When unexpected sounds disrupt eye movements...

Our recent work on the inhibition of eye movements by auditory distraction has just been accepted for publication in Psychophysiology.

Part of our results. Aggregate sound novelty distraction effect on the Sacadic Reaction Time (SRT) in anti- and pro-saccade conditions. Relative to a control, standard, condition, the unexpected sounds significantly delay saccades in both tasks but more so in the anti-saccade task. (Figure by Martin Vasilev)

Abstract: Unexpected sounds have been shown to trigger a global and transient inhibition of motor responses. Recent evidence suggests that the movement of the eyes may also be inhibited in a similar way, but it is not clear how quickly unexpected sounds can affect eye-movement responses. Additionally, little is known about whether they affect only voluntary saccades or also reflexive saccades. In this study, participants performed a pro-saccade and an anti-saccade task while the timing of sounds relative to stimulus onset was manipulated. Pro-saccades are generally reflexive and stimulus-driven, whereas anti-saccades require the generation of a voluntary saccade in the opposite direction of a peripheral stimulus. Unexpected novel sounds inhibited the execution of both pro- and anti-saccades compared to standard sounds, but the inhibition was stronger for anti-saccades. The timeline of the novelty distraction effect was relatively stable– it was observed from 150 ms before target onset to 25ms after target onset. Interestingly, unexpected sounds also reduced anti-saccade task errors, indicating that they aided inhibitory control. Overall, these results suggest that unexpected sounds yield a global and rapid inhibition of eye-movement responses. This inhibition also helps suppress reflexive eye-movement responses in favour of more voluntarily-generated ones.

Reference: Vasilev, M. R., Ozkan, Z. G., Kirkby, J. A., Nuthmann, A., & Parmentier, F. B. R. (in press). Unexpected sounds induce a rapid inhibition of eye-movement responses. Psychophysiology.

This study is part of the ongoing collaboration between Fabrice Parmentier, Martin Vasilev (UCL, UK) and Julie Kirkby (University of Bournemouth, UK) and is supported by Project PID2020-114117GB-I00 funded by MICIU/AEI /10.13039/501100011033.

Unexpected sounds hinder response repetition and help response change

The first results fron Elena García-López’s PhD research have just been published. The study investigated the modulation of motor responses by auditory distractors.

Reference: García-López, E., & Parmentier, F. B. R. (2024). Distraction by unexpected sounds: comparing response repetition and response switching. Frontiers in Psychology, 15:1451008. doi: 10.3389/fpsyg.2024.1451008

Abstract: Numerous studies using oddball tasks have shown that unexpected sounds presented in a predictable or repeated sequence (deviant vs standard sounds) capture attention and negatively impact ongoing behavioral performance. Here, we examine an aspect of this effect that has gone relatively unnoticed: the impact of deviant sounds is stronger for response repetitions than for response switches. Our approach was two-fold. First, we carried out a simulation to estimate the likelihood that stimuli sequences used in past work may not have used balanced proportions of response repetition and switch trials. More specifically, we sought to determine whether the larger distraction effect for response repetitions may have reflected a rarer, and thereby more surprising, occurrence of such trials. To do so, we simulated 10,000 stimuli sets for a 2-AFC task with a proportion of deviant trial of .1 or .16. Second, we carried out a 2-AFC oddball task in which participants judged the duration of a tone (short vs long). We carefully controlled the sequence of stimuli to ensure to balance the proportions of response repetitions and response switches across the standard and deviant conditions. The results of the stimuli simulation showed that, contrary to our concerns, response switches were more likely than response repetitions when left uncontrolled for. This suggests that the larger distraction found for response repetition in past work may in fact have been underestimated. In the tone duration judgment task, the results showed a large impact of the response type on distraction as measured by response times: Deviants sounds significantly delayed response repetitions but notably accelerated switches. These findings suggest that deviant sound hinder response repetition and encourage or bias the cognitive system towards a change of responses. We discuss these findings in relation to the adaptive nature of the involuntary detection of unexpected stimuli and in relation to the notion of partial repetition costs. We argue that results are in line with the binding account as well as with the signaling theory. 

We conducted an Ex-Gaussien analysis of response times Unexpected sounds delayed repeated responses but speeded up responses switches (mu). Longer responses tended to show lower variability (sigma). Finally, the slope of the RT distribution (tau) proved to be sensitive to auditory distraction byt independently of the type if response (switch vs repetition).

Looking for biomarkers of dementia and cognitive decline in patients with type 2 diabetes. Is the answer in the liver?

A multidisciplinary effort by Pilar Andrés and colleagues from various centers in Palma and in Madrid publishes evidence that liver fibrosis might be a valid biomarker of dementia and cognitive decline.

Reference :Pujol, A., Sanchis, P., Tamayo, M. I., Godoy, S., Calvó, P., Olmos, A., Andrés, P., Speranskaya, A., Espino, A., Estremera, A., Rigo, E., Amengual, G. J., Rodríguez, M., Ribes, J. L., Gomila, I., Grases, F., González-Freire, M., & Masmiquel, L. (2024). Metabolic-Associated Fatty Liver Disease and Cognitive Performance in Type 2 Diabetes: Basal Data from the Phytate, Neurodegeneration and Diabetes (PHYND) Study. Biomedicines, 12(9), 1993. https://doi.org/10.3390/BIOMEDICINES12091993

Abstract: The effect of liver fibrosis on mild cognitive impairment (MCI) and dementia risk in type 2 diabetes mellitus (T2DM) patients is unclear. Therefore, we performed a prospective cross-sectional study on 219 patients with T2DM and older than 60 years to evaluate the association between liver fibrosis, liver steatosis, and cognitive impairment. The Montreal Cognitive Assessment (MoCA) was used to screen for MCI or dementia. Liver fibrosis was estimated using the non-invasive Fibrosis-4 (FIB-4) score, and liver steatosis was assessed with the hepatic steatosis index. The mean age was 71 ± 6 years, 47% were women and according to MoCA cut-off values, 53.88% had MCI and 16.43% had dementia. A moderate or high risk of advanced fibrosis was significantly higher in patients with MCI or dementia compared to those with normal cognition (p < 0.001). After adjusting for confounders, a FIB-4 score greater than 1.54 was associated with MCI or dementia (p = 0.039). Multivariate analysis identified age over 70.5 years, antiplatelet medication use, and a FIB-4 score above 1.54 as the most relevant risk factors. Liver fibrosis, but not liver steatosis, is associated with MCI or dementia in older T2DM patients, suggesting that FIB-4 score might be a simple biomarker for the detection of cognitive impairment.

Perturbation of the force

Our latest research on the impact of auditory distractors on motor activity is out!

Reference: Sabu, S., Parmentier, F. B. R., & Horváth, J. (2024). Involuntary motor responses are elicited both by rare sounds and rare pitch changes. Scientific Reports 2024 14:1, 14(1), 1–12. https://doi.org/10.1038/s41598-024-70776-x

Abstract: Unpredictable deviations from an otherwise regular auditory sequence, as well as rare sounds following a period of silence, are detected automatically. Recent evidence suggests that the latter also elicit quick involuntary modulations of ongoing motor activity emerging as early as 100 ms following sound onset, which was attributed to supramodal processing. We explored such force modulations for both rare and deviant sounds. Participants (N=29) pinched a force sensitive device and maintained a force of 1-2 N for periods of 1 min. Task-irrelevant tones were presented under two conditions. In the Rare condition, 4000 Hz tones were presented every 8-to-16 s. In the Roving condition, 4000 Hz and 2996 Hz tones were presented at rate of 1 sec, with infrequent (p=1/12) frequency changes. In the Rare condition, transient force modulations were observed with a significant increase at ~234 ms, and a decrease at ~350 ms. In the Roving condition with low frequency deviant tones, an increase in force was observed at ~277 ms followed by a decrease at ~413 ms. No significant modulations were observed during perception of high frequency deviants. These results suggest that both rare silence-breaking sounds and low-pitched deviants evoke automatic fluctuations of motor responses, which opens up the possibility that these force modulations are triggered by stimulus-specific change-detection processes.

Unexpected sounds inhibit eye movements

A new study carried out in collaboration with our partners at the Unievrsity of Bournemouth (UK) shows that the presentation of unexpected sounds disrupt eye movements through their transient inhibition. This work is part of Fabrice Parmentier’s current nationally-funded project and follows up on the solid collaboration established with Prof. Julie Kirkby and Dr. Martin Vasilev.

Reference: Vasilev, M. R., Lowmann, M., Bills, K., Parmentier, F. B. R., & Kirkby, J. A. (2023). Unexpected sounds inhibit the movement of the eyes during reading and letter scanning. Psychophysiology, 023;00:e14389. doi: 10.1111/psyp.14389.

Abstract: Novel sounds that unexpectedly deviate from a repetitive sound sequence are well known to cause distraction. Such unexpected sounds have also been shown to cause global motor inhibition, suggesting that they trigger a neurophysiological response aimed at stopping ongoing actions. Recently, evidence from eye movements has suggested that unexpected sounds also temporarily pause the movements of the eyes during reading, though it is unclear if this effect is due to inhibition of oculomotor planning or inhibition of language processes. Here, we sought to distinguish between these two possibilities by comparing a natural reading task to a letter scanning task that involves similar oculomotor demands to reading, but no higher level lexical processing. Participants either read sentences for comprehension or scanned letter strings of these sentences for the letter ‘o’ in three auditory conditions: silence, standard, and novel sounds. The results showed that novel sounds were equally distracting in both tasks, suggesting that they generally inhibit ongoing oculomotor processes independent of lexical processing. These results suggest that novel sounds may have a global suppressive effect on eye-movement control