Cyclic cortical reorganization during early childhood.

EEG coherence was computed from 8 left and 8 right intrahemispheric electrode pairs from 253 children ranging in mean age from 6 months to 7 years. The first derivative of mean coherence was computed in order to study growth spurts or rapid changes in mean coherence over the early childhood period. Growth spurts in EEG coherence were approximately 6 months to 1 year in duration and involved a cyclical process composed of a sequential lengthening of intracortical connections in the left hemisphere and a sequential contraction of intracortical connections in the right hemisphere. Each growth spurt cycle had a period of approximately 2 to 4 years and involved both a rostral-caudal expansion and contraction as well as a lateral-to-medial rotation. Data support the view that the functions of the left and right hemisphere are established early in human development through complementary developmental sequences and that these sequences appear to recapitulate differences in adult hemispheric function.     

Performance and Private Speech of Children with Attention-Deficit/Hyperactivity Disorder While Taking the Tower of Hanoi Test: Effects of Depth of Search,Diagnostic Subtype,and Methylphenidate

We administered the Tower of Hanoi to demographically comparable samples of control participants (n = 34) and children with the Combined (n = 22) and Inattentive subtypes (n = 19) of Attention-Deficit/Hyperactivity Disorder (ADHD). Controls excelled over children with the Inattentive subtype, who outperformed patients with the Combined subtype. These results replicated findings of greater executive deficits in the Combined than in the Inattentive type of ADHD. Double-blind administration of methylphenidate improved task performance only for patients with the Inattentive subtype. In a drug-free Baseline session, children with both subtypes of ADHD made more private verbalizations than controls, particularly when failing puzzles. In later sessions, regardless of drug condition, the inattentive sample exhibited a smaller increase in self-regulatory utterances under failure. In contrast, the combined sample decreased self-regulatory verbalizations under failure only under methylphenidate. The results support some differences between the two subtypes of ADHD in executive functioning and in their response to stimulant therapy. Portions of these results were submitted as part of H. Theresa Chang's PhD dissertation (Chang, 2000) and Helena Kopecky's unpublished master's research, both conducted at the University of Rochester and supervised by Rafael Klorman.     

Sustainable system-of-systems and francophone activity-centered approaches in ergonomics: Converging and diverging lines of dialogue

This paper initiates a dialogue between the sustainable system-of-systems (SSoS) approach and one particular situated approach of activity analysis within francophone activity-centered ergonomics (FACE). This paper explores the possible cross-fertilizations between FACE and SSoS in coping with the challenge of enlargement which ergonomists have to face in order to address sustainability issues. We present how the SSoS model and FACE have currently considered the challenges of sustainable development and the theoretical-methodological principles that frame their approaches. Then, eight topics of dialogue are introduced and debated in order to open the dialogue between the two approaches where emerging lines of convergence are generated. We conclude by further discussing the complementarity between FACE and SSoS in the objectives of their approaches and the levels analysed by each approach, and by highlighting the importance of taking into account the emergent and complex aspects of systems. One possible way forward might be to “situate the sustainable system-of-systems” while also “systemizing systems of sustainable situations” for the future.