Different Types Of Stimuli Research Articles

Changes of EEG power spectrum in response to the emotional auditory stimuli in patients in acute and recovery stages of TBI (traumatic brain injury)

We investigated variability of responses to emotionally important auditory stimulation in different groups of TBI (Traumatic Brain Injury) in acute state or recovery. The patients sampling consisted of three different groups: patients in coma or vegetative state, patients with Severe and Moderate TBI in recovery period. Subjects were stimulated with auditory stimuli containing important physiological sounds (coughing, vomiting), emotional sounds (laughing, crying), nature sounds (bird song, barking), unpleasant household sounds (nails scratching the glass), natural sounds (sea, rain, fire) and neutral sounds (white noise). The background encephalographic activity was registered during at least 7 minutes. EEG was recorded while using portable device "Entsefalan". Significant differences of power of the rhythmic activity registered during the presentation of different types of stimuli were analyzed using Mathlab and Statistica 6.0. Results showed that EEG-response to the emotional stimuli differed depending on consciousness level, stimuli type, severity of TBI. Most valuable changes in EEG spectrum power for a patient with TBI were found for unpleasant auditory stimulation. Responsiveness to the pleasant stimulation could be registered in later stages of coming out of coma than to unpleasant stimulation. Alpha-activity is reducing in patients with TBI: the alpha rhythm depression is most evident in the control group, less in group after moderate TBI, and even less in group after severe TBI. Patients in coma or vegetative state didn't show any response in rhythmic power in the frequency of alpha rhythm.

Genetic association of interleukin-6 polymorphism (-174 G/C) with chronic liver diseases and hepatocellular carcinoma

Interleukin-6 (IL-6) is a pleiotropic cytokine which is expressed in many inflammatory cells in response to different types of stimuli, regulating a number of biological processes. The IL-6 gene is polymorphic in both the 5' and 3' flanking regions and more than 150 single nucleotide polymorphisms have been identified so far. Genetic polymorphisms of IL-6 may affect the outcomes of several diseases, where the presence of high levels of circulating IL-6 have been correlated to the stage and/or the progression of the disease itself. The -174 G/C polymorphism is a frequent polymorphism, that is located in the upstream regulatory region of the IL-6 gene and affects IL-6 production. However, the data in the literature on the genetic association between the -174 G/C polymorphism and some specific liver diseases characterized by different etiologies are still controversial. In particular, most of the studies are quite unanimous in describing a correlation between the presence of the high-producer genotype and a worse evolution of the chronic liver disease. This is valid for patients with hepatitis C virus (HCV)-related chronic hepatitis and liver cirrhosis and hepatocellular carcinoma (HCC) whatever the etiology. Studies in hepatitis B virus-related chronic liver diseases are not conclusive, while specific populations like non alcoholic fatty liver disease/non-alcoholic steatohepatitis, autoimmune and human immunodeficiency virus/HCV co-infected patients show a higher prevalence of the low-producer genotype, probably due to the complexity of these clinical pictures. In this direction, a systematic revision of these data should shed more light on the role of this polymorphism in chronic liver diseases and HCC.

Implicaciones clínicas del uso del tamaño pupilar como indicador de actividad psicológica: una breve revisión

Desde los años 60 la reactividad pupilar ha sido utilizada en Psicología como un indicador psicofisiológico del procesamiento cognitivo y emocional. Con el objetivo de mostrar su utilidad en la investigación psicológica, en este artículo ofrecemos un breve recorrido histórico desde los primeros y controvertidos trabajos que se centraron en estudiar el efecto que tenían diferentes tipos de estímulos en el tamaño de la pupila hasta las últimas investigaciones que han utilizado este índice como medida de procesamiento afectivo en diversos trastornos psicológicos. También se revisan los estudios que relacionan la actividad mental o carga cognitiva con procesos de dilatación pupilar y se discuten las implicaciones clínicas del uso de este sencillo indicador Since the 60's, pupil reactivity has been used in Psychology as a psychophysiological index of cognitive and emotional processing. In this paper, we provide a brief review from early and controversial studies focused on studying the effect of different types of stimuli on pupil size to the latest research that has used this index as a measure of affective processing in different psychological disorders. We also review studies that link mental activity or cognitive load with pupil dilations. We discuss the clinical implications of the use of this simple psychophysiological index.

Is there a generalized magnitude system in the brain? Behavioral, neuroimaging, and computational evidence

Some 10 years ago, it was proposed that different quantities, including time, space or number, are processed by a common mechanism (Walsh, 2003; Pinel et al., 2004; Cohen Kadosh et al., 2005), henceforth called generalized magnitude system (GMS). This presented an important attempt at theoretically integrating data across various literatures, and became very influential (e.g., Burr et al., 2010; Lourenco and Longo, 2011; Bonato et al., 2012). However, in this paper we will evaluate the concept in a critical way. We first argue that such a mechanism faces conceptual difficulties. Second, we look at empirical findings that were proposed to support a GMS and will offer a different explanation of these findings based on computational modeling and recent empirical observations. Third, we review positive evidence in favor of distinct magnitude mechanisms. We discuss alternatives for a GMS in a final paragraph.

Inhibitory Function of the Dorsomedial Hypothalamic Nucleus on the Hypothalamic–Pituitary–Adrenal Axis Response to an Emotional Stressor but not Immune Challenge

Accumulating evidence implicates the dorsomedial hypothalamic nucleus (DMH) in the regulation of autonomic and neuroendocrine stress responses. However, although projections from the DMH to the paraventricular hypothalamic nucleus (PVN), which is the critical site of the neuroendocrine stress axis, have been described, the impact of DMH neurones in the modulation of hypothalamic-pituitary-adrenal (HPA) axis activation during stress is not fully understood. The present study aimed to investigate the role of the DMH in HPA axis responses to different types of stimuli. Male Sprague–Dawley rats fitted with a chronic jugular venous catheter were exposed to either an emotional stressor (elevated platform-exposure) or immune challenge (systemic interleukin-1β administration). Bilateral electrolytic lesions of the DMH disinhibited HPA axis responses to the emotional stressor, as indicated by higher plasma adrenocorticotrophic hormone levels during and after elevated platform exposure in lesioned animals compared to sham-lesioned controls. Moreover, DMH-lesioned animals showed increased neuronal activation in the PVN, as indicated by a higher c-Fos expression after elevated-platform exposure compared to controls. By contrast, DMH-lesions had no effects on HPA axis responses to immune challenge. Taken together, our data suggest an inhibitory role of DMH neurones on stress-induced HPA axis activation that is dependent upon the nature of the stimulus being important in response to an emotional stressor but not to immune challenge.

Characterization of cognitive and motor performance during dual-tasking in healthy older adults and patients with Parkinson’s disease

The primary purpose of this study was to investigate the effect of dual-tasking on cognitive performance and gait parameters in patients with idiopathic Parkinson's disease (PD) without dementia. The impact of cognitive task complexity on cognition and walking was also examined. Eighteen patients with PD (ages 53-88, 10 women; Hoehn and Yahr stage I-II) and 18 older adults (ages 61-84; 10 women) completed two neuropsychological measures of executive function/attention (the Stroop Test and Wisconsin Card Sorting Test). Cognitive performance and gait parameters related to functional mobility of stride were measured under single (cognitive task only) and dual-task (cognitive task during walking) conditions with different levels of difficulty and different types of stimuli. In addition, dual-task cognitive costs were calculated. Although cognitive performance showed no significant difference between controls and PD patients during single or dual-tasking conditions, only the patients had a decrease in cognitive performance during walking. Gait parameters of patients differed significantly from controls at single and dual-task conditions, indicating that patients gave priority to gait while cognitive performance suffered. Dual-task cognitive costs of patients increased with task complexity, reaching significantly higher values then controls in the arithmetic task, which was correlated with scores on executive function/attention (Stroop Color-Word Page). Baseline motor functioning and task executive/attentional load affect the performance of cognitive tasks of PD patients while walking. These findings provide insight into the functional strategies used by PD patients in the initial phases of the disease to manage dual-task interference.

Evidence for central sensitization in chronic whiplash: A systematic literature review

It has been suggested that sensitization of the central nervous system plays an important role in the development and maintenance of chronic (pain) complaints experienced by whiplash patients. According to the PRISMA guidelines, a systematic review was performed to screen and evaluate the existing clinical evidence for the presence of central sensitization in chronic whiplash. DATABASES AND DATA TREATMENT: Predefined keywords regarding central sensitization and chronic whiplash were combined in electronic search engines PubMed and Web of Science. Full text clinical reports addressing studies of central sensitization in human adults with chronic complaints due to a whiplash trauma were included and reviewed on methodological quality by two independent reviewers. From the 99 articles that were identified, 24 met the inclusion criteria, and 22 articles achieved sufficient scores on methodological quality and were discussed. These studies evaluated the sensitivity to different types of stimuli (mechanical, thermal, electrical). Findings suggest that although different central mechanisms seem to be involved in sustaining the pain complaints in whiplash patients, hypersensitivity of the central nervous system plays a significant role. Persistent pain complaints, local and widespread hyperalgesia, referred pain and (thoracic) allodynia, decreased spinal reflex thresholds, inefficient diffuse noxious inhibitory controls activation and enhanced temporal summation of pain were established in chronic whiplash patients. Although the majority of the literature provides evidence for the presence of central sensitization in chronic whiplash, underlying mechanisms are still unclear and future studies with good methodological quality are necessary. In addition, international guidelines for the definition, clinical recognition, assessment and treatment of central sensitization are warranted.

Scale-invariant amplitude spectrum modulation for visual saliency detection.

Saliency detection is one of the key issues in simulating visual attention selection. Most attention models adopt the competitive structure to simulate the human visual system. Although these models provide remarkable results and convincing biological plausibility, they are still confronted with many difficulties in practical applications because of their extreme time cost and parameter sensitivity. Recently, a new saliency detection approach based on Fourier transform, as represented by spectral residual (SR) and phase Fourier transform (PFT), has been attracting much attention for its excellent accuracy and computational speed. All these models can be unified into one framework called amplitude spectrum modulation (ASM). The aim of this paper is to explore the intrinsic mechanism of ASM and develop an advanced ASM model. After analyzing SR and PFT, we give a mathematical description for the fundamental idea and the inherent limitations of the existing ASM models. A new saliency detective model, based on the scale-invariant ASM, scene and context-based modulation, and competitive structure, is also proposed breaking through the limitations of the traditional ASM models. Simulation results suggest that the proposed model is more accurate in predicting human eye fixation and is more robust against different types of stimulus when compared with competing models.

Audio-visual localization with hierarchical topographic maps: Modeling the superior colliculus

A key attribute of the brain is its ability to seamlessly integrate sensory information to form a multisensory representation of the world. In early perceptual processing, the superior colliculus (SC) takes a leading role in integrating visual, auditory and somatosensory stimuli in order to direct eye movements. The SC forms a representation of multisensory space through a layering of retinotopic maps which are sensitive to different types of stimuli. These eye-centered topographic maps can adapt to crossmodal stimuli so that the SC can automatically shift our gaze, moderated by cortical feedback. In this paper we describe a neural network model of the SC consisting of a hierarchy of nine topographic maps that combine to form a multisensory retinotopic representation of audio-visual space. Our motivation is to evaluate whether a biologically plausible model of the SC can localize audio-visual inputs live from a camera and two microphones. We use spatial contrast and a novel form of temporal contrast for visual sensitivity, and interaural level difference for auditory sensitivity. Results are comparable with the performance observed in cats where coincident stimuli are accurately localized, while presentation of disparate stimuli causes a significant drop in performance. The benefit of crossmodal localization is shown by adding increasing amounts of noise to the visual stimuli to the point where audio-visual localization significantly out performs visual-only localization. This work demonstrates how a novel, biologically motivated model of low level multisensory processing can be applied to practical, real-world input in real-time, while maintaining its comparability with biology.

Broad cortical activation in response to tactile stimulation in newborns

Tactile sensation, which is one of the earliest developing sensory systems, is very important in the perception of an individual's body and the surrounding physical environment, especially in newborns. However, currently, only little is known about the response of a newborn's brain to tactile sensation. The objective of the present study was to determine the response of a newborn's brain to tactile sensation and to compare the brain responses to various sensory stimuli. Ten healthy newborns, 2-9 days after birth, were enrolled. A multichannel near-infrared spectroscopy system was used to measure brain responses. The probe array covered broad cortical areas, including the parietal, temporal, and occipital areas. We measured cortical hemodynamic changes in response to three different types of stimuli: tactile, auditory, and visual. Activated areas were analyzed by t-tests, and the number of activated channels among the three different stimuli was compared by χ²-tests. The results showed that when the brain responded to each type of stimulation, the corresponding primary sensory area was activated, and tactile stimuli induced broader areas of brain activation than the other two types of stimuli (auditory or visual). Thus, broad brain areas, including the temporal and parietal areas, were activated by tactile stimuli in early newborn periods. These results suggest that there are differences in newborns' reactions to various types of sensory stimuli, which may reflect the importance of tactile sensation in the early newborn period.

The Role of Alveolar Epithelial Cells in Initiating and Shaping Pulmonary Immune Responses: Communication between Innate and Adaptive Immune Systems

Macrophages and dendritic cells have been recognized as key players in the defense against mycobacterial infection. However, more recently, other cells in the lungs such as alveolar epithelial cells (AEC) have been found to play important roles in the defense and pathogenesis of infection. In the present study we first compared AEC with pulmonary macrophages (PuM) isolated from mice in their ability to internalize and control Bacillus Calmette-Guérin (BCG) growth and their capacity as APCs. AEC were able to internalize and control bacterial growth as well as present antigen to primed T cells. Secondly, we compared both cell types in their capacity to secrete cytokines and chemokines upon stimulation with various molecules including mycobacterial products. Activated PuM and AEC displayed different patterns of secretion. Finally, we analyzed the profile of response of AEC to diverse stimuli. AEC responded to both microbial and internal stimuli exemplified by TLR ligands and IFNs, respectively. The response included synthesis by AEC of several factors, known to have various effects in other cells. Interestingly, TNF could stimulate the production of CCL2/MCP-1. Since MCP-1 plays a role in the recruitment of monocytes and macrophages to sites of infection and macrophages are the main producers of TNF, we speculate that both cell types can stimulate each other. Also, another cell-cell interaction was suggested when IFNs (produced mainly by lymphocytes) were able to induce expression of chemokines (IP-10 and RANTES) by AEC involved in the recruitment of circulating lymphocytes to areas of injury, inflammation, or viral infection. In the current paper we confirm previous data on the capacity of AEC regarding internalization of mycobacteria and their role as APC, and extend the knowledge of AEC as a multifunctional cell type by assessing the secretion of a broad array of factors in response to several different types of stimuli.

Maternal Consumption of High-Fat Diet Disturbs Hypothalamic Neuronal Function in the Offspring: Implications for the Genesis of Obesity

Obesity is a consequence of the loss of the coordinated control of caloric intake and energy expenditure. The homeostasis of this system and, thus, the maintenance of body mass stability depends on the activity of hypothalamic neurons, which are controlled by hormones, nutrients, environmental temperature, and physical activity, providing signals that play pivotal roles in the modulation of hunger, body temperature, motility, and storage of surplus energy (1). Leptin is the most important factor regulating the physiological response to changes in the body energy stores (2). Progressive loss of hypothalamic neuronal response to leptin is a hallmark of obesity, a condition known as hypothalamic resistance to leptin (3). This phenomenon has been characterized at the clinical and molecular levels in experimental models and described, by indirect means, in obese humans (4). As for systemic insulin resistance in type 2 diabetes, hypothalamic resistance to leptin is a consequence of the activation of an inflammatory response in the hypothalamus (5, 6). All of the currently known molecular mechanisms of leptin resistance are activated by inflammatory signals, which target the transduction of the leptin signal by a number of different means. Thus, suppressor of cytokine signaling-3 (SOCS3) can physically block the leptin receptor signal transduction and can also accelerate the proteasome degradation of important downstream targets of this pathway (7); inhibitor of B kinase, C-Jun Nterminal kinase, and protein kinase Ccan catalyze the inhibitory serine phosphorylation of intermediaries of the leptin and insulin signaling systems in the hypothalamus and can also induce the transcription of additional inflammatory genes that boost inflammation in the region (8– 10); and finally, protein tyrosine phosphatase 1B can dephosphorylate and inactivate proteins of the leptin and insulin signaling cascade (11, 12). However, it was only recently that we learned how these inflammatory pathways are triggered. The excessive dietary consumption of saturated fats, one of the most important environmental factors contributing to the global increase of obesity, leads to the activation of signal transduction through Toll-like receptor 4 (TLR4), a receptor of the innate immune system, and the induction of endoplasmic reticulum stress, a cellular mechanism of response to different types of stimuli that can disrupt the physiological protein folding capacity of the endoplasmic reticulum (9, 13). Both these mechanisms can activate inflammation and eventually apoptosis in different cell systems. So far, most studies in this field have focused on adult obesity. However, there are a number of experimental and human studies showing that maternal consumption of high-fat diets during gestation increase the risk for obesity, diabetes, and other components of the metabolic syndrome in the offspring (14, 15). In this issue of Endocrinology, Eva Rother and her colleagues (16) from the University Hospital of Cologne in Germany have evaluated the outcomes of maternal high-fat feeding during gestation and lactation on hypothalamic gene expression in the offspring. According to the experimental approach employed in the study, lean female mice were introduced to a diet containing 35% fat at detection of pregnancy and were maintained on this diet throughout gestation and lactation until

Sound reception in crabs: Keeping an ear to the wind and a leg to the ground

Event Abstract Back to Event Sound reception in crabs: Keeping an ear to the wind and a leg to the ground Micah J. Waltz1* and Jim H. Belanger1, 2 1 West Virginia University, Dept of Physiology and Pharmacology, United States 2 West Virginia University, Dept. of Biology, United States Acoustic information from the environment can exist in two different forms: medium-borne pressure waves in air or water, or vibrations traveling through a solid substrate such as rock or earth. Many animals have specialized sensors for detecting this kind of information, and using it to direct behavior. For example, some land crabs use acoustic information in mating behaviors and startle responses. They have sensors that are thought to respond to sound waves (Barth’s myochordotonal organs on the walking legs) and other sensors that are thought to respond to substrate vibration (campaniform sensillae on the dactyls). We are interested in the differing sensory capabilities of these organs, and in particular the ways that sound and vibration stimuli may be combined for behavioral decisions. As a first step in this study, we are analyzing the response characteristics of the sensors to different types of stimuli. In fiddler crabs (Uca pugnax),airborne stimulation of the membrane overlying Barth’s myochordotonal organ produces much larger responses (higher frequency and greater diversity of action potentials) than tactile stimulation of the membrane. In contrast, only tactile stimulation of the campaniform sensillae produces any response. . This suggests that the two types of organs are responding to different aspects of sound, allowing crabs to construct a fuller picture of the environment. Keywords: acoustic, crustacean, Hearing, Sound, vibrations Conference: Tenth International Congress of Neuroethology, College Park. Maryland USA, United States, 5 Aug - 10 Aug, 2012. Presentation Type: Poster (but consider for student poster award) Topic: Sensory: Audition Citation: Waltz MJ and Belanger JH (2012). Sound reception in crabs: Keeping an ear to the wind and a leg to the ground. Conference Abstract: Tenth International Congress of Neuroethology. doi: 10.3389/conf.fnbeh.2012.27.00343 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 Apr 2012; Published Online: 07 Jul 2012. * Correspondence: Mr. Micah J Waltz, West Virginia University, Dept of Physiology and Pharmacology, Morgantown, WV, 26505, United States, mwaltz@hsc.wvu.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Micah J Waltz Jim H Belanger Google Micah J Waltz Jim H Belanger Google Scholar Micah J Waltz Jim H Belanger PubMed Micah J Waltz Jim H Belanger Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Aqueous polymeric micelles of poly[N-isopropylacrylamide-b-sodium 2-(acrylamido)-2-methylpropanesulfonate] with a spiropyran dimer pendant: quadruple stimuli-responsiveness

Poly[N-isopropylacrylamide-b-sodium 2-(acrylamido)-2-methylpropane sulfonate] tagged with a spiropyran dimer at the poly(N-isopropylacrylamide) end (SP2-b-NIPAM154-b-AMPS148) was synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization to investigate multiple stimuli-responsive micelles. The micelles formed in aqueous solutions were stimulated by various chemical and physical stimuli and characterized by dynamic light scattering, scanning electron microscopy, transmission electron microscopy, UV-Vis spectroscopy and ζ-potential measurements. It was found that the block copolymer is responsive to four different types of stimulus viz. light, temperature, metal ion and pH. The NIPAM154 block gives thermo-responsiveness to the block copolymer and the AMPS148 block shows metal ion responsiveness. Due to the presence of the photochromic spiropyran moiety, the block copolymer also shows light and thermo-responsiveness. To the best of our knowledge this is the first report that deals with quadruple stimuli-responsive polymeric micelles. Such quadruple stimuli-responsive block copolymer micelles are expected to open up new applications in a variety of fields.

Lexical- and perceptual-based object effects in the two-rectangle cueing paradigm

Previous studies demonstrate that attentional selection can be object-based, in which the object is defined in terms of Gestalt principles or lexical organizations. Here we investigate how attentional selection functions when the two types of objects are manipulated jointly. Experiment 1 replicated Li and Logan (2008) by showing that attentional shift between two Chinese characters is more efficient when they form a compound word than when they form a nonword. Experiment 2A presented characters either alone or within rectangles (Egly, Driver, & Rafal, 1994) and the characters in a rectangle formed either a word or a nonword. Experiment 2B differed from Experiment 2A in that the two characters forming a word were in different rectangles. Experiment 3A presented the two characters of a word either within a rectangle or in different rectangles. Experiment 3B used the same design as Experiment 3A but presented stimuli of different types in random orders, rather than in blocks as in Experiments 2A, 2B and 3A. In blocked presentation, detection responses to the target color on a character were faster when this character and the cue character formed a word than when they did not, and the size of this lexical-based object effect did not vary according to whether the two characters were presented alone or within or between rectangles. In random presentation, however, the lexical-based object effect was diminished when the two characters of a word were presented in different rectangles. Overall, these findings suggest that the processes that constrain attention deployment over conjoined objects can be strategically adjusted.

T-I-066 RELATIONSHIP BETWEEN SYMPATHETIC AND CORTICAL REACTIVITY IN RESPONSE TO RESPIRATORY EVENTS DURING SLEEP

Introduction and Objectives: Several studies have suggested a tight and reciprocal relationship between autonomic and cortical reactivity to different types of stimuli during sleep, with concomitant cortical arousal and sympathetic activation after the stimulus and an increase in sympathetic basal activity when the stimulus gives rise to an arousal. However, this relationship remains unclear in case of respiratory events. Thus, we studied autonomic reactivity after respiratory events according to sleep stages, type of respiratory events, presence of cortical arousal (CA) and autonomic activity during respiratory events. Materials and Methods: Fourteen untreated patients with obstructive sleep apneas/hypopneas syndrome underwent laboratory polysomnographic recordings. RR intervals (RR) and spectral analysis of RR by wavelet transform were used to study sympathetic (LFWV and LFWV/HFWV ratio) and parasympathetic (HFWV) activities before and after the end of respiratory events. These RR variability indexes were compared according to sleep stages (stage 2, slow wave sleep and paradoxical sleep), to the severity of respiratory events (hypopnea with or without oxygen desaturation, and obstructive apnea) and presence cortical arousal. The possible relationship between RR variability indexes before the end of respiratory events and the occurrence of subsequent CA were studied by adjusted multivariate statistic analysis. Results: After respiratory events, RR (p<0.001) and HFWV (p=0.033) decrease whereas LFWV (p=0.006) and LFWV/HFWV ratio (p=0.001) increase, without any statistical difference according to sleep stages and severity of respiratory events. Decrease in RR (p=0.001) and increase in LFWV/HFWV ratio (p=0.008) were significantly higher when respiratory events gave rise to CA. Multivariate analysis showed that high level of LFWV and LFWV/HFWV ratio during respiratory events were related to CA (p<0.001). Conclusion: These results suggest that the sympathetic cardiac reactivity to respiratory events is modulated by arousal process rather than by sleep stages or severity of respiratory events, and reciprocally, sympathetic dominance during respiratory events could facilitate the occurrence of subsequent cortical arousal.

Experience-dependent reactivations of ventral tegmental area neurons in the rat

The hippocampus stores information during the acquisition of new memory episodes. These memories are replayed during sleep as part of a memory consolidation process. The neural mechanisms underlying these reactivations are currently under investigation. One hypothesis is that reactivation occurs as a result of local attractor dynamics within the structure in which they occur. Another possibility is that reactivation in these various areas is at least in part inherited from one or several other structures that project to them. Theoretical and experimental work on reinforcement learning have proposed many ways in which learning can be modulated by the value associated with a stimulus. Beyond initial memory acquisition, however, it is still unclear why specific memory items are consolidated and others are not [1,2]. One possibility is that, as with memory acquisition, the consolidation process is modulated by the value associated with a specific memory item. Research has shown that this value may be at least in part encoded by subcortical structures such as the ventral tegmental area (VTA) [3,4]. We provide new evidence in the rodent that 45% VTA neurons are sensitive to and selective for different types of stimuli. In three different tasks involving various amounts spatial and reward components, we show that putative dopaminergic VTA neurons strongly reactivate during a rest period following the tasks. This reactivation takes the form of population-wide activity patterns lasting from a few 100 ms up to a few seconds. In the non-spatial task, a statistical analysis of this reactivation using the explained variance measure showed that most of the reactivation relies on the activity of stimulus-sensitive neurons. Stimulus insensitive neurons exhibited significant reactivation if the task used involved motor and spatial components. VTA has widespread connections to the rest of the brain, including hippocampus and neocortex. Almost all experiments that have shown memory trace reactivation were based on tasks that involved rewards. The selective reactivation of non-GABAergic cells in the VTA suggests that reactivations in hippocampus and cortex could be modulated by the VTA. The finding that reward-sensitive neurons primarily reactivated when rewards were present during the task suggests a mechanism by which hippocampal and neocortical reactivations can be modulated by the value of the memory items they encode. In turn, cortex and hippocampus could modulate VTA activity as part of a loop in which memory content and memory value are dynamically and selectively established. Future conceptual and computational models of reinforcement learning and memory consolidation could account for the type of selectivity and dynamics of VTA neural firing we described here.

The Impact of Stimuli on Affect in Persons With Dementia

To examine how presentation of different stimuli impacts affect in nursing home residents with dementia. Participants were 193 residents aged 60 to 101 years from 7 Maryland nursing homes who had a diagnosis of dementia (derived from the medical chart or obtained from the attending physician). Cognitive functioning was assessed via the Mini-Mental State Examination (MMSE), and data pertaining to activities of daily living were obtained through the Minimum Data Set. Affect was assessed using observations of the 5 moods from Lawton's Modified Behavior Stream. Baseline observations of affect were performed for comparisons. During the study, each participant was presented with 25 predetermined engagement stimuli in random order over a period of 3 weeks. Stimuli were categorized as live social, simulated social, manipulative, work/task-related, music, reading, or individualized to the participant's self-identity. The dates of data collection were 2005-2007. Differences between stimulus categories were significant for pleasure (F(6,144) = 25.137, P < .001) and interest (F(6,144) = 18.792, P < .001) but not for negative affect. Pleasure and interest were highest for the live social category, followed by self-identity and simulated social stimuli for pleasure, and for manipulative stimuli in terms of the effect on interest. The lowest levels of pleasure and interest were observed for music. Participants with higher cognitive function had significantly higher pleasure (F(1,97) = 6.27, P < .05). Although the general trend of the impact of the different categories was similar for different levels of cognitive function, there were significant differences in pleasure in response to specific stimuli (interaction effect: F(6,92) = 2.31, P < .05). Overall, social stimuli have the highest impact on affect in persons with dementia. The findings of the present study are important, as affect is a major indicator of quality of life and this study is the first to systematically examine the impact of specific types of stimuli on affect. As live social stimuli are not always readily available, particularly in busy nursing home environments, simulated social stimuli can serve as an effective substitute, and other stimuli should have a role in the activity tool kit in the nursing home. The relative ranking of stimuli was different for interest and pleasure. The findings demonstrate the differential effect of presentation of different types of stimuli on the affect of persons with dementia, and that, while the impact is greater on persons with higher levels of cognitive function, there is a different effect of varying stimuli even in persons with MMSE scores of 3 or lower. Future research should attempt to ascertain a person's degree of interest in stimuli prior to developing an intervention.

Flashlight – Recording information acquisition online

A flashlight enables a person to see part of the world in the dark. As a person directs a flashlight beam to certain places in the environment, it serves as a manifestation of their attention, interest and focus. In this paper we introduce Flashlight, an open-source (free) web-based software package that can be used to collect continuous and non-obtrusive measures of users’ information acquisition behavior. Flashlight offers a cost effective and rapid way to collect data on how long and how often a participant reviews information in different areas of visual stimuli. It provides the functionality of other open source process tracing tools, like MouselabWeb, and adds the capability to present any static visual stimulus. We report the results from three different types of stimuli presented with both the Flashlight tool and a traditional eye-tracker. We found no differences measuring simple outcome data (e.g., choices in gambles or performance on algebraic tasks) between the two methods. However, due to the nature of the more complicated information acquisition, task completion takes longer with Flashlight than with an eye-tracking system. Other differences and commonalities between the two recording methods are reported and discussed. Additionally we provide detailed instructions on the installation and setup of Flashlight, the construction of stimuli, and the analysis of collected data.

Seven principles in the regulation of adult neurogenesis

Seven key elements describing the regulation of adult neurogenesis are proposed. (i) A distinction must be made between regulation and 'control' at the transcriptional level in order to appreciate the hierarchy of regulatory factors. (ii) The regulatory hierarchy comprises conceptual levels from behaviour to genes. Consequently, 'regulation' of neurogenesis can be confounded by confusing rather than integrating factors, levels and concepts. The immense spectrum of neurogenic regulators reflects the sensitivity of adult neurogenesis to many different types of stimuli, and provides a means of abstraction. (iii) Age per se does not seem to play a constant role in the modulation of this process, as the dramatic 'age-related' changes in adult neurogenesis only take place early in life. (iv) The regulatory hierarchy at any given time-point is corresponded by the directionality and sequential interdependence of different regulatory factors in the course of development. Regulation goes from non-specific to specific, and the following steps build on regulation at the previous ones. (v) This complexity is reflected at the genetic level in that adult neurogenesis is highly heritable and highly polygenic with single factors explaining little of the variance. (vi) As regulation is additive, there is an element of self-reinforcement in the regulation of adult neurogenesis, allowing the formation of regulatory reserves for situations of functional demand. (vii) The complexity of regulation makes adult neurogenesis sensitive to pathological disturbance at various levels, suggesting that different molecular events might result in similar and shared behavioural or functional phenotypes originating in the dentate gyrus.