Use Of Different Stimuli Research Articles

Hierarchical peroxiredoxin assembly through orthogonal pH-response and electrostatic interactions.

Morpheeins are proteins that adapt their morphology and function to the environment. Therefore, their use in nanotechnology opens up the bottom-up preparation of anisotropic metamaterials, based on the sequential use of different stimuli. A prominent member of this family of proteins is peroxiredoxins (Prx), with dual peroxidase and chaperone function, depending on the pH of the media. At high pH, they show a toroidal morphology that turns into tubular stacks upon acidification. While the toroidal conformers have been explored as building blocks to yield 1D and 2D structures, the obtention of higher ordered materials remain unexplored. In this research, the morpheein behaviour of Prx is exploited to yield columnar aggregates, that are subsequently self-assembled into 3D anisotropic bundles. This is achieved by electrostatic recognition between the negatively charged protein rim and a positively charged porphyrin acting as molecular glue. The subsequent and orthogonal input lead to the alignment of the monodimensional stacks side-by-side, leading to the precise assembly of this anisotropic materials.

Influence of task instructions and stimuli on the neural network of face processing: An ALE meta-analysis

Many neuroimaging studies have investigated the neural correlates of face processing. However, the location of face-preferential regions differs considerably between studies, possibly due to the use of different stimuli or tasks. By using Activation likelihood estimation meta-analyses, we aimed to a) delineate regions consistently involved in face processing and b) to assess the influence of stimuli and task on convergence of activation patterns. In total, we included 77 neuroimaging experiments in healthy subjects comparing face processing to a control condition. Results revealed a core face-processing network encompassing bilateral fusiform gyrus (FFG), inferior occipital (IOG) gyrus, superior temporal sulcus/middle temporal gyrus (STS/MTG), amygdala, inferior frontal junction (IFJ) and gyrus (IFG), left anterior insula as well as pre-supplementary motor area (pre-SMA). Furthermore, separate meta-analyses showed, that while significant convergence across all task and stimuli conditions was found in bilateral amygdala, right IOG, right mid-FFG, and right IFG, convergence in IFJ, STS/MTG, right posterior FFG, left FFG and pre-SMA differed between conditions. Thus, our results point to an occipito-frontal-amygdalae system that is involved regardless of stimulus and attention, whereas the remaining regions of the face-processing network are influenced by the task-dependent focus on specific facial characteristics as well as the type of stimuli processed.

Negative Facial Expressions - But Not Visual Scenes - Enhance Human Working Memory in Younger and Older Participants.

Many studies have investigated the influence of emotion on memory processes across the human lifespan. Some results have shown older adults (OA) performing better with positive stimuli, some with negative items, whereas some found no impact of emotional valence. Here we tested, in two independent studies, how younger adults (YA) and OA would perform in a visuospatial working memory (VSWM) task with positive, negative, and neutral images. The task consisted of identifying the new location of a stimulus in a crescent set of identical stimuli presented in different locations in a touch-screen monitor. In other words, participants should memorize the locations previously occupied to identify the new location. For each trial, the number of occupied locations increased until 8 or until a mistake was made. In study 1, 56 YA and 38 OA completed the task using images from the International Affective Picture System (IAPS). Results showed that, although YA outperformed OA, no effects of emotion were found. In study 2, 26 YA and 25 OA were tested using facial expressions as stimuli. Data from this study showed that negative faces facilitated performance and this effect did not differ between age groups. No differences were found between men and women. Taken together, our findings suggest that YA and OA’s VSWM can be influenced by the emotional valence of the information, though this effect was present only for facial stimuli. Presumably, this may have happened due to the social and biological importance of such stimuli, which are more effective in transmitting emotions than IAPS images. Critically, our results also indicate that the mixed findings in the literature about the influence of aging on the interactions between memory and emotion may be caused by the use of different stimuli and methods. This possibility should be kept in mind in future studies about memory and emotion across the lifespan.

Reprogrammable Logic Gate and Logic Circuit Based on Multistimuli-Responsive Raspberry-like Micromotors.

In this paper, we report a polymer-based raspberry-like micromotor. Interestingly, the resulting micromotor exhibits multistimuli-responsive motion behavior. Its on-off-on motion can be regulated by the application of stimuli such as H2O2, near-infrared light, NH3, or their combinations. Because of the versatility in motion control, the current micromotor has great potential in the application field of logic gate and logic circuit. With use of different stimuli as the inputs and the micromotor motion as the output, reprogrammable OR and INHIBIT logic gates or logic circuit consisting of OR, NOT, and AND logic gates can be achieved.

Stimuli-responsive behavior of composites integrating thermo-responsive gels with photo-responsive fibers

Materials that could be reconfigured multiple times into different shapes with the use of different stimuli could dramatically impact manufacturing processes.

Assessment of visual fixation in vegetative and minimally conscious states.

BackgroundVisual fixation plays a key role in the differentiation between vegetative state/unresponsive wakefulness (VS/UWS) syndrome and minimally conscious state (MCS). However, the use of different stimuli changes the frequency of visual fixation occured in patients, thereby possibly affecting the accuracy of the diagnosis. In order to establish a standardized assessment of visual fixation in patients in disorders of consciousness (DOC), we compared the frequency of visual fixation elicited by mirror,a ball and a light.MethodVisual fixation was assessed in eighty-one post-comatose patients diagnosed with a MCS or VS/UWS. Occurrence of fixation to different stimuli was analysis used Chi-square testing.Result40 (49%) out of the 81 patients showed fixation to visual stimuli. Among those, significantly more patients (39, 48%) had visual fixation elicited by mirror compared to a ball (23, 28%) and mirror compared to a light (20, 25%).ConclusionThe use of a mirror during the assessment of visual fixation showed higher positive response rate, compared to other stimuli in eliciting a visual fixating response. Therefore, fixation elicited by a mirror can be a very sensitive and accurate test to differentiate the two disorders of consciousness.

Neurosedative and antioxidant activities of phenylpropanoids from ballota nigra.

Ballota nigra is a European plant known for its neurosedative properties. In this study, the ability of five phenylpropanoids (verbascoside, forsythoside B, arenarioside, ballotetroside, and caffeoyl malic acid) isolated from a hydroalcoholic extract, to bind to benzodiazepine, dopaminergic, and morphinic receptors was investigated. To carry out these studies, affinity tests with rat striata, entire brains and receptor rich preparations were employed. In addition, the phenolic aspect of these five phenylpropanoid esters led to investigate antioxidant activities using cell-free experiments and cellular experiments including isolated polymorphonuclear neutrophils (PMN). Effects of phenylpropanoid esters against reactive oxygen species as superoxide anion, peroxide hydrogen, hypochlorous acid and hydroxyl radical were tested. These molecules are liberated by PMN during inflammatory disorders, so that reproduction of this process in vitro stimulating PMN by chemical stimulants was undertaken. Results show that four of the five compounds are able to bind to the studied receptors. Inhibitory concentrations at 50% were determined and vary from 0.4 to 4.7 mg/ml. This may be in relation with the Ballota nigra known neurosedative activities. Results concerning antioxidant investigations evidence an ability to scavenge reactive oxygen species. Inhibitory concentrations at 50% obtained are comparable to those of known antioxidant drugs (mesna or N-acetyl cysteine). Moreover, the use of different stimuli having various pathways of action on PMN oxidative metabolism permits to establish that each phenylpropanoid ester has its own particular way of action by using proteine kinase C or phospholipase C pathways.

Reorganization of Equivalence Classes After Reversal of Baseline Relations

Pilgrim and Galizio (1995) reversed baseline conditional discriminations after the emergence of equivalence classes. College students' performance was consistent with the reversed baselines in subsequent symmetry tests, but was consistent with pre reversal baselines in transitivity tests. The present study replicated systematically Pilgrim and Galizio's experiment. Following the emergence of two four-members equivalence classes, 9 college students were exposed to reversal of a baseline conditional discrimination, training of a new conditional discrimination, reversal of another baseline conditional discrimination, and return to the original baseline. Both symmetry and transitivity performances were consistent with the reversed baselines for most participants. These results may be due to increased strength of the reversed baselines, trained with continuous reinforcement and reviewed before probes, whereas Pilgrim and Galizio trained reversals with intermittent reinforcement in the context of probing. The use of different stimuli and stimulus display may have also affected the results.

A Novel Demonstration of Enhanced Memory Associated with Emotional Arousal

The relationship between emotional arousal and long-term memory is addressed in two experiments in which subjects viewed either a relatively emotionally neutral short story (presented as a brief slide show) or a closely matched but more emotionally arousing story and were tested for retention of the story 2 weeks later. Experiment 1 provides essential replication of the results of Heuer and Reisberg (1990) and illustrates the common interpretive problem posed by the use of different stimuli (slides) in the neutral versus emotional stories. In Experiment 2, identical slides (and sequence) were used in both the neutral and arousal stores. Two different stories were created by varying the narration that accompanied each slide. In both experiments, subjects who viewed the arousal story both experienced a greater emotional reaction to the story than did the subjects who viewed the neutral story, and subsequently exhibited enhanced memory for the story. Subjects in Experiment 2 who viewed the arousal story also recalled more slides than did the subjects who viewed the neutral story. This effect was greatest for story phase 2, the phase in which the emotional slide narration occurred. Because this enhanced retention of the story slides cannot be explained by any differences in the slides themselves, the results provide new evidence to support the contention that emotional arousal influences long-term memory in normal human subjects.

Psychological reactivity to discrepant events: Support for the curvilinear hypothesis

80 male and 60 female infants were observed under 5 a priori judged levels of discrepancy to assess whether sustained attention was linearly or curvilinearly related to degree of discrepancy from an experimental standard. Following habituation, 7 1 2 -month-old infants were exposed to either the repetition of the standard, a minimal, first- or second-level moderate discrepancy, or a novel stimulus having no relation to the standard. The related stimuli, varying in elongation, were sphere, pear, club, and cylinder-shaped objects; the novel stimulus was a different colored, tooth-like object. 80 infants observed the sphere as the standard and the cylinder as the second-level moderate discrepancy; 60 infants were exposed to the reverse order with the cylinder as the standard. The use of different stimuli at each discrepancy level controlled for specific stimulus effects. Habituation and recovery of responding were observed in an operant paradigm. Lever pressing, fixation, and vocalization increased most to the second-level moderate stimuli and decreased most to the familiar and novel objects; fretting was highest to the redundant stimuli and lowest to the moderate objects. There were no stimulus main effects or interactions. The results support the hypothesis of a curvilinear relation between stimulus discrepancy and sustained attention, excitement, and preference.

Attention and verbalization: Differential responsivity of cardiovascular and electrodermal systems

A recent study showed, (1) that changes in heart rate (HR) were indicators of a subject's attention: acceleratory HR corresponding to environmental rejection (thinking) and deceleratory HR to environmental intake; and (2) that skin conductance (SC) increased in both rejection and intake situations. These results were challenged by several authors who failed to find differential GSR and HR responding and who found some evidence to suggest that HR acceleration was an artifact of verbalization. In order to clarify these contradictory findings, the present study used constant stimuli for intake, rejection and verbalization conditions since the previous designs were confounded by the use of different stimuli for the various manipulations. GSR and HR were recorded from 48 male Ss who observed slides under four conditions: (1) looking at (INV: intake-no verbalization); (2) reading aloud (IV: intake-verbalization; (3) adding silently (RNV: rejection-verbalization); and (4) adding aloud (RV: rejection-verbalization). Each slide was presented for fifteen seconds and consisted of thirteen numbers arranged to elicit interest. The 48 Ss were divided into four groups of twelve with a Latin Square design utilized for presenting the four conditions (4 slides per condition) in four different orders. The analysis of the data showed that for both the SC and HR variables, responsivity differed among the four conditions. For the HR data, (1) the RV and IV conditions resulted in acceleratory changes with the RV change being greater; (2) the RNV condition resulted in virtually no change; and (3) the INV heart rate was deceleratory. The means for the amount of SC change and base HR paralleled those of the HR change with the RV condition demonstrating the greatest amount of change in SC and highest base HR, and the INV condition the smallest change in SC and the lowest base HR. Correlations among the HR changes scores across conditions showed that the changes for the INV conditions were independent of the changes for the other three conditions which were related to each other. Results of the study suggested (1) that HR changes are a function of an interaction between verbalization and attention, (2) that a modified concept of general arousal theory which posits separate arousal continuums for either situations resulting in HR acceleration or situations resulting in HR deceleration may explain previous contradictory findings and (3) that it may be profitable to classify Ss into categories of HR accelarators and HR decelerators.

An operation on dogs for obtaining pure pancreatic juice in long experiments

A method of operating on dogs has been developed in which the intestine is injured, but insignificantly, and the pancreatic and chyme secretion is not impaired. Pure pancreatic juice may be obtained with the use of different stimuli, including food. A scheme of a special fistula is given.