Hypoglycemia-induced suppression of luteinizing hormone (LH) secretion in intact female rhesus macaques: role of vasopressin and endogenous opioids

The first objective of this study was to determine whether insulin-induced hypoglycemia (IIH) inhibits LH secretion in unrestrained female macaques during the follicular phase of the menstrual cycle. There was a consistent inhibitory effect of hypoglycemia on LH secretion within 3 h in these females. This inhibition was likely an indirect effect since low glucose levels did not inhibit GnRH secretion from GT1-1 neurones in vitro. We next investigated whether administration of a vasopressin antagonist (AVPa) either alone, or with naloxone could reverse the IIH-induced inhibition of LH release. Females were studied in the follicular phase during 10 h periods with blood samples collected every 10 min. Experimental groups were IIH (n=6), IIH+AVPa (n=5) and IIH+AVPa+naloxone (n=4). The first 5 h of each study served as a control and hypoglycemia was then induced with insulin. The AVPa was given as a bolus (180 microg) just before the insulin and was followed by a continuous infusion (180 microg/h) for 5 h. Naloxone (5 mg/kg) was given with the AVPa and followed by a continuous infusion (5 mg/kg/h) for 5 h. In the IIH group, LH reached its lowest value 3-4 h after insulin. Neither AVPa nor AVPa+naloxone infusion reversed the inhibitory action of hypoglycemia on LH release. These data suggest that if there are inhibitory actions of vasopressin and endogenous opioids on GnRH release induced by hypoglycemia, they are not sufficient to explain the suppression of GnRH/LH release in intact female primates.     

Patients with generalized social phobia direct their attention away from faces

The experiment tested whether patients with social phobia direct their attention to or away from faces with a range of emotional expressions. A modified dot probe paradigm (J. Abnorm. Psychol. 95 (1986) 15) measured whether participants attended more to faces or to household objects. Twenty patients with social phobia were faster in identifying the probe when it occurred in the location of the household objects, regardless of whether the facial expressions were positive, neutral, or negative. In contrast, controls did not exhibit an attentional preference. The results are in line with recent theories of social phobia that emphasize the role of reduced processing of external social cues in maintaining social anxiety.     

Ablation of cerebellar nuclei prevents H-reflex down-conditioning in rats

While studies of cerebellar involvement in learning and memory have described plasticity within the cerebellum, its role in acquisition of plasticity elsewhere in the CNS is largely unexplored. This study set out to determine whether the cerebellum is needed for acquisition of the spinal cord plasticity that underlies operantly conditioned decrease in the H-reflex, the electrical analog of the spinal stretch reflex. Rats in which the cerebellar output nuclei dentate and interpositus (DIN) had been ablated were exposed for 50 d to the H-reflex down-conditioning protocol. DIN ablation, which in itself had no significant long-term effect on H-reflex size, entirely prevented acquisition of a smaller H-reflex. Since previous studies show that corticospinal tract (CST) transection also prevents down-conditioning while transection of the rubrospinal tract and other major descending tracts does not, this result implies that DIN output that affects cortex is essential for generation of the CST activity that induces the spinal cord plasticity, which is, in turn, directly responsible for the smaller H-reflex. The result extends the role of the cerebellum in learning and memory to include participation in induction of plasticity elsewhere in the CNS, specifically in the spinal cord. The cerebellum might simply support processes in sensorimotor cortex or elsewhere that change the spinal cord, or the cerebellum itself might undergo plasticity similar to that occurring with vestibulo-ocular reflex (VOR) or eyeblink conditioning.     

言语表情标记在儿童寓言故事理解中的作用

运用听读理解测验的方法探讨言语表情标记对6～8岁儿童寓言故事理解的影响。结果表明。言语表情标记能促进各年龄组儿童对故事的理解,这种促进作用在6、7岁儿童身上表现得非常显著。男、女儿童对有、无言语表情标记的故事的理解不存在显著差异。     

家庭居住与机构居住老年人社会支持的比较研究

以65位家庭居住和92位机构居住的老年人为样本,采用Sherbourne和Stewart的MOS社会支持问卷和自编社会支持问卷调查了老年人的社会支持现状,比较了家庭居住与机构居住老年人社会支持的不同特点。结果发现：（1）家庭居住和机构居住老年人在社会支持维度上存在显著差异：在心理支持、行为支持、活动支持等维度上,机构居住的老年人显著高于家庭居住的老年人;而在感情支持维度上家庭居住的老年人显著高于机构居住的老年人。（2）社会支持对老年人的身心健康具有显著影响。（3）性别,年龄,教育水平,职业状况,婚姻状况,子女数量,健在兄弟姐妹数量等人口统计变量对不同居住背景老年人的社会支持有显著影响。     

Restraint and Cancellation: Multiple Inhibition Deficits in Attention Deficit Hyperactivity Disorder

We used variations of the stop signal task to study two components of motor response inhibition—the ability to withhold a strong response tendency (restraint) and the ability to cancel an ongoing action (cancellation)—in children with a diagnosis of attention deficit hyperactivity disorder (ADHD) and in non-ADHD controls of similar age (ages 7–14 years). The goal was to determine if restraint and cancellation were related and if both were deficient in ADHD. The stop signal task involved a choice reaction time task (go task) which required a rapid response. The demand for inhibitory control was invoked through the presentation of a stop signal on a subset of go trials which required that the ongoing response be suspended. The stop signal was presented either concurrently with the go signal (restraint version) or after a variable delay (cancellation version). In Study 1, we compared ADHD and control children on the cancellation version of the stop task; in Study 2, we compared ADHD and controls on the restraint version. In Study 3, a subset of ADHD and control participants completed both tasks so that we could examine convergence of these dimensions of inhibition. Compared to control participants, ADHD participants showed a deficit both in the ability to cancel and to restrain a speeded motor response. Performance on the restraint version was significantly correlated with performance on the cancellation version in controls, but not in ADHD participants. We conclude that ADHD is associated with deficits in both restraint and cancellation subcomponents of inhibition.     

Two steps forward and one back: Learning to walk affects infants' sitting posture

The transition from sitting to walking is a major motor milestone for the developing postural system. This study examined whether this transition to walking impacts the previously established posture (i.e., sitting). Nine infants were examined monthly from sitting onset until 9 months post-walking. Infants sat on a saddle-shape chair either independently or with their right hand touching a stationary contact surface. Postural sway was measured by sway amplitude, variability, area, and velocity of the center of pressure trajectory. The results showed that for all the postural measures in the no-touch condition, a peak before or at walk onset was observed in all the infants. At the transition age, when peak sway occurred, infants' postural sway measures were significantly greater than at any other age. Further, infants' postural sway was attenuated by touch only at this transition. We suggest that this transient disruption in sitting posture results from a process involving re-calibration of an internal model for the sensorimotor control of posture so as to accommodate the newly emerging bipedal behavior of independent walking.     

Evaluating the Individualism and Collectivism Scale for use in mainland China

A Chinese translation of the 27-item Individualism and Collectivism Scale was administered in southern mainland China to 626 Chinese university students (210 men and 416 women) with a mean age of 19.9 yr. (SD = 1.5). From analysis of the responses to these items, the prior four factors, Horizontal Individualism, Vertical Individualism, Horizontal Collectivism, and Vertical Collectivism, did not clearly emerge in the Chinese sample. Further research on the viability of the scale and conceptualization of the horizontal and vertical distinction in the Chinese context is recommended.     

Where (who) are collectives in collectivism? Toward conceptual clarification of individualism and collectivism

In psychological research on cultural differences, the distinction between individualism and collectivism has received the lion's share of attention as a fundamental dimension of cultural variation. In recent years, however, these constructs have been criticized as being ill-defined and "a catchall" to represent all forms of cultural differences. The authors argue that there is a conceptual confusion about the meaning of ingroups that constitute the target of collectivism. Collectives are rarely referred to in existing measures to assess collectivism. Instead, networks of interpersonal relationships dominate the operational definition of "ingroups" in these measures. Results from a content analysis of existing scales support this observation. To clarify and expand the individualism-collectivism distinction, a theoretical framework is proposed that draws on M. B. Brewer and G. Gardner's (1996) conceptualization of individual, relational, and collective selves and their manifestation in self-representations, beliefs, and values. Analyses of data from past studies provide preliminary support for this conceptual model. The authors propose that this new theoretical framework will contribute conceptual clarity to interpretation of past research on individualism and collectivism and guide future research on these important constructs.