Lack of the metabotropic glutamate receptor subtype 7 selectively modulates Theta rhythm and working memory

Metabotropic glutamate receptors (mGluRs) are known to play a role in synaptic plasticity and learning. We have previously shown that mGluR7 deletion in mice produces a selective working memory (WM) impairment, while other types of memory such as reference memory remain unaffected. Since WM has been associated with Theta activity (6-12 Hz) in EEGs, and since EEG abnormalities have been observed in these mice before, we studied the effect of mGluR7 gene ablation on EEG activity in the hippocampus, in particular in the Theta range, during performance of a WM task. In an eight-arm maze with four arms baited, mGluR7 knock-out (KO) and wild-type mice committed the same number of reference memory errors, whereas KOs committed more WM errors. While performing the task, KO mice showed substantially higher Theta amplitudes, and the ratio of Theta to overall EEG power was much increased. No change was seen in the Delta (0-5 Hz), or Gamma (30-40 Hz) EEG bands compared with controls. When recording EEGs during periods of rest in the home cages, no difference was seen between groups. These findings suggest that mGluR7 is important for modulation and control of Theta activity. Since only WM was affected, and only the Theta range of EEG activity was altered, these results show a correlation between Theta rhythm and WM performance, and therefore support the concept that Theta activity in the hippocampus is involved in WM storage.     

Structural equation modeling of paired-comparison and ranking data

L. L. Thurstone's (1927) model provides a powerful framework for modeling individual differences in choice behavior. An overview of Thurstonian models for comparative data is provided, including the classical Case V and Case III models as well as more general choice models with unrestricted and factor-analytic covariance structures. A flow chart summarizes the model selection process. The authors show how to embed these models within a more familiar structural equation modeling (SEM) framework. The different special cases of Thurstone's model can be estimated with a popular SEM statistical package, including factor analysis models for paired comparisons and rankings. Only minor modifications are needed to accommodate both types of data. As a result, complex models for comparative judgments can be both estimated and tested efficiently.     

On raising the international dissemination of German research: Does changing publication language to English attract foreign authors to publish in a German basic psychology research journal?

It has been proposed that German basic psychology journals should change publication language to English in order to facilitate access to research from German-speaking countries. However, to truly increase the dissemination of German research, it seems crucial to progress towards an internationalization of authors and readers. We applied bibliometric analysis to investigate the impact of the transition to English on the rate of foreign authors publishing in Zeitschrift für Experimentelle Psychologie/Experimental Psychology, as well as possible associated changes in citation patterns. There was an increase in the rate of articles published by foreign authors from 14.6 and 8.7 per cent, respectively, for the last biannual periods as German-language journal, to 52.7 per cent in the first biannual period as English-language journal. Regarding citations patterns, the clearest changes emerged for domestic authors. The results illustrate possible consequences of a transition to English as publication language, and reveal that Experimental Psychology has successfully established certain prerequisites for an increase of the international dissemination of German psychology research.     

"I'm OK but you're not" and other peer-relational schemas: explaining individual differences in children's social goals

This study examined the links among 5th and 6th graders' (279 girls and 310 boys) self- and peer perceptions, social goals, and social behavior. Social goals mediated the effects of self- and peer perceptions on 3 types of behavior: proactive aggression, prosocial behavior, and withdrawal. In addition to their main effects (self-perception predicting variance in agentic goals, peer perception being related to communal goals), self- and peer perception interacted in influencing social goals; for instance, the effects of a positive view of oneself were different in the contexts of a positive versus a negative perception of peers. It is suggested that in order to predict children's social behavior more accurately, researchers should investigate children's dual perceptions of themselves and of their peers--that is, their peer-relational schemas--instead of assessing self-perception and peer perception in isolation from each other.     

Treatment of panic disorder: live therapy vs. self-help via the Internet

A randomized trial was conducted comparing 10 individual weekly sessions of cognitive behaviour therapy for panic disorder (PD) with or without agoraphobia with a 10-module self-help program on the Internet. After confirming the PD diagnosis with an in-person structured clinical interview (SCID) 49 participants were randomized. Overall, the results suggest that Internet-administered self-help plus minimal therapist contact via e-mail can be equally effective as traditional individual cognitive behaviour therapy. Composite within-group effect sizes were high in both groups, while the between-group effect size was small (Cohen's d=16). One-year follow-up confirmed the results, with a within-group effect size of Cohen's d=0.80 for the Internet group and d=0.93 for the live group. The results from this study generally provide evidence to support the continued use and development of Internet-distributed self-help programs.     

Shadowed reality or the 'Prometheus-complex': analytical psychotherapy after political imprisonment and persecution

Traumatic experiences of violence like those that were brought about by the communist regime of the former German Democratic Republic (GDR) are still present as if they happened yesterday, causing severe disadvantages in everyday life even after all those years. Consequently, in cases of extreme traumatization induced by political imprisonment, persecution and applied psychological methods of disintegration, regressive processes take place which corrode the ego. The breakdown of cathexis, i.e., the failure of empathic connection at the time of the trauma, is the strongest characteristic of severe traumatization. As a result of this destruction for the traumatized there is an inability to keep upright an inner empathic, emotional connection. As we try to grasp, from a Jungian point of view, the psychodynamics of severe traumatization, we can speak of a powerful pathogenous complex, which I call the 'Prometheus-complex'. Gustav Bovensiepen speaks of this complex as a sub-network, a limited fragment of the matrix of all internalized experiences, consisting of internal working models, feelings and patterns of anticipation which interact mutually. The human being, captured in such isolation and paralysis of the mind, can find himself 'in the therapist' on a mental level.     

Deficits of anticipatory grip force control after damage to peripheral and central sensorimotor systems

Healthy subjects adjust their grip force economically to the weight of a hand-held object. In addition, inertial loads, which arise from arm movements with the grasped object, are anticipated by parallel grip force modulations. Internal forward models have been proposed to predict the consequences of voluntary movements. Anesthesia of the fingers impairs grip force economy but the feedforward character of the grip force/load coupling is preserved. To further analyze the role of sensory input for internal forward models and to characterize the consequences of central nervous system damage for anticipatory grip force control, we measured grip force behavior in neurological patients. We tested a group of stroke patients with varying degrees of impaired fine motor control and sensory loss, a single patient with complete and permanent differentation from all tactile and proprioceptive input, and a group of patients with amyotrophic lateral sclerosis (ALS) that exclusively impairs the motor system without affecting sensory modalities. Increased grip forces were a common finding in all patients. Sensory deficits were a strong but not the only predictor of impaired grip force economy. The feedforward mode of grip force control was typically preserved in the stroke patients despite their central sensory deficits, but was severely disturbed in the patient with peripheral sensory deafferentation and in a minority of stroke patients. Moderate deficits of feedforward control were also obvious in ALS patients. Thus, the function of the internal forward model and the precision of grip force production may depend on a complex anatomical and functional network of sensory and motor structures and their interaction in time and space.     

Changing scenes: memory for naturalistic events following change blindness

Research on scene perception indicates that viewers often fail to detect large changes to scene regions when these changes occur during a visual disruption such as a saccade or a movie cut. In two experiments, we examined whether this relative inability to detect changes would produce systematic biases in event memory. In Experiment 1, participants decided whether two successively presented images were the same or different, followed by a memory task, in which they recalled the content of the viewed scene. In Experiment 2, participants viewed a short video, in which an actor carried out a series of daily activities, and central scenes' attributes were changed during a movie cut. A high degree of change blindness was observed in both experiments, and these effects were related to scene complexity (Experiment 1) and level of retrieval support (Experiment 2). Most important, participants reported the changed, rather than the initial, event attributes following a failure in change detection. These findings suggest that attentional limitations during encoding contribute to biases in episodic memory.     

When is all understood and done? The psychological reality of the recognition point

Using lexical decision, the effects of primes of different length on spoken word recognition were evaluated in three partial repetition priming experiments. Prime length was determined via gating (Experiments 1a and 2a). It was shorter than, equivalent to, or longer than the recognition point (RP), or a complete word. In Experiments 1b and 1c, priming increased with prime length and was independent of reaction time. The influence of sensory information following the RP was investigated in Experiment 2b. Latencies decreased with increasing prime length, but priming decreased only for complete words. RP and complete words have a special status. Lexical representations are activated to different degrees at the RP and at word offset.     

Positive facial expressions are recognized faster than negative facial expressions, but why?

Three experiments examined the recognition speed advantage for happy faces. The results replicated earlier findings by showing that positive (happy) facial expressions were recognized faster than negative (disgusted or sad) facial expressions (Experiments 1 and 2). In addition, the results showed that this effect was evident even when low-level physical differences between positive and negative faces were controlled by using schematic faces (Experiment 2), and that the effect was not attributable to an artifact arising from facilitated recognition of a single feature in the happy faces (up-turned mouth line, Experiment 3). Together, these results suggest that the happy face advantage may reflect a higher-level asymmetry in the recognition and categorization of emotionally positive and negative signals.