A cross‐syndrome study of the differential effects of sleep on declarative memory consolidation in children with neurodevelopmental disorders

Sleep plays an active role in memory consolidation. Because children with Down syndrome (DS) and Williams syndrome (WS) experience significant problems with sleep and also with learning, we predicted that sleep‐dependent memory consolidation would be impaired in these children when compared to typically developing (TD) children. This is the first study to provide a cross‐syndrome comparison of sleep‐dependent learning in school‐aged children. Children with DS (n = 20) and WS (n = 22) and TD children (n = 33) were trained on the novel Animal Names task where they were taught pseudo‐words as the personal names of ten farm and domestic animals, e.g. Basco the cat, with the aid of animal picture flashcards. They were retested following counterbalanced retention intervals of wake and sleep. Overall, TD children remembered significantly more words than both the DS and WS groups. In addition, their performance improved following night‐time sleep, whereas performance over the wake retention interval remained stable, indicating an active role of sleep for memory consolidation. Task performance of children with DS did not significantly change following wake or sleep periods. However, children with DS who were initially trained in the morning continued to improve on the task at the following retests, so that performance on the final test was greater for children who had initially trained in the morning than those who trained in the evening. Children with WS improved on the task between training and the first retest, regardless of whether sleep or wake occurred during the retention interval. This suggests time‐dependent rather than sleep‐dependent learning in children with WS, or tiredness at the end of the first session and better performance once refreshed at the start of the second session, irrespective of the time of day. Contrary to expectations, sleep‐dependent learning was not related to baseline level of performance. The findings have significant implications for educational strategies, and suggest that children with DS should be taught more important or difficult information in the morning when they are better able to learn, whilst children with WS should be allowed a time delay between learning phases to allow for time‐dependent memory consolidation, and frequent breaks from learning so that they are refreshed and able to perform at their best.     

Changes in the relationship between movement velocity and movement distance in primary focal hand dystonia

The authors examined the relationship between movement velocity and distance and the associated muscle activation patterns in 18 individuals with focal hand dystonia (FHD) compared with a control group of 18 individuals with no known neuromuscular condition. Participants performed targeted voluntary wrist and elbow flexion movements as fast as possible across 5 movement distances. Individuals with FHD were slower than controls across all distances, and this difference was accentuated for longer movements. Muscle activation patterns were triphasic in the majority of individuals with FHD, and muscle activation scaled with distance in a similar manner to controls. Cocontraction did not explain movement slowing in individuals with dystonia, but there was a trend toward underactivation of the 1st agonist burst in the dystonic group. The authors concluded that slowness is a consistent feature of voluntary movement in FHD and is present even in the absence of dystonic posturing. Underactivation of the 1st agonist burst appears to be the most likely reason to explain slowing.     

When attitudes do not fit: discordance of acculturation attitudes as an antecedent of intergroup threat

Recent research has shown that the perspectives of both minorities and majorities should be taken into account to reach a deeper understanding of the acculturation process and its consequences for intergroup relations. The authors report two experiments that investigated the impact of discordant acculturation attitudes on perceived threat. In Study 1 (N=183), Germans were asked for their attitudes toward Turks and Italians. Different levels of concordance of acculturation attitudes were induced by presenting participants with newspaper articles describing the acculturation attitude of the respective out-group and perceived threat was measured. In Study 2 (N=100), two fictitious immigrant groups were used as target groups. Results in both studies showed that discordance of acculturation attitudes leads to higher perceptions of intergroup threat than concordance of acculturation attitudes. Furthermore, both studies supported the assumption that a similar out-group is perceived as less threatening than a dissimilar out-group.     

Effects of acceptance-oriented versus evaluative emotional processing on heart rate recovery and habituation

The effects of emotional processing on stress response trajectories may depend on the nature of processing, as evaluative rumination about emotions can prolong distress. In contrast, observing negative emotions in an accepting manner may promote efficient recovery from stressful situations. The present study examined the effect of acceptance-oriented versus evaluative emotional processing on cardiovascular habituation and recovery. Across two experimental sessions, 81 participants were randomly assigned to write about an ongoing stressful experience while either (1) evaluating the appropriateness of their emotional response (EVAL), (2) attending to their emotions in an accepting way (ACC), or (3) describing the objective details of the experience (CTL). Heart rate was assessed continuously throughout baseline, writing, and recovery. Results suggest that writing about emotions in an evaluative way leads to less efficient heart rate habituation and recovery than processing emotions in an accepting manner. These findings highlight a potential mechanism of mindfulness- and acceptance-based interventions' effects on health outcomes and further suggest that habitually evaluating the appropriateness of one's emotional responses rather than accepting them as they unfold may have consequences for cardiovascular health.     

Prenatal intervention and support for low-income fathers

The focus of this study was to determine the effectiveness of prenatal intervention with low socioeconomic, first-time fathers whose partners were experiencing a high- or low-risk pregnancy. Of the 67 men, who were recruited by their partners, half were randomly assigned to participate in an intervention program designed to acquaint fathers-to-be with information, insights, and clinically appropriate techniques in responsive care for infants. Intervention group fathers received two intensive 1¹/₂-hour sessions emphasizing the nature and capabilities of the prebornhewborn and sensitive responsiveness to preborn/newborn cues and to partner cues. Postnatally, fathers were videotaped with their infants during two feeding interactions. At Time 1, intervention fathers were rated from videotapes as significantly more sensitive during feeding interactions with their newborn infants. At Time 2, 1 month later, differences between father groups approached significance.     

The effects of physostigmine and scopolamine on recognition memory in monkeys

The visual recognition of rhesus monkeys was evaluated by means of a delayed nonmatching-to-sample task with trial-unique objects. Each daily session consisted of two lists of 20 objects each, which untreated animals were able to recognize at approximately 75% accuracy. When they were performing at this level reliably, doses of physostigmine (0.32, 1.0, 3.2, 10.0, 32.0, 56.0 micrograms/kg), scopolamine (1.0, 3.2, 5.6, 10.0, 17.8, 32.0 micrograms/kg), or saline were administered 20 min prior to the session. Physostigmine and scopolamine produced dose-related increases and decreases, respectively, in the number of objects correctly remembered. The systematic changes in performance support the view that cholinergic mechanisms contribute to recognition memory and suggest that tasks with trial-unique objects may be particularly useful for studying the mnemonic effects of cholinergic drugs.     

The processing of interlexical homographs in translation recognition and lexical decision: Support for non-selective access to bilingual memory

In three experiments we looked at the processing of interlexical homographs by Dutch-English bilinguals. In Experiment 1 we employed the translation recognition task, a task that forces the participants to activate both language systems simultaneously. In this task the processing of interlexical homographs was inhibited substantially compared to the processing of matched control words, especially when the homograph reading to be selected was the less frequent of the homograph's two readings. In Experiments 2 and 3 we used the lexical decision task: In one condition we asked the participants to categorize letter strings as words or nonwords in Dutch; in a second condition we asked them to do so in English. The makeup of the stimulus set in Experiment 2 permitted the participants to ignore the instructions and to instantiate the task in a language-neutral form-that is, to categorize the letter strings as words in either Dutch or English. Under these circumstances a small, frequency-dependent inhibitory effect for homographs was obtained, but only in condition Dutch. In Experiment 3 the participants were forced in a language-specific processing mode by the inclusion of "nonwords" that were in fact words in the non-target language. Large frequency-dependent inhibitory effects for homographs were now obtained in both language conditions. The combined results are interpreted as support for the view that bilingual lexical access is non-selective.