Leonie Polzer

Autism Spectrum Disorder (ASD) is associated with altered attentional function. This has been associated with enhanced visual search performance. Addressing a gap in the literature, we investigate the longitudinal development of visual search alongside ASD symptoms. Using eye‐tracking, we studied performance in a single‐feature visual search task with visual search accuracy and time to target. We investigated preschoolers with ASD ( n = 60, age = 47 months) and a cohort of developmental age‐matched typically developing (TD) children ( n = 50, age = 35 months) at baseline and after approximately 3 years. We further explored associations of visual search performance with parent‐reported ASD symptom domains. Both groups showed similar visual search accuracy and time to target at baseline. At the 3‐year follow‐up, the ASD group showed significantly lower visual search accuracy and shorter time to target than the TD group. Within the ASD cohort, higher accuracy and shorter time to target were associated with higher social communication impairments. The often‐reported ASD advantage in visual search may not be as pronounced as assumed to differentiate between ASD and neurotypical development. It may also be dependent on the measure reported. More accurate and faster search may be associated with certain symptom severity profiles of ASD, supporting broad heterogeneity in the autism spectrum.

Background: Altered social cognition in autism may be influenced by difficulties in domain‐general functions, such as selective attention. Here, we manipulated the requirement for selective attention during a visual perspective taking (VPT) task and used neurophysiological indices to delineate underlying mechanisms. Methods: 43 autistic and 38 neurotypical children and youth completed a VPT paradigm. Participants' and an avatar's perspectives were either congruent or incongruent, manipulating the demand for selective attention to inhibit irrelevant information processing. Group differences in dependence on the attended perspective and congruency were examined for behavioral performance, event‐related potentials (ERPs), and in a subsample, stimulus‐evoked pupil response (SEPR). Results: Autistic participants showed reduced accuracy when rating an avatar's perspective and pronounced perspective‐related differences in a late‐frontal slow wave (LFSW). Incongruency elicited stronger effects on behavioral performance and LFSW in autistic relative to neurotypical participants. Additionally, generally larger and more sustained SEPR was observed for autistic participants, reflecting an alteration that was dissociable from LFSW differences. Across groups, SEPR and ERP measures explained both distinct and partially overlapping variance in response slowing. Conclusions: Findings support attenuated VPT abilities and difficulties to deploy selective attention in autistic youth. Altered fronto‐cortical activation patterns in the LFSW likely reflect an increased top‐down involvement in VPT. Concurrently, pupil responses indicate an increased cognitive effort when reporting visual perspectives. Findings emphasize a co‐characterization of social cognition difficulties by social and domain‐general functions in autism.

Background: Sensory processing requires selectivity to salient sensory input. Many autistic individuals report different sensory processing, which has been associated with altered sensory selectivity. The locus-coeruleus norepinephrine (LC-NE) system modulates the neuronal gain of sensory input, which represents a neurophysiological mechanism of sensory selectivity. In autistic individuals, we hypothesized that LC-NE tonic upregulation reduces sensory selectivity and underlies different sensory processing. Methods: Autistic (n = 139) and non-autistic (n = 98) individuals were assessed during a passive auditory oddball task with pupillometry and electroencephalography. For every trial, a baseline pupil size (BPS) assessed LC-NE tonic activity that coincides with current arousal, while a stimulus-evoked pupillary response (SEPR) assessed LC-NE phasic activity that estimated sensory selectivity. Electroencephalography assessed amplitudes of mismatch negativity (MMN-amp) that estimated pre-attentive change detection as a brain-activity readout of sensory selectivity. Measures were modeled between groups within the task by combining Frequentist and Bayesian approaches. Results: Across groups, higher BPS was associated with more negative MMN-amp to standards and oddballs. A more negative MMN-amp to standards was associated with a higher SEPR to standards. Controlling for these associations, autistic versus non-autistic individuals showed a higher SEPR in response to standards. In addition, a positive association of BPS and SEPR to standards was specific to autistic individuals. With task progression, autistic versus non-autistic individuals showed a higher initial increase and subsequently steeper decrease of BPS. This was supported by Bayesian posterior distribution estimates. Limitations: A short trial duration required concatenating trials to epochs and applying a linear-time invariant filter to capture the slow pupil changes. Without an LC-NE manipulation, we cannot rule out that pupil changes are evoked by other cortical pathways than the LC-NE. Conclusions: Across groups, LC-NE tonic upregulation is emphasized as a general mechanism that un-specifically increases pre-attentive change detection to all sensory stimuli, which then increases sensory selectivity to frequent stimuli. In autistic individuals, different sensory processing is characterized by increased sensory selectivity to frequent stimuli. This is likely caused by an LC-NE tonic upregulation. It associates autistic sensory processing with increased arousal upregulation that increases sensory selectivity to inconspicuous auditory information.

Previous work has shown that the eye’s pupil dilates briefly after salient auditory stimuli, reflecting a transient orienting response to sensory input. Here we studied this phenomenon in 4-6-month-old infants, including how the pupillary orienting response habituates to repeated stimulus presentations. While infants were observing a continuous visual action, an auditory stimulus was either coinciding with a distinct visual event (multisensory condition) or was played out of sync with visual events (unisensory condition). The shape of the pupil response following the auditory cue differed markedly between the two conditions, indicating that the two elicited distinct types of sensory processing. Irrespective of condition, we found some evidence that the pupil dilation diminished over stimulus presentations, indicating habituation. This study provides new insights into contextual modulation of auditory processing in human infants and provides novel leads on how pupillometry can help expand the methodological toolbox in developmental science.

Attenuated social attention has been described as a reduced preference for social compared to geometric motion in preschoolers with autism spectrum disorder (ASD). The locus coeruleus‐norpinephrine (LC‐NE) system modulates sensory reactivity and is a promising underlying mechanism. LC‐NE activity is indexed by a stimulus‐evoked pupillary response (SEPR) and partially by a luminance‐adaptation pupillary response (LAPR), which were both shown to be aberrant in ASD. We examined whether SEPR and LAPR explain an attenuated social motion preference. We applied pupillometry via video‐based eye tracking in young children (18–65 months) with ASD (n = 57) and typically developing (TD) children (n = 39) during a preferential looking paradigm of competing social and geometric motion and a changing light condition paradigm. We found an attenuated social motion preference in the ASD compared to the TD group. This was accompanied by atypical pupillometry showing a smaller SEPR to social motion, a larger SEPR to geometric motion and a reduced LAPR to a dark screen. SEPR but not LAPR explained the group difference in social motion preference. An ASD diagnosis was statistically predicted by the social motion preference, while this effect was mediated by the inclusion of SEPR to geometric and social motion. Our findings suggest a decreased sensory reactivity to social and increased reactivity to non‐social motion in ASD, which may concurrently contribute to an attenuated social attention. The LC‐NE system is supported as a promising underlying mechanism of altered social attention in young children with ASD, while the specificity of findings remains to be addressed.