Use of Functional Magnetic Resonance Imaging in the Early Identification of Alzheimer's Disease

A growing body of evidence suggests that a preclinical phase of Alzheimer's disease (AD) exists several years or more prior to the overt manifestation of clinical symptoms and is characterized by subtle neuropsychological and brain changes. Identification of individuals prior to the development of significant clinical symptoms is imperative in order to have the greatest treatment impact by maintaining cognitive abilities and preserving quality of life. Functional magnetic resonance imaging (fMRI) offers considerable promise as a non-invasive tool for detecting early functional brain changes in asymptomatic adults. In fact, evidence to date indicates that functional brain decline precedes structural decline in preclinical samples. Therefore, fMRI may offer the unique ability to capture the dynamic state of change in the degenerating brain. This review examines the clinical utility of blood oxygen level dependent (BOLD) fMRI in those at risk for AD as well as in early AD. We provide an overview of fMRI findings in at-risk groups by virtue of genetic susceptibility or mild cognitive decline followed by an appraisal of the methodological issues concerning the diagnostic usefulness of fMRI in early AD. We conclude with a discussion of future directions and propose that BOLD-fMRI in combination with cerebral blood flow or diffusion techniques will provide a more complete accounting of the neurovascular changes that occur in preclinical AD and thus improve our ability to reliably detect early brain changes prior to disease onset.     

Multiple regression analyses in artificial-grammar learning: the importance of control groups

In artificial-grammar learning, it is crucial to ensure that above-chance performance in the test stage is due to learning in the training stage but not due to judgemental biases. Here we argue that multiple regression analysis can be successfully combined with the use of control groups to assess whether participants were able to transfer knowledge acquired during training when making judgements about test stimuli. We compared the regression weights of judgements in a transfer condition (training and test strings were constructed by the same grammar but with different letters) with those in a control condition. Predictors were identical in both conditions-judgements of control participants were treated as if they were based on knowledge gained in a standard training stage. The results of this experiment as well as reanalyses of a former study support the usefulness of our approach.     

The hidden persuaders break into the tired brain

There is a long-lasting debate on whether subliminal advertising actually works. In this context there are some studies suggesting that subjects’ motivation is a crucial point. Karremans et al. [Karremans, J. C., Stroebe, W., & Claus, J. (2006). Beyond Vicary’s fantasies: The impact of subliminal priming and brand choice. Journal of Experimental Social Psychology, 42, 792-798] showed that subjects were influenced in their intention to drink a specific brand of soft drink by a subliminally presented brand prime, but only if they were thirsty. In the present study, we adapted their paradigm to the concept of ‘concentration’ and embedded the subliminal presentation of a brand logo into a computer game. Actual subsequent consumption of dextrose pills (of the presented or a not presented brand) was measured dependent on the level of participants’ tiredness and the subliminally presented logo. We found the same pattern as Karremans et al. (2006): only tired participants consumed more of the subliminally presented than the not presented brand. Therefore, the findings confirm that subjects are influenced by subliminally presented stimuli if these stimuli are need-related and if subjects are in the matching motivational state.     

Maternal correlates of 2‐year‐old American Indian children's social‐emotional development in a Northern Plains tribe

The developmental experiences of very young American Indian children today are not well documented in the current literature. The present study sought to explore the social‐emotional development of American Indian toddlers living on a Northern Plains reservation, as a function of maternal variables. Mothers completed self‐report questionnaires about their experiences and their children's development. Observer ratings of children's development also were conducted. Maternal stress, substance use/abuse, perceptions of stress in the mother–child relationship, social support, and American Indian cultural identity were significantly related to children's social‐emotional development. This study is the first to explore these relationships in a Northern Plains American Indian sample of young children and their mothers. Results suggest possible points of intervention for improving the developmental outcomes of very young American Indian children.     

When one cue is not enough: combining fast and frugal heuristics with compound cue processing

One-reason decision-making heuristics as proposed by Gigerenzer, Todd, and the ABC Research Group (1999) have been shown to perform accurately. However, such strategies cannot deal with compound cues. We propose the Take The Best Configural Cue (TTB-Configural) as a fast and frugal heuristic that processes compound cues. In a series of three experiments, we analysed whether participants used this heuristic when making cue-based inferences on which of two alternatives had a higher criterion value. In two of the experiments, two cues were amalgamated into a valid compound cue by applying the AND or the OR logical rule, respectively. In the third experiment, there was no valid compound cue. Within each experiment, we also manipulated causal mental models through instructions. In the configural causal model, cues were said to act through the same causal mechanism. In the elemental causal model, cues were said to act through different causal mechanisms. In the neutral causal model, the causal mechanism was not specified. When a highly valid compound existed, and participants had a configural causal model, for the majority of them the strategy that could best account for their choices was TTB-Configural. Otherwise, the strategy that best predicted their choices was the Take The Best (TTB) heuristic.     

Does causal knowledge help us be faster and more frugal in our decisions?

One challenge that has to be addressed by the fast and frugal heuristics program is how people manage to select, from the abundance of cues that exist in the environment, those to rely on when making decisions. We hypothesize that causal knowledge helps people target particular cues and estimate their validities. This hypothesis was tested in three experiments. Results show that when causal information about some cues was available (Experiment 1), participants preferred to search for these cues first and to base their decisions on them. When allowed to learn cue validities in addition to causal information (Experiment 2), participants also became more frugal (i.e., they searched fewer of the available cues), made more accurate decisions, and were more precise in estimating cue validities than was a control group that did not receive causal information. These results can be attributed to the causal relation between the cues and the criterion, rather than to greater saliency of the causal cues (Experiment 3). Overall, our results support the hypothesis that causal knowledge aids in the learning of cue validities and is treated as a meta-cue for identifying highly valid cues.     

Resilience in the Face of Maternal Psychopathology and Adverse Life Events

Maternal psychopathology has long been recognized as a risk factor for psychopathology in offspring; however, some resilient youth achieve a favorable outcome in the presence of maternal psychopathology. We identified factors that predicted resilience among youth who were exposed to adverse life events, and also examined whether the same factors protected youth against maternal psychopathology and adverse life events. Main and interaction effects of child and family factors were examined employing cross-sectional data from a household probability sample of 1285 youth aged 9 through 17 collected at four sites. On average, children exhibited a greater degree of resilience when they had higher IQ, closer parental monitoring, better family functioning, higher educational aspiration, and were female. Interaction between maternal psychopathology and IQ was significant, and there was a trend between maternal psychopathology and gender. A higher IQ is a protective factor against both maternal psychopathology and adverse life events; whereas being a girl seems to be a protective factor against maternal psychopathology, but not adverse life events.     

Maltreated Children's Emotional and Behavioral Problems: Do Teachers and Parents See the Same Things?

We examined whether parent/caregivers and teacher/therapists differ in their perceptions of the behavior problems of young maltreated children. The sample consisted of 33 maltreated preschoolers (58% neglected, 24% sexually abused, 18% physically abused, 59% African American, 41% Caucasian) enrolled in a metropolitan-area treatment center providing an educational/intervention program for maltreated children and their families. Most (82%) of the participant families had an annual income of $10,000 or less. Parent/caregivers and teacher/ therapists provided data about the children, employing the Colorado Child Temperament Inventory, Child Behavior Checklist, and Preschool Behavior Questionnaire. The results indicate that the teacher/therapists and the parent/caregivers perceived the same child as behaving differently. Implications concerning how teachers and parents might communicate are discussed, as well as possible reasons for the two different perceptions of the same child. Three potential reasons for the differences are that they are due to the different perspectives of parents and teachers in assessing child behaviors, to situational variation in child behavior (e.g., home versus school), or to some combination of both effects.     

Going around transparent and grid‐like barriers: detour ability as a perception–action skill

Early detour ability may not generalize immediately across similar problems in different perception–action systems, but instead may reveal a pattern of developmental onset that is more domain‐specific. To investigate this possibility, we examined how 10‐month‐old (n = 24) and 12‐month‐old (n = 24) infants performed detours via different action modes and around barriers that differed in transparency. Infants made reaching and locomotor detours to retrieve an object located behind either an upright transparent barrier or an upright transparent barrier overlaid with a grid pattern. The results indicated that infants were more likely to make reaching than locomotor detours and explored the transparent and grid barriers differently. Additionally, younger infants more often attempted to contact the object through the entirely transparent barrier than did older infants, especially when making a reaching detour. The results suggest that during detour development, infants learn to coordinate relevant perceptual information with emerging actions.