimination task. In vivo dopamine and calcium imaging in freely behaving mice revealed that this dopaminergic projection modulates striatal tone representations, and tone-evoked striatal dopamine release inversely correlated with the evidence strength of tones. Optogenetic inhibition of D1-receptor expressing neurons and pharmacological inhibition of D1 receptors in the auditory striatum dampened choice performance accuracy. Our study uncovers a phasic mechanism within the nigrostriatal system that regulates auditory decisions by modulating ongoing auditory perception.

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.

Dentate granule cells encode auditory decisions after reinforcement learning in rats

Auditory-cued goal-oriented behaviors requires the participation of cortical and subcortical brain areas, but how neural circuits associate sensory-based decisions with goal locations through learning remains poorly understood. The hippocampus is critical for spatial coding, suggesting its possible involvement in transforming sensory inputs to the goal-oriented decisions. Here, we developed an auditory discrimination task in which rats learned to navigate to goal locations based on the frequencies of auditory stimuli. Using in vivo calcium imaging in freely behaving rats over the course of learning, we found that dentate granule cells became more active, spatially tuned, and responsive to task-related variables as learning progressed. Furthermore, only after task learning, the activity of dentate granule cell ensembles represented the navigation path and predicts auditory decisions as early as when rats began to approach the goals. Finally, chemogenetic silencing of dentate gyrus suppressed task learning. Our results demonstrate that dentate granule cells gain task-relevant firing pattern through reinforcement learning and could be a potential link of sensory decisions to spatial navigation.

Auditory decisions in the supplementary motor area.

In human speech and communication across various species, recognizing and categorizing sounds is fundamental for the selection of appropriate behaviors. However, how does the brain decide which action to perform based on sounds? We explored whether the supplementary motor area (SMA), responsible for linking sensory information to motor programs, also accounts for auditory-driven decision making. To this end, we trained two rhesus monkeys to discriminate between numerous naturalistic sounds and words learned as target (T) or non-target (nT) categories. We found that the SMA at single and population neuronal levels perform decision-related computations that transition from auditory to movement representations in this task. Moreover, we demonstrated that the neural population is organized orthogonally during the auditory and the movement periods, implying that the SMA performs different computations. In conclusion, our results suggest that the SMA integrates acoustic information in order to form categorical signals that drive behavior.

On auditory choreography: How walking anticipates sound and movement resonates

Abstract Benjamin Vandewalle and Yoann Durant label their performance as an auditory choreography. Starting from an elaboration on the etymology of choreography I research what the auditory dimension adds and changes to choreography. Choreographing based on auditory decisions inverses sound and movement. This inversion has consequences from the process to the end result. Based on the sonic quality as main decision principle I unravel the creation process of Hear in seven main action: to stand, to walk, to breathe, to look, to move, to disappear and to sound. This division reveals how the actual choreographing doesn't stop at the end of the creation process. In the second half of the paper, I turn to the experience of an auditory choreography, where the body of the audience functions as a resonance box. The discomfort of a blindfold during the experience, leads to the installation of a delicate intimacy and reveals the close connection between sound, touch and movement. The precariousness of the installed intimacy triggers and enforces the audience imagination. Through my own experience of Hear I discover how the audience in an auditory choreography becomes a co-creator.

Auditory Perceptual History Is Propagated through Alpha Oscillations.

SummaryPerception is a proactive, “predictive” process, in which the brain relies, at least in part, on accumulated experience to make best guesses about the world to test against sensory data, updating the guesses as new experience is acquired. Using novel behavioral methods, the present study demonstrates the role of alpha rhythms in communicating past perceptual experience. Participants were required to discriminate the ear of origin of brief sinusoidal tones that were presented monaurally at random times within a burst of uncorrelated dichotic white noise masks. Performance was not constant but varied with delay after noise onset in an oscillatory manner at about 9 Hz (alpha rhythm). Importantly, oscillations occurred only for trials preceded by a target tone to the same ear, either on the previous trial or two trials back. These results suggest that communication of perceptual history generates neural oscillations within specific perceptual circuits, strongly implicating behavioral oscillations in predictive perception and with formation of working memory.

Post-decision processing in primate prefrontal cortex influences subsequent choices on an auditory decision-making task.

Perceptual decisions do not occur in isolation but instead reflect ongoing evaluation and adjustment processes that can affect future decisions. However, the neuronal substrates of these across-decision processes are not well understood, particularly for auditory decisions. We measured and manipulated the activity of choice-selective neurons in the ventrolateral prefrontal cortex (vlPFC) while monkeys made decisions about the frequency content of noisy auditory stimuli. As the decision was being formed, vlPFC activity was not modulated strongly by the task. However, after decision commitment, vlPFC population activity encoded the sensory evidence, choice, and outcome of the current trial and predicted subject-specific choice biases on the subsequent trial. Consistent with these patterns of neuronal activity, electrical microstimulation in vlPFC tended to affect the subsequent, but not current, decision. Thus, distributed post-commitment representations of graded decision-related information in prefrontal cortex can play a causal role in evaluating past decisions and biasing subsequent ones.

Choice-Selective Neurons in the Auditory Cortex and in Its Striatal Target Encode Reward Expectation.

Learned behavioral responses to sounds depend largely on the expected outcomes associated with each potential choice. Where and how the nervous system integrates expectations about reward with auditory sensory information to drive appropriate decisions is not fully understood. Using a two-alternative choice task in which the expected reward associated with each sound varied over time, we investigated potential sites along the corticostriatal pathway for the integration of sound signals, behavioral choice, and reward information in male mice. We found that auditory cortical neurons encode not only sound identity, but also the animal's choice and the expected size of reward. This influence of reward expectation on sound- and choice-related activity was further enhanced in the major striatal target of the auditory cortex: the posterior tail of the dorsal striatum. These results indicate that choice-specific information is integrated with reward signals throughout the corticostriatal pathway, potentially contributing to adaptation in sound-driven behavior.SIGNIFICANCE STATEMENT Learning and maintenance of sensory-motor associations require that neural circuits keep track of sensory stimuli, choices, and outcomes. It is not clear at what stages along the auditory sensorimotor pathway these signals are integrated to influence future behavior in response to sounds. Our results show that the activity of auditory cortical neurons and of their striatal targets encodes the animals' choices and expectation of reward, in addition to stimulus identity. These results challenge previous views of the influence of motor signals on auditory circuits and identifies potential loci for integration of task-related information necessary for updating auditory decisions in changing environments.

Stable representation of sounds in the posterior striatum during flexible auditory decisions

The neuronal pathways that link sounds to rewarded actions remain elusive. For instance, it is unclear whether neurons in the posterior tail of the dorsal striatum (which receive direct input from the auditory system) mediate action selection, as other striatal circuits do. Here, we examine the role of posterior striatal neurons in auditory decisions in mice. We find that, in contrast to the anterior dorsal striatum, activation of the posterior striatum does not elicit systematic movement. However, activation of posterior striatal neurons during sound presentation in an auditory discrimination task biases the animals’ choices, and transient inactivation of these neurons largely impairs sound discrimination. Moreover, the activity of these neurons during sound presentation reliably encodes stimulus features, but is only minimally influenced by the animals’ choices. Our results suggest that posterior striatal neurons play an essential role in auditory decisions, and provides a stable representation of sounds during auditory tasks.

ERPs reveal weaker effects of spelling on auditory rhyme decisions in children than in adults.

A classic finding in psycholinguistics is that orthographic form influences the processing of auditory words. The aim of the present study was to examine how reading experience changes this effect. Specifically, we tested the prediction that top-down visual modulation of spoken word recognition is reduced in children compared to adults, owing to their reduced experience with print. Event-related potentials (ERPs) were measured as 8-10-year-old children and adults made rhyme decisions about spoken word pairs that were either orthographically similar or dissimilar. When orthography did not conflict (e.g., throat-boat), both age groups demonstrated a robust rhyme effect marked by greater N400 to no-rhyme versus rhyme trials. For rhyming trials that differed in orthography (e.g., vote-boat) and non-rhyming trials that shared orthography (e.g., warm-farm), adults showed more interference than children. Differences in orthographic interference suggest an extended developmental schedule for top-down mechanisms in speech recognition.

Confidence as a Common Currency between Vision and Audition.

The idea of a common currency underlying our choice behaviour has played an important role in sciences of behaviour, from neurobiology to psychology and economics. However, while it has been mainly investigated in terms of values, with a common scale on which goods would be evaluated and compared, the question of a common scale for subjective probabilities and confidence in particular has received only little empirical investigation so far. The present study extends previous work addressing this question, by showing that confidence can be compared across visual and auditory decisions, with the same precision as for the comparison of two trials within the same task. We discuss the possibility that confidence could serve as a common currency when describing our choices to ourselves and to others.

Causal contribution of primate auditory cortex to auditory perceptual decision-making.

Auditory perceptual decisions are thought to be mediated by the ventral auditory pathway. However, the specific and causal contributions of different brain regions in this pathway, including the middle-lateral (ML) and anterolateral (AL) belt regions of the auditory cortex, to auditory decisions have not been fully identified. To identify these contributions, we recorded from and microstimulated ML and AL sites while monkeys decided whether an auditory stimulus contained more low-frequency or high-frequency tone bursts. Both ML and AL neural activity was modulated by the frequency content of the stimulus. However, only the responses of the most stimulus-sensitive AL neurons were systematically modulated by the monkeys’ choices. Consistent with this observation, microstimulation of AL—but not ML—systematically biased the monkeys’ behavior toward the choice associated with the preferred frequency of the stimulated site. Together, these findings suggest that AL directly and causally contributes sensory evidence used to form this auditory decision.

Relating Pupil Dilation and Metacognitive Confidence during Auditory Decision-Making.

The sources of evidence contributing to metacognitive assessments of confidence in decision-making remain unclear. Previous research has shown that pupil dilation is related to the signaling of uncertainty in a variety of decision tasks. Here we ask whether pupil dilation is also related to metacognitive estimates of confidence. Specifically, we measure the relationship between pupil dilation and confidence during an auditory decision task using a general linear model approach to take into account delays in the pupillary response. We found that pupil dilation responses track the inverse of confidence before but not after a decision is made, even when controlling for stimulus difficulty. In support of an additional post-decisional contribution to the accuracy of confidence judgments, we found that participants with better metacognitive ability – that is, more accurate appraisal of their own decisions – showed a tighter relationship between post-decisional pupil dilation and confidence. Together our findings show that a physiological index of uncertainty, pupil dilation, predicts both confidence and metacognitive accuracy for auditory decisions.

Corticostriatal neurons in auditory cortex drive decisions during auditory discrimination

The neural pathways by which information about the acoustic world reaches the auditory cortex are well characterised, but how auditory representations are transformed into motor commands is not known. Here we have used a perceptual decision-making task to study this transformation. We directly demonstrate the role of corticostriatal projection neurones in auditory decisions by specifically manipulating the activity of these neurones in rats performing an auditory frequency discrimination task. Targeted Channelrhodopsin-21,2 (ChR2)-mediated stimulation of corticostriatal neurones during the task biased decisions in the direction predicted by the frequency tuning of the stimulated neurones, whereas archaerhodopsin-33 (Arch)-mediated inactivation biased decisions in the opposite direction. Striatal projections are widespread in cortex and may provide a general mechanism for the control of motor decisions by sensory cortex.

Maximum capacity for sequential one-bit auditory decisions.

Studied the maximum intrinsic rate of channel intermittency for sequential decisions in 9 21-30 yr. old Ss, each submitted to about 30 runs of a simple, externally paced task. Any run consisted of a series of 150 stimuli delivered at a regular interval between 2 and .15 sec. 50% of the stimuli were nonsignal clicks randomly mixed with the signal clicks (20-30 db. higher in intensity) to which S was asked to press a Morse key. Analysis of data on hits and false alarms showed that the achieved decisional rate started to lag behind the required rate at about 1.1/sec and it reached a maximum for rates of stimulus presentation of 3-5/sec. The mean maximum rate of correct decisions under such steady-state sensory overload was estimated by 4 methods as 2.15, 2.33, 2.64, and 2.64/sec. The maximum rate is related to decisional rather than to motor effector limitations and may reflect a basic perceptual mechanism of the brain, as suggested from correlative studies on cerebral evoked potentials. (21 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1970 American Psychological Association.