Synaptic plasticity is a cellular mechanism putatively underlying learning and memory. However, it is unclear whether learning induces synaptic modification globally or only in a subset of neurons in associated brain regions. In this study, we genetically identified neurons activated during contextual fear learning and separately recorded synaptic efficacy from recruited and nonrecruited neuron...

The present experiment examined the influence of excitotoxic lesions of the basolateral amygdala (BLA) on morphine-induced saccharin avoidance. Neurologically intact subjects rapidly learned to avoid drinking the taste conditioned stimulus (CS), an effect that was sustained throughout the experiment. Although the BLA-lesioned (BLAX) rats showed CS avoidance over the first few trials, the effect...

Endocannabinoids (eCBs) modulate a variety of brain functions via activation of the widely expressed CB1 receptor. One site of high density of this receptor is the basolateral amygdala (BLA), a structure involved in the formation of aversive memories. The activation and blockade of CB1 receptors by systemic or hippocampal drug administrations have been shown to modify memory processing. However...

The basolateral amygdala (BLA) and the dorsal hippocampus (dHPC) are both structures with key roles in contextual fear conditioning. During fear conditioning, it is postulated that contextual representations of the environment are formed in the hippocampus, which are then associated with foot shock in the amygdala. However, it is not known to what extent a functional connection between these tw...

The influence of overtraining on the magnitude of fear-conditioning deficits produced by neurotoxic lesions of the basolateral amygdala (BLA) was examined. Either 1 d before or 1 week after the administration of neurotoxic BLA lesions, rats received either 1 or 25 conditioning trials consisting of the delivery of unsignaled foot shock in a novel observation chamber; freezing served as the measu...

Memory consolidation studies, including those examining the role of the basolateral amygdala (BLA), have traditionally used techniques limited in their temporal and spatial precision. The development of optogenetics provides increased precision in the control of neuronal activity that can be used to address the temporal nature of the modulation of memory consolidation. The present experiments, ...

In a new rat model of obsessive-compulsive disorder (OCD), 'compulsive' behaviour is induced by attenuating a signal indicating that a lever-press response was effective in producing food. We have recently found that compulsive lever pressing is increased following lesions to the rat orbital cortex, in accordance with several lines of evidence implicating the orbitofrontal cortex in the pathoph...

Responses to threat-related stimuli are influenced by conscious and unconscious processes, but the neural systems underlying these processes and their relationship to anxiety have not been clearly delineated. Using fMRI, we investigated the neural responses associated with the conscious and unconscious (backwardly masked) perception of fearful faces in healthy volunteers who varied in threat se...