Defense reaction elicited by microinjection of kainic acid into the medial hypothalamus of the rat: antagonism by a GABAA receptor agonist.

Electrical stimulation of either the midbrain central gray or the medial hypothalamus induces a defense reaction in the rat, characterized mainly by increased locomotion, rearing, and leaping. However, microinjection of the excitatory amino acid glutamate was effective only in the former region. Because excitatory amino acids do not depolarize axons of passage, it was suggested that the hypothalamus is devoid of soma/dendrites of neurons commanding the defense reaction. In the present study, we show that a subtoxic dose (60 pmol) of another excitatory amino acid, kainic acid, injected into the medial hypothalamus significantly enhanced locomotion and rearing of Wistar rats systematically observed in an open field. Similar behavioral changes have been reported following microinjection of drugs impairing GABAergic neurotransmission. Local pretreatment with the GABAA receptor agonist THIP (2 nmol) blocked the effect of kainic acid. Therefore, the medial hypothalamus of the rat seems to contain a population of neuronal cell bodies commanding the defense reaction, which is activated by excitatory amino acids and tonically inhibited by GABAergic fibers.     

Short- and long-term effects of juvenile stressor exposure on the expression of GABAA receptor subunits in rats

During the juvenile period rodents are particularly sensitive to stressors. Aversive events encountered during this period may have enduring effects that are not evident among animals initially stressed as adults. Interestingly, experiencing stressor during juvenile period was found to elicit a biphasic behavioral pattern over the course of development. During the juvenile period, the expression of several GABAA receptor subunits is subject to elevated plasticity, rendering the GABAergic system sensitive to stressors. In the present investigation, animals were exposed to a juvenile variable stressor regimen (JUV-S) at 27-29 postnatal days (PND): 27 PND-acute swim stress (10 min), 28 PND-elevated platform stress (3 sessions×30 min each), and 29 PND-restraint (2 h). One hour following the last exposure to stressor or in adulthood (60 PND), anxiety-related behaviors were assessed in a 5-min elevated plus maze test. The western blotting technique was used to evaluate whether the juvenile stress induced behavioral pattern will be accompanied by respective changes in GABAA α1, α2, and α3 protein expression in male rats. Our findings further established that juvenile stressor elicits hyper-reactivity when rats were tested as juveniles, whereas rats exhibited reduced activity and increased anxiety when tested as adults. Additionally, the effects of juvenile stressor on α1, α2, and α3 were more pronounced among juvenile stressed rats that were challenged as adults compared with rats that were only challenged as juveniles. Interestingly, the stress-induced modulation of the subunits was particularly evident in the amygdala, a brain region closely associated with anxiety. Thus, age- and region-specific alterations of the α subunits may contribute to the age-specific behavioral alterations observed following juvenile stress exposure.     

Mapping grief: A study in practice using a quantitative and qualitative approach to exploring and addressing the range of responses to loss

The Adult Attitude to Grief (AAG) scale was devised for an earlier study (Machin, 2001) to test the validity of a concept of loss, which proposed that grief reactions fall broadly into three categories — ‘overwhelmed’, ‘balanced’ and ‘controlled’. There was statistical support for the proposed differences but the AAG scale, more importantly, provided insight into the diverse reactions taking place in individual bereaved respondents. This paper describes a second study undertaken to examine the clinical usefulness of the AAG scale with clients receiving help within the Psychological Services Operating Unit of the North Staffordshire Combined Healthcare (NHS) Trust. The scale has been used both in its original form with bereaved clients and in a modified form with clients having distress symptoms associated with other losses, such as relationship breakdown or the onset of chronic illness. The use of the AAG scale in this clinical setting suggests that, both as an assessment tool and as a cue for therapeutic dialogue, it provides a promising way of mapping the general and particular characteristics of response to loss in individual clients. Consideration is also given to varying therapeutic approaches needed to help clients regain the equilibrium disturbed by their grief.     

The in vivo/in vitro approach to cognition: the case of analogy

A new way of investigating cognition is proposed that combines naturalistic (in vivo) and experimental (in vitro) methods into a single approach. Investigating analogical reasoning by scientists 'live' at laboratory meetings (in vivo) we found that the types of analogies they use change with their goals. Unlike subjects in many cognitive 'reminding' experiments, scientists frequently used structural similarities in their analogies, as opposed to superficial similarities. By subsequently using the in vitro approach, we found that the use of structural information was associated with being asked to generate analogies and with the use of complex scenarios. Similar results are obtained in other areas of reasoning such as hypothesis testing and causal reasoning.     

Multiple serotonergic mechanisms contributing to sensitization in aplysia: evidence of diverse serotonin receptor subtypes

The neurotransmitter serotonin (5-HT) plays an important role in memory encoding in Aplysia. Early evidence showed that during sensitization, 5-HT activates a cyclic AMP-protein kinase A (cAMP-PKA)-dependent pathway within specific sensory neurons (SNs), which increases their excitability and facilitates synaptic transmission onto their follower motor neurons (MNs). However, recent data suggest that serotonergic modulation during sensitization is more complex and diverse. The neuronal circuits mediating defensive reflexes contain a number of interneurons that respond to 5-HT in ways opposite to those of the SNs, showing a decrease in excitability and/or synaptic depression. Moreover, in addition to acting through a cAMP-PKA pathway within SNs, 5-HT is also capable of activating a variety of other protein kinases such as protein kinase C, extracellular signal-regulated kinases, and tyrosine kinases. This diversity of 5-HT responses during sensitization suggests the presence of multiple 5-HT receptor subtypes within the Aplysia central nervous system. Four 5-HT receptors have been cloned and characterized to date. Although several others probably remain to be characterized in molecular terms, especially the Gs-coupled 5-HT receptor capable of activating cAMP-PKA pathways, the multiplicity of serotonergic mechanisms recruited into action during learning in Aplysia can now be addressed from a molecular point of view.     

Selective mutism in children: A structural family therapy approach to treatment

When children refuse to speak in some social settings, but can understand and speak in other settings, the diagnosis of selective mutism must be considered. A review of the literature describes the disorder, the various types of mutism, and related family dynamics. A family systems approach to treatment using structural family therapy is suggested. The case history presented illustrates one type of mutism as well as the family rules and hierarchy which appeared to be maintaining it. Structural and strategic family systems theory techniques that were used to move the family toward resolution of this problem are discussed.Diane Wolf Tatem, MA, MS, completed graduate work in marriage and family therapy at New Mexico State University, Las Cruces, NM. She is employed at Life Management Center of El Paso's Child Development Services and also has a private practice in marriage and family therapy in El Paso, Texas. Robert L. DelCampo, PhD is a professor of family science at New Mexico State University and maintains a private practice with Associates for Marriage and Family Therapy in Las Cruces, NM. Please address all correspondence to Dr. DelCampo at Box 3470, New Mexico State University, Las Cruces, NM, 88003-3470.Appreciation is expressed to Dr. Charles Huber, New Mexico State University in Las Cruces, for his insightful critique of the final draft of this paper. This paper was presented at the Texas Association for Marriage and Family Therapy Annual Conference, January 25–29, 1995 in Dallas, TX.     

A Bayesian approach to exploring expertise and putting success in adolescent and young adult golfers

ObjectivesPutting behaviour was examined to explore if age influenced performance and the development of motor and perceptual-cognitive expertise during late adolescence and early adulthood. We also examined if motor control and perceptual-cognitive expertise was related to performance on a representative putting task.MethodTwenty elite golfers (15 male; 17–24 years old; mean handicap of 0.5) completed eight straight and eight sloped putts at two distances (8ft/2.44m and 15ft/4.57m), on an indoor golf surface. Participants wore an eye tracker whilst putting and putting performance was assessed via putts holed and eye-movement behaviour, examining Quiet Eye (QE, the duration of the final fixation on the ball). A baseline profile for each participant was created using kinematic stroke data (collected using SAM PuttLab), average putts per round, greens in regulation and current practice hours (subjective self-report measures).ResultsBayesian statistical analysis revealed ‘moderate’ evidence that age and baseline kinematic factors did not influence putting success rates. Eye movement data revealed ‘moderate’ evidence that i) successful performance was associated with less variability in QE duration and ii) extended periods of QE were associated with a decline in performance. Previous experience and current skill level were ruled out as potential confounds.ConclusionOur findings reveal that performance and perceptual-cognitive expertise, did not improve with age. We suggest that post 18 years, age should not be considered a factor in talent development programmes for golf putting. We discuss the benefits of adopting a Bayesian approach and suggest future studies employ longitudinal designs to examine changes in expertise over time.     

Selective attention to the parts of an object

Recent empirical results suggest that there is a decrement in dividing attention between two objects in a scene compared with focusing attention on a single object. However, objects can be made of individual parts. Is there a decrement for dividing attention across different parts of a single object? We addressed this question in two experiments. In Experiment 1, we demonstrated that attention can exhibit part-based selection—that is, the subjects were more accurate in reporting two attributes from the same part of an object than they were in reporting attributes from different parts of an object. In Experiment 2, we demonstrated that part-based attentional decrements occurred simultaneously with object-based attentional decrements. The results from Experiment 2 demonstrated that part-based attention is evident at the same time as objects are processed as coherent wholes. Our results imply that there is an attentional mechanism that can select either objects or their parts.     

Selective antagonism of the rate-decreasing effect of d-amphetamine by chlorpromazine in a repeated-acquisition task.

Pigeons acquired a different four-response chain each session by responding sequentially on three keys in the presence of four colors. The response chain was maintained by food presentation under a fixed-ratio schedule. When d-amphetamine was administered alone, the overall response rate decreased and the percent errors increased with increasing doses. When a small dose of chlorpromazine, which was ineffective when given alone, was administered in combination with d-amphetamine, the rate-decreasing effect was antagonized. The antagonism was selective, however, in that the error-increasing effect of d-amphetamine was augmented by chlorpromazine. The nature of the joint effect of the two drugs thus depended on the behavioral measure: rate vs. accuracy.     

Negotiating the spaces: exploring issues of human rights in an Indian text

This article is an attempt to negotiate the spaces between a number of problematic positions concerning Hinduism and human rights through the close study of one particular text, the Rājadharmaparvan of the Mahābhārata. By examining safeguards and provisions for subjects articulated in the text’s discourse of kingly duty, it engages with some of the arguments forwarded in the theoretical literature on human rights. Here it interrogates, in particular, the idea that Hinduism is distinctively incompatible with these norms in a way other historical or cultural traditions are not. The article concludes by asking whether it is possible to counter Eurocentric tendencies in global debates without furthering illiberal agendas within local ones. Discussing the appropriation of ‘Raj dharma,’ and the texts that deal with it, by the Hindu Right, it briefly outlines some recent moves in human rights theory that help facilitate the reclamation of a rich and plural textual heritage.     

The representation of negative numbers: exploring the effects of mode of processing and notation

The representation of negative numbers was explored during intentional processing (i.e., when participants performed a numerical comparison task) and during automatic processing (i.e., when participants performed a physical comparison task). Performance in both cases suggested that negative numbers were not represented as a whole but rather their polarity and numerical magnitudes were represented separately. To explore whether this was due to the fact that polarity and magnitude are marked by two spatially separated symbols, participants were trained to mark polarity by colour. In this case there was still evidence for a separate representation of polarity and magnitude. However, when a different set of stimuli was used to refer to positive and negative numbers, and polarity was not marked separately, participants were able to represent polarity and magnitude together when numerical processing was performed intentionally but not when it was conducted automatically. These results suggest that notation is only partly responsible for the components representation of negative numbers and that the concept of negative numbers can be grasped only through that of positive numbers.     

Birth order effects on the separation process in young adults: an evolutionary and dynamic approach

The present study analyzes the differential contribution of a familial or social focus in imaginative ideation (the personal fable and imagined audience mental constructs) to the separation-individuation process of firstborn, middleborn, and lastborn children. A total of 160 young adults were divided into 3 groups by birth order. Participants' separation-individuation process was evaluated by the Psychological Separation Inventory, and results were cross-validated by the Pathology of Separation-Individuation Inventory. The Imaginative Ideation Inventory tested the relative dominance of the familial and social environments in participants' mental constructs. The findings showed that middleborn children had attained more advanced separation and were lower in family-focused ideation and higher in nonfamilial social ideation. However, the familial and not the social ideation explained the variance in the separation process in all the groups. The findings offer new insights into the effects of birth order on separation and individuation in adolescents and young adults.     

Influence of chronic corticosterone and glucocorticoid receptor antagonism in the amygdala on fear conditioning

Glucocorticoid receptor activation within the basolateral amygdala (BLA) during fear conditioning may mediate enhancement in rats chronically exposed to stress levels of corticosterone. Male Sprague-Dawley rats received corticosterone (400 microg/ml) in their drinking water (days 1-21), a manipulation that was previously shown to cause hippocampal CA3 dendritic retraction. Subsequently, rats were adapted to the fear conditioning chamber (day 22), then trained (day 23), and tested for conditioned fear to context and tone (day 25). Training consisted of two tone (20s) and footshock (500 ms, 0.25 mA) pairings. In Experiment 1, muscimol (4.4 nmol/0.5 microl/side), a GABAergic agonist, was microinfused to temporarily inactivate the BLA during training. Rats given chronic corticosterone showed enhanced freezing to context, but not tone, compared to vehicle-supplemented rats. Moreover, BLA inactivation impaired contextual and tone conditioning, regardless of corticosterone treatment. In Experiment 2, RU486 (0, 0.3, and 3.0 ng/0.2 microl/side) was infused on training day to antagonize glucocorticoid receptors in the BLA. Corticosterone treatment enhanced fear conditioning to context and tone when analyzed together, but not separately. Moreover, RU486 (3.0 ng/side) selectively exacerbated freezing to context in chronic corticosterone-exposed rats only, but failed to alter tone conditioning. Serum corticosterone levels were negatively correlated with contextual, not tone, conditioning. Altogether, these suggest that chronic corticosterone influences fear conditioning differently than chronic stress as shown previously. Moreover, chronic exposure to corticosteroids alters BLA functioning in a non-linear fashion and that contextual conditioning is influenced more than tone conditioning by chronic corticosterone and BLA glucocorticoid receptor stimulation.     

Emotion regulation and its effects on mood improvement in response to an in vivo peer rejection challenge

This study examined children's spontaneous use of behavioral emotion regulation (ER) strategies and their effects on subsequent mood change in response to an in vivo peer rejection manipulation. Participants (N = 186), ranging between 10 and 13 years of age, played a computer game based on the television show Survivor and were randomized to either peer rejection (being voted out of the game) or nonrejection control. In response to rejection, more than one third of the participants (38%) displayed a marked worsening (i.e., reliable change) in state mood. After receiving feedback, time spent on several behavioral ER strategies during a 5-minute postfeedback period was assessed. At the end of the postfeedback period, children's cognitive activity was also assessed. More time spent on behavioral distraction was positively linked to subsequent increases in positive affect, whereas the reverse pattern was found for disengagement/passive behavior. Moreover, higher endorsement ratings for the strategy of "cognitive analysis" were associated with stronger increases in negative affect.     

Runway width effects in the visual approach to landing

The effect of changes in runway width on the perception of glide-slope has been the subject of extensive investigations. Despite considerable research, an explanation of this effect has been elusive. A mathematical model for glide-slope perception was published recently based on the premise that a desirable goal of perception is to form a perception with minimal uncertainty. One of the qualitative predictions of that model was that changes in the aspect ratio of the runway would affect the perceived glide-slope. In this article, the predictions of the model are quantified and are shown to be in close agreement with experimental results in the literature.