Learning to suppress a distractor may not be unconscious.

The additional singleton task has become a popular paradigm to explore visual statistical learning and selective attention. In this task, participants are instructed to find a different-shaped target among a series of distractors as fast as possible. In some trials, the search display includes a singleton distractor with a different color, making search more difficult. This singleton distractor appears more often in one location than in the remaining locations. The typical results of these experiments show that participants learn to ignore the area of the screen that is more likely to contain the singleton distractor. It is often claimed that this learning takes place unconsciously, because at the end of the experiment participants seem to be unable to identify the location where the singleton distractor appeared most frequently during the task. In the present study, we tested participants' awareness in three high-powered experiments using alternative measures. Contrary to previous studies, the results show clear evidence of explicit knowledge about which area of the display was more likely to contain the singleton distractor, suggesting that this type of learning might not be unconscious.

The role of working memory in probabilistic cuing of visual search.

In a typical probabilistic cuing experiment, participants are asked to find a visual target among a series of distractors. Although participants are not informed about this, the target appears more frequently in one region of the display, resulting in faster search times for targets located in this region. This bias is thought to depend on a habit-like attentional control mechanism, unconstrained by the availability of working memory (WM) resources. However, the only study that has explored this feature in the past suffers from methodological shortcomings that leave the results open to alternative explanations. In three experiments, we aimed to confirm whether probabilistic cuing is unaffected by visual, spatial, and spatiotemporal WM load. For each experiment, one group of participants performed the visual search task during the retention interval of a WM task (high-load group), whereas another group of participants (no-load group) carried out the visual search task after the WM task. We hypothesized that the probabilistic cuing effect would be larger for the no-load group compared to the high-load group. This hypothesis was confirmed in one experiment, but exploratory analyses suggest that the results can be highly dependent on the analytic approach, casting doubts on its robustness. Overall, our results provide partial support for the hypothesis that probabilistic cuing is not affected by a secondary task. However, given that some analyses reveal an effect of WM load, we conclude that it might be premature to rule out the possibility that the expression of this attentional bias requires WM resources. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The role of working memory in contextual cueing of visual attention.

It is usually easier to find objects in familiar contexts that we have seen before. The type of learning that underlies this facilitation, known as contextual cueing, has been understood as an incidental and automatic process given that, among other reasons, it seems to be independent of working memory (WM) resources. This claim has found support in previous research showing that contextual cueing can be acquired latently, while participants perform a demanding WM task. However, previous studies have not always found this pattern of results and, in general, the available evidence is far from conclusive. The aim of the present study was to clarify the role of WM in contextual learning with two large-sample, confirmatory experiments. Our results show a robust contextual cueing effect even when visuospatial working memory resources were recruited by a demanding secondary task.

Hypothalamic Crh/Avp, Plasmatic Glucose and Lactate Remain Unchanged During Habituation to Forced Exercise.

It has been demonstrated that physical activity contributes to a healthier life. However, there is a knowledge gap regarding the neural mechanisms producing these effects. One of the keystones to deal with this problem is to use training programs with equal loads of physical activity. However, irregular motor and stress responses have been found in murine exercise models. Habituation to forced exercise facilitates a complete response to a training program in all rodents, reaching the same load of physical activity among animals. Here, it was evaluated if glucose and lactate - which are stress biomarkers - are increased during the habituation to exercise. Sprague-Dawley rats received an 8-days habituation protocol with progressive increments of time and speed of running. Then, experimental and control (non-habituated) rats were subjected to an incremental test. Blood samples were obtained to determine plasmatic glucose and lactate levels before, immediately after and 30 min after each session of training. Crh and Avp mRNA expression was determined by two-step qPCR. Our results revealed that glucose and lactate levels are not increased during the habituation period and tend to decrease toward the end of the protocol. Also, Crh and Avp were not chronically activated by the habituation program. Lactate and glucose, determined after the incremental test, were higher in control rats without previous contact with the wheel, compared with habituated and wheel control rats. These results suggest that the implementation of an adaptive phase prior to forced exercise programs might avoid non-specific stress responses.