Biology subjects

Sperandio, I.

Publications and source records attributed to Sperandio, I..

3 recordsLinked to original sources

bioRxiv2025

Pre-conscious reactions to faces as the biological roots of emotion perception

Bodies respond to others emotions through subtle physiological changes. Whether these responses require conscious emotion recognition is debated. Here, we examined the relationship between visual awareness and physiological arousal in response to emotional faces. We recorded facial electromyography (EMG), electrodermal activity (EDA), and pupil dilation during the presentation of fearful, happy, and neutral faces, as well as their phase-scrambled versions, to the left eye. Meanwhile, rapidly changing Mondrian patterns were displayed to the right eye to suppress the left-eye stimuli. Participants pressed a button when they noticed a change from the flickering mask. This setup allowed us to compare behavioural and physiological responses during conscious versus subconscious processing of emotional content. Results showed faster breakthrough times for happy faces and moderate physiological responses to emotional information, even without conscious perception. Specifically, pupils and facial EMG were more responsive to fearful than to happy or neutral expressions. EDA was higher for faces compared to control stimuli, regardless of the emotional expression. Once visual awareness was established, emotional expressions elicited distinct responses that aligned with the perceived emotion. An exploratory analysis revealed a negative correlation between pupil dilation and autistic, alexithymic, and schizotypal traits, whereas empathy traits correlated positively. Our findings highlight the role of subcortical visual processing in detecting emotionally relevant stimuli and show that social abilities are linked to the physiological processing of emotions at a subconscious level. They underscore how subcortical mechanisms interact with the autonomic nervous system, enhancing our understanding of the biological foundations of emotion perception.

neuroscience↗

bioRxiv2025

Perspective matters: using past experiences to understand others' insensitivity to physical pain.

Prior research has shown that autobiographical memory (AM) supports empathy, allowing individuals to use the self as a model for understanding others. However, when the subjective experience of an event diverges between observer and target, relying on AM may hinder empathic processes, rather than support them. In this study, we recorded electroencephalographic (EEG) data from 36 healthy young adults during a pain decision task to investigate empathy for individuals described as either sensitive to physical pain (like the participants) or clinically insensitive to physical pain. Participants reported lower empathy for insensitive than for sensitive targets, regardless of whether they had personally experienced the specific event that caused physical pain. Event-related potential (ERP) analyses revealed differences in neural responses to sensitive and insensitive targets at a late stage of processing, in the discending phase of the P300 component; these differences were positively correlated with individual differences in empathy. To determine the underlying mechanisms, we applied multivariate pattern analysis (MVPA) to assess whether empathy for physical painrelies on AM reactivation or instead engages active perspective taking. We observed that AM reactivation can serve as a flexible mechanism that supports empathy by enabling observers to shift perspective when direct experiential overlap is lacking.

neuroscience↗

bioRxiv2018

Temporal evolution from retinal image size to perceived size in human visual cortex

Our visual system affords a distance-invariant percept of object size by integrating retinal image size with viewing distance (size constancy). Single-unit studies with animals have shown that real changes in distance can modulate the firing rate of neurons in primary visual cortex and even subcortical structures, which raises an intriguing possibility that the required integration for size constancy may occur in the initial visual processing in V1 or even earlier. In humans, however, EEG and brain imaging studies have typically manipulated the apparent (not real) distance of stimuli using pictorial illusions, in which the cues to distance are sparse and not congruent. Here, we physically moved the monitor to different distances from the observer, a more ecologically valid paradigm that emulates what happens in everyday life. Using this paradigm in combination with electroencephalography (EEG), we were able for the first time to examine how the computation of size constancy unfolds in real time under real-world viewing conditions. We showed that even when all distance cues were available and congruent, size constancy took about 150 ms to emerge in the activity of visual cortex. The 150-ms interval exceeds the time required for the visual signals to reach V1, but is consistent with the time typically associated with later processing within V1 or recurrent processing from higher-level visual areas. Therefore, this finding provides unequivocal evidence that size constancy does not occur during the initial signal processing in V1 or earlier, but requires subsequent processing, just like any other feature binding mechanisms.

neuroscience↗