Aggressive behavior induced by electrical stimulation in the midbrain central gray of male rats

Electrical stimulation via electrodes implanted in the lateral hypothalamus may induce intraspecific aggressive behavior. Small electrolytic lesions placed via these electrodes resulted in a five– to tenfold increase in the current threshold for aggression. Degenerating fibers were stained by means of the Fink-Heimer method and could be followed caudally to the dorsal midbrain central gray and to the mammillary bodies. A few axons could be traced rostrally to the medial septum. Aggression could be induced from 10 of 112 electrodes implanted in the central gray; the other electrodes elicited either locomotion, vocalization, jump, or “alarm-like reactions.” The morphology of the induced aggression was similar to the morphology of the hypothalamically induced aggression, though it was often accompanied with motor disturbances and was less intense. Hypothalamic stimulation was combined with simultaneous central gray stimulation in rats with electrodes both in the hypothalamus and in the central gray. Hypothalamic thresholds for aggression could be lowered by this stimulation of the central gray, even when no aggressive responses were observed during central gray stimulation alone. This suggests that, although aggression is not manifest, electrical stimulation may activate neural tissue involved in aggressive behavior. It is concluded that in rats central gray and hypothalamus are part of the same neural network mediating intraspecific aggression.     

组织内信任与创造力的关系：元分析的证据

采用元分析技术探讨了组织内部水平信任、垂直信任和系统信任对创造力的影响。通过文献搜索纳入元分析的研究有85项, 共99个独立效应量。其中, 水平信任与创造力关系的元分析有41个独立样本, 垂直信任与创造力关系的元分析有34个独立样本, 系统信任与创造力关系的元分析有24个独立样本。元分析结果表明, 水平信任(r = 0.50)、垂直信任(r = 0.38)和系统信任(r = 0.48)与创造力之间存在显著正相关。水平信任、垂直信任、系统信任三者与创造力的关系受到信任测量工具的调节作用, 但是不受文化背景和知识水平的调节影响。     

一次性双管喉罩在泌尿外科侧卧位手术中应用探讨

观察一次性双管喉罩全屏静脉麻醉与气管插管全屏静脉在泌外侧卧位手术中对患者循环及并发症的影响。选取泌尿外科侧卧位手术患者60例,随机分为两组,每组30例,A组为双管喉罩组,B组为气管插管组,记录麻醉前（T1）及建立气道后1min（T2）、建立后5min（T3）,拔管后1min（T4）、拔管后5min（T5）对应时刻平均动...     

Chapter 13: Live a Little Before You Die a Lot: Creative Living in the Later Years

SUMMARY

Calling for a radical new paradigm for living the latter third of life, this article suggests that persons can continue to grow, improve, create, and experience a quality of life never known by previous generations of older persons. Issues such as freedom, courage, adaptability, and expansiveness, along with an openness to God's transforming power, are suggested as a means of accomplishing this goal.     

A型肉毒素注射结合括约肌浅表松解术与传统术式的疗效比较分析

为了探讨临床应用A型肉毒素结合病灶小切口括约肌浅表松解术治疗肛裂的新方法,将Ⅱ期、Ⅲ期肛裂患者80例随机分成试验组和对照组,征求患者和伦理委员会同意后进行研究,对比观察试验组的A型肉毒素内括约肌侧方注射配合病灶小切口括约肌浅表松解术与对照组的传统肛裂切除扩创术加部分内括约肌侧方切断术手术治疗的效果.结果显示,试验组VAS疼痛评分(24h)、排便时间、手术所需时间、创面愈合时间、切口愈合分级及切口愈合后瘢痕面积大小情况均优于对照组.静息向量容积和收缩向量容积两组都有所减低(P＜0.05).因此,A型肉毒素内括约肌侧方注射配合病灶小切口括约肌浅表松解术的疗效治疗方法简单,伤口愈合快,有很好的应用价值.     

Intraspecific aggression in male hamsters is inhibited by intrahypothalamic vasopressin-receptor antagonist

The present study examines the effect of the arginine vasopressin (AVP) receptor antagonist, d(CH₂)₅Tyr(Me)AVP, on intraspecific aggression between pairs of male Golden hamsters in a neutral territory. Subjects drawn from a group of 24 animals were paired once each with novel partners from the group under each of three experimental conditions: 1) both members of a pair were microinjected into the anterior hypothalamus with saline (S/S), 2) one member of a pair was microinjected with AVP-receptor antagonist and its partner with saline (A/S), and 3) both members of a pair were microinjected with AVP-receptor antagonist (A/A). There were significantly (P < .01) fewer attacks during encounters between pairs of hamsters in the A/A condition compared to pairs in the A/S condition. Similarly, pairs in the A/S condition attacked significantly (P < .025) less often than pairs of hamsters in the S/S condition. These results confirm our earlier work showing that AVP-receptor antagonist reduces intraspecific aggression. In addition, saline-treated hamsters initiated significantly (P < .001) fewer attacks toward antagonist treated hamsters than would have been predicted if their opponent was not drug treated. These latter results suggest that hamsters microinjected into the anterior hypothalamus with an AVP-receptor antagonist also elicit less aggression from conspecifics.     

The neural basis of mirror symmetry detection: a review

The human visual system is extremely sensitive to the presence of bilateral (mirror) symmetry. In this review, I summarise the results of recent work investigating the neural basis of mirror symmetry detection, focusing in particular on brain stimulation evidence. Overall, available findings converge in pointing to the lateral occipital (LO) complex, especially in the right hemisphere, as a key region causally involved in symmetry detection. Interestingly, they also suggest that another region in the right extrastriate visual cortex, the occipital face area (OFA), is causally implied in symmetry detection, posing an interesting connection at the neural level between visual cortex responses to faces and to symmetry. Finally, this review also considers evidence on haptic symmetry detection in sighted and early blind individuals that points to LO as a multi-modal symmetry-sensitive region, and suggests that symmetry is a salient perceptual feature mediated by LO even when any visual experience is missing.     

Her heart is in the right place: an investigation of the ‘heartbeat hypothesis’ as an explanation of the left side cradling preference in a mother with dextrocardia

A majority of mothers, whether right- or left-handed, exhibit a preference to hold their babies to the left of the body midline. One of the earliest explanations for this finding proposed that babies were being held close to the mother's heart [Salk, L. (1960). World Mental Health, 12 , 168–175]. Salk suggested that the foetus becomes imprinted on the sound of the maternal heartbeat in utero. This paper reports a left holding preference in a mother who has the heart positioned on the right rather than the normal left side of the body. Salk's ‘heartbeat hypothesis’ is not supported by the holding preference of the dextrocardiac mother, nor by the detailed patterns of holding in the control group. © 1998 John Wiley & Sons, Ltd.     

Targets and tactics: The analysis of moment-to-moment decision making in animal combat

Even though injury and death are more common consequences of fighting among animals than once believed, they are still relatively infrequent. Modern evolutionary models of animal combat have emphasized that given the threat of retaliation, animals only escalate to more injurious fighting if the benefits outweigh the costs, and then only if threat and bluff fail to achieve the goal. Such models stress the role of communication as to whether animals decide to escalate or not. An alternative view is that failure to produce injury or death arises from the neutralization of one animal's attack by another's defense. That is, attack and defense end in a stalemate that may be misinterpreted by outside observers as an absence of injury producing behavior. As attack typically involves the biting or striking of specific body targets, movements and postures occurring during combat need to be analyzed with respect to their role in gaining or averting such contact. For example, in the combat of muroid rodents the attacker targets the lower dorsum and flanks (low threshold) or face (high threshold), whereas a defender may defensively launch counterstrikes against the attacker's face. Two combat tactics (supine defense and lateral attack) typically present in the fighting of muroid rodents are analyzed in detail to illustrate how targets constrain the movements of combatants. Such a functional analysis of combat assumes that the movements and postures performed are related to their role in the attack and defense of targets. Deviations from such a strict functional interpretation reveal some of the other factors that may constrain the combatants' behavior. For example, body morphology and the aggressiveness of the opponent are shown to be important in deciding the type of combat tactic to use and how it is performed. Finally, movements and postures that are neutral or even counterproductive for attack and defense may be revealed as communicatory. This approach provides a means of analyzing behavior during the "heat of combat" that is typically not dealt with in traditional evolutionary models. Aggr. Behav. 23:107–129, 1997.© 1997 Wiley-Liss, Inc.     

Neurochemical mechanisms underlying amygdaloid modulation of aggressive behavior in the cat

Studies designed to determine the respective roles of substance P, excitatory amino acids, and enkephalins in amygdaloid modulation of defensive rage behavior in the cat are presented. The basic design of these studies involved three stages. In stage I, cannula electrodes for stimulation and drug infusion were implanted into medial hypothalamic or midbrain periaqueductal gray (PAG) sites from which defensive rage behavior could be elicited. Then, a stimulating electrode was implanted into a site within the medial, basal, or central nuclear complex from which modulation of the defensive rage response could be obtained. Amygdaloid modulation of defensive rage was determined in the following manner: it employed the paradigm of dual stimulation in which comparisons were made of response latencies between alternate trials of dual (i. e., amygdala = medial hypothalamus [or PAG]) and single stimulation of the hypothalamus or PAG alone. Thus, stage I established the baseline level ofmodulation (i. e., facilitation or suppression of defensive rage) in the predrug stimulation period. In stage II, a selective or nonselective receptor antagonist for a given transmitter system was administered either peripherally or intracerebrally at the defensive rage site, after which time the same dual stimulation paradigm was then repeated over the ensuing 180 min postinjection period in order to determine the effects of drug delivery upon amygdaloid modulation of defensive rage. Stage III of the study took place at the completion of the pharmacological testing phase. The retrograde axonal tracer, Fluoro-Gold, was microinjected into the defensive rage site within the medial hypothalamus or PAG, and following a 6-14 day survival period, animals were sacrificed and brains were processed for histological and immunocytochemical analyses for the neurotransmitters noted above. This procedure thus permitted identification of cells within the amygdala which were labeled retrogradely and which were also immunostained positively for substance P, excitatory amino acids, or enkephalin. For studies involving substance P, defensive rage was elicited from the medial hypothalamus and for studies examining the roles of excitatory amino acids and enkephalin, defensive rage was elicited from the PAG. In the first study, facilitation of hypothalamically elicited defensive rage was obtained with dual stimulation of the medial nucleus of the amygdala. In separate experiments, the selective NK₁ non-peptide antagonist, CP 96,345, was administered both peripherally as well as intracerebrally into the hypothalamic defensive rage sites in doses of 0.5-4.0 mg/kg (i. p.) and 0.5-2.5 nmol (i. c.). Following drug delivery, the facilitatory effects of medial amygdaloid stimulation were blocked in a dose- and time-dependent manner in which the effects were noted as early as 5 min postinjection. The maximum drug dose (4.0 mg/kg) employed for peripheral administration resulted in a 42% reduction in the facilitatory effects of the medical amygdala (P < 0.002). This drug, when microinjected directly into medial hypothalamic defensive rage sites at the maximum dose level of 2.5 nmol, resulted in an 84% reduction of the suppressive effects of amygdaloid stimulation (P < 0.5) at 5 min postinjection. In the next study, an N-methyl-D-aspartate (NMDA) antagonist, DL-α-amino-7-phosphonoheptanoic acid (AP-7), was administered either peripherally (0.1-1.0 mg/kg) or intracerebrally (0.2 and 2.0 nmol) into PAG defensive rage sites. Facilitation of defensive rage behavior, which was observed following dual stimulation of the basal amygdala and PAG, was significantly reduced by either route of drug administration in a dose- and time-dependent manner. At the maximum dose level of peripheral administration, AP-7 reduced amygdaloid facilitation of defensive rage by 63% (P < 0.001) for 60 min, postinjection. A smaller (i. e., 19%) but still significant (P < 0.05) reduction in facilitation was obtained following intracerebral administration of the drug. In a third study, the non-selective opioid receptor antagonist, naloxone (27.5 nmol), infused directly into PAG defensive rage sites, totally blocked the suppressive effects of central amygdaloid stimulation for a period of 30 min (P < 0.05) in a dose- and time-dependent manner. The anatomical phase of this study revealed the following relationships: 1) that large numbers of neurons projecting to the medial hypothalamus from the medial amygdala immunoreact positively for substance P; 2) that neurons projecting to the PAG from the basal complex of amygdala immunoreact positively for glutamate and aspartate; and 3) that neurons located within the central nucleus of the amygdala which project to the PAG immunoreact positively for met-enkephalin. Collectively, these observations provide new evidence which characterizes the likely neurotransmitters linked with specific amygdaloid pathways subserving the modulation of defensive rage behavior in the cat.