the most important risk factors for anxiety disorders include genes, early life stress, and current stress. these factors do not act independently but interact with each other throughout human development through examples such as epigenetic modifications and complex forms of learning. the neural substrate of pathological anxiety includes hyperactivity in the amygdala and other limbic brain regi...

introduction: previous studies have shown that the basolateral amygdale (bla) is rich of cb1 cannabinoid receptors and involved in cannabinoid-induced antinociception. also, it seems that there are functional interactions between the cannabinoid cb1 and opioid receptors in the process of sensitization to opiates. in the present study, we tried to examine the role of intra-bla cannabinoid recept...

In extinction of auditory fear conditioning, rats learn that a tone no longer predicts the occurrence of a footshock. Recent lesion and unit recording studies suggest that the medial prefrontal cortex (mPFC) plays an essential role in the inhibition of conditioned fear following extinction. mPFC has robust projections to the amygdala, a structure that is known to mediate the acquisition and exp...

How do the hippocampus and amygdala interact with thalamocortical systems to regulate cognitive and cognitive-emotional learning? Why do lesions of thalamus, amygdala, hippocampus, and cortex have differential effects depending on the phase of learning when they occur? In particular, why is the hippocampus typically needed for trace conditioning, but not delay conditioning, and what do the exce...

Associative learning processes play many important roles in the control of food consumption. Although these processes can complement regulatory mechanisms in the control of eating by providing opportunities for the anticipation of upcoming needs, they may also contribute to inappropriate or pathological consumption patterns by overriding internal regulatory signals. In this article, we first re...

Lesion and electrophysiological studies in rodents have identified the amygdala and hippocampus (HPC) as key structures for Pavlovian fear conditioning, but human functional neuroimaging studies have not consistently found activation of these structures. This could be because hemodynamic responses cannot detect the sparse neuronal activity proposed to underlie conditioned fear. Alternatively, d...

Citation: Yuan T-F and Su H (2015) Fear learning through the two visual systems, a commentary on: " A parvalbumin-positive excitatory visual pathway to trigger fear responses in mice. " Front. Neural Circuits 9:56. A commentary on BRAIN CIRCUITS. A parvalbumin-positive excitatory visual pathway to trigger fear responses in mice. The theory of two visual systems was firstly proposed in 1960s, to...

The central nucleus of the amygdala (CeA) has been traditionally viewed in fear conditioning to serve as an output neural center that transfers conditioned information formed in the basolateral amygdala to brain structures that generate emotional responses. Recent studies suggest that the CeA may also be involved in fear memory consolidation. In addition, corticotropin-releasing factor systems ...

The role of the basolateral amygdala (LA) in the acquisition and expression of Pavlovian fear conditioning was examined in 80 rats. Excitotoxic lesions were made in the BLA using N-methyl-D-aspartate 7 days before or 1, 14, or 28 days after Pavlovian fear conditioning. Conditioning consisted of three pairings of a tone with an aversive footshock in a novel chamber, and freezing behavior served ...