An Acute Stressor Enhances Sensitivity to a Chemical Irritant and Increases 51CrEDTA Permeability of the Colon in Adult Rats

We investigated the effect of prior acute stress on colonic permeability induced by a chemical irritant known to induce symptoms similar to inflammatory bowel disease in rodents. Adult male rats (n = 12) were stressed by a single session of ten unpredictable, uncontrollable foot shocks, and half were home cage controls (n = 12). Twenty-nine days later, half of each treatment group was exposed to 4% DSS (dextran sulphate sodium) solution in their drinking water for 48 hours while half received pure water over two periods separated by 17 days. After food deprivation overnight and light isoflurane anaesthesia the following morning, the animals were given a colonic infusion of 2000 nCi (nanocurie) 51CrEDTA (51Cr-labelled ethylenediaminetetraacetic acid) and then placed individually in metabolic cages for a six hours continuous urine collection. Radioactivity in urine was measured by a gamma counter and percentage recovery of 51CrEDTA calculated as an indicator of colonic mucosal permeability. Results concluded that pre-shocked animals exposed to DSS showed significantly higher mucosal permeability than the pre-shocked animals given water, and the non-shocked animals given either DSS or water. Pre-shock in combination with two exposures to a chemical irritant separated by 17 days had a pronounced effect on colonic permeability, indicating that stress should be considered a possible initiating or contributory factor to increased intestinal permeability related to a mucosal challenge.     

Clamped Corticosterone (B) Reveals the Effect of Endogenous B on Both Facilitated Responsivity to Acute Restraint and Metabolic Responses to Chronic Stress

To determine the effects of both corticosterone (B) and chronic stressors on acute ACTH responses to restraint, young male rats were exposed to streptozotocin-induced diabetes, cold (5-7 degreesC) or intracerebroventricular (icv) neuropeptide Y (NPY) for 5 d and then exposed to restraint within 2 h after lights on. Two groups of rats were studied: intact and adrenalectomized replaced with B pellets that maintained plasma B in the normal mean 24-h range of intact rats. In addition to ACTH and B responses to restraint on d 5, body weight, food intake, fat depots, glucose and other hormones were measured to determine the role of stress-induced elevations in B on energy balance. ACTH responses to restraint were normal in intact rats subjected to diabetes or cold. By contrast, there was no ACTH or B response to restraint in NPY-infused intact rats. All 3 groups of chronically stimulated adrenalectomized rats with clamped B had facilitated ACTH responses to restraint compared to their treatment controls. Overall food intake increased in all groups of stressed rats; however, augmented intake occurred only during the light in intact rats and equally in the light and dark in B-clamped rats. White adipose depot weights were decreased by both diabetes and cold and increased by NPY in intact rats; the decreases with cold and increases with NPY were both blunted and changes in fat stores were not significant in adrenalectomized, B-clamped rats. We conclude that: 1. diabetes- and cold-induced facilitation of restraint-induced afferent input to hypothalamic control of the hypothalamo-pituitary-adrenal (HPA) axis is opposed in intact rats by the elevated feedback signal of B secretion; 2. NPY does not induce facilitation of afferent stress pathways; 3. chronic stimulation of the HPA axis induces acute hyperresponsiveness of hypothalamic neurons to restraint provided that the afferent input of this acute stimulus is not prevented by B feedback; 4. stimulus-induced elevations in B secretion result in day-time feeding; 5. insensitivity of both caloric efficiency and white fat stores to chronic stress in adrenalectomized, B-clamped rats results from loss of normally variable B levels.     

Sad and happy emotion discrimination in music by children with cochlear implants

Children using cochlear implants (CIs) develop speech perception but have difficulty perceiving complex acoustic signals. Mode and tempo are the two components used to recognize emotion in music. Based on CI limitations, we hypothesized children using CIs would have impaired perception of mode cues relative to their normal hearing peers and would rely more heavily on tempo cues to distinguish happy from sad music. Study participants were children with 13 right CIs and 3 left CIs (M = 12.7, SD = 2.6 years) and 16 normal hearing peers. Participants judged 96 brief piano excerpts from the classical genre as happy or sad in a forced-choice task. Music was randomly presented with alterations of transposed mode, tempo, or both. When music was presented in original form, children using CIs discriminated between happy and sad music with accuracy well above chance levels (87.5%) but significantly below those with normal hearing (98%). The CI group primarily used tempo cues, whereas normal hearing children relied more on mode cues. Transposing both mode and tempo cues in the same musical excerpt obliterated cues to emotion for both groups. Children using CIs showed significantly slower response times across all conditions. Children using CIs use tempo cues to discriminate happy versus sad music reflecting a very different hearing strategy than their normal hearing peers. Slower reaction times by children using CIs indicate that they found the task more difficult and support the possibility that they require different strategies to process emotion in music than normal.     

阅读预期对快速阅读理解的影响的实验研究

探讨阅读预期对快速阅读的理解水平与进程的影响。实验１探讨阅读预期对快速阅读理解水平的影响。阅读文章前分别给予被试正确、中性与误导的标题提示,结果表明,不同类型的标题提示对快速阅读的理解成绩有显著的影响,而对正常速度阅读的理解成绩影响效果不显著。实验２探讨阅读预期对快速阅读过程的词句加工程度的影响。结果表明,对优生来说,正确标题提示组发现文章中锗字的成绩显著低于误导标题提示组,差生的不同标题提示组发现错字的成绩差异不显著。两个实验的结果初步表明,快速阅读文章过程会更多地利用概念推动,较少地需要材料信息。     

Proactive sensitizing effects of acute stress on acoustic startle responses and experimentally induced colitis in rats: relationship to corticosterone

In humans, some individuals develop a syndrome after trauma (post-traumatic stress disorder, PTSD) characterized by increased startle responses and lower than normal cortisol secretion. We explored a rat model using the acoustic startle response (ASR) as a behavioral indicator of the effect of a short series of shocks. Because gastrointestinal disorders have been associated with prior stress, we also studied the rats' vulnerability to a chemically-induced colitis. After initial blood sampling, 12 rats were exposed to ten 1 mA 5 s foot-shocks while 12 rats served as controls. Nineteen days later the rats were tested for ASR. Thirty trials (10 trials at each of 95, 105, and 115 dB, pseudo-randomized) were given. After exposure for 6 days to dextran sulphate sodium in their drinking water, the rats were killed and the colons examined for erosions. Shocked rats showed greater startle responses and more colonic erosion than unshocked rats, but the shock effects were significant only for animals with low initial plasma corticosterone levels. Shocked rats also showed higher levels of granulocyte marker protein (GMP) in their faeces. These results suggest that low corticosterone secretion may represent a marker for vulnerability to long term effects of shocks as indicated by increased startle responses and colonic pathology.     

Kommunizierende Agenten: Gestische und natürlichsprachliche Interaktion

Communicating agents: Gesture and natural language interaction Summary. An important scientific method within cognitive science consists in the synthesis of cognitive abilities, of forms of behavior by developing specific artificial agents. Many current approaches make use of the notion of an agent in order to develop concepts of cognitive behavior on different levels of abstraction. Basic properties of agents are: reactivity, autonomy, goal directed activity, and communication. This contribution examines the communicative aspect, i.e. the interaction by gesture or language and their integration, e.g. in identifying referents. Since we conceive communicating agents as systems able to synthesize such interactions as well as their integration, this will be illustrated with respect to two artificial systems. The GRAVIS system detects objects as well as pointing gestures of an instructor, and the camera agent is able to focus on specific objects. The CoRA system processes situated natural language instructions, and the simulated robot agent is able to integrate the use of language, perception and action. Finally we propose an integration of both approaches. Zusammenfassung. Ein wichtiger Forschungsansatz innerhalb der Kognitionswissenschaft besteht in der Synthese kognitiver Fähigkeiten und Verhaltensweisen durch den Bau geeigneter, künstlicher Systeme. Viele der in jüngerer Zeit verfolgten Ansätze nutzen dabei den Begriff des Agenten, um kognitives Verhalten auf unterschiedlichen Abstraktionsebenen zu konzeptualisieren. Grundeigenschaften von Agenten sind u.a. Reaktivität, Autonomie, Zielgerichtetheit und Kommunikationsfähigkeit. In dem vorliegenden Beitrag interessieren wir uns für die Ebene kommunikativen Verhaltens, bei der Gestik und Sprache zur Vermittlung eines Sachverhaltes zusammenwirken, und verstehen unter einem kommunizierenden Agenten ein System, das für solches Verhalten einen nennenswerten Kompetenzausschnitt realisiert. Wir stellen hierzu beispielhaft zwei Systeme vor. Das System GRAVIS demonstriert die Referenzierung von Objekten im Blickfeld eines Kamerakopfes durch Handzeigegestik eines Instrukteurs. Das System CoRA demonstriert die Verarbeitung sprachlicher Handlungsanweisungen im Kontext der Kooperation mit einem simulierten Roboter. Abschließend wird die Integration der beiden Ansätze diskutiert.     

An acute stressor enhances sensitivity to a chemical irritant and increases51CrEDTA permeability of the colon in adult rats

We investigated the effect of prior acute stress on colonic permeability induced by a chemical irritant known to induce symptoms similar to inflammatory bowel disease in rodents. Adult male rats (n=12) were stressed by a single session of ten unpredictable, uncontrollable foot shocks, and half were home cage controls (n=12). Twenty-nine days later, half of each treatment group was exposed to 4% DSS (dextran sulphate sodium) solution in their drinking water for 48 hours while half received pure water over two periods separated by 17 days. After food deprivation overnight and light isoflurane anaesthesia the following morning, the animals were given a colonic infusion of 2000 nCi (nanocurie)⁵¹CrEDTA (⁵¹Cr-labelled ethylenediaminetetraacetic acid) and then placed individually in metabolic cages for a six hours continuous urine collection. Radioactivity in urine was measured by a gamma counter and percentage recovery of⁵¹CrEDTA calculated as an indicator of colonic mucosal permeability. Results concluded that pre-shocked animals exposed to DSS showed significantly higher mucosal permeability than the pre-shocked animals given water, and the non-shocked animals given either DSS or water. Pre-shock in combination with two exposures to a chemical irritant separated by 17 days had a pronounced effect on colonic permeability, indicating that stress should be considered a possible initiating or contributory factor to increased intestinal permeability related to a mucosal challenge.     

A Study of the Effects of Restraint Stress on Colitis Induced by Dextran Sulphate Sodium in Singly Housed Rats

The inflammatory bowel diseases (Crohn's disease and ulcerative colitis) are multifactorial diseases. Clinical reports indicate that emotional stress may contribute to the onset, progression and remission of these diseases. Using an experimental animal model of ulcerative colitis, the effect of stress on the development of and recovery from symptoms was studied prospectively. Singly housed rats received 4 percent dextran sulphate sodium orally until fecal blood was detected, indicating the presence of colonic erosions. Tap water was then administered until there were no signs of fecal blood. Two hours of restraint stress were administered daily over four successive days, either prior to or after the induction of colitis. Latencies in days to symptom development and recovery were compared to an unstressed group. Daily measures of fluid-intake, body-weight, and hemoglobulin in feces were made. RESULTS: Rats exposed to restraint stress procedures prior to induction of colitis had shorter latencies to development of symptoms. There was no significant difference in latency to recovery. The amount of fluid-intake did not significantly differ between groups, nor did the groups differ in body-weight. CONCLUSION: There is an effect of stress on the latency to develop colitis induced by dextran sulphate sodium. This preliminary study suggests that the impact of stress may be one factor underlying the emergence of ulcerative colitis.