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1
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Electrical hippocampal activity during danger and safety signals in classical conditioning in the rat

100%
Kasicki S., Jelen P., Olszewski M., Slawinska U.
Acta Neurobiologiae Experimentalis
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2009
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vol. 69
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issue 1
119-128
EN
The effect of stimuli predicting danger (DS) and safety (SS) in Pavlovian aversive conditioning on hippocampal local field potentials (LFP) was studied in 25 partially restrained adult male rats (Long-Evans). DS lasting 5 s preceded tail-shock, while SS overlapping DS during DS last 3 s predicted omission of shock. The power spectra of LFPs during trials were analyzed in theta and delta frequency bands. In DS, theta frequency during the last 3 s was lower that in first 2 s. In danger and safety situation theta peak frequency was different for dorsal CA1 activity (5.99 Hz vs. 6.86 Hz, respectively), while delta peak frequency was different for ventral CA1 (1.56 Hz vs. 1.07 Hz) for the last 3 s of trial. Differences in theta frequency in danger and safety situation may reflect differences in sensory processing during induced emotional states and/or related differences in motor behavior.
2
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Heart rate changes in partially restrained rats during behaviorally and pharmacologically evoked emotional states

88%
Jelen P., Zagrodzka J.
Acta Neurobiologiae Experimentalis
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2001
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vol. 61
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issue 1
53-67
EN
The effect of fear and relief from fear on heart rate (HR) was studied in partially restrained adult male rats. The emotional state was influenced behaviorally with the use of Pavlovian aversive conditioning procedure, and pharmacologically by injections of the selected anxiolytics and anxiogenics. A signal of danger (DS) - light or tone, preceded tail-shock (excitatory trials), while a signal of safety (SS), respectively tone or light, overlapped last 3s of 5s DS and predicted an omission of this expected aversive event (inhibitory trials). To assess the stability of HR changes to DS and SS we analyzed whether and how the experimental conditions (modality and position of signals, the ratio of numbers of excitatory to inhibitory trials in the session) influenced HR. HR changes to DS were different in pattern, stability and direction when compared to HR changes in response to SS. Reactions to DS, although accompanied mainly by conditioned bradycardia, were not consistent and depended on experimental conditions. However, the SS always evoked conditioned tachycardia. Anxiolitycs - benzodiazepines (diazepam and midazolam) and buspirone - influenced HR in nonconsistent manner. Anxiogenics - PTZ and FG7142 were without significant effects on HR. HR could not be trusted therefore as direct index of pharmacologically induced emotional states. The results are discussed in the context of possible biobehavioral meaning of HR changes in response to danger and safety and their reliability as fear/relief correlates.
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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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.
5
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Fear behavior and regional brain monoamines distribution after R(+)-8-OHDPAT and R(+)-UH-301 injections into the dorsal raphe nucleus in rats

75%
Koprowska M., Krotewicz M., Romaniuk A., Strzelczuk M., Wieczorek M.
Acta Neurobiologiae Experimentalis
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2002
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vol. 62
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issue 2
63-74
EN
The effects of R(+)-8-Hydroxy-dipropyl-aminotetralin, (R(+)-8-OHDPAT) and R(+)-5-Fluoro-Hydroxy-dipropyloaminotetralin (R(+)-UH-301) injection into the dorsal raphe nucleus (DRN) on fear behavior in a modified version of the light-dark transitions test and regional brain monoamines (NA, DA, 5-HT) and their metabolites ( MHPG, DOPAC, 5-HIAA) in the hypothalamus (HPT), midbrain central gray matter (MID), amygdala (AMY), hippocampus (HIP) and pons (PO) were examined. An injection of R(+)-8-OHDPAT (300 ng) as well R(+)-UH-301 (300 ng) into the DRN evoked i) an increase in the number of head dipping from dark to the illuminated compartment of chamber; ii) an increase of time spent motionless in the dark compartment; iii) decrease of time of locomotion activity in the illuminated compartment. There was no effect on (1) time out from the illuminated to the dark compartment; (2) time of locomotion activity in the dark compartment; (3) time spent motionless in the illuminated compartment; 4) the number of returns from the dark to the illuminated compartment. HPLC analysis showed reduction of 5-HIAA/5-HT ratio in the HPT, HIP and PO, reduction of 5-HT in the MID, increase of NA content in the HPT and AMY, increase of MHPG/NA ratio in the HIP and PO, and increase of DA content in the HPT, AMY and HIP and increase of DOPAC content in the HIP after R(+)-8-OHDPAT injection into the DRN. But injection of R(+)-UH-301 into the DRN reduced 5-HT in the MID and increased in the AMY, reduced 5-HIAA content in the HIP and increased in the MID, reduced NA content in the HIP and increased in the HPT and decreased MHPG/NA ratio in the PO. These results indicate that both 5-HT1A receptor agonists, R(+)-8-OHDPAT and R(+)-UH-301, acting on the 5HT1A autoreceptors caused the anxiolytic effects, reduced fear behavior on the rat connected with infringement of dynamic balance between the serotonergic and catecholaminergics systems.
6
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Acoustic startle response in the opossum Monodelphis domestica in comparison with the wistar albino rat

75%
Blaszczyk J. W., Turlejski K.
Acta Neurobiologiae Experimentalis
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2005
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vol. 65
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issue 2
201-204
EN
The acoustic startle response (ASR) was studied in 20 gray short-tailed opossums (Monodelphis domestica) and its characteristics were compared with those obtained from responses of 20 Wistar albino rats. The animals were exposed to 10 ms, 110 dB white noise acoustic pulses in the Coulbourn apparatus. Amplitude of ASR was normalized to the weight of animals and then analyzed. The results show that probability of a freezing response is much higher in the opossums that generally respond with lower startle amplitudes in comparison to rats. These differences may reflect different emotional characteristics of the two species, different reactions to fear in opossum and/or different ecological specializations of the two species.
7
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Age-related changes in fear behavior and regional brain monoamines distribution in rats

75%
Koprowska M., Krotewicz M., Romaniuk A., Strzelczuk M.
Acta Neurobiologiae Experimentalis
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2004
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vol. 64
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issue 2
131-142
EN
Differences in fear level assessment based on the time of motionless in the illuminated compartment, time spent in light compartment, number of head dipping from dark to the illuminated compartment and number of returns from dark to the illuminated compartment registered in light/dark transitions test and brain monoamines (NA, DA, 5-HT) and their metabolites (MHPG, DOPAC, 5-HIAA) in the hypothalamus, midbrain, amygdala, hippocampus and pons were examined in 3, 12 and 24 months old Wistar rats. The lowest level of fear was registered in 12 months old rats, a slightly higher level in 3 months old rats and the highest in 24 months old rats. Locomotion activity showed a decreasing tendency within age according to a linear dependence in 3, 12 and 24 months old rats. Neurochemical data showed the decreased activity of NA system and increased activity of DA system in most structures already occurred in 12 months old rats. It remained at the same level in aged rats. The correlation analysis between the behavioral markers of fear level and distribution of monoamines in young, mature and aged rats showed diversified data, only some of them being consistent with the 'serotonergic hypothesis' of fear/anxiety. Therefore, we cannot conclude what neurochemical background of fear is.
8
Content available remote

Affective percept and voluntary action: A hypothesis

63%
Zernicki B.
Acta Neurobiologiae Experimentalis
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2002
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vol. 62
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issue 2
99-110
EN
. I present a hypothesis concerning the neuronal, mental and behavioral effects of all kinds of affective (emotional) stimuli, i.e., of unpleasant and pleasant stimuli. I use the term stimulus in its broad sense. Affective stimuli evoke two associated percepts: ?cognitive? and ?affective?. A food in the mouth, for example, evokes the gustatory percept and the percept of pleasure. However, affective percepts are unstable parts of cognitive-affective compounds. Five types of affective percepts are pain, fear, pleasure, ?desire? and appetite in the broad sense of these words. Desire is evoked by inadequate pleasant stimuli. Affective percepts are ?lower? or ?higher?. The latter are not directly associated with bodily needs. Esthetic and social percepts are higher, for example. Although pain and pleasure are essentially innate, they can be modified by sensory experience. Alimentary and esthetic preferences and social values are modifiable, for example. The neurons of pain and fear and of the unpleasant components of desire and appetite motivate four types of voluntary actions. These are, respectively, escape, avoidance, ?optimization? and approach actions. All these actions eliminate the motivating displeasure. In addition, avoidance actions protect from the signaled pain, optimization actions increase the existing pleasure and approach actions provide the signaled pleasure. Thus, voluntary actions associated with different percepts occur according to one universal principle. Voluntary actions are ?internal? and behavioral. During internal actions a goal and then an action plan are decided. These actions often provide the images of the goal stimuli and of particular movements.
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