Using hippocampal-striatal loops for spatial navigation and goal-directed decision-making

The hippocampus plays a central role in spatial representation, declarative and episodic memory. In this area, so-called place cells possess high spatial selectivity, firing preferentially when the individual is within a small area of the environment. Interestingly, it has been found in rats that these cells can be active also when the animal is outside the location or context of their corresponding place field producing so-called “forward sweeps”. These typically occur at decision points during task execution and seem to be utilized, among other things, for the evaluation of potential alternative paths. Anticipatory firing is also found in the ventral striatum, a brain area that is strongly interconnected with the hippocampus and is known to encode value and reward. In this paper, we describe a biologically based computational model of the hippocampal-ventral striatum circuit that implements a goal-directed mechanism of choice, with the hippocampus primarily involved in the mental simulation of possible navigation paths and the ventral striatum involved in the evaluation of the associated reward expectancies. The model is validated in a navigation task in which a rat is placed in a complex maze with multiple rewarding sites. We show that the rat mentally activates place cells to simulate paths, estimate their value, and make decisions, implementing two essential processes of model-based reinforcement learning algorithms of choice: look-ahead prediction and the evaluation of predicted states.     

Nonautomated Pre-Performance Routine in Tennis: An Intervention Study

The effect of a nonautomated pre-performance routine (PPR) on performance in a high-pressure situation was investigated. Twenty-nine tennis players served in a low- and high-pressure condition in a pre- and posttest design. The intervention group learned a nonautomated PPR for 4 weeks. Increases in subjective but not objective (i.e., cortisol) levels of stress were detected in the high-pressure conditions. The intervention group showed a significant decrease in performance in the high-pressure condition in the pretest (p =.005) but not posttest (p =.161). Using a nonautomated PPR may benefit athletes who experience a drop in performance in high-pressure situations.     

Parallel Group Treatment of Pre-School Children and Their Mothers

Object relations concepts are applicable in children's group psychoanalytic psychotherapy. The author attempts to explore and delineate areas in which developmental conflicts in object relations, emotional deprivations, traumas, and family pathologies are recapitulated in the group, and how the manifestations of pathologies can be rectified by the process and formation of the group and the role of the therapist as a “new object” in the management of individual and group transferences. Clinical examples are presented.     

Neural processing of acoustic duration and phonological German vowel length: Time courses of evoked fields in response to speech and nonspeech signals

Recent experiments showed that the perception of vowel length by German listeners exhibits the characteristics of categorical perception. The present study sought to find the neural activity reflecting categorical vowel length and the short-long boundary by examining the processing of non-contrastive durations and categorical length using MEG. Using disyllabic words with varying /a/-durations and temporally-matched nonspeech stimuli, we found that each syllable elicited an M50/M100-complex. The M50-amplitude to the second syllable varied along the durational continuum, possibly reflecting the mapping of duration onto a rhythm representation. Categorical length was reflected by an additional response elicited when vowel duration exceeded the short-long boundary. This was interpreted to reflect the integration of an additional timing unit for long in contrast to short vowels. Unlike to speech, responses to short nonspeech durations lacked a M100 to the first and M50 to the second syllable, indicating different integration windows for speech and nonspeech signals.     

Dimensional comparisons: Much is known about the effects,less about the processes

Dimensional comparisons are comparisons between different domains. They are well known in educational psychology. Here, they explain the seemingly paradoxical finding that students' math and verbal self-concepts of ability usually show correlations close to zero, although students' math and verbal achievements show strong positive correlations. This finding can be explained by the fact that students overemphasize potential differences between their math and verbal achievements when they form their self-concepts. However, dimensional comparisons also take place and affect self-evaluations outside the educational context, and the number of studies examining dimensional comparisons in different contexts has significantly increased during the last few years. This paper provides an up-to-date overview of findings on dimensional comparisons. It presents findings from studies that have examined effects of dimensional comparisons (as most studies dealing with dimensional comparisons have done so far), as well as studies that have focused on an understanding of the psychological processes involved in dimensional comparison (which relatively few studies have done so far). It is hoped that this paper will help broaden awareness of dimensional comparisons and stimulate further research on this type of comparison, especially in disciplines other than educational psychology.     

Covered in stigma? The impact of differing levels of Islamic head‐covering on explicit and implicit biases toward Muslim women

Given the prominence of Muslim veils—in particular the hijab and full‐face veil—in public discourse concerning the place of Muslims in Western society, we examined their impact on non‐Muslims’ responses at both explicit and implicit levels. Results revealed that responses were more negative toward any veil compared with no veil, and more negative toward the full‐face veil relative to the hijab: for emotions felt toward veiled women (Study 1), for non‐affective attitudinal responses (Study 2), and for implicit negative attitudes revealed through response latency measures (Studies 3a and 3b). Finally, we manipulated the perceived reasons for wearing a veil, finding that exposure to positive reasons for wearing a veil led to better predicted and imagined contact (Study 4). Practical and theoretical implications are discussed.     

Developmental stimulation in child care centers contributes to young infants’ cognitive development

This study examined whether the quality of caregiver behavior in child care centers contributes to infant cognitive development at 9 months of age. Sixty-four infants (34 boys) were observed with their primary caregivers in child care centers at 3, 6, and 9 months of age. Caregiver behavior was rated for sensitivity and for stimulation of infant development during one-to-one caregiving interactions. Infant cognitive development was assessed using the Bayley Scales of Infant Development-II (Mental Development Index). Higher levels of developmental stimulation in the centers predicted higher levels of infant cognitive development at 9 months, beyond infant cognitive development at 3 months (just before entering child care), parental education, and maternal sensitivity. The results suggest that even small increases in developmental stimulation provided in child care centers in the first year of life may foster infants’ cognitive development.     

Long-Term Outcome of a Cluster-Randomized Universal Prevention Trial Targeting Anxiety and Depression in School Children

The present study concerns a 3-year follow-up of a universal prevention trial targeting anxiety and depressive symptoms in school children. In addition to evaluating the long-term effect of the prevention program, we also examined attrition and its effect on the outcome. High rates of attrition have commonly been observed in studies in the field. However, the role of attrition is not sufficiently understood regarding internal and external validity biases. The current study comprised 695 children (aged 8–11 at baseline) from 17 schools in Sweden. Schools were cluster-randomized to either the intervention or control condition. Children completed measures of anxiety and depressive symptoms and parents completed measures of their child’s anxiety and general mental health. We found no evidence of long-term effects of the prevention program, except for a small effect regarding parent reports of child anxiety. However, that effect was not found to be of clinical significance. Regarding attrition, children with missing data at the 3-year follow-up displayed higher levels of psychiatric symptoms at baseline and increasing symptoms across time. Furthermore, children in the control condition with missing follow-up data were found to be significantly deteriorated across time compared to the corresponding children in the intervention condition regarding depressive symptoms and total difficulties. In other words, attrition served as a moderator of the effect, which suggests that the overall result was biased toward a null-result. Our study highlights that large and nonrandom attrition severely limits the validity of the results. Further, given the common problem of retaining participants in long-term evaluations of school-based prevention trials, previous studies may suffer from the same limitations as the current study.     

From randomness to stability

The present study describes how the association between randomly chosen variables changes at the successive steps of temporal processes to converge into stable values as suggested by I. Prigogine. To generalize the results to any specific area so results may be applied to concrete problems in different sciences, randomly chosen matrices of random numbers were successively multiplied to generate temporal sequences that before reaching stability had different number of steps. Our results indicate that the obtained poliphasic stability is irreversible.