The effects of acute nicotine administration (0.09 mg/kg nicotine), chronic nicotine administration (6.3 mg/kg/d nicotine for 14 d), and withdrawal from chronic nicotine administration on fear conditioning in C57BL/6 mice were examined. Mice were trained using two coterminating conditioned stimulus (30 s; 85 dB white noise)--unconditioned stimulus (2 s; 0.57 mA foot shock) pairings and tested 2...

The role of the hippocampus in pavlovian fear conditioning is controversial. Although lesion and pharmacological inactivation studies have suggested a key role for the dorsal hippocampus in contextual fear conditioning, the involvement of the ventral part is still uncertain. Likewise, the debate is open with regard to the putative implication of each hippocampal subdivision in fear conditioning...

BACKGROUND Fear conditioning is a traditional model for the acquisition of fears and phobias. Studies of the genetic architecture of fear conditioning may inform gene-finding strategies for anxiety disorders. The objective of this study was to determine the genetic and environmental sources of individual differences in fear conditioning by means of a twin sample. METHODS Classic fear conditio...

Memory loss is one of the hallmark symptoms of Alzheimer's disease (AD). It has been proposed that soluble amyloid-beta (Abeta) oligomers acutely impair neuronal function and thereby memory. We here report that natural Abeta oligomers acutely impair contextual fear memory in mice. A natural Abeta oligomer solution containing Abeta monomers, dimers, trimers, and tetramers was derived from the co...

Research across species highlights the critical role of the amygdala in fear conditioning. However, fear conditioning, involving direct aversive experience, is only one means by which fears can be acquired. Exploiting aversive experiences of other individuals through social fear learning is less risky. Behavioral research provides important insights into the workings of social fear learning, an...

BACKGROUND Midazolam may suppress conditioned fear after an aversive event by disrupting the memory trace formed during conditioning, by altering the emotional part of the aversive event, or by the combination of both effects. The purpose of the present study was to determine whether affective-related processes contribute to the amnesic-like effects of midazolam on aversive events. METHODS Th...

Rac1, a member of the Rho family of small GTPases, is crucial for morphological changes of the mature neuronal synapse including spine formation and activity-dependent spine enlargement, while its role in the formation of associated memories, such as conditioned fear memory, is not clear. Here, we report that selective deletion of Rac1 in excitatory neurons, but not in parvalbumin inhibitory ne...

Fear conditioning is a valuable behavioral paradigm for studying the neural basis of emotional learning and memory. The lateral nucleus of the amygdala (LA) is a crucial site of neural changes that occur during fear conditioning. Pharmacological manipulations of the LA, strategically timed with respect to training and testing, have shed light on the molecular events that mediate the acquisition...

Introduction: One of the hallmark symptoms of posttraumatic stress disorder (PTSD) is the impaired extinction of traumatic memory. Single prolonged stress (SPS) has been suggested as an animal model of PTSD, since SPS rats exhibited the impaired fear extinction. Oxytocin (OXT) has been recently suggested as a potential pharmacotherapy for treatment of PTSD. In this study, using SPS rats we inve...

The basolateral amygdala's involvement in fear acquisition and expression to visual and auditory stimuli is well known. The involvement of the basolateral and other amygdala areas in fear acquisition and expression to stimuli of other modalities is less certain. We evaluated the contribution of the basolateral and medial amygdala to olfactory and to context fear and fear conditioning by infusin...