Gene x environment interaction and cognitive performance: animal studies on the role of corticosterone

A fundamental question in the neurobiology of cognition is how stress and glucocorticoids modify learning and memory processes. Why some individuals develop cognitive deficits after stress, while other individuals improve in cognitive performance under similar adverse conditions is still unresolved. To address these questions we focus on those issues. First, corticosterone, which appears to be the preferred glucocorticoid for the rodent and human brain, acts via brain mineralocorticoid (MR) and glucocorticoid receptors (GR) on the expression of networks of corticosteroid-responsive genes. Different effects are achieved by MR and GR activation. Second, the experimental context that determines the timing and the consequences of corticosterone action during the various stages of information processing is reviewed. Third, the genetic context and the environmental context are investigated. Using apolipoprotein E knockout (apoE0/0) mice we show that apoE (apoE4 is a genetic risk factor for Alzheimer's disease) is a candidate gene with an important function in shaping the cognitive outcome (genotype x environment interaction).     

Macropremies: underprivileged newborns

The focus of neonatal intensive care has been on very low birthweight infants, who comprise only 1.4% of neonates. Too little attention is paid to moderately preterm infants that we call macropremies or moderately low birthweight infants (MLBW, with birthweights 1500-2500 grams). Admitting over half MLBW infants to normal nurseries presumes that they have few needs and an excellent prognosis similar to fullterm newborns. It does not take into account the macropremie's vulnerability to complications of prematurity due to immature organ systems. Obstetricians are increasingly willing to deliver these infants prematurely for signs of fetal distress. As many as 25% of children with cerebral palsy referred to a disability clinic in Paris were MLBW, with hypoxic-ischemic-inflammatory associated disorders in one-third. The majority of MLBW infants who required neonatal intensive care at a tertiary care center in Baltimore had complications of prematurity: 47% had respiratory problems, 20% had feeding intolerance and 9% had hypoglycemia. MLBW infants comprise 5-7% of the neonatal population but account for 14% of neonatal deaths, 18-37% of children with cerebral palsy and 7-12% of children with mental retardation. Increasing the level of neonatal care for the macropremie's transition to extrauterine life would be economically feasible if it prevented as few as 30% of cases of major disability. A change in attitude towards this low risk (but not risk free) group of MLBW infants will both reduce morbidity and improve their health and neurodevelopmental outcome. It includes: 1) Providing an intermediate level of neonatal care for a short duration, with close monitoring and prompt intervention as needed, and 2) Neonatal neurodevelopmental screening to allow focused neurodevelopmental followup of MLBW infants with abnormalities.     

Sustained attention to local and global target features is different: Performance and tympanic membrane temperature

Vision researchers have investigated the differences between global and local feature perception. No one has, however, examined the role of global and local feature discrimination in sustained attention tasks. In this experiment participants performed a sustained attention task requiring either global or local letter target discriminations or watched the same displays without any work imperative. Reaction time to targets was slower when global feature discriminations were required than when local feature discriminations were required. Tympanic membrane temperature (TMT) was utilized in this study as an index of cerebral activation. Participants in the global letter detection condition had elevated post-task right TMT, indicative of reduced cerebral activation in the right hemisphere, in comparison to participants in the local letter detection or no-work imperative conditions. Both the performance and physiological results of this study indicate increased cognitive fatigue when global feature discriminations are required.     

Application of a CBPR Framework to Inform a Multi-level Tobacco Cessation Intervention in Public Housing Neighborhoods

African American women in urban, high poverty neighborhoods have high rates of smoking, difficulties with quitting, and disproportionate tobacco-related health disparities. Prior research utilizing conventional "outsider driven" interventions targeted to individuals has failed to show effective cessation outcomes. This paper describes the application of a community-based participatory research (CBPR) framework to inform a culturally situated, ecological based, multi-level tobacco cessation intervention in public housing neighborhoods. The CBPR framework encompasses problem identification, planning and feasibility/pilot testing, implementation, evaluation, and dissemination. There have been multiple partners in this process including public housing residents, housing authority administrators, community health workers, tenant associations, and academic investigators. The advisory process has evolved from an initial small steering group to our current institutional community advisory boards. Our decade-long CBPR journey produced design innovations, promising preliminary outcomes, and a full-scaled implementation study in two states. Challenges include sustaining engagement with evolving study partners, maintaining equity and power in the partnerships, and long-term sustainability of the intervention. Implications include applicability of the framework with other CBPR partnerships, especially scaling up evolutionary grassroots involvement to multi-regional partnerships.     

Contrast of hemispheric lateralization for oro-facial movements between learned attention-getting sounds and species-typical vocalizations in chimpanzees: Extension in a second colony

Studies involving oro-facial asymmetries in nonhuman primates have largely demonstrated a right hemispheric dominance for communicative signals and conveyance of emotional information. A recent study on chimpanzee reported the first evidence of significant left-hemispheric dominance when using attention-getting sounds and rightward bias for species-typical vocalizations (Losin, Russell, Freeman, Meguerditchian, Hopkins & Fitch, 2008). The current study sought to extend the findings from Losin et al. (2008) with additional oro-facial assessment in a new colony of chimpanzees. When combining the two populations, the results indicated a consistent leftward bias for attention-getting sounds and a right lateralization for species-typical vocalizations. Collectively, the results suggest that both voluntary-controlled oro-facial and gestural communication might share the same left-hemispheric specialization and might have coevolved into a single integrated system present in a common hominid ancestor.     

Lateralized reaching as dynamical symmetry breaking in the bushbaby (Otolemur garnettii): preliminary evidence

Eight bushbabies were subjected to an extensive series of hand preference trials in which they were required to reach for a raisin from a rotating platform approaching from the right- or left-hand side of their visual field. Three principal types of behavior were observed. Several individuals known to be stable in hand preference continued to show a strong preference for a single hand. Another group, including some previously categorized as stable, exhibited "ambidextrous" cross-body reaching behavior. One individual exhibited far more complex behavior, being ambidextrous at low and very high speeds but lateralized at intermediate speeds. A straightforward adaptation of the dynamical neural field theory of Sch?ner et al. (1997) provides a model allowing each type of behavior, except possibly the shift from lateralized behavior to ambidextrous behavior at high speed, which might nonetheless be accommodated with minor modification.     

The Heuristic Power Of Oppositionality In An Incidental-Memory Task: In Support Of The Construing Process

From a personal construct view, construing is a top-down process in which wider meanings predicate narrower, targeted meanings. Predicate contexts are invariably oppositional, as Kelly's (1955) theory reflects. Two memory experiments using college subjects are presented. Subjects were asked to focus on a series of 30 target words to determine if they were similar in meaning to a predicating word (e.g., friendly). Ten of these target words were relevant (e.g., congenial), 10 were opposite (e.g., impolite), and 10 were irrelevant (e.g., abstract) in meaning to the predicating word. Subjects were then (unexpectedly) asked to recall as many words as possible. In line with experimental instructions, the majority of these recalled words were relevant to the predicating word. However, as predicted, in both experiments significantly more opposite than irrelevant words were recalled (p < .001). The results are in support of a personal construct view of human cognition.     

Blacky the Cat,I: Semantic Differential Ratings

Two criteria for an alternate form of the Blacky Test, designed to facilitate female identification with Blacky are suggested: 1) the main character must be perceived by females as more feminine than the original stimulus, and 2) the main character must not be viewed differently by male and female Ss in other respects. Semantic Differential ratings of both the original Blacky stimuli and a revised “sexually neutral” cat form (N = 320) indicated that an alternate version could meet both these requirements. Differences between the responses of female Ss to both forms were further shown to be a) generally specific to female Ss, b) specific to the character of Blacky (rather than Mama) and c) often enhanced when Ss made judgments after having seen all twelve cartoons of the test, rather than only the first two.