Concept maps boost learning
Concept maps are diagrammatic, often hierarchical representations of how different concepts relate to each other (see image below). They encourage the learner to crystallise relationships between concepts and to elaborate on their own understanding. As such, they are thought to produce deeper, more meaningful learning.
By conducting a meta-analysis of research into the effectiveness of concept maps, Schroeder and colleagues show that this method produces superior learning compared to a host of other learning methods, such as attending lectures, studying texts, or constructing texts. This superiority held across all ages examined (intermediate school years to post-secondary), across both STEM and non-STEM fields, and regardless of whether learners constructed their own concept map or studied one presented to them. The issue of why concept mapping was superior to other learning approaches was not resolved, and the authors recommend future studies more specifically address this question.
Synapses keep overlapping memories separate
Memories are stored as activity in specific ensembles of neurons, and closely related memories show considerable overlap in which neurons they engage. How does the brain ensure these closely related memories are independent and distinguishable?
To answer this, researchers from Japan’s University of Toyama attempted to erase just one of two overlapping memories. Using sophisticated genetic, optical and behavioral approaches, the authors achieved this, specifically removing one memory while leaving a second memory (which utilized an overlapping pool of neurons) intact. Their experiments suggest that closely related memories retain independence because the active synapses differ, even if the ensemble of active neurons is similar.
Abdou et al. (2018) Synapses-specific representation of the identity of overlapping memory engrams. Science 360: 1227-1231 DOI: https://doi.org/10.1126/science.aat3810
Genetics predicts years of schooling
Educational attainment – the number of years spent in formal schooling – correlates with various social, economic and health outcomes. Although the time spent in schooling is influenced by factors like parental education levels and family wealth, it is also heritable – a 2016 study found that genetic differences at 74 sites could be used to predict 3% of the variation in educational attainment.
Now a new study, which analysed DNA from a larger sample of people (over 1.1 million), has identified over 1200 locations that affect educational attainment. Together, these DNA differences can account for more than 10% of the variation in people’s schooling – nearly as informative as the education levels of a person’s parents, and more informative than parental wealth. Perhaps unsurprisingly, the researchers showed that these DNA variants were associated with genes important for brain development and synaptic communication.
Lee et al. (2018) Gene discovery and polygenic prediction from a genome-wide association study of educational attainment in 1.1 million individuals. Nature Genetics DOI: https://doi.org/10.1038/s41588-018-0147-3
Recovering ‘lost’ infant memories
Memories formed in infancy are lost by adulthood, a phenomenon known as ‘infantile amnesia’. Whether these memories are erased completely, or whether they still exist in adulthood but cannot be accessed, is unknown.
Paul Frankland and colleagues from the University of Toronto used genetic and optical techniques to answer this question. They genetically tagged the neurons involved in an infant memory, which allowed the researchers to artificially reactivate the memory several weeks after encoding. As expected, these infant memories were soon forgotten by the mice. However, optical reactivation of the genetically tagged neurons could reinstate the memory, as measured by behavioural changes.
The study shows that in mice, fear-related memories formed in infancy are not erased completely. Instead they are inaccessible but can be reactivated by artificial means.
Guskjolen et al. (2018) Recovery of “lost” infant memories in mice. Current Biology 28: 1-8 DOI: https://doi.org/10.1016/j.cub.2018.05.059