Metacognitive Awareness of Difficulty in Action Selection: The Role of the Cingulo-opercular Network

The question whether and how we are able to monitor our own cognitive states (metacognition) has been a matter of debate for decades. Do we have direct access to our cognitive processes, or can we only infer them indirectly based on their consequences? In the current study, we wanted to investigate the brain circuits that underlie the metacognitive experience of fluency in action selection. To manipulate action-selection fluency, we used a subliminal response priming paradigm. On each trial, both male and female human participants additionally engaged in the metacognitive process of rating how hard they felt it was to respond to the target stimulus. Despite having no conscious awareness of the prime, results showed that participants rated incompatible trials (during which subliminal primes interfered with the required response) to be more difficult than compatible trials (where primes facilitated the required response), reflecting metacognitive awareness of difficulty. This increased sense of subjective difficulty was mirrored by increased activity in the rostral cingulate zone and the anterior insula, two regions that are functionally closely connected. Importantly, this reflected activations that were unique to subjective difficulty ratings and were not explained by RTs or prime–response compatibility. We interpret these findings in light of a possible grounding of the metacognitive judgment of fluency in action selection in interoceptive signals resulting from increased effort.

Thematic bootstrapping: Performance differences between expert chess players and novices

Previous research has revealed that memory-based processes are one of the most consistent differences between a novice and a chess expert. The current study used a priming task in 57 adults to investigate whether priming improves the accuracy in finding the best candidate move for a given chess configuration. The stimuli were theme-based chess configurations that served as the prime and target during the procedure. Results indicated for experts that accurate processing of a prime's theme in a congruent trial results in a response priming effect, that is, more correct answers and a decrease in response time. The theoretical implications along with the possible applications of the results are discussed.

Two sides of the same story in grapevine–pathogen interactions

Proteases are an integral part of plant defence systems, and their role in plant–pathogen interactions is unequivocal. Emerging evidence suggests that different protease families contribute to the establishment not only of hypersensitive response, priming, and signalling, but also of recognition events through complex proteolytic cascades. Moreover, they play a crucial role in pathogen/microbe-associated molecular pattern (PAMP/MAMP)-triggered immunity as well as in effector-triggered immunity. However, despite important advances in our understanding of the role of proteases in plant defence, the contribution of proteases to pathogen defence in grapevine remains poorly understood. In this review, we summarize current knowledge of the main grapevine pathosystems and explore the role of serine, cysteine, and aspartic proteases from both the host and pathogen point of views.

Non-Thermal Plasma—A New Green Priming Agent for Plants?

Since the earliest agricultural attempts, humankind has been trying to improve crop quality and yields, as well as protect them from adverse conditions. Strategies to meet these goals include breeding, the use of fertilisers, and the genetic manipulation of crops, but also an interesting phenomenon called priming or adaptive response. Priming is based on an application of mild stress to prime a plant for another, mostly stronger stress. There are many priming techniques, such as osmopriming, halopriming, or using physical agents. Non-thermal plasma (NTP) represents a physical agent that contains a mixture of charged, neutral, and radical (mostly reactive oxygen and nitrogen species) particles, and can cause oxidative stress or even the death of cells or organisms upon interaction. However, under certain conditions, NTP can have the opposite effect, which has been previously documented for many plant species. Seed surface sterilization and growth enhancement are the most-reported positive effects of NTP on plants. Moreover, some studies suggest the role of NTP as a promising priming agent. This review deals with the effects of NTP treatment on plants from interaction with seed and cell surface, influence on cellular molecular processes, up to the adaptive response caused by NTP.

Visual Awareness Is Essential for Grouping Based on Mirror Symmetry

We examined whether symmetry-based grouping can take place in the absence of visual awareness. To this end, we used a priming paradigm, sandwich masking as an invisibility-inducing method, and primes and targets composed of two vertical symmetric or asymmetric lines. The target could be congruent or incongruent with the prime in symmetry. In Experiment 1, participants were presented with masked primes and clearly visible targets. In each trial, the participants performed a two-alternative discrimination task on the target, and then rated the visibility of the prime on a subjective visibility four-point scale (used to assess prime awareness). Subjectively invisible primes failed to produce response priming, suggesting that symmetry processing might depend on visual awareness. However, participants barely saw the prime, and the results for the visible primes were inconclusive, even when we used a conservative criterion for awareness. To rule out the possibility that our prime stimuli could not produce priming per se, we conducted a control visibility experiment (Experiment 2), in which participants were presented with unmasked, clearly visible primes and performed a target task. The results showed that our primes could elicit significant response priming when visible. Taken together, our findings indicate that symmetry-based grouping requires visual awareness.

Perceived and one’s own motion in response priming

In response priming, motor pre-activations from a prime to the response to a target can be measured, as a function of whether they require the same (compatible) or different (incompatible) responses. With moving primes and static arrow targets, the results depend on the stimulus onset asynchrony between prime and target: with short SOAs, there were faster responses to compatible than incompatible targets, with longer SOAs, the pattern reverses. However, this reversal was not found with more biological motions. The current study comprised 3 experiments in order to replicate several findings from previous research and add evidence regarding the interplay of one’s own and perceived motions. Subjects performed a response priming task with moving prime stimuli while in motion themselves. With this paradigm, we tested the general influence of motion on responding and compatibility effects in response priming with moving prime stimuli. Furthermore, we assessed specific interactions of features of the perceived stimuli (e.g., moving vs. static; direction of the prime or target) and the own motion (e.g., walking vs. standing; direction of being rotated). We used two different own motions (walking on a treadmill, Exp. 1 & 3; rotating in a human gyroscope, Exp. 2) and two different visual stimulus types (rows-of-dots, Exp. 1 & 2; point light displays, Exp. 3). Compatibility effects were, in general, neither increased nor decreased during motion. Their size depended on the stimulus type, the velocity of one’s own motion, and several interactions of perceived and own motion. We discuss our findings with respect to perception-action interactions and previous findings on response priming with moving prime stimuli.