Developmental Transitions in Private Speech: Implications for Real World Executive Function

The use of private speech (PS), non-social speech that is audible or internalized, is important for engaging in the successful use of executive functions (EFs). EFs are general mechanisms that allow us to control and regulate our behaviors, thoughts and feelings. A developmental transition has been posited in private speech during early childhood, changing from overt to more covert with age; this transition might support developmental improvements in EFs. However, previous research has focused on a limited set of tasks, has not tested whether overt private speech might decrease with age due to other factors (e.g., talkativeness), and has not tested how private speech relates to real-world EF. The current study investigated the developmental transition in private speech in a cross-sectional sample of 30 children between the ages of 5 and 7 years old. The use of four cognitive tasks allowed a test of the generalizability of developmental changes in private speech. Correlations were found across a few tasks but not across the entire battery, which may suggest that children utilize different levels of PS based on task demands. Two covariate measures (talkativeness and extroversion) allowed a test of whether other factors may play a role in overt private speech. Extroversion was significantly positively correlated with some tasks, and negatively correlated with age, which suggests that developmental decreases in overt speech may be driven by developmental decreases in extroversion. Real-world EF was assessed via a parent questionnaire, the Behavior Rating Inventory of Executive Function (BRIEF). Use of PS on some tasks was trending with BRIEF scores, which suggests that PS may play a role in real world EF

Non-paretic Forelimb Training Does Not Interfere with Recovery of Paretic Forelimb Strength After Experimental Middle Cerebral Artery Occlusion

Humans often compensate with their unimpaired (non-paretic) forelimb after surviving a stroke. Research in rats suggests that this can be maladaptive after focal motor cortical strokes. Forelimb weakness is understudied in rodent models of stroke. The purpose of the study is to determine whether behavioral experience with the non-paretic forelimb differentially affects paretic forelimb strength recovery after ischemic injury caused by middle cerebral artery occlusion (MCAo). Because behavioral manipulations can influence patterns of neural connectivity post-stroke, the present study also examined how training with non-paretic limb influenced corticostriatal projections. After training to proficiency with the preferred forelimb on the Isometric Pull Task, rats underwent MCAo in the hemisphere contralateral to this limb. One week after MCAo, rats were probed for initial impairment level and then assigned to either Non-Paretic Limb Training (NPT) or non-training control conditions for 14 days. Paretic limb performance was probed one day later. All rats then received six weeks of Rehabilitative Training (RT). The anterograde tract tracer BDA was then injected into the lesioned hemisphere. Training with the non-paretic limb (NPT) does not interfere with paretic limb recovery on the Isometric Pull Task, increase reliance on the impaired forelimb, or influence ipsi corticostriatal axon quantities after MCAo. Compensatory use of the non-paretic forelimb after strokes involving subcortical damage or cortical damage primarily in the somatosensory region may not be maladaptive for strength. Understanding how behavioral recovery varies with lesion locus could influence clinical management of patients

Decomposing the effect of height on income in China: The role of market and political channels

It is well known that height is positively associated with earnings. Based on individual level data, this paper investigates the channels through which height influences income in China. Our first key finding is that taller people are more likely to become members of the Communist Party, resulting in an increase in their income level. We label this the height premium in earnings through the political channel. Second, controlling for the political channel of the height premium, height is positively associated with income in the labor market. We label this the height premium through the market channel. Third, the height premium in earnings through the market channel is larger than that through the political channel