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1
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Intertrial responses in defensive instrumental learning

100%
Zielinski K.
Acta Neurobiologiae Experimentalis
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1993
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vol. 53
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issue 1
215-229
EN
Data by the author, as well as from other laboratories, show residual fear as the main source of intertrial responses (ITR) during defensive instrumental training in rats, cats and dogs.. Between-subject differencies in ITR rate arise in the course of training. The differences depend on training conditions and on subject's emotionality. Under the same conditions higher ITR rates correspond to more rapid avoidance learning. The increase of ITR rate is regularly observed in the following circumstances: at early stages of training, after transfer to a less salient discriminative stimulus, and after a change of the taskrequirements. The decrease of ITR rate corresponds to the plateau level of avoidance or escape performance. Both a lower ITR rate and reduced flexibility of behavior are found after lesions of the amygdala nuclei.
2
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Influence of emotional arousal on the N150 of the Auditory Evoked Potential from the rat amygdala

88%
Knippenberg J. M. J., Maes J. H. R., Coenen A. M. L., van_ L. G.
Acta Neurobiologiae Experimentalis
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2009
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vol. 69
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issue 1
109-118
EN
This study tested whether a general increase in emotional arousal is a sufficient determinant for the evocation of the N150, a negative wave in amygdalar Auditory Evoked Potentials (AEPs). Rats received one of three conditioning protocols: either conditioned stimulus (CS) presentations alone (Control), CS-shock pairings (Paired), or unpaired presentations of the CS and shock (Unpaired). Amygdalar AEPs were recorded in response to the CS. It was hypothesized that if a state of emotional arousal is a sufficient condition for the manifestation of the N150, its amplitude should be enhanced in the Paired and Unpaired conditions relative to the Control condition, which was indeed found. In addition, it was found that the N150 had a larger amplitude in the Paired than in the Unpaired condition. This suggests that an additional N150 increase is established when animals learn the CS-US association. The results are discussed in relation to literature on amygdala function.
3
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Correlation between long latency evoked potentials from amygdala and evoked cardiac response to fear conditioned stimulus in rats

88%
Kuniecki M., Coenen A. M. l., Kaiser J.
Acta Neurobiologiae Experimentalis
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2002
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vol. 62
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issue 2
85-92
EN
We investigated relation between activity of central nucleus of amygdala (CE) and phasic heart rate deceleration during differential fear conditioning. We found that P2 component of long-lasting event potential (EP) to CS+ but not to CS- correlated strongly with HR deceleration in the 1st second after stimulus onset. Obtained results are discussed in the light of LeDoux?s and Kapp?s findings showing crucial role of amygdala in processing of emotionally relevant stimulation and it?s involvement in initiating autonomic responses.
4
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Expression of c-fos in response to stressogenic stimuli in the amygdala of old vs. young rats ? a preliminary study

88%
Boguszewski P., Zagrodzka J.
Acta Neurobiologiae Experimentalis
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2005
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vol. 65
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issue 2
191-194
EN
During aging many of the brain functions became deteriorated or altered. One of the most important age related changes is an increase of anxiety level, reported both in humans and in animals. Our study was intended to compare c-fos gene expression in amygdala, the key structure in anxiety/fear regulation, in old (24 months old) and young (4 months old) rats exposed to various behavioral stimulations. There were no differences between age groups in basal c-Fos expression. After social encounter c-Fos expression level in amygdala increased significantly, but still remained independent on age. Significant differences between both groups appeared after open field test and immobilization test. Contrary to the findings on young adults indicating the correlations between increased anxiety level and higher c-Fos expression, old rats showed increased anxiety together with significantly lower c-Fos expression.
5
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Involvement of the lateral and dorsolateral amygdala in conditioned stimulus modality dependent two-way avoidance performance

75%
Werka T.
Acta Neurobiologiae Experimentalis
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1998
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vol. 58
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issue 2
131-147
EN
Post-lesion learning and performance of shuttle-box avoidance and subsequent transfer to two warning signals (CSs) of different modality were investigated in 27 rats subjected either to a sham lesion (Group NORM), electrolytic injuries of the lateral amygdaloid nucleus (Group LAT), or combined lesions of the amygdalostriatal transition area and dorsolateral amygdala (Group D-LAT). All groups were divided into two subgroups according to warning signal sequences. In the first subgroup (D-DN-N sequence) the subjects were initially trained with the visual CS (darkness - D), then transferred to the more salient visual and auditory compound CS (darkness and noise - DN), and finally to the auditory CS alone (noise - N). The opposite arrangement of the CSs (N-ND-D sequence) was employed in the second subgroup. A small interference with shuttle-box learning, and no transfer deficit were seen in Group LAT, whereas D-LAT rats showed dramatically slow and inconsistent acquisition of avoidance responding followed by rapid weakening of performance during the training. In contrast to controls, in both lesioned groups avoidance and intertrial responding (ITR) were independent of the CS modality changes. The results indicate differential involvement of the lateral, and also of the dorsolateral amygdala, and amygdalostriatal transition area in CS processing, as well as in the mechanisms related to consolidation of the associations created during avoidance training.
6
Content available remote

Post-stress analgesia in rats with partial amygdala lesions

63%
Werka T.
Acta Neurobiologiae Experimentalis
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1994
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vol. 54
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issue 2
127-132
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