'Amygdala' and 'amygdalar complex' are terms that now refer to a highly differentiated region near the temporal pole of the mammalian cerebral hemisphere. Cell groups within it appear to be differentiated parts of the traditional cortex, the claustrum, or the striatum, and these parts belong to four obvious functional systems--accessory olfactory, main olfactory, autonomic and frontotemporal co...

Neurosteroids are formed de novo in the brain and can modulate both inhibitory and excitatory neurotransmission. Recent evidence suggests that the anxiolytic effects of neurosteroids are mediated by the amygdala, a key structure for emotional and cognitive behaviors. Tonic inhibitory signaling via extrasynaptic type A γ-aminobutyric acid receptors (GABA(A)Rs) is known to be crucially involved i...

Increasing evidence suggests that parallel plastic processes in the amygdala involve inhibitory elements to control fear and extinction memory. GABAergic medial paracapsular intercalated cells (mpITCs) are thought to relay activity from basolateral nucleus (BLA) and prefrontal cortex to inhibit central amygdala output during suppression of fear. Recently, projection diversity and differential b...

Background: Temporal lobe epilepsy (TLE) is the most common type of intractable and partial epilepsies. The only standard treatment for seizure-free status with manifest TLE surgical which includes amygdala-hippocampectomy. majority temporal seizures originate in mesial structures, primarily hippocampus, para hippocampal gyrus amygdala.

Active avoidance (AA) is an important paradigm for studying mechanisms of aversive instrumental learning, pathological anxiety, and active coping. Unfortunately, AA neurocircuits are poorly understood, partly because behavior is highly variable and reflects a competition between Pavlovian reactions and instrumental actions. Here we exploited the behavioral differences between good and poor avoi...

Epilepsy is among the most common disorders of the central nervous system and there is not an absolute method for its treatment. It has been shown that each seizure has a depressing effect on the following seizure. Thus, finding the mechanisms responsible in this phenomenon can improve our knowledge toward new ways for epilepsy treatment. In this study, the role of adenosine A1 receptors in ...

Background: The amygdala is one of the nerve centers involved in drug reward. It is suggested that the central nucleus of the amygdala (CeA) is involved in morphine dependency. The CeA gamma-aminobutyric acid-ergic (GABAergic) system is a mediator of morphine rewarding effects. In this research, the effects of stimulation or inhibition of CeA GABA type B (GABAB) receptors on sensitization acqui...

Data from both rodents and humans show that testosterone reduces fear. This effect is hypothesized to result from testosterone's down regulating effects on the amygdala, a key region in the detection of threat and instigator of fight-or-flight behavior. However, neuroimaging studies employing testosterone administration in humans have consistently shown increased amygdala responsivity. Yet, no ...

Why are emotionally arousing experiences well-remembered? Since the amygdala and hippocampus play pivotal roles in emotion and memory, respectively, the interaction between these brain regions may underlie the formation of enhanced memory for emotionally arousing events. Behavioral experiments using animals have demonstrated that lesions of the amygdaloid nuclei or infusions of drugs into the a...

As a central fear processor of the brain, the amygdala initiates a cascade of critical physiological and behavioral responses. Neuroimaging studies have shown that the human amygdala responds not only to fearful and angry facial expressions but also to fearful and threatening scenes such as attacks, explosions, and mutilations. Given the relative importance of facial expressions in adaptive soc...