30 Theta waves in the amygdala are known to be synchronized with theta waves 31 in the hippocampus. Synchronization between amygdala and hippocampal theta waves 32 is considered important for neuronal communication between these regions during the 33 memory-retrieval process. These theta waves are also observed during rapid eye 34 movement (REM) sleep. However, few studies have examined the mec...

In experiment 1, we assessed the role of the primate amygdala and hippocampus in the acquisition of learned fear measured with fear-potentiated startle. Three groups of six rhesus monkeys were prepared with bilateral ibotenic acid lesions of the amygdaloid complex and the hippocampus or were sham operated. Selective ibotenic acid lesions of the amygdala, but not the hippocampus, blocked the acq...

Bilateral lesions of the amygdaloid complex result in elimination or attenuation of the conditioned freezing that is normally seen in the conditioned emotional response (CER) paradigm and the active avoidance (AA) task. We observed the effect of amygdalar tissue transplantation on the ability of lesioned (central nucleus of amygdala, CeA) rats to learn CER and AA. In two groups of adult Wistar ...

Prosody (i.e. speech melody) is an important cue to infer an interlocutor's emotional state, complementing information from face expression and body posture. Inferring fear from face expression is reported as impaired after amygdala lesions. It remains unclear whether this deficit is specific to face expression, or is a more global fear recognition deficit. Here, we report data from two twins w...

Two types of bilateral amygdalar lesions were performed successively. The first operation, involving the dorsomedial part, produced aphagia and subsequent hypophagia, vomiting and apathy. Consequently the body weight was reduced. After a few weeks partial recovery occurred. The second operation, involving the lateral part of the amygdaloid complex, produced hyperphagia, increase of body weight ...

The role of the amygdala central nucleus (CeN) in habit learning was assessed in two experiments. First, we examined the effects of bilateral lesions of the anterior CeN on an overtraining-induced lever press habit evaluated using an outcome devaluation protocol. Overtraining generated habitual performance and rendered sham lesioned rats insensitive to outcome devaluation, an effect that was al...

The present study was designed to examine whether lesions of the insular cortex (IC; Experiment 1), the basolateral amygdala (BLA) or medial amygdala (MeA; Experiment 2) influence the neophobic reactions to orally consumed liquid stimuli. Three different types of stimuli were used: taste (0.5% saccharin), olfactory (0.1% amyl acetate), and trigeminal (0.01 mM capsaicin). Rats with IC, BLA and M...

  In this study, the effect of an experimentally increased excitability in hippocampal neurons, via hippocampal kindling, on amygdala kindling rate was investigated in rats. Animals were divided into 4 groups. In all groups, except group 2, tripolar electrodes were implanted in the amygdala and CAI region of the dorsal hippocampus. Group 2 animals were only implanted with tripolar electrodes in...

CONTEXT Despite the repeated findings of impaired fear conditioning and affective recognition in psychopathic individuals, there has been a paucity of brain imaging research on the amygdala and no evidence suggesting which regions within the amygdala may be structurally compromised in individuals with psychopathy. OBJECTIVE To detect global and regional anatomical abnormalities in the amygdal...

The neural basis of auditory fear conditioning (AFC) is almost universally believed to be the amygdala, where auditory fear memories are reputedly acquired and stored. This widely-accepted amygdala model holds that the auditory conditioned stimulus (CS) and the nociceptive unconditioned stimulus (US) first converge in the lateral nucleus of the amygdala (AL), and are projected independently to ...