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1
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Central control of heart rate changes during visual affective processing as revealed by fMRI

100%
Kuniecki M., Urbanik A., Sobiecka B., Kozub J., Binder M.
Acta Neurobiologiae Experimentalis
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2003
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vol. 63
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issue 1
39-48
EN
In the present study we addressed the question of central control of heart rate (HR) in emotions. Parallel measurement of HR changes and changes of local intensity of blood flow as indexed by fMRI in a procedure eliciting emotions allowed us to pinpoint areas of the brain responsible for HR variations during emotional arousal. In condition eliciting positive emotions we detected activation of occipito-temporal regions, anterior insula, and hypothalamus. In condition eliciting negative emotions we also detected activation of occipito-temporal regions and additionally activation of bilateral anterior insulae, right amygdala and right superior temporal gyrus. The results show that structures constituting neural network involved in HR control during emotional arousal are affect specific. Particularly the central circuit controlling HR in negative affect includes the amygdala, while central circuit controlling HR in positive affect includes the hypothalamus. Additionally activation of bilateral occipito-temporal cortex proves enhancement of visual processing of emotional material as compared to neutral material in both positive and negative affect. This might be attributed to top-down processes originating in the frontal lobe and related to shifting attention to the emotionally relevant stimuli. Activation of insular cortex is probably related to autonomic arousal accompanying watching emotional content (e.g. sweating, heart-rate changes etc.). Activation of the amygdala in the negative condition supports the well documented engagement of this structure in processing of fear and disgust.
2
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The evoked cardiac response as a function of cognitive load in subjects differing on the individual difference variable of reaction time

100%
Kaiser J., Beauvale A., Bener J.
Acta Neurobiologiae Experimentalis
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1996
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vol. 56
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issue 1
209-213
EN
We report research on different phasic evoked cardiac responses associated with differences in cogintive activity.These were examined in relation to a stable individual difference variable, mean simple reaction time (RT). Individual means on RT were found to be sufficiently stable over a 10 month period to consider them as individual functional characteristics. Subjects were divided into two subgroups on the basis of the first measure of their individual mean RT (above and below the group median). Each subject received 10 innocuous auditory stimuli with randomly varying interstimulus intervals. Stimuli were presented in one of two conditions defined by instructions allowing them to ignore (irrelevant condition), or requiring them to count the stimuli (relevant condition). A main effect of instruction was obtained in the evoked cardiac response. The initial heart rate deceleration was significantly larger in the relevant condition. Short-RT subjects had smaller heart rate changes to the irrelevant stimuli. The data are discussed in terms of the intensity of stimulus processing (both physical and cognitive) as a factor which may be related fundamentally to stable individual differences in RT.
3
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Exogenous hydrogen sulfide produces hemodynamic effects by triggering central neuroregulatory mechanisms

100%
Ufnal M., Sikora M., Dudek M.
Acta Neurobiologiae Experimentalis
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2008
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vol. 68
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issue 3
382-388
EN
Recently, it was found that hydrogen sulfide (H2S) may serve as an important transmitter in peripheral organs as well as in the brain. The aim of the present study was to evaluate the possible function of H2S in the brain regulation of the circulatory system. Experiments were performed on conscious, male, Wistar-Kyoto rats. Mean arterial blood pressure (MABP) and heart rate (HR) were recorded continuously under baseline conditions and during infusions into the lateral cerebral ventricle (LCV) of the experimental animals. In control series LCV infusion of vehicle (Krebs-Henseleit bicarbonate-buffer) did not cause significant changes in MABP or HR. LCV infusion of H2S donor (NaHS) at the rate of 400 nM/h resulted in an increase in MABP, whereas infusions at the rate of 100 nM/h and 200 nM/h failed to change MABP. On the other hand LCV infusion of H2S donor at the rate of 200 nM/h caused a significant increase in HR while infusion at the rate of 400 nM/h produced an increase in HR, which was smaller than this observed during infusion at the rate of 200 nM/h. H2S donor administered at the rate of 100 nM/h failed to affect HR. In conclusion, the present study demonstrates that exogenous hydrogen sulfide changes hemodynamic parameters by centrally mediated mechanisms. The hemodynamic effect seems to be dependent on H2S concentration in cerebrospinal fluid. It appears that the hypertensive response may occur at a concentration, which does not exceed twice the physiological level.
4

Monitoring of the cardiac activity of the Baltic isopod Saduria entomon exposed to hypoxia, using non-invasive, computer-aided techniques

100%
Miac J.
Oceanological Studies
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2001
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vol. 30
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issue 3-4
115-124
EN
The repertoires of physiological responses which invertebrates possess play a major role in determining their distribution and survival potential. In the present study the effect of severe hypoxia on the heart rate of S. entomon has been investigated. Saduria entomon are often exposed to extended periods of severe hypoxia and anoxia in their natural habitats. The animals were exposed to conditions of a reduced level of oxygen (< 10% O2 saturation) for 24 hours. The experiment confirms that the pattern of their heart rate changed considerably with time and experimental condition. Under hypoxic condition a steady, regular heart rate was observed and the variability of beat rate decreased in comparison with normoxic one. The mean heart rate of the unburied animals in normoxia was higher than that of the buried S.entomon with considerably lower inter-individual variability. The mean heart rate of animals in hypoxic conditions was similar for all individuals (41.66 ? 2.03 (mean ? SD)), but not significantly different in normoxic conditions (Student t-test, p > 0.05).
5
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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.
6
Content available remote

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.
7
Content available remote

Changing difficulty level in a one-dimensional tracking task and corresponding heart rate changes

88%
Bohdenecky Z., Indra M., Radil T.
Acta Neurobiologiae Experimentalis
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1995
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vol. 55
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issue 1
49-55
EN
Subjects were required to track a target consisting of two vertical bars moving with either a constant or a sinusoidally modulated speed an osciloscope scren with a joystick-controlled light-spot.Either target size or velocity of the target movement(velocity quided tasks), varied throughout different tasks determined by subject's performance.The target's initial movement period was either 2 or 3 seconds.The following parameters were studied: time on-terget intervals, time off-target intervals, number of tracking errors, heart rate and tracking error incidence over the cardiac cycle.Time on-target intervals were longer for the velocity quided tasks then for the size quided ones.The same was true for time off-terget intervals.Values for both types of intervals decreased gradually over the fixed sequence of tasks for velocity but not for size quided tasks.Heart rate was higher in the size quided task.Tracking error incidence did not depend on the phase of cardiac cycle.
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