The effects of diurnal variability and modality on false memories formation.

The main objective of the current study was to investigate the effect of time of day on visual and auditory, short-term memory (STM), and long-term memory (LTM) distortions using a hybrid Deese-Roediger-McDermott procedure. In Experiment 1, we used semantically related words, whereas in Experiment 2 - words were characterized by phonological similarity. The results showed a relationship between modality and types of stimuli. In STM, more semantic errors were found in the evening for items presented visually and more errors following auditory presentation for phonologically similar words. In LTM, the analysis revealed a higher rate of semantic distortions in the evening hours for auditorily presented words. For words with phonological similarity, we observed more errors in the evening without the effect of modality. The results support the hypothesis that more reliance is placed on elaborative processing in the evening and more on maintenance processing in the morning; however, this is not modality invariant.

Dynamics of working memory process revealed by independent component analysis in an fMRI study.

Human memory is prone to errors in many everyday activities but also when cultivating hobbies such as traveling and/or learning a new language. For instance, while visiting foreign countries, people erroneously recall foreign language words that are meaningless to them. Our research simulated such errors in a modified Deese-Roediger-McDermott paradigm for short-term memory with phonologically related stimuli aimed at uncovering behavioral and neuronal indices of false memory formation with regard to time-of-day, a variable known to influence memory. Fifty-eight participants were tested in a magnetic resonance (MR) scanner twice. The results of an Independent Component Analysis revealed encoding-related activity of the medial visual network preceding correct recognition of positive probes and correct rejection of lure probes. The engagement of this network preceding false alarms was not observed. We also explored if diurnal rhythmicity influences working memory processes. Diurnal differences were seen in the default mode network and the medial visual network with lower deactivation in the evening hours. The GLM results showed greater activation of the right lingual gyrus, part of the visual cortex and the left cerebellum in the evening. The study offers new insight into the mechanisms associated with false memories, suggesting that deficient engagement of the medial visual network during the memorization phase of a task results in short-term memory distortions. The results shed new light on the dynamics of working memory processes by taking into account the effect of time-of-day on memory performance.

The relation between the depth of pigment disposition and men's skin thickness, the age and tattoo locations on the body.

The most important function of the skin is to protect the body against harmful mechanical, physical and chemical factors. Its regenerative capacity is sufficient for self-repair in the event of damage, for example, during tattooing, which can be treated as an invasive procedure introducing pigment molecules into skin layers. In the present research on tattoo pigment deposition, the structure of the dermis and epidermis was evaluated using the standard histological technique with hematoxylin and eosin staining. In addition, statistically significant differences between the depth of pigment deposition on the one hand and age, dermis and epidermis thickness and tattoo location on the other were demonstrated.

Meaningful Versus Meaningless Sounds and Words.

The current study assessed memory performance for perceptually similar environmental sounds and speech-based material after short and long delays. In two studies, we demonstrated a similar pattern of memory performance for sounds and words in short-term memory, yet in long-term memory, the performance patterns differed. Experiment 1 examined the effects of two different types of sounds: meaningful (MFUL) and meaningless (MLESS), whereas Experiment 2 assessed memory performance for words and nonwords. We utilized a modified version of the classical Deese-Roediger-McDermott (Deese, 1959; Roediger & McDermott, 1995) procedure and adjusted it to test the effects of acoustic similarities between auditorily presented stimuli. Our findings revealed no difference in memory performance between MFUL and MLESS sounds, and between words and nonwords after short delays. However, following long delays, greater reliance on meaning was noticed for MFUL sounds than MLESS sounds, while performance for linguistic material did not differ between words and nonwords. Importantly, participants' memory performance for words and nonwords was accompanied by a more lenient response strategy. The results are discussed in terms of perceptual and semantic similarities between MLESS and MFUL sounds, as well as between words and nonwords.

Beyond the Low Frequency Fluctuations: Morning and Evening Differences in Human Brain.

Human performance, alertness, and most biological functions express rhythmic fluctuations across a 24-h-period. This phenomenon is believed to originate from differences in both circadian and homeostatic sleep-wake regulatory processes. Interactions between these processes result in time-of-day modulations of behavioral performance as well as brain activity patterns. Although the basic mechanism of the 24-h clock is conserved across evolution, there are interindividual differences in the timing of sleep-wake cycles, subjective alertness and functioning throughout the day. The study of circadian typology differences has increased during the last few years, especially research on extreme chronotypes, which provide a unique way to investigate the effects of sleep-wake regulation on cerebral mechanisms. Using functional magnetic resonance imaging (fMRI), we assessed the influence of chronotype and time-of-day on resting-state functional connectivity. Twenty-nine extreme morning- and 34 evening-type participants underwent two fMRI sessions: about 1 h after wake-up time (morning) and about 10 h after wake-up time (evening), scheduled according to their declared habitual sleep-wake pattern on a regular working day. Analysis of obtained neuroimaging data disclosed only an effect of time of day on resting-state functional connectivity; there were different patterns of functional connectivity between morning (MS) and evening (ES) sessions. The results of our study showed no differences between extreme morning-type and evening-type individuals. We demonstrate that circadian and homeostatic influences on the resting-state functional connectivity have a universal character, unaffected by circadian typology.

Assessing the role of bed sediments in the persistence of red mud pollution in a shallow lake (Kinghorn Loch, UK).

Red mud is a by-product of alumina production. Little is known about the long-term fate of red mud constituents in fresh waters or of the processes regulating recovery of fresh waters following pollution control. In 1983, red mud leachate was diverted away from Kinghorn Loch, UK, after many years of polluting this shallow and monomictic lake. We hypothesised that the redox-sensitive constituents of red mud leachate, phosphorus (P), arsenic (As) and vanadium (V), would persist in the Kinghorn Loch for many years following pollution control as a result of cycling between the lake bed sediment and the overlying water column. To test this hypothesis, we conducted a 12-month field campaign in Kinghorn Loch between May 2012 and April 2013 to quantify the seasonal cycling of P, As, and V in relation to environmental conditions (e.g., dissolved oxygen (DO) concentration, pH, redox chemistry and temperature) in the lake surface and bottom waters. To confirm the mechanisms for P, As and V release, a sediment core incubation experiment was conducted using lake sediment sampled in July 2012, in which DO concentrations were manipulated to create either oxic or anoxic conditions similar to the bed conditions found in the lake. The effects on P, As, and V concentrations and species in the water column were measured daily over an eight-day incubation period. Phosphate (PO4-P) and dissolved As concentrations were significantly higher in the bottom waters (75.9 ± 30.2 µg L-1 and 23.5 ± 1.83 µg L-1, respectively) than in the surface waters (12.9 ± 1.50 µg L-1 and 14.1 ± 2.20 µg L-1, respectively) in Kinghorn Loch. Sediment release of As and P under anoxic conditions was confirmed by the incubation experiment and by the significant negative correlations between DO and P and As concentrations in the bottom waters of the lake. In contrast, the highest dissolved V concentrations occurred in the bottom waters of Kinghorn Loch under oxic conditions (15.0 ± 3.35 µg L-1), with the release from the bed sediment apparently being controlled by a combination of competitive ion concentrations, pH and redox conditions.

Assessing the Legacy of Red Mud Pollution in a Shallow Freshwater Lake: Arsenic Accumulation and Speciation in Macrophytes.

Little is known about long-term ecological responses in lakes following red mud pollution. Among red mud contaminants, arsenic (As) is of considerable concern. Determination of the species of As accumulated in aquatic organisms provides important information about the biogeochemical cycling of the element and transfer through the aquatic food-web to higher organisms. We used coupled ion chromatography and inductively coupled plasma mass spectrometry (ICP-MS) to assess As speciation in tissues of five macrophyte taxa in Kinghorn Loch, U.K., 30 years following the diversion of red mud pollution from the lake. Toxic inorganic As was the dominant species in the studied macrophytes, with As species concentrations varying with macrophyte taxon and tissue type. The highest As content measured in roots of Persicaria amphibia (L.) Gray (87.2 mg kg(-1)) greatly exceeded the 3-10 mg kg(-1) range suggested as a potential phytotoxic level. Accumulation of toxic As species by plants suggested toxicological risk to higher organisms known to utilize macrophytes as a food source.

Do Format Differences in the Presentation of Information Affect Susceptibility to Memory Distortions? The Three-Stage Misinformation Procedure Reconsidered.

To date most studies within the misinformation paradigm have used the visual presentation of a to-be-remembered event that is later tested verbally or visually. However, the well-established encoding specificity hypothesis predicts that congruence between encoding and test phases should lead to fewer memory errors. In Study 1, we examined the susceptibility to misinformation after encoding original information in 1 of 4 different formats: as a film, slides, and as a written or auditory narrative. All participants were tested verbally, and those who encoded original information pictorially (as a video or slides) were more likely to incorrectly accept verbally suggested information. This might be-a consequence of encoding-retrieval format match. In Study 2, using either verbal or pictorial modality during encoding, postevent information, and test (fully crossed design), we partially supported the encoding-retrieval format match hypothesis; however, auditory presentation of original or postevent information modified the effect, showing that a memory trace created after auditory description was the strongest.

Misremembering what you see or hear: Dissociable effects of modality on short- and long-term false recognition.

False working memories readily emerge using a visual item-recognition variant of the converging associates task. Two experiments, manipulating study and test modality, extended prior working memory results by demonstrating a reliable false recognition effect (more false alarms to associatively related lures than to unrelated lures) within seconds of encoding in either the visual or auditory modality. However, false memories were nearly twice as frequent when study lists were seen than when they were heard, regardless of test modality, although study-test modality mismatch was generally disadvantageous (consistent with encoding specificity). A final experiment that varied study-test modality using a hybrid short- and long-term memory test (Flegal, Atkins & Reuter-Lorenz, 2010) replicated the auditory advantage in the short term but revealed a reversal in the long term: The false memory effect was greater in the auditory study-test condition than in the visual study-test condition. Thus, the same encoding conditions gave rise to an opposite modality advantage depending on whether recognition was tested under short-term or long-term memory conditions. Although demonstrating continuity in associative processing across delay, the results indicate that delay condition affects the availability of modality-dependent features of the memory trace and, thus, distinctiveness, leading to dissociable patterns of short- and long-term memory performance.

Encoding strategy affects false recall and recognition: Evidence from categorical study material.

The present research investigated memory vulnerability to distortions. Different encoding strategies were used when categorized lists were studied. The authors assumed that an imagery strategy would be responsible for decreasing false memories more than a word-whispering strategy, which is consistent with the model of semantic access and previous research in the Deese-Roediger-McDermott paradigm (the DRM paradigm; Deese, 1959; Roediger & McDermott, 1995). A normative study of category lists and 4 experiments were conducted to verify the memory vulnerability to different encoding strategies (imagery, word-whispering, control). Half of subjects recalled and half recognized previously studied words. The results revealed a marked reduction in false recognition and recall after imagery encoding, relative to after word-whispering encoding.

Opposite effect of capsaicin and capsazepine on behavioral thermoregulation in insects.

Transient receptor potential channels are implicated in thermosensation both in mammals and insects. The aim of our study was to assess the effect of mammalian vanilloid receptor subtype 1 (TRPV1) agonist (capsaicin) and antagonist (capsazepine) on insect behavioral thermoregulation. We tested behavioral thermoregulation of mealworms larvae intoxicated with capsaicin and capsazepine in two concentrations (10(-7) and 10(-4) M) in a thermal gradient system for 3 days. Our results revealed that in low concentration, capsaicin induces seeking lower temperatures than the ones selected by the insects that were not intoxicated. After application of capsazepine in the same concentration, the mealworms prefer higher temperatures than the control group. The observed opposite effect of TRPV1 agonist and antagonist on insect behavioral thermoregulation, which is similar to the effect of these substances on thermoregulation in mammals, indicates indirectly that capsaicin may act on receptors in insects that are functionally similar to TRPV1.

Vanilloid receptors--comparison of structure and functions in mammals and invertebrates.

The vanilliod receptor subfamily belongs to the transient receptor potential family of ion channels. Vanilloid receptors are calcium-permeable channels highly expressed in many different cells, both excitable and nonexcitable, in invertebrates (nematodes, insects) and vertebrates (mammals). These receptors are sensitive to a wide range of stimuli (chemical, mechanical, osmotic and temperature) that often activate the same channel. This review focuses on recent information, both bibliographic and experimental evidence of the author, concerning the structure and functions of vanilloid receptors, especially those connected with thermoregulation.