Effect of stress induced by electrical stimulation of the hypothalamus on the electrical stability of the heart in rabbits

The influence of stress on cardiac electrical stability (CES) and chaotic dynamics of the electrical activity of the heart was studied in acute and chronic experiments in rabbits. Stress was caused by 2-3 h daily immobilization of the animals with electrical stimulation of emotiogenic centers of the hypothalamus through implanted electrodes. CES was estimated by the thresholds for ventricular arrhythmia: paroxysmal ventricular tachycardia, repeated ventricular extrasystoles and ventricular fibrillation (VF). The results showed: (i) CES in stressed rabbits was decreased significantly compared with controls; (ii) the level of chaos at the onset of VF in stressed rabbits was increased significantly compared with controls; (iii) heart rate of stressed rabbits was significantly greater than in controls; (iv) changes in CES parameters depended on whether stress was acute or chronic; (v) acute stress promoted transition of spontaneously reversible VF into spontaneously irreversible VF. Thus, stress increased the degree of disorganization of heart electrical activity and also decreased its electrical stability. The experiments indicate that stress is a destabilizing factor influencing the reversibility of heart rate disorders. The probability of such reversibility depends on whether stress is acute or chronic: acute stress is more likely to lead to irreversible spontaneous VF.     

A note on ECG changes observed during Pavlovian conditioning in a rhesus monkey following coronary arterial occlusion

Changes in the ECG of a rhesus monkey during a classical aversive conditioning trial conducted 10 minutes after occlusion of the marginal branch of the left circumflex coronary artery have been observed. This appears to reflect an instance where myocardial ischemia following coronary occlusion was exacerbated by presentation of a conditional stimulus.     

Stimulated release of tissue plasminogen activator from artery wall sympathetic nerves: implications for stress-associated wall damage

Recurrent stress is clinically associated with early onset hypertension and coronary artery disease. A mechanism linking emotion to pathogenic remodeling of the artery wall has not been identified. Stress stimulates acute regulated release of tissue plasminogen activator (t-PA) into the circulation, which is presently attributed to the vascular endothelium. Sympathetic neurons also synthesize t-PA and axonally transport it to the arterial smooth muscle. Unlike release by the endothelium, a stress-stimulated sympathetic discharge would potentially accelerate degradation of the wall matrix by plasmin. To assess whether sympathetic axons are the principal source of acute stress-induced arterial release of t-PA, we compared the output from small densely innervated and large sparsely innervated isolated artery segments before and after sympathetic stimulation, and after ablations. Following phenylephrine infusion densely-innervated microvessels in uveal eyecups were released over 60-fold greater amounts of active t-PA per milligram than the sparsely innervated aorta; and ten-fold more than carotid artery segments. Mesenteric artery release was 4.8-fold greater than release by the carotid artery. In vivo, uveal release of t-PA increased more than three-fold within one minute following superior cervical sympathetic ganglion electrical stimulation, and after phenylephrine, or nicotine infusions of the anterior chamber. Circulating levels of t-PA fell 70% following chemical sympathectomy. We propose that sympathetic nerves are the primary source of stress-induced release of t-PA into and from the densely innervated resistance arteries and arterioles, where dysregulated plasmin-induced proteolysis could damage the wall matrix.     

Cardiac arrhythmias in the monkey during classically conditioned fear and excitement

Rhesus monkeys(Macaca mulatto) were tested in classic aversive and appetitive conditioning paradigms following complete coronary artery occlusion (CO) to test the hypothesis that “emotional stress” induces ventricular arrhythmias. Findings were based upon conditioning trials conducted for one or more weeks after occlusion in 13 animals. When all data from each animal for the week following CO were considered, there was no demonstrable tendency for arrhythmias to increase during “fear” conditioned to unavoidable electric shock or during “excitement” in anticipation of food. However, selected trials from six monkeys did reveal instances when changes in the frequency of occurrence of arrhythmias were coupled with behavioral conditioning. While analysis of these trials did not reveal any simple relationship between emotional stress and the development of ventricular arrhythmias after myocardial infarction, certain of the behavioral situations may be more potentially arrhythmogenic than others. For these selected trials, with respect to control, the number of arrhythmias may have increased or decreased upon presentation of the conditional stimulus; the exact response appears to depend upon the immediate physiologic status of the animal as well as on the behavioral condition. “More stressful” situations, such as aversive conditioning, are not necessarily associated with greater numbers of arrhythmias than were “less stressful” situations, such as appetitive conditioning. Arrhythmias appear to occur more frequently when an animal’s heart rate is within a given range; this may reflect underlying cardiac sympathetic and parasympathetic nerve activity.     

Automatic recognition of eye blinking in spontaneously occurring behavior

Previous researchin automatic facial expression recognition has been limited to recognition of gross expression categories (e.g., joy or anger) in posed facial behavior under well-controlled conditions (e.g., frontal pose and minimal out-of-plane head motion). We have developed a system that detects a discrete and important facial action (e.g., eye blinking) in spontaneously occurring facial behavior that has been measured with a nonfrontal pose, moderate out-of-plane head motion, and occlusion. The system recovers three-dimensional motion parameters, stabilizes facial regions, extracts motion and appearance information, and recognizes discrete facial actions in spontaneous facial behavior. We tested the system in video data from a two-person interview. The 10 subjects were ethnically diverse, action units occurred during speech, and out-of-plane motion and occlusion from head motion and glasses were common. The video data were originally collected to answer substantive questions in psychology and represent a substantial challenge to automated action unit recognition. In analysis of blinks, the system achieved 98% accuracy.     

Locomotor, avoidance,and maze behavior in rats with selective disruption of hippocampal output.

Behavioral correlates of selective disruption of hippocampal output were investigated in a series of five experiments. In two experiments an attempt was made through behavioral investigation to determine whether the CA1 neurons project to the fimbria or to the subiculum. The results supported recent views that the subiculum is the recipient of CA1 axons. Disruption of the CA1 output in the dorsal hippocampus of rats produced increased open-field activity, whereas passive avoidance and spontaneous alternation behaviors remained unchanged. No differentiation was obtained between CA1 damage and neocortical lesions in maze learning. Blocking of the fimbrial CA3 output from the dorsal hippocampus improved passive avoidance performance and impaired active avoidance performance, whereas open-field and spontaneous alternation behaviors were unaffected. Interruption of the CA3 output from the ventral hippocampus improved active avoidance performance and reduced spontaneous alternation behavior. Open-field behavior and passive avoidance performance remained unchanged. Total fimbrial sections increased open-field activity, improved passive and active avoidance, and reduced spontaneous alternation. The results are discussed in terms of functional differentiation between the CA1 and CA3 of the dorsal hippocampus and in terms of functional differences in the fimbrial CA3 output from the dorsal and ventral hippocampus.     

166例冠心病患者活动平板试验中室性心律失常的分析

探讨冠心病患者冠状动脉狭窄程度与室性心律失常的关系,用Mar-quette Case16型活动平板系统测试,采用改良的Bruce方案。结果显示,偶发室早在单支狭窄和多支狭窄中无明显差异,恶性室性心律失常发生率在多支狭窄中较单支狭窄明显增高。冠心病患者出现的恶性室性心律失常提示病变严重或预后较差。     

Linkages between facial expressions of anger and transient myocardial ischemia in men with coronary artery disease

The authors examined whether facial expressions of emotion would predict changes in heart function. One hundred fifteen male patients with coronary artery disease underwent the Type A Structured Interview, during which time measures of transient myocardial ischemia (wall motion abnormality and left ventricular ejection fraction) were obtained. Facial behavior exhibited during the ischemia measurement period was videotaped and later coded by using the Facial Action Coding System (P. Ekman & W. V. Friesen, 1978). Those participants who exhibited ischemia showed significantly more anger expressions and nonenjoyment smiles than nonischemics. Cook-Medley Hostility scores did not vary with ischemic status. The findings have implications for understanding how anger and hostility differentially influence coronary heart disease risk.     

The temporal structure of motivation. V. A within-episodes analysis of priming and provocation

Rats provided with chronic, continuous access to intracranial self-stimulation (ICS) exhibit discrete episodic response patterns. Response episodes under two conditions were examined for systematic trends in the spacing of times between successive responses (interresponse times; IRTs) to better identify the motivational bases of ICS. Three trends were observed in self-initiated and experimenter-provoked episodes. First, initial responses of spontaneous episodes typically had declining interresponse times. Second, this trend was not present when responses were provoked rather than spontaneous. Third, absolute times between responses varied across conditions, with provoked behavior having significantly lower initial IRTs. The findings suggest that for spontaneously initiated responding a transient facilitatory process cumulates at the beginning of ICS episodes. For provoked responding, it is possible that a manipulation which increased the initial probability of responding over time may have done so by maximizing an initial phasic priming process. At their onset, spontaneous and provoked episodes may be characterized by quantitatively differing motivational profiles.     

Galpha(i2) inhibition of adenylate cyclase regulates presynaptic activity and unmasks cGMP-dependent long-term depression at Schaffer collateral-CA1 hippocampal synapses

Cyclic AMP signaling plays a central role in regulating activity at a number of synapses in the brain. We showed previously that pairing activation of receptors that inhibit adenylate cyclase (AC) and reduce the concentration of cyclic AMP, with elevation of the concentration of cyclic GMP is sufficient to elicit a presynaptically expressed form of LTD at Schaffer collateral-CA1 synapses in the hippocampus. To directly test the role of AC inhibition and G-protein signaling in LTD at these synapses, we utilized transgenic mice that express a mutant, constitutively active inhibitory G protein, Galpha(i2), in principal neurons of the forebrain. Transgene expression of Galpha(i2) markedly enhanced LTD and impaired late-phase LTP at Schaffer collateral synapses, with no associated differences in input/output relations, paired-pulse facilitation, or NMDA receptor-gated conductances. When paired with application of a type V phosphodiesterase inhibitor to elevate the concentration of intracellular cyclic GMP, constitutively active Galpha(i2) expression converted the transient depression normally caused by this treatment to an LTD that persisted after the drug was washed out. Moreover, this effect could be mimicked in control slices by pairing type V phosphodiesterase inhibitor application with application of a PKA inhibitor. Electrophysiological recordings of spontaneous excitatory postsynaptic currents and two-photon visualization of vesicular release using FM1-43 revealed that constitutively active Galpha(i2) tonically reduced basal release probability from the rapidly recycling vesicle pool of Schaffer collateral terminals. Our findings support the hypothesis that inhibitory G-protein signaling acts presynaptically to regulate release, and, when paired with elevations in the concentration of cyclic GMP, converts a transient cyclic GMP-induced depression into a long-lasting decrease in release.     

Theta synchronizes the activity of medial prefrontal neurons during learning

Memory consolidation is thought to involve the gradual transfer of transient hippocampal-dependent traces to distributed neocortical sites via the rhinal cortices. Recently, medial prefrontal (mPFC) neurons were shown to facilitate this process when their activity becomes synchronized. However, the mechanisms underlying this enhanced synchrony remain unclear. Because the hippocampus projects to the mPFC, we tested whether theta oscillations contribute to synchronize mPFC neurons during learning. Thus, we obtained field (LFP) and unit recordings from multiple mPFC sites during the acquisition of a trace-conditioning task, where a visual conditioned stimulus (CS) predicted reward delivery. In quiet waking, the activity of mPFC neurons was modulated by theta oscillations. During conditioning, CS presentation caused an increase in mPFC theta power that augmented as the CS gained predictive value for reward delivery. This increased theta power coincided with a transient theta phase locking at distributed mPFC sites, an effect that was also manifest in the timing of mPFC unit activity. Overall, these results show that theta oscillations contribute to synchronize neuronal activity at distributed mPFC sites, suggesting that the hippocampus, by generating a stronger theta source during learning, can synchronize mPFC activity, in turn facilitating rhinal transfer of its activity to the neocortex.     

The tickly homunculus and the origins of spontaneous sensations arising on the hands

Everyone has felt those tingling, tickly sensations occurring spontaneously all over the body in the absence of stimuli. But does anyone know where they come from? Here, right-handed subjects were asked to focus on one hand while looking at it (convergent focusing) and while looking away (divergent focusing) and subsequently to map and describe the spatial and qualitative attributes of sensations arising spontaneously. The spatial distribution of spontaneous sensations followed a proximo-distal gradient, similar to the one previously described for the density of receptive units. The intensity and spatial extent of the reported sensations were modulated by the focusing condition, especially in respect of the left hand. Convergent focusing acted upon the conscious perception of sensations by enhancing or suppressing them. To our knowledge, this is the first ever study of spontaneous sensations, and it offers considerable insight into their sources. The presence of the proximo-distal distributional gradient is a clear sign that receptive units are involved. The enhancement/suppression effects also confirm the involvement of attention. Finally, left-hand dominance suggests several right-hemisphere processes may be involved, such as spatial and tactile perception, and probably interoception.     

Effects of attention state on electrodermal activity during auditory stimulation of children.

During passive and active listening tasks electrodermal activity of 49 healthy school children was studied. The procedure included baseline recording, a passive listening task, instructions, and simple and discriminative active-listening tasks. On the passive task from Trials 1 to 10, habituation of the amplitude of the skin conductance response (SCR) occurred. Habituation of SCR amplitude did not occur during the active tasks. The children seemed to pay more attention during the active tasks than during the passive task, since the need to press the key is apt to require and may even increase general attention. As for temporal variables of SCR, the frequency of spontaneous SCRs showed a significant negative correlation with SCR latency and rise time. Reaction time exhibited a significant negative correlation with age. An increase in reaction time was found during the discriminative active-listening task over that for the simple active-listening task during the course of 10 trials. The younger children (6-8 yr.) seemed to require longer to pay attention than the older ones (10-12 yr.). Children seemed to pay more attention during the discriminative than during the simple active-listening task, since the need to press the key for discrimination should require and is likely to increase general attention.     

Coronary blood flow in dogs: Effect of person

Experiments on dogs with electromagnetic flow probes implanted around a coronary artery and the ascending aorta indicate that the entry of a person into the experimental chamber can cause a remarkable increase in coronary blood flow. Heart rate usually increases considerably, blood pressure increases only slightly, while aortic blood flow increases at variable times before and after coronary blood flow. It is not yet clear whether these cardiovascular effects are due purely to “effect of person” or to conditioning, with the person as the signal for the momentary coronary occlusion (which the person subsequently accomplishes by manually closing a snare).     

Coronary blood flow in dogs: Effect of person

Experiments on dogs with electromagnetic flow probes implanted around a coronary artery and the ascending aorta indicate that the entry of a person into the experimental chamber can cause a remarkable increase in coronary blood flow. Heart rate usually increases considerably, blood pressure increases only slightly, while aortic blood flow increases at variable times before and after coronary blood flow. It is not yet clear whether these cardiovascular effects are due purely to “effect of person” or to conditioning, with the person as the signal for the momentary coronary occlusion (which the person subsequently accomplishes by manually closing a snare).     

The meanings and functions of tunes that come into one's head

This paper is devoted to the study of internally generated auditory imagery, specifically tunes that appear spontaneously in one's consciousness exclusive of external musical input. Melodies that appear in the periphery of one's awareness during directed activity can protect the ego from the interference of internal desires or demands. Music present in consciousness irrespective of any specific melody may be experienced as a protective, omnipotent parental companion and thus guard against danger and the painful loneliness of separation and loss. The frequent or continuous spontaneous appearance of music in one's consciousness is considered to be a characterological mode of thinking--thinking in music.     

β受体阻滞剂是冠心病中的重要一线治疗药物

冠心病的治疗包括三个层面：血管重建治疗解决局部狭窄;改善生活方式是基础;全面合理的药物治疗是核心。而β受体阻滞剂又是重要的一线治疗药物,不仅能降低动脉粥样硬化及急性冠脉综合征的发生发展,还能有效预防、缓解心绞痛发生,改善梗死后左室重构和心功能;降低心肌再梗死率,降低心性猝死和病死率。临床上应用β受体阻滞剂的时机和剂量非常重要。     

变异性心绞痛患者心率变异性与冠状动脉病变关系的研究

研究变异性心绞痛患者 ST 段抬高对心率变异性的影响。回顾性分析122例变异性心绞痛患者 ST 段抬高幅度及持续时间对心率变异性的影响;心率变异性与冠状动脉病变及病变支数、狭窄程度有相关性。结果心率变异性在 ST 段抬高≥0．4mv 患者中较 ST 段抬高＜0．4mv 患者中明显降低（P＜0．05）;其在 ST 段抬高持续时间≥3min 患者中较 ST 段抬高持续时间＜3min 患者中明显降低（P＜0．05）;其在冠状动脉狭窄≥50％患者中较冠状动脉狭窄＜50％患者中明显降低（P＜0．05）;心率变异性在多支较单支病变明显降低（P ＜0．05）,单支病变狭窄程度≥75％较50％～75％者明显降低（P＜0．05）。提示变异性心绞痛患者自主神经系统受损程度与冠状动脉缺血严重程度,缺血持续时间密切相关,心率变异性能一定程度反映变异性心绞痛患者冠状动脉病变严重程度。     

急性冠脉综合征患者血液Rho激酶活性分析

探讨 Rho 激酶（ROCK）活性与急性冠脉综合征（ACS）患者冠状动脉狭窄程度及预后的关系。选取2012年6月至2013年3月住院的129例患者,其中急性心肌梗死（AMI）组68例、不稳定型心绞痛（UA）组30例、对照（CON ）组31例。Western Blot 检测血液白细胞中 ROCK 、ROCK1、ROCK2活性,同时根据冠状动脉的狭窄程度及是否发生心血管意外分组再次比较。 AMI 组和 UA 组 ROCK 、ROCK1、ROCK2活性均增高;且 AMI 组高于 UA 组;三支、双支、单支病变组活性依次减低,Gensini 评分≥20分组及发生心血管意外组均高于 Gensini 评分＜20分组及未发生心血管意外组,差异均有统计学意义（P＜0．05）。 ROCK 活性可能对 ACS 患者预后观察、评估有重要意义。