Spatial analysis after perinatal stroke: patterns of neglect and exploration in extra-personal space

This study was conducted to determine whether school-aged children who had experienced a perinatal stroke demonstrate evidence of persistent spatial neglect, and if such neglect was specific to the visual domain or was more generalized. Two studies were carried out. In the first, 38 children with either left hemisphere (LH) or right hemisphere (RH) damage and 50 age-matched controls were given visual cancellation tasks varying in two factors: target stimuli and stimulus array. In the second study, tactile neglect was evaluated in 41 children with LH or RH damage and 72 age-matched controls using a blindfolded manual exploration task. On the visual cancellation task, LH subjects omitted more target stimuli on the right, but also on the left, compared with controls. Children with RH lesions also produced a larger number of omissions on both the left and right sides than controls, but with poorer performance on the left. On the manual exploration task, LH children required significantly longer times to locate the target on both sides of the board than did controls. RH children had significantly prolonged search times on the left side, but not on the right, compared with controls. In both tasks, LH subjects employed unsystematic search strategies more often than both control and RH children. The search strategy of RH children also tended to be erratic when compared to controls, but only in the random arrays of the visual cancellation tasks; structure of the target stimuli improved their organization. These results demonstrate that children with early LH brain damage display bilateral difficulties in visual and tactile modalities; a pattern that is in contrast to that seen in adults with LH damage. This may result from disorganized search strategies or other subtle spatial or attentional deficits. Results of performance of RH children suggests the presence of contralateral neglect in both the visual and tactile modalities; a finding that is similar to the neglect in adult stroke patients with RH lesions. The fact that deficits in spatial attention and organizational strategies are present after very early focal damage to either the LH or the RH broadens our understanding of the differences in functional lateralization between the immature and mature brain. These results also add to evidence for limitations to plasticity in the developing brain. Our findings may have therapeutic and rehabilitative implications for the management of children with early focal brain lesions.     

Does luck have a place in epistemology?

Some epistemologists hold that exploration and elaboration of the nature of luck will allow us to better understand knowledge. I argue this is a mistake.     

Childhood anxiety associated with low BMI in women with Anorexia Nervosa

Objective

Extremely low body mass index (BMI) values are associated with increased risk for death and poor long-term prognosis in individuals with anorexia nervosa (AN). The present study explores childhood personality characteristics that could be associated with the ability to attain an extremely low BMI.

Methods

Participants were 326 women from the Genetics of Anorexia Nervosa (GAN) Study who completed the Structured Interview for Anorexia Nervosa and Bulimic Syndromes and whose mother completed the Child Behavioral Checklist and/or Revised Dimensions of Temperament Survey.

Results

Children who were described as having greater fear or anxiety by their mothers attained lower BMIs during AN (p < 0.02). Path analysis in the GAN and a validation sample, Price Foundation Anorexia Nervosa Trios Study, confirmed the relation between early childhood anxiety, caloric restriction, qualitative food item restriction, excessive exercise, and low BMI. Path analysis also confirmed a relation between childhood anxiety and caloric restriction, which mediated the relation between childhood anxiety and low BMI in the GAN sample only.

Conclusion

Fearful or anxious behavior as a child was associated with the attainment of low BMI in AN and childhood anxiety was associated with caloric restriction. Measures of anxiety and factors associated with anxiety-proneness in childhood may index children at risk for restrictive behaviors and extremely low BMIs in AN.     

Distractor effects on latent inhibition are a consequence of generalization decrement

In two experiments rats were exposed to a novel vinegar solution and subsequently given a single conditioning trial on which consumption of vinegar was followed by an injection of lithium chloride. In conformity to other results on distractor effects, the latent inhibition produced by this treatment could be disrupted if the rats drank a second novel solution (sucrose) immediately after their initial exposure to vinegar. But latent inhibition was equally disrupted if rats were initially exposed to vinegar alone and subsequently drank vinegar immediately followed by sucrose on the conditioning trial. Thus latent inhibition was disrupted whenever there was a change between the solutions presented on initial exposure and conditioning trials. Generalization decrement seems the most parsimonious explanation of this pattern of results.     

The Perceptions of Persons Living with Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome About Their Experiences in Regaining Productive Occupations: A Delphi Study

Research supports the importance of occupational role engagement for people living with human immunodeficiency virus and acquired immunodeficiency syndrome. This qualitative Delphi study obtained the perspectives of participants in a community-based program for persons living with human immunodeficiency virus/acquired immunodeficiency syndrome about their resumption of productive occupations. Data analysis revealed four themes of self-worth, finances, health, and social systems. Within each theme, motivators, obstacles, and supports were identified. These findings can be used to guide occupational therapy practitioners working with persons living with human immunodeficiency virus/acquired immunodeficiency syndrome to facilitate supports, surmount barriers, and empower persons living with human immunodeficiency virus/acquired immunodeficiency syndrome to resume and retain desired and meaningful occupational roles.     

The Soritical Centipede

Two philosophical questions arise about rationality in centipede games that are logically prior to attempts to apply the formal tools of game theory to this topic. First, given that the players have common knowledge of mutual rationality and common knowledge that they are each motivated solely to maximize their own profits, is there a backwards‐induction argument that (i) employs only familiar non‐technical concepts about rationality, (ii) leads to the conclusion that the first player is rationally obligated to end the game at the first step, (iii) is deductively valid, (iv) employs premises all of which are prima facie highly plausible, and (v) is prima facie sound (in virtue of features (iii) and (iv))? Second, if there is such an argument, then is it actually sound, or is it instead defective somehow despite being prima facie sound? Addressing these two questions is our project. We present a backwards‐induction argument that is prima facie sound; we argue that it is an instance of the notorious sorites paradox, and hence that the concepts of rational obligatoriness and rational permissibility are vague; and we briefly address the potential consequences of all this for the foundations of game theory and decision theory.