Prompt-facilitated learning: The development of unprompted memory integration and subsequent self-derivation.

What are the boundaries that limit expansion of semantic knowledge across development? One striking contender is the necessity of a prompt to integrate and self-generate new information. The present research was an investigation of 7-9-year-olds' and 18-22-year-olds' prompted versus unprompted memory integration and subsequent self-derivation of new knowledge. Children and adults (Experiments 1 and 2, respectively) were exposed to sets of novel, true facts that could be integrated to self-derive new knowledge. On some trials they were prompted to integrate and self-derive and on others they were not. Both children and young adults capitalized more effectively on prompted opportunities to self-derive compared with unprompted opportunities, and the mechanism of this difference in performance likely underlies memory integration. Thus, the current work illustrates the importance of the conditions under which memory integration occurs, regardless of age. Results also offer evidence consistent with developmental change in unprompted integration and self-derivation performance, such that children and adults may engage the process of self-derivation differently. This work is particularly important in highlighting the necessity of appropriate scaffolding to foster successful learning opportunities and understanding the conditions under which semantic knowledge is accumulated.

Generative and active engagement in learning neuroscience: A comparison of self-derivation and rephrase.

It is crucial to identify cognitive mechanisms that support knowledge growth. One such mechanism that is known to improve learning outcomes is generative processing: the construction of novel information beyond what is directly taught. In this study of college students, we investigate the learning outcomes associated with the generative process of self-derivation through integration, the integration of multiple related facts to generate novel information. We compare the effects of self-derivation versus an active rephrase control condition on retrieval, application, and organization of neuroscience classroom content. In the self-derivation condition, learners were prompted to generate inferences based on integration of two explicitly-taught facts. In the rephrase condition, learners were explicitly provided these inferences and asked to rephrase them. We found few overall differences between learning manipulation conditions. However, we found that, regardless of the learning manipulation condition to which learners were exposed, learners generated their own information on some trials. This generation predicted success on retrieval and application of learned information. Further, self-derivation, when successful, led to particularly high rates of retrieval when compared with active rephrase. These findings inform theory on generative processing, and demonstrate that self-derivation is a mechanism of knowledge growth that may be useful for retrieval.

Chronic hyperoxia alters the expression of neurotrophic factors in the carotid body of neonatal rats.

Chronic exposure to hyperoxia alters the postnatal development and innervation of the rat carotid body. We hypothesized that this plasticity is related to changes in the expression of neurotrophic factors or related proteins. Rats were reared in 60% O(2) from 24 to 36h prior to birth until studied at 3d of age (P3). Protein levels for brain-derived neurotrophic factor (BDNF) were significantly reduced (-70%) in the P3 carotid body, while protein levels for its receptor, tyrosine kinase B, and for glial cell line-derived neurotrophic factor (GDNF) were unchanged. Transcript levels in the carotid body were downregulated for the GDNF receptor Ret (-34%) and the neuropeptide Vgf (-67%), upregulated for Cbln1 (+205%), and unchanged for Fgf2; protein levels were not quantified for these genes. Immunohistochemical analysis revealed that Vgf and Cbln1 proteins are expressed within the carotid body glomus cells. These data suggest that BDNF, and perhaps other neurotrophic factors, contribute to abnormal carotid body function following perinatal hyperoxia.