Biology subjects

Boehler, N. C.

Publications and source records attributed to Boehler, N. C..

2 recordsLinked to original sources

bioRxiv2024

The interplay of spontaneous pupil-size fluctuations and EEG power in near-threshold detection

Detection of near-threshold stimuli depends on the properties of the stimulus and the state of the observer. In visual detection tasks, improved sensitivity is associated with larger pre-stimulus pupil size. However, it is still unclear whether this association is due to optical effects (more light entering the eye), correlations with arousal, correlations with cortical excitability (as reflected in alpha power), or a mix of these. To better understand this, we investigated the relative contributions of pupil size and power in the alpha, beta, and theta frequency bands on near-threshold detection. We found that larger pre-stimulus pupil size is associated with improved sensitivity and a more liberal criterion (the likelihood of reporting that a stimulus was detected). Importantly, the relationship between pupil size and sensitivity was not mediated by any of the measured neural variables; the relationship with criterion however was mediated by power in the beta band (12-30 Hz). Pupil size was positively correlated with power in the alpha and beta bands. Additionally, we show that pre-stimulus theta suppression (4 - 8 Hz) is associated with improved sensitivity and a more liberal criterion. Taken together, our results show an independent effect of pupil size on detection sensitivity that is not driven by cortical excitability, but may be driven by optical effects, arousal, or a mix of both.

neuroscience↗

bioRxiv2024

Mind the instructions: reward cues are liked first, wanted later

Current theories propose that mental effort is invested only when the anticipated benefits, such as rewards, outweigh the associated costs, like task difficulty. Yet, it remains unclear whether this motivational and mitigating aspect of reward processing is reflected in the evaluation of reward/difficulty cues as such, and to what extent it depends on task experience. In a pre-registered experiment (N=84), we used the affect misattribution procedure (AMP) to gauge affective evaluations of nonword cues predicting reward and task difficulty levels. Contrary to previous studies, the AMP was administered at the outset, after cue instructions, and after the cues were used in a random dot motion (RDM) task. Compared to baseline, cues predicting a larger reward were evaluated more positively after RDM task experience, and most importantly, already after cue instructions, with no difference between the two phases. This evaluative effect manifested in increased performance after larger reward cues in the RDM task. Our results suggest that AMP effects may generally capture performance expectations which are independent of task experience. Importantly, these instructed expectations of reward and difficulty play a crucial role in the evaluation and subsequent investment of mental effort.

animal behavior and cognition↗