666 resultados para panic attacks
Resumo:
Changes in brain-derived neurotrophic factor (BDNF)mediated signaling in the hippocampus have been implicated in the etiology of depression and in the mode of action of antidepressant drugs. There is also evidence from animal studies to suggest that BDNF-induced changes in the hippocampus may play a role in another stress-related pathology: anxiety. However, it is still unknown whether this neurotrophin plays a differential role in defensive responses associated with distinguished subtypes of anxiety disorders found in the clinic, such as generalized anxiety and panic disorder. In the present study, we investigated the effect of an acute BDNF injection into the rat dorsal hippocampus (DH) on inhibitory avoidance acquisition and escape expression measured in the elevated T-maze (ETM). We also assessed whether serotonergic neurotransmission may account for such effects. Intra-DH BDNF injection (200 pg) facilitated inhibitory avoidance in ETM. BDNF was equally anxiogenic in the light/dark transition test. Preadministration of the 5-HT1A receptor antagonist WAY-100635 fully counteracted the anxiogenic effect of BDNF in both tests. Intra-DH midazolam administration (10 nmol) impaired avoidance acquisition in ETM, suggesting an anxiolytic effect. Therefore, in the DH, facilitation of BDNF signaling seems to enhance 5-HT1A receptor-mediated neurotransmission to exert an anxiogenic effect associated with generalized anxiety. Behavioural Pharmacology 23:80-88 (C) 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins.
Resumo:
A wealth of evidence indicates that the dorsal raphe nucleus (DR) is not a homogenous structure, but an aggregate of distinctive populations of neurons that may differ anatomically, neurochemically and functionally. Other findings suggest that serotonergic neurons within the mid-caudal and caudal part of the DR are involved in anxiety processing while those within the lateral wings (IwDR) and ventrolateral periaqueductal gray (vIPAG) are responsive to panic-evoking stimuli/situations. However, no study to date has directly compared the activity of 5-HT and non-5HT neurons within different subnuclei of the DR following the expression of anxiety- and panic-related defensive responses. In the present investigation, the number of doubly immunostained cells for Fos protein and tryptophan hydroxylase, a marker of serotonergic neurons, was assessed within the rat DR, median raphe nucleus (MRN) and PAG following inhibitory avoidance and escape performance in the elevated T-maze, behaviors associated with anxiety and panic, respectively. Inhibitory avoidance, but not escape, significantly increased the number of Fos-expressing serotonergic neurons within the mid-caudal part of the dorsal subnucleus, caudal and interfascicular subnuclei of the DR and in the MRN. Escape, on the other hand, caused a marked increase in the activity of non-5HT cells within the IwDR, vIPAG, dorsolateral and dorsomedial columns of the PAG. These results strongly corroborate the view that different subsets of neurons in the DR are activated by anxiety- and panic-relevant stimuli/situations, with important implications for the understanding of the pathophysiology of generalized anxiety and panic disorders. (C) 2012 IBRO. Published by Elsevier Ltd. All rights reserved.
Resumo:
Objectives: To observe postpartum migraine recurrence among migraine sufferers before pregnancy, its classifications and associated factors and to compare women, who were exclusively breastfeeding, with those that used other forms of infant feeding. Methods: Out of 686 consecutively assisted women, at the first postnatal week, 266 were identified as migraine sufferers before pregnancy. Among those, one in five that were exclusively breastfeeding (53) and all the ones consecutively using others forms of infant feeding (40) were interviewed at the first and forth postpartum weeks. Results: After multivariable analysis, exclusive breastfeeding, no breastfeeding problems, and low income were associated with decrease in migraine recurrence at the first postpartum week. At the fourth week, exclusive breastfeeding continued to be a protective factor. Conclusions: A decrease in postpartum migraine recurrence seems to be another advantage of exclusive breastfeeding.
Resumo:
Objective: To review the clinical characteristics of patients with neuromyelitis optica (NMO) and to compare their visual outcome with those of patients with optic neuritis (ON) and multiple sclerosis (MS). Methods: Thirty-three patients with NMO underwent neuro-ophthalmic evaluation, including automated perimetry along with 30 patients with MS. Visual function in both groups was compared overall and specifically for eyes after a single episode of ON. Results: Visual function and average visual field (VF) mean deviation were significantly worse in eyes of patients with NMO. After a single episode of ON, the VF was normal in only 2 of 36 eyes of patients with NMO compared to 17 of 35 eyes with MS (P < 0.001). The statistical analysis indicated that after a single episode of ON, the odds ratio for having NMO was 6.0 (confidence interval [CI]: 1.6-21.9) when VF mean deviation was worse than -20.0 dB while the odds ratio for having MS was 16.0 (CI: 3.6-68.7) when better than -3.0 dB. Conclusion: Visual outcome was significantly worse in NMO than in MS. After a single episode of ON, suspicion of NMO should be raised in the presence of severe residual VF deficit with automated perimetry and lowered in the case of complete VF recovery.
Resumo:
The hypothalamus is a forebrain structure critically involved in the organization of defensive responses to aversive stimuli. Gamma-aminobutyric acid (GABA)ergic dysfunction in dorsomedial and posterior hypothalamic nuclei is implicated in the origin of panic-like defensive behavior, as well as in pain modulation. The present study was conducted to test the difference between these two hypothalamic nuclei regarding defensive and antinociceptive mechanisms. Thus, the GABA A antagonist bicuculline (40 ng/0.2 µL) or saline (0.9% NaCl) was microinjected into the dorsomedial or posterior hypothalamus in independent groups. Innate fear-induced responses characterized by defensive attention, defensive immobility and elaborate escape behavior were evoked by hypothalamic blockade of GABA A receptors. Fear-induced defensive behavior organized by the posterior hypothalamus was more intense than that organized by dorsomedial hypothalamic nuclei. Escape behavior elicited by GABA A receptor blockade in both the dorsomedial and posterior hypothalamus was followed by an increase in nociceptive threshold. Interestingly, there was no difference in the intensity or in the duration of fear-induced antinociception shown by each hypothalamic division presently investigated. The present study showed that GABAergic dysfunction in nuclei of both the dorsomedial and posterior hypothalamus elicit panic attack-like defensive responses followed by fear-induced antinociception, although the innate fear-induced behavior originates differently in the posterior hypothalamus in comparison to the activity of medial hypothalamic subdivisions.
Resumo:
[EN]Spoofing identities using photographs is one of the most common techniques to attack 2-D face recognition systems. There seems to exist no comparative stud- ies of di erent techniques using the same protocols and data. The motivation behind this competition is to com- pare the performance of di erent state-of-the-art algo- rithms on the same database using a unique evaluation method. Six di erent teams from universities around the world have participated in the contest.
Resumo:
L’avanzare delle tecnologie ICT e l’abbattimento dei costi di produzione hanno portato ad un aumento notevole della criminalità informatica. Tuttavia il cambiamento non è stato solamente quantitativo, infatti si può assistere ad un paradigm-shift degli attacchi informatici da completamente opportunistici, ovvero senza un target specifico, ad attacchi mirati aventi come obiettivo una particolare persona, impresa o nazione. Lo scopo della mia tesi è quello di analizzare modelli e tassonomie sia di attacco che di difesa, per poi valutare una effettiva strategia di difesa contro gli attacchi mirati. Il lavoro è stato svolto in un contesto aziendale come parte di un tirocinio. Come incipit, ho effettuato un attacco mirato contro l’azienda in questione per valutare la validità dei sistemi di difesa. L’attacco ha avuto successo, dimostrando l’inefficacia di moderni sistemi di difesa. Analizzando i motivi del fallimento nel rilevare l’attacco, sono giunto a formulare una strategia di difesa contro attacchi mirati sotto forma di servizio piuttosto che di prodotto. La mia proposta è un framework concettuale, chiamato WASTE (Warning Automatic System for Targeted Events) il cui scopo è fornire warnings ad un team di analisti a partire da eventi non sospetti, ed un business process che ho nominato HAZARD (Hacking Approach for Zealot Attack Response and Detection), che modella il servizio completo di difesa contro i targeted attack. Infine ho applicato il processo all’interno dell’azienda per mitigare minacce ed attacchi informatici.
Resumo:
This thesis collects the outcomes of a Ph.D. course in Telecommunications Engineering and it is focused on the study and design of possible techniques able to counteract interference signal in Global Navigation Satellite System (GNSS) systems. The subject is the jamming threat in navigation systems, that has become a very increasingly important topic in recent years, due to the wide diffusion of GNSS-based civil applications. Detection and mitigation techniques are developed in order to fight out jamming signals, tested in different scenarios and including sophisticated signals. The thesis is organized in two main parts, which deal with management of GNSS intentional counterfeit signals. The first part deals with the interference management, focusing on the intentional interfering signal. In particular, a technique for the detection and localization of the interfering signal level in the GNSS bands in frequency domain has been proposed. In addition, an effective mitigation technique which exploits the periodic characteristics of the common jamming signals reducing interfering effects at the receiver side has been introduced. Moreover, this technique has been also tested in a different and more complicated scenario resulting still effective in mitigation and cancellation of the interfering signal, without high complexity. The second part still deals with the problem of interference management, but regarding with more sophisticated signal. The attention is focused on the detection of spoofing signal, which is the most complex among the jamming signal types. Due to this highly difficulty in detect and mitigate this kind of signal, spoofing threat is considered the most dangerous. In this work, a possible techniques able to detect this sophisticated signal has been proposed, observing and exploiting jointly the outputs of several operational block measurements of the GNSS receiver operating chain.
Resumo:
Fourteen non-terrorist attackers of public figures in Germany between 1968 and 2004 were intensively studied, with a particular focus on warning behaviors, attack behaviors, and the relationship between psychiatric diagnosis, symptoms, and motivations for the assault. A large proportion of the attackers were severely mentally ill, and most likely to be in the potentially lethal rather than the non-lethal group. A new typology of seven warning behaviors was applied to the data, and all were present, most frequently fixation and pathway warning behavior, and least frequently a direct threat. Psychiatric diagnosis could be closely linked to motivation when analyzed at the level of symptom and content of thought, often delusional. Most of the attacks were directed at political figures, and the majority occurred after 1995.
Resumo:
Patients with panic disorder (PD) have a bias to respond to normal stimuli in a fearful way. This may be due to the preactivation of fear-associated networks prior to stimulus perception. Based on EEG, we investigated the difference between patients with PD and normal controls in resting state activity using features of transiently stable brain states (microstates). EEGs from 18 drug-naive patients and 18 healthy controls were analyzed. Microstate analysis showed that one class of microstates (with a right-anterior to left-posterior orientation of the mapped field) displayed longer durations and covered more of the total time in the patients than controls. Another microstate class (with a symmetric, anterior-posterior orientation) was observed less frequently in the patients compared to controls. The observation that selected microstate classes differ between patients with PD and controls suggests that specific brain functions are altered already during resting condition. The altered resting state may be the starting point of the observed dysfunctional processing of phobic stimuli.