Biology subjects

Antono, J. E.

Publications and source records attributed to Antono, J. E..

4 recordsLinked to original sources

bioRxiv2023

Modulation of perception by visual, auditory, and audiovisual reward predicting cues

Rewards influence information processing in the primary sensory areas specialized to process stimuli from a specific sensory modality. In real life situations, we receive sensory inputs not only from one single modality, but stimuli are often multisensory. It is however not known whether the reward-driven modulation of perception follows the same principles when reward is cued through a single or multiple sensory modalities. We previously showed that task-irrelevant reward cues modulate perception both intra- as well as cross-modally, likely through a putative enhancement in the integration of the stimulus parts into a coherent object. In this study, we explicitly test this possibility by assessing whether reward enhances the integration of unisensory components of a multisensory object in accordance with the supra-additive principle of multisensory integration. Towards this aim, we designed a simple detection task using reward predicting cues that were either unisensory (auditory or visual, both above the detection threshold) or multisensory (audiovisual). We conducted two experiments, behavioral (experiment 1) and simultaneous behavioral and neuroimaging testing (experiment 2). We expected that reward speeds up reaction times in response to all stimulus configurations, and that additionally the reward effects in multisensory cues fulfill the supra-additive principle of multisensory integration. We observed that reward decreased response times in both experiments with the strongest effect found for the multisensory stimuli in experiment 1. However, this behavioral effect did not fulfill the supra-additive principle. Neuroimaging results demonstrated sensory supra-additivity at the classical areas involved in multisensory integration such as the Superior Temporal areas (STS), while reward modulation was found in the midbrain and fronto-parietal areas, reflecting the typical areas that receive dopaminergic projections. However, reward did not enhance the supra-additivity in the STS compared to a no reward condition. Instead, we observed that some of the reward-related areas showed a sub-additive modulation by rewards and areas exhibiting a weaker supra-additive response to audiovisual stimuli, namely the fusiform gyrus, were modulated by rewards of audiovisual stimuli as measured by a conjunction analysis. Overall, our results indicate that reward does not enhance the multisensory integration through a supra-additive rule. These findings inspire a model where reward and sensory integration processes are regulated by two independent mechanisms, where sensory information is integrated at an early stage in a supra-additive manner, while reward modulates perception at a later stage sub-additively. Moreover, an associative area in the Fusiform gyrus exhibits a convergence of both reward and multisensory integration signals, indicating that it may be a hub to integrate different types of signals including rewards to disambiguate the information from different sensory modalities.

neuroscience↗

bioRxiv2023

Distinct mechanisms underlie value-driven modulation of visual cortex by previously rewarded visual and auditory stimuli

Past reward associations may be signaled by stimuli from different sensory modalities, however it remains unclear how different types of reward-associated stimuli modulate perception. In this human fMRI study, we employed a paradigm involving a visual discrimination task, where a visual target was simultaneously presented with either an intra-(visual) or a cross-modal (auditory) cue that was previously associated with rewards. We hypothesized that depending on the sensory modality of the cues distinct neural pathways underlie the value-driven modulation of visual areas. Two steps of analyses were conducted: first, using a multivariate approach, we confirmed that previously reward-associated cues enhanced the target representation in the early visual areas. Then, using effective connectivity analysis, we tested three possible patterns of communication across the brain regions that could underlie the modulation of visual cortex: a direct pathway from the frontal valuation areas to the visual areas, a mediated pathway through the attention-related areas, and a mediated pathway that additionally involved distinct sensory association areas for auditory and visual rewards. We found evidence for the third model and demonstrate that reward-related information is communicated across the valuation and attention-related brain regions such as the intraparietal sulcus across for both visual and auditory cues. Additionally, the long-range communication of reward information also involved the superior temporal areas in case of auditory reward-associated stimuli. These results suggest that in the presence of previously rewarded stimuli from different sensory modalities, a combination of domain-general and domain-specific mechanisms are recruited across the brain to adjust visual processing.

neuroscience↗

bioRxiv2022

Modality-specific and modality-general representations of reward value in frontal cortex

Standard neuroeconomics theories state that the value of different classes of stimuli, for instance the hedonic value of food versus music, is transformed to a common reference scale that is independent of their sensory properties. However, adaptive behaviour in a multimodal dynamic environment requires that our brain also encodes information about the sensory features of rewarding stimuli. How these two processes, i.e. deriving a common reference scale for valuation and maintaining sensitivity to the sensory contexts for goal-directed behaviour, are implemented in the brain remains inadequately understood. Here, we acquired fMRI data while human participants were engaged in a dynamic foraging task requiring them to integrate the reward history of auditory or visual choice options and update the subjective value assigned to each sensory modality. Univariate fMRI analysis revealed modality-specific and modality-general value representations in orbitofrontal cortex (OFC) and ventromedial prefrontal cortex (vmPFC), respectively. Crucially, modality-specific value representations were absent when the task involved instruction-based rather than value-based choices. The analysis of effective connectivity further demonstrated that the modality-specific value representations emerged as a result of selective bidirectional interactions across the auditory and visual sensory cortices, the corresponding OFC clusters and the vmPFC. These results show how a valuation process that is sensitive to the sensory context of rewarding stimuli is enabled in the brain.

neuroscience↗

bioRxiv2020

Dissociable effects of subliminal incentives on initiation and velocity control of goal-directed eye movements

Over the last decades, several studies have demonstrated that conscious and unconscious reward incentives both affect performance in physical and cognitive tasks, suggesting that goal-pursuit can arise from an unconscious will. Whether the planning of goal-directed saccadic eye movements during an effortful task can also be affected by subliminal reward cues has not been systematically investigated. We employed a novel task where participants had to make several eye movements back and forth between a fixation point and a number of peripheral targets. The total number of targets visited by the eyes in a fixed amount of time determined participants monetary gain. The magnitude of the reward at stake was briefly shown at the beginning of each trial and was masked by pattern images superimposed in time. We found that when reward cues were fully visible and thus consciously perceived, higher reward enhanced all saccade parameters. However, a dissociation was observed between the effects of subliminal rewards on saccade initiation and peak velocities. While truly subliminal reward cues did increase the number of saccades, they did not enhance saccades peak velocity. Additionally, participants who had reached a truly subliminal level of reward perception showed a decrement in accuracy as a function of reward across all visibility levels, as saccade endpoint error was larger when higher reward incentives were expected. This suboptimal speed-accuracy trade-off did not occur in the supraliminal group. These results suggest that although saccades initiation can be triggered by subconscious mechanisms, conscious awareness is required to optimally adjust the velocity and accuracy of eye movements based on the expected rewards.

neuroscience↗