Conditioned Fear
Mostrando 13-24 de 57 artigos, teses e dissertações.
-
13. Efeito do pentilenotetrazol e do midazolam na aquisição e na expressão da resposta defensiva de ratos submetidos ao condicionamento olfatório de medo
Pavlovian fear conditioning or first-order fear conditioning has been widely used to study the neuroanatomical, cellular and molecular basis of fear. This paradigm occurs when an emotionally neutral stimulus is presented in conjunction with an aversive unconditioned stimulus (US). After one or several pairings the stimulus, previously neutral, acquires the a
Publicado em: 2009
-
14. Envolvimento de receptores 5-HT2A da substância cinzenta periaquedutal dorsal no medo condicionado e incondicionado de ratos / 5HT2 receptor mechanisms of the dorsal periaqueductal gray in the conditioned and unconditioned fear in rats
Sabe-se que o medo condicionado contextual (MCC) pode ativar diversas áreas mesencefálicas, como a Substância Cinzenta Periaquedutal Dorsal (SCPd). Diversos estudos avaliaram como mecanismos serotoninérgicos modulam o comportamento defensivo induzido pela estimulação elétrica da SCPd. Uma função proeminente dos receptores 5-HT2A é regular estados a
Publicado em: 2007
-
15. Mecanismos dopaminérgicos na aquisição e expressão do medo condicionado: envolvimento de receptores D1 e D2 / Dopaminergic mechanisms in the acquisition and expression of conditioned fear: involviment of D1 and D2 receptors
The increase in the startle reflex in the presence of a stimulus that has been previously paired to footshock is taken as an index of fear and named fear potentiated startle (FPS). Freezing behavior, a cessation of all observable movements, except those associated with respiration, has also been used as an index of fear in rats. A growing body of evidence ha
Publicado em: 2006
-
16. SYSTEMIC ADMINISTRATION OF POLYAMINERGIC AGENTS MODULATE FEAR CONDITIONING IN RATS. / ADMINISTRAÇÃO SISTÊMICA DE AGENTES POLIAMINÉRGICOS MODULA A MEMÓRIA NA TAREFA DE MEDO CONDICIONADO EM RATOS
The polyamines, spermine, spermidine and putrescine, are a group of aliphatic amines that interact with diverse cellular targets such as nucleic acids and proteins. The polyamines may act as physiological modulators of N-methyl-D-aspartate (NMDA) receptors. The processes mediated by NMDA receptor include synaptic plasticity and formation of neural circuitry
Publicado em: 2006
-
17. Bioterrorismo, biodefensa, bioética
The terrorist attacks launched on September 11, 2001, ignited fear of further aggression with biological weapons, leading to a discourse and allocation of resources for both defensive and dissuasive/ offensive use in order to counteract such threats. Many such measures involved the investigation and production of biological agents, and the public health fiel
Cadernos de Saúde Pública. Publicado em: 2003-02
-
18. Neural organization of the mesencephalic system responsible for the freezing behavior. / Organização do sistema neural mesencefálico responsável pela resposta de congelamento.
Freezing to a context previously associated to footshock is attenuated by ventrolateral periaqueductal gray (vlPAG) lesion. Moreover, electrical stimulation or microinfusion of compounds that interfere with GABA neurotransmission in the dorsolateral periaqueductal gray (dlPAG) provoke freezing and escape. The present study examined the possibility of this fr
Publicado em: 2003
-
19. The brain decade in debate: III. Neurobiology of emotion
This article is a transcription of an electronic symposium in which active researchers were invited by the Brazilian Society of Neuroscience and Behavior (SBNeC) to discuss the advances of the last decade in the neurobiology of emotion. Four basic questions were debated: 1) What are the most critical issues/questions in the neurobiology of emotion? 2) What d
Brazilian Journal of Medical and Biological Research. Publicado em: 2001-03
-
20. Generalization of conditioned fear along a dimension of increasing fear intensity
The present study investigated the extent to which fear generalization in humans is determined by the amount of fear intensity in nonconditioned stimuli relative to a perceptually similar conditioned stimulus. Stimuli consisted of graded emotionally expressive faces of the same identity morphed between neutral and fearful endpoints. Two experimental groups u
Cold Spring Harbor Laboratory Press.
-
21. Damage to the Lateral and Central, but Not Other, Amygdaloid Nuclei Prevents the Acquisition of Auditory Fear Conditioning
It is well established that the amygdala plays an essential role in Pavlovian fear conditioning, with the lateral nucleus serving as the interface with sensory systems that transmit the conditioned stimulus and the central nucleus as the link with motor regions that control conditioned fear responses. The lateral nucleus connects with the central nucleus dir
Cold Spring Harbor Laboratory Press.
-
22. AX+, BX- Discrimination Learning in the Fear-Potentiated Startle Paradigm: Possible Relevance to Inhibitory Fear Learning in Extinction
The neural mechanisms of fear suppression most commonly are studied through the use of extinction, a behavioral procedure in which a feared stimulus (i.e., one previously paired with shock) is nonreinforced repeatedly, leading to a reduction or elimination of the fear response. Although extinction is perhaps the most convenient index of fear inhibition, a gr
Cold Spring Harbor Laboratory Press.
-
23. Nonassociative learning processes determine expression and extinction of conditioned fear in mice
Freezing to a tone following auditory fear conditioning is commonly considered as a measure of the strength of the tone-shock association. The decrease in freezing on repeated nonreinforced tone presentation following conditioning, in turn, is attributed to the formation of an inhibitory association between tone and shock that leads to a suppression of the e
Cold Spring Harbor Laboratory Press.
-
24. Reciprocal patterns of c-Fos expression in the medial prefrontal cortex and amygdala after extinction and renewal of conditioned fear
After extinction of conditioned fear, memory for the conditioning and extinction experiences becomes context dependent. Fear is suppressed in the extinction context, but renews in other contexts. This study characterizes the neural circuitry underlying the context-dependent retrieval of extinguished fear memories using c-Fos immunohistochemistry. After fear
Cold Spring Harbor Laboratory Press.