Event-related potentials to overlapping shapes: Effects of saliency and interference

Visual perception is often challenged by various difficulties that act concomitantly and whose respective impacts may therefore be hard to distinguish. We used event-related potentials to dissociate the impact of target saliency, generated by occlusion, from that of interference produced by incongruent nontargets. In one block, the target (a square) partially occluded another square tilted by 45°. This nontarget square interfered only to a small extent with target perception. In another block, the target was the occluded stimulus, and interference from the nontarget was substantial. Blocks including two kinds of overlapping shapes (a cross and a square) were added to control for the interference effect. Block comparisons revealed that occlusion modulated an occipital N250 and reaction times. In contrast, interference modulated a parietal N380 but not reaction times.     

The tripartite model of fear in children with specific phobias: assessing concordance and discordance using the behavioral approach test

Lang’s tripartite model posits that three main components characterize a fear response: physiological arousal, cognitive (subjective) distress, and behavioral avoidance. These components may occur in tandem with one another (concordance) or they may vary independently (discordance). The behavioral approach test (BAT) has been used to simultaneously examine the three components of the fear response. In the present study, 73 clinic-referred children and adolescents with a specific phobia participated in a phobia-specific BAT. Results revealed an overall pattern of concordance: correlation analyses revealed the three indices were significantly related to one another in the predicted directions. However, considerable variation was noted such that some children were concordant across the response components while others were not. More specifically, based on levels of physiological arousal and subjective distress, two concordant groups (high arousal–high distress, low arousal–low distress) and one discordant (high arousal–low distress or low arousal–high distress) group of youth were identified. These concordant and discordant groups were then compared on the percentage of behavioral steps completed on the BAT. Analyses revealed that the low arousal–low distress group completed a significantly greater percentage of steps than the high arousal–high distress group, and a marginally greater percentage of steps than the discordant group. Potential group differences associated with age, gender, phobia severity, and phobia type were also explored and no significant differences were detected. Implications for theory and treatment are discussed.     

Serum β-Amyloid Correlates with Neuropsychological Impairment

ABSTRACT

Aims: Evidence suggests a relationship between peripheral Aβ and AD. We hypothesized that higher levels of serum Aβ_1–42 would be associated with memory impairment, thought to occur early in the disease, and rises in serum Aβ_1–40, which occur later, would be associated with impairment in non-memory measures. Methods: Using a cross-sectional design, we examined the relationship of serum Aβ_1–40, Aβ_1–42, and the ratio of Aβ_{1–42/1–40} to neuropsychological measures in 40 cognitively normal controls, 13 MCI subjects, and 25 AD patients. Results: Serum Aβ_1–42 and the ratio of Aβ_{1–42/1–40} were significantly higher in the MCI group compared to the controls. A significant relationship in the hypothesized direction (poorer scores associated with higher Aβ_1–40 serum levels) was found between Aβ_1–40 and measures of executive functions across the entire cohort of individuals tested and with measures of language and processing speed in the AD group. Regression analysis found that neuropsychological measures accounted for 26% of the variance in serum Aβ_1–40, in the MCI/AD but not the controls. Furthermore that language and executive measures were significant predictors. Conclusions: Results provide preliminary data to partially support our hypotheses and suggest that changes in serum Aβ levels may be attributed to pathological changes within the brain.     

The structure of individual differences in batteries of rapid acquisition tasks in mice

Two experiments examined the structure of individual differences in mice by means of tasks that produced significant acquisition within 1 session. In Experiment 1, 5 cognitive tasks-detour, winshift, olfactory discrimination, fear conditioning, and operant acquisition-were used in conjunction with two control procedures: an open field and a light- dark test. In Experiment 2, some modifications were made to the tasks used in the 1st experiment, and 3 new tasks were used in conjunction with the same control procedures. The battery consisted of 5 learning tasks: detour, Hebb-Williams, radial maze, olfactory foraging, and fear conditioning. Results of both experiments indicate that when cognitive tasks and control procedures were included in principal-components analyses most of the variance attached principally to individual tasks rather than to a general component as is found typically in human cognitive batteries. When control procedures were eliminated, there was better evidence for the presence of a general cognitive factor, particularly in Experiment 2.     

On the alleged normative significance of a platitude

It seems to be a platitude that the belief that p is correct iff it is true that p. And the claim that truth is the correct‐making feature of belief seems to be just another way of expressing this platitude. It is often thought that this indicates that truth constitutes a normative standard or criterion of correctness for belief because it seems to follow from this platitude that having a false belief is believing wrongly, and having a true belief is believing rightly or correctly. In this paper, I aim to show that when we judge the platitude in question to be indisputably true, we do not endorse that truth is normative for belief but merely the triviality that the belief that p is true iff it is true that p.     

Adapting to changing memory retrieval demands: Evidence from event-related potentials

This study investigated preparatory processes involved in adapting to changing episodic memory retrieval demands. Event-related potentials (ERPs) were recorded while participants performed a general old/new recognition task and a specific task that also required retrieval of perceptual details. The relevant task remained either constant or changed (predictably or randomly) across trials. Responses were slowed when participants switched from the specific to the general task but not vice versa. Hence, asymmetrical switch costs were observed, suggesting that retrieval preparation is dependent not only on the current retrieval goal but also influenced by recent retrieval attempts. Consistently, over posterior scalp regions ERPs associated with advance preparation were modulated by the preceding task, reflecting increased attentional selection requirements for the general task, and by the foreknowledge about the task sequence. When retrieval demands remained constant, frontal slow-waves elicited by retrieval-cues were more positive going for the specific task, indicating full implementation of a retrieval orientation that allows more efficient retrieval of perceptual details.     

Post-traumatic feeding disorders in infancy: Behaviors predicting treatment outcome

The purpose of this study was to examine whether specific problem feeding behaviors exhibited by infants with post-traumatic feeding disorders (PTFD) predict treatment outcome. In this case series, 24 infants aged 7 weeks to 34 months received a three-component intervention for the treatment of their PTFD. The three components of the interventions included (1) physiological and environmental changes to regularize hunger-satiety cycles and promote good eating habits and routines; (2) nutritional monitoring; and (3) behavior therapy (flooding). Infants with PTFD who exhibited passive refusal to swallow food placed in their mouths and did not chew/suck/move food placed in their mouths for more than 5 sec were significantly less likely to respond to treatment, compared to infants with PTFD who did not exhibit these behaviors. Further, compared with infants with PTFD who responded to treatment, more infants with PTFD who did not respond had anatomical/mechanical problems of their upper airway such as tracheoesophageal fistula or lung disease such as bronchopulmonary dysplagia. The findings have direct implications for the assessment and treatment of PTFD in infancy.     

“Working model of the child interview”: Infant clinical status related to maternal perceptions

Parental perceptions and subjective experience of infants have long been considered important in clinical work with infants and families. Using three different samples of infants, we compare mothers' representations of their infants in clinically referred and nonreferred groups, using the Working Model of the Child Interview (WMCI). Twenty-four mothers of infants with failure to thrive (and 25 matched controls), 17 mothers of toddlers with sleep disorders (and 20 matched controls), and 13 mothers of infants seen in a general infant psychiatry clinic participated. Compared to their nonclinical counterparts, mothers of infants with clinical problems had representations of their infants that were significantly more likely to be classified distorted or disengaged. Infant gender, age, and birth order were independent of maternal classifications. We conclude that the WMCI is a useful structured interview to categorize mothers' perceptions and subjective experience of their infant and relationship with the infant. Mothers' WMCI classifications are associated with the clinical status of the infant. © 1997 Michigan Association for Infant Mental Health