248 research outputs found
Adaptive contextualization: A new role for the default mode network in affective learning.
Safety learning describes the ability to learn that certain cues predict the absence of a dangerous or threatening event. Although incidental observations of activity within the default mode network (DMN) during the processing of safety cues have been reported previously, there is as yet no evidence demonstrating that the DMN plays a functional rather than a corollary role in safety learning. Using functional magnetic resonance imaging and a Pavlovian fear conditioning and extinction paradigm, we investigated the neural correlates of danger and safety learning. Our results provide evidence for a functional role of the DMN by showing that (i) the DMN is activated by safety but not danger cues, (ii) the DMN is anti-correlated with a fear-processing network, and (iii) DMN activation increases with safety learning. Based on our results, we formulate a novel proposal, arguing that activity within the DMN supports the contextualization of safety memories, constrains the generalization of fear, and supports adaptive fear learning. Our findings have important implications for our understanding of affective and stress disorders, which are characterized by aberrant DMN activity, as they suggest that therapies targeting the DMN through mindfulness practice or brain stimulation might help prevent pathological over-generalization of fear associations. Hum Brain Mapp 38:1082-1091, 2017. © 2016 Wiley Periodicals, Inc
Development of a network for the on-farm conservation of crop genetic resources: First results of a pilot project for the re-introduction of old Lactuca varieties to the market
In a pilot project, we examined the chance of maintaining plant genetic resources by commercial utilization of old varieties using Lactuca sativa as a model plant. Nine market gardens in the region of Berlin and Brandenburg cultivated 18 old varieties during four cultivation periods to test field performance. They supplied the products to the market in their customary manner to analyse marketing success. Seven of the market gardens practice organic horticulture. In a complementary field trial at Humboldt-Universität zu Berlin, we established data concerning the field performance of the varieties, analysed dry matter contents, nitrate and phenol concentrations, and observed shelf life for two days under simulated retail conditions (18°C, 80% rel. air humidity). Generally, yield was acceptable for market purposes. However, cultivation in autumn failed because of the cold climate. Biotic and abiotic factors like slugs or hail caused non-specific damages. Specific problems of particular varieties were less important. Based on the results of 2007, the varieties can be put preliminarily into three categories: suitable for on-farm conservation, suitable for home gardens, and varieties with contrasting results depending on the respective market garden.The nitrate concentrations of all varieties were clearly below the EU acceptable limit of 2500 mg/kg fresh weight of lettuce grown in the field. The phenol concentrations varied from 3.3 to 17.2 mg GAE/g dry weight. Generally, the cultivars had a reasonable shelf life of one to two days, however three varieties showed a better storability whereas four other cultivars deteriorated rapidly. Marketing success was good in Berlin City but poor in the countryside of Brandenburg. The regular customers of the market gardens in Berlin who prefer organic food are a promising target group for further stimulation of interest to buy rare crop varieties. The on-farm conservation of old varieties in market gardens requires relatively large quantities of seeds of good quality. However there might arise problems in seed supply as the VERN e.V. was confronted with bottleneck problems. Therefore, we organised a network of interested market gardens who take on maintenance and propagation of individual varieties. The network will be developed in co-operation with the VERN e.V. who will also process the seed as well as organise the exchange of the various varieties within the network. Further, the network will deal with problems concerning maintenance breeding and seed quality
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What is going on around here? Intolerance of uncertainty predicts threat generalization
Attending to stimuli that share perceptual similarity to learned threats is an adaptive strategy. However, prolonged threat generalization to cues signalling safety is considered a core feature of pathological anxiety. One potential factor that may sustain over-generalization is sensitivity to future threat uncertainty. To assess the extent to which Intolerance of Uncertainty (IU) predicts threat generalization, we recorded skin conductance in 54 healthy participants during an associative learning paradigm, where threat and safety cues varied in perceptual similarity. Lower IU was associated with stronger discrimination between threat and safety cues during acquisition and extinction. Higher IU, however, was associated with generalized responding to threat and safety cues during acquisition, and delayed discrimination between threat and safety cues during extinction. These results were specific to IU, over and above other measures of anxious disposition. These findings highlight: (1) a critical role of uncertainty-based mechanisms in threat generalization, and (2) IU as a potential risk factor for anxiety disorder development
Practical active and semi-active strategies for the control of room acoustics in the low frequency range
Modal acoustics is one of the main sources of annoyance in the low frequency range in rooms. Active noise control techniques can be deployed to reach sufficient acoustic benefit, but limited to a single frequency, whereas broader efficiency would require complex systems with a large number of transducers. After a short presentation of the state-of-the-art active modal control techniques, this paper will introduce the semi-active concept of “electroacoustic absorbers”, which are able to handle low-frequency room acoustics problems along significant frequency bandwidth, in the experimental context of the damping of the first modal frequencies of a test chamber. This study will focus on highlighting advantages and drawbacks of such techniques when compared to active strategies (performances, complexity,…), concluding with practical consideration (integration, cost,…)
Update of the Swiss source model for road traffic noise
In Switzerland, the calculation method of road traffic noise is specified in the Ordonnance sur la protection contre le bruit (OPB) (Noise Protection Ordonnance (NPO)). This method is mainly based on observations that were realized in the 80s, and that are not satisfactory many situations anymore. Since the 80s, the traffic volumes have increased, new developments in car and road technologies have occurred, behaviors of users have changed. All these parame-ters contribute to lower reliability of the initial method. Even if the model is still correct in some case such as for fluid traffic, the obtained levels in different types of traffic are hardly reliable. In collaboration with the Swiss Federal Office for the Environment (FOEN), a re-search program has been setup to update the method according to those observations. The ob-jective was to give new guidelines to evaluate emission levels of roads. An important collect of data from cantons and others acoustics partners has been performed as well as measure-ments in real traffic conditions. That made it possible to gather about 7500 points of mea-surement through all Switzerland for several types of road and traffic conditions
The relationship between moral judgment and cooperation in children with high-functioning autism.
This study investigated moral judgment in children with high-functioning autism and their cooperation in prisoner's dilemma game with partners of different moralities. Thirty-eight 6- to 12-year-old high-functioning autistic (HFA) children and 31 typically developing (TD) children were recruited. Children were asked to judge story protagonists' morality. After making this moral judgment correctly, they were asked to play with the morally nice and the morally naughty child in a repeated prisoner's dilemma game. Results showed that both HFA and TD children made correct moral judgments, and that HFA children might even have more rigid criteria for what constitutes morally naughty acts. HFA children's cooperation did not differ depending on the morality of the interaction partner, while TD children showed higher cooperation when interacting with the morally nice than the morally naughty child did. Thus, partner's morality did influence TD children's but not HFA children's subsequent cooperation
Dynamic Visuomotor Transformation Involved with Remote Flying of a Plane Utilizes the ‘Mirror Neuron’ System
Brain regions involved with processing dynamic visuomotor representational transformation are investigated using fMRI. The perceptual-motor task involved flying (or observing) a plane through a simulated Red Bull Air Race course in first person and third person chase perspective. The third person perspective is akin to remote operation of a vehicle. The ability for humans to remotely operate vehicles likely has its roots in neural processes related to imitation in which visuomotor transformation is necessary to interpret the action goals in an egocentric manner suitable for execution. In this experiment for 3rd person perspective the visuomotor transformation is dynamically changing in accordance to the orientation of the plane. It was predicted that 3rd person remote flying, over 1st, would utilize brain regions composing the ‘Mirror Neuron’ system that is thought to be intimately involved with imitation for both execution and observation tasks. Consistent with this prediction differential brain activity was present for 3rd person over 1st person perspectives for both execution and observation tasks in left ventral premotor cortex, right dorsal premotor cortex, and inferior parietal lobule bilaterally (Mirror Neuron System) (Behaviorally: 1st>3rd). These regions additionally showed greater activity for flying (execution) over watching (observation) conditions. Even though visual and motor aspects of the tasks were controlled for, differential activity was also found in brain regions involved with tool use, motion perception, and body perspective including left cerebellum, temporo-occipital regions, lateral occipital cortex, medial temporal region, and extrastriate body area. This experiment successfully demonstrates that a complex perceptual motor real-world task can be utilized to investigate visuomotor processing. This approach (Aviation Cerebral Experimental Sciences ACES) focusing on direct application to lab and field is in contrast to standard methodology in which tasks and conditions are reduced to their simplest forms that are remote from daily life experience
Working Together May Be Better: Activation of Reward Centers during a Cooperative Maze Task
Humans use theory of mind when predicting the thoughts and feelings and actions of others. There is accumulating evidence that cooperation with a computerized game correlates with a unique pattern of brain activation. To investigate the neural correlates of cooperation in real-time we conducted an fMRI hyperscanning study. We hypothesized that real-time cooperation to complete a maze task, using a blind-driving paradigm, would activate substrates implicated in theory of mind. We also hypothesized that cooperation would activate neural reward centers more than when participants completed the maze themselves. Of interest and in support of our hypothesis we found left caudate and putamen activation when participants worked together to complete the maze. This suggests that cooperation during task completion is inherently rewarding. This finding represents one of the first discoveries of a proximate neural mechanism for group based interactions in real-time, which indirectly supports the social brain hypothesis
Sex Differences and Autism: Brain Function during Verbal Fluency and Mental Rotation
Autism spectrum conditions (ASC) affect more males than females. This suggests that the neurobiology of autism: 1) may overlap with mechanisms underlying typical sex-differentiation or 2) alternately reflect sex-specificity in how autism is expressed in males and females. Here we used functional magnetic resonance imaging (fMRI) to test these alternate hypotheses. Fifteen men and fourteen women with Asperger syndrome (AS), and sixteen typically developing men and sixteen typically developing women underwent fMRI during performance of mental rotation and verbal fluency tasks. All groups performed the tasks equally well. On the verbal fluency task, despite equivalent task-performance, both males and females with AS showed enhanced activation of left occipitoparietal and inferior prefrontal activity compared to controls. During mental rotation, there was a significant diagnosis-by-sex interaction across occipital, temporal, parietal, middle frontal regions, with greater activation in AS males and typical females compared to AS females and typical males. These findings suggest a complex relationship between autism and sex that is differentially expressed in verbal and visuospatial domains
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