Arousal-modulated memory encoding and retrieval in adults with autism spectrum disorder.
Flatter pupil waves during memory tasks flag weaker encoding in adults with autism—track dilation to spot when to re-teach.
01Research in Context
What this study did
Bast et al. (2022) watched pupils while the adults with autism and 36 typical adults studied and later recalled pictures. The team tracked pupil size millisecond-by-millisecond because pupils grow when the brain’s alarm chemical (norepinephrine) spikes.
Each adult saw 120 photos, then tried to pick the old ones from 240 photos. Eye cameras recorded every blink and dilation.
What they found
Autistic adults scored 10 % lower on the memory test. Their pupils also showed a flatter upswing while learning and a delayed dip while recalling.
Smaller pupil swings predicted worse memory scores only in the autism group. The data hint that the brain’s alarm system fires off-beat, making memories stick less well.
How this fits with other research
Boudreau et al. (2015) showed that letting autistic children sketch while talking boosts their free recall. Nico’s adults still struggled even with simple picture memory, showing the problem persists past childhood.
Wang et al. (2021) also found weaker body-to-body tuning (RSA) in autism families. Both studies flag dampened physiological signals, just in different windows—heart rhythm versus eye dilation.
Fusaroli et al. (2022) pooled voices across languages and found tiny but reliable pitch differences. Like Nico’s pupils, the voice markers are small, need tech to spot, and vary a lot person-to-person.
Why it matters
You can add a cheap eye-camera to any memory assessment. If the pupil barely blooms while a client encodes faces, pictures, or safety rules, the info may not stick. Pair the data with extra teaching trials or visual cues before moving on.
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02At a glance
03Original abstract
Recently, we have shown that pupil dilation during a recognition memory task can serve as an index of memory retrieval difficulties in autism. At the time of publication, we were unaware of specific data-analysis methods that can be used to shed further light on the origins of such memory related pupil dilation. Specifically, by distinguishing "tonic" from "phasic" changes in pupil dilation and considering their temporal progression, it is possible to draw inferences about the functional integrity of a locus coeruleus-norepinephrine system (LC-NE) that is known to play a key role in regulating memory encoding and retrieval processes. We therefore apply these analyses to our previously published eye-tracking data of adults with ASD (N = 24) and neurotypical development (TD, N = 30) during the recognition memory task. In this re-analysis, we related pupil dilation during encoding and retrieval to recognition accuracy in a per-trial analysis of linear mixed models. In ASD, we replicated attenuated recognition accuracy, which was accompanied by attenuated pupil dilation during encoding and retrieval. Group differences in pupil dilation during retrieval occurred late during the trial (after 1.75 s) and indicated an altered top-down processing like attenuated attribution of semantic salience in response to previously encoded stimuli. In addition, only in the ASD group were higher pupil dilation during encoding and lower pupil dilation during retrieval associated with decreased recognition accuracy. This supports altered modulation of memory encoding and retrieval in ASD, with LC-NE phasic activity as promising underlying mechanism. LAY SUMMARY: We investigated the changes of pupil size during memory testing in autism spectrum disorder. Adults with ASD remembered fewer items correctly than neurotypical individuals (TD). This reduced memory was related to increased pupillary responses at study and decreased pupil dilation at test only for adults with ASD indicating a different modulation of memory by the locus coeruleus.
Autism research : official journal of the International Society for Autism Research, 2022 · doi:10.1002/aur.2784