Metacognitive awareness in the sound-induced flash illusion.

Hundreds (if not thousands) of multisensory studies provide evidence that the human brain can integrate temporally and spatially discrepant stimuli from distinct modalities into a singular event. This process of multisensory integration is usually portrayed in the scientific literature as contributing to our integrated, coherent perceptual reality. However, missing from this account is an answer to a simple question: how do confidence judgements compare between multisensory information that is integrated across multiple sources, and multisensory information that comes from a single, congruent source in the environment? In this paper, we use the sound-induced flash illusion to investigate if confidence judgements are similar across multisensory conditions when the numbers of auditory and visual events are the same, and the numbers of auditory and visual events are different. Results showed that congruent audiovisual stimuli produced higher confidence than incongruent audiovisual stimuli, even when the perceptual report was matched across the two conditions. Integrating these behavioural findings with recent neuroimaging and theoretical work, we discuss the role that prefrontal cortex may play in metacognition, multisensory causal inference and sensory source monitoring in general. This article is part of the theme issue 'Decision and control processes in multisensory perception'.

The effects of clearcut harvesting on moss chloroplast lipidome and adaptation to light stress during boreal forest regeneration.

Moss plays an important role in boreal forest ecosystems as an understory bryophyte species. Clearcut harvesting is a common boreal forest regeneration method that can expose understory vegetation to abiotic stressors impeding their recovery following post-harvest conditions. Very little is known concerning how moss remodel their chloroplast lipidome to enhance photosynthetic performance for successful acclimation to light and water stress during boreal forest regeneration following clearcut harvesting. The chloroplast lipidome and photosynthetic performance of Sphagnum sp. and three feathermoss species (Pleurozium schreberi, Hylocomium splendens, and Ptilium crista-castrensis) from a boreal black spruce (Picea mariana) forest were assessed using liquid chromatography-mass spectrometry (LC-MS), photospectrometry, and light response curves. We observed an overall increase in monogalactosyldiacylglycerol (MGDG) and sulfoquinovosyldiacylglycerol (SQDG) and decrease in digalactosyldiacylglycerol (DGDG) and phosphatidylglycerol (PG). In addition, unsaturation of the chloroplast lipidome occurred concomitant with photoprotection by carotenoid pigments to enhance the efficiency and photosynthetic capacity in moss exposed to light and water stress following clearcut harvesting. This appears to be a successful acclimation strategy used by moss to circumvent light stress during boreal forest regeneration following clearcut harvesting. These findings could be of significance in the development of boreal forest management strategies following resource harvesting.

The Effects of Cold Saponification on the Unsaponified Fatty Acid Composition and Sensory Perception of Commercial Natural Herbal Soaps.

Saponification is the process in which triglycerides are combined with a strong base to form fatty acid metal salts during the soap-making process. The distribution of unsaturated and saturated fatty acid determines the hardness, aroma, cleansing, lather, and moisturizing abilities of soaps. Plant extracts, such as rosemary, vegetable, and essential oils are frequently added to soaps to enhance quality and sensory appeal. Three natural soaps were formulated using cold saponification to produce a base or control bar (BB), hibiscus rosehip bar (H), and a forest grove bar (FG). Rosemary extract (R) or essential oil (A) blends were added as additives to each formulation prior to curing to evaluate the effects of natural plant additives on the lipid composition and sensory characteristics of these natural herbal soaps. A total of seven natural soaps, three without additives (BB, H, FG) and four with additives (BBR, HA, FGR, FGA), were manufactured and studied. The majority (86⁻99%) of the polyunsaturated fatty acids (5.0⁻7.0 µg/mg) remained unsaponified in the manufactured natural soaps regardless of feedstock used. Principal component analysis (PCA) analyses showed the unsaponifiable fatty acids were different in the hibiscus bar compared to the other bars. There was a very strong correlation between the content of unsaponified C18:3n3 and C18:1n9 in all natural soaps. These results indicate that unsaponified fatty acids are important contributors to the quality and overall sensory perception and preference of natural herbal soaps following manufacturing by cold saponification.