Požari su čovječanstvu poznati od njegovog nastanka. Ranije pripisivani nadnaravnim moćima, danas sve više uzrokovani ljudskim faktorom, predstavljaju kriznu situaciju od koje strahuju svi. Veliki ...materijalni gubici, strah, nemogućnost normalnog funkcioniranja i ljudske žrtve su sastavni dio svakog većeg požara. Proaktivno djelovanje ne može u potpunosti spriječiti požare te se sve više usmjeravaju radnje na reaktivno djelovanje. Gašenje iz zraka je u dosta situacija presudno, tako da se požar u potpunosti ugasi ili se usmjeri u pravcu da zemaljske snage mogu uspješno ugasiti požar. Federacija Bosne i Hercegovine teži formirati svoju jedinicu za gašenje požara iz zraka, što je složen proces koji na kraju daje velike prednosti. Formiranje jedinice i odabir optimalnog zrakoplova su opisani u radu.
Wildfires have been known to mankind since its inception. Formerly attributed to supernatural powers, today increasingly caused by the human factor, they represent a crisis situation that everyone fears. Great material losses, fear, inability to function normally and human casualties are an integral part of any major wildfire outbreak. Proactive action cannot entirely prevent wildfires, and actions are increasingly focused on reactive action. Aerial firefighting is crucial in many situations so that the fire is thoroughly extinguished or managed in such way that ground forces can successfully suppress the fire. Federation of Bosnia and Herzegovina is striving to form its own aerial firefighting unit, a complex process that ultimately offers great benefits. The formation of such unit and the selection of the optimal aircraft are described in the paper.
BackgroundThe main objective of this study was to investigate the frequency and type of oral pathological changes, oral subjective symptoms and the knowledge about oral cancer in the population of ...Croatian military invalids from the Homeland War.Material and MethodsA total of 102 Croatian military invalids from the Homeland War participated in the study. Data were collected on the presence of subjective symptoms in the oral cavity, and a detailed clinical examination of the oral mucosa was performed.ResultsAlmost half of the participants, 46 (45.1%), reported being smokers, and 64 (62.7%) consumed alcohol daily. Subjective symptoms in the oral cavity were reported by 25 (24.5%) of them. Pathological changes were found in 35 (34.3%) participants, of whom 14 (13.7%) had potentially malignant changes. Pathohistological findings confirmed the diagnosis of a potentially malignant lesion in 10 subjects and indicated the presence of moderate dysplasia in two, carcinoma in situ in one, and invasive carcinoma in one.ConclusionsParticipants didn't show adequate knowledge of risk factors. Forty-one changes in the oral cavity were found in 35 subjects, and as many as 14 were potentially malignant. According to the participants, most dentists and family physicians don't thoroughly and regularly examine their patients' oral mucosa. Key words:Oral cancer, oral lichen planus, leukoplakia, erythroplakia, actinic cheilitis, Croatian Homeland War invalids.
Action versus valence in decision making Guitart-Masip, Marc; Duzel, Emrah; Dolan, Ray ...
Trends in cognitive sciences,
04/2014, Letnik:
18, Številka:
4
Journal Article
Recenzirano
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Highlights • Pavlovian responses couple action and valence. • This coupling interferes with instrumental learning and performance. • Action dominates valence in the striatum and dopaminergic ...midbrain. • Boosting dopamine enhances the dominance of action over valence in the striatum. • Boosting dopamine decreases the extent of the behavioral coupling between action and valence.
Aerobic exercise in young adults can induce vascular plasticity in the hippocampus, a critical region for recall and recognition memory. In a mechanistic proof-of-concept intervention over 3 months, ...we investigated whether healthy older adults (60-77 years) also show such plasticity. Regional cerebral blood flow (rCBF) and volume (rCBV) were measured with gadolinium-based perfusion imaging (3 Tesla magnetic resonance image (MRI)). Hippocampal volumes were assessed by high-resolution 7 Tesla MRI. Fitness improvement correlated with changes in hippocampal perfusion and hippocampal head volume. Perfusion tended to increase in younger, but to decrease in older individuals. The changes in fitness, hippocampal perfusion and volume were positively related to changes in recognition memory and early recall for complex spatial objects. Path analyses indicated that fitness-related changes in complex object recognition were modulated by hippocampal perfusion. These findings indicate a preserved capacity of the aging human hippocampus for functionally relevant vascular plasticity, which decreases with progressing age.
Animal models point towards a key role of brain-derived neurotrophic factor (BDNF), insulin-like growth factor-I (IGF-I) and vascular endothelial growth factor (VEGF) in mediating exercise-induced ...structural and functional changes in the hippocampus. Recently, also platelet derived growth factor-C (PDGF-C) has been shown to promote blood vessel growth and neuronal survival. Moreover, reductions of these neurotrophic and angiogenic factors in old age have been related to hippocampal atrophy, decreased vascularization and cognitive decline. In a 3-month aerobic exercise study, forty healthy older humans (60 to 77years) were pseudo-randomly assigned to either an aerobic exercise group (indoor treadmill, n=21) or to a control group (indoor progressive-muscle relaxation/stretching, n=19). As reported recently, we found evidence for fitness-related perfusion changes of the aged human hippocampus that were closely linked to changes in episodic memory function. Here, we test whether peripheral levels of BDNF, IGF-I, VEGF or PDGF-C are related to changes in hippocampal blood flow, volume and memory performance. Growth factor levels were not significantly affected by exercise, and their changes were not related to changes in fitness or perfusion. However, changes in IGF-I levels were positively correlated with hippocampal volume changes (derived by manual volumetry and voxel-based morphometry) and late verbal recall performance, a relationship that seemed to be independent of fitness, perfusion or their changes over time. These preliminary findings link IGF-I levels to hippocampal volume changes and putatively hippocampus-dependent memory changes that seem to occur over time independently of exercise. We discuss methodological shortcomings of our study and potential differences in the temporal dynamics of how IGF-1, VEGF and BDNF may be affected by exercise and to what extent these differences may have led to the negative findings reported here.
•Exercise-related changes in BDNF, IGF, VEGF and PDGF were measured in older adults•Changes in hippocampal perfusion, volume (via 7T MRI) and memory were assessed•Fitness-related vascular hippocampal plasticity was not linked to growth factors•Changes in IGF-I, hippocampal volume and memory were linked independent of exercise•Potential reasons for negative findings and methodological shortcomings are discussed
Reward and novelty are potent learning signals that critically rely on dopaminergic midbrain responses. Recent findings suggest that although reward and novelty are likely to interact, both functions ...may be subserved by distinct neuronal clusters. We used high-resolution functional magnetic resonance imaging (fMRI) to isolate neural responses to reward and novelty within the human substantia nigra/ventral tegmental area (SN/VTA) complex to investigate the spatial delineation and integration of reward- and novelty-related activity clusters. We demonstrate that distinct clusters within the caudal portion of the medial SN/VTA and the lateral portion of the right SN are predominantly modulated by the anticipation of reward, while a more rostral part of the medial SN/VTA was exclusively modulated by novelty. In addition, the caudal medial SN/VTA cluster embodied an interaction between novelty and reward where novelty selectively increased reward-anticipation responses. This interaction, in turn, was paralleled by differences in the functional-connectivity patterns of these SN/VTA regions. Specifically, novel as compared to familiar reward-predictive stimuli increased the functional connectivity of the medial SN/VTA with mesolimbic regions, including the nucleus accumbens and the hippocampus, as well as with the primary visual cortex. This functional correlation may highlight how afferents of the medial SN/VTA provide integrative information about novelty and reward, or, alternatively, how medial SN/VTA activity may modulate memory processes for novel events associated with rewards.
► High-resolution fMRI delineates responses to novelty and reward in the human SN/VTA. ► Novelty increases reward-anticipation responses in the caudal medial SN/VTA. ► This novelty-related augmentation increases mesolimbic functional connectivity. ► The study highlights the midbrain's integrative role in human behavior and memory.
Decision-making invokes two fundamental axes of control: affect or valence, spanning reward and punishment, and effect or action, spanning invigoration and inhibition. We studied the acquisition of ...instrumental responding in healthy human volunteers in a task in which we orthogonalized action requirements and outcome valence. Subjects were much more successful in learning active choices in rewarded conditions, and passive choices in punished conditions. Using computational reinforcement-learning models, we teased apart contributions from putatively instrumental and Pavlovian components in the generation of the observed asymmetry during learning. Moreover, using model-based fMRI, we showed that BOLD signals in striatum and substantia nigra/ventral tegmental area (SN/VTA) correlated with instrumentally learnt action values, but with opposite signs for go and no-go choices. Finally, we showed that successful instrumental learning depends on engagement of bilateral inferior frontal gyrus. Our behavioral and computational data showed that instrumental learning is contingent on overcoming inherent and plastic Pavlovian biases, while our neuronal data showed this learning is linked to unique patterns of brain activity in regions implicated in action and inhibition respectively.
► Expectation of valence interferes with action learning in human participants. ► Computational modeling disentangles influences of instrumental and Pavlovian systems. ► Striatum and SN/VTA track action values and bind them to the control of vigor. ► Successful control is associated with activity in the inferior prefrontal cortex.
Senescence affects the ability to utilize information about the likelihood of rewards for optimal decision-making. Using functional magnetic resonance imaging in humans, we found that healthy older ...adults had an abnormal signature of expected value, resulting in an incomplete reward prediction error (RPE) signal in the nucleus accumbens, a brain region that receives rich input projections from substantia nigra/ventral tegmental area (SN/VTA) dopaminergic neurons. Structural connectivity between SN/VTA and striatum, measured by diffusion tensor imaging, was tightly coupled to inter-individual differences in the expression of this expected reward value signal. The dopamine precursor levodopa (L-DOPA) increased the task-based learning rate and task performance in some older adults to the level of young adults. This drug effect was linked to restoration of a canonical neural RPE. Our results identify a neurochemical signature underlying abnormal reward processing in older adults and indicate that this can be modulated by L-DOPA.
Rationale
Decision-making involves two fundamental axes of control namely valence, spanning reward and punishment, and action, spanning invigoration and inhibition. We recently exploited a go/no-go ...task whose contingencies explicitly decouple valence and action to show that these axes are inextricably coupled during learning.
This results in a disadvantage in learning to go to avoid punishment and in learning to no
-
go to obtain a reward
. The neuromodulators dopamine and serotonin are likely to play a role in these asymmetries: Dopamine signals anticipation of future rewards and is also involved in an invigoration of motor responses leading to reward, but it also arbitrates between different forms of control. Conversely, serotonin is implicated in motor inhibition and punishment processing.
Objective
To investigate the role of dopamine and serotonin in the interaction between action and valence during learning.
Methods
We combined computational modeling with pharmacological manipulation in 90 healthy human volunteers, using levodopa and citalopram to affect dopamine and serotonin, respectively.
Results
We found that, after administration of levodopa, action learning was less affected by outcome valence when compared with the placebo and citalopram groups. This highlights in this context a predominant effect of levodopa in controlling the balance between different forms of control. Citalopram had distinct effects, increasing participants’ tendency to perform active responses independent of outcome valence, consistent with a role in decreasing motor inhibition.
Conclusions
Our findings highlight the rich complexities of the roles played by dopamine and serotonin during instrumental learning.
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