What is synesthesia?
Synesthesia is a condition in which a single stimulus generates two or more sensory responses simultaneously. In the case of a sound-color synesthete, listening to a song on the radio - an auditory input - evokes both the sound of music and the image of pastel colors - a visual association. Synesthesia is thought to be caused by overlaps in sensory neural networks.
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There are many different forms of synesthesia - with the most common forms being grapheme-color (in which written symbols, like numbers and letters, are associated with a color) and sound-color (in which sounds are associated with a color). A rarer form of synesthesia, called sequence spatial, results in sequences of time being experienced as three dimensional shapes surrounding the synesthete, with some days or times corresponding to colors.
Color builds strong connections for many synesthetes.
Color builds strong connections for many synesthetes.
It is not entirely clear how synesthesia impacts learning. Some researchers believe synesthesia can hinder learning if innate associations do not match what is being taught. However, others believe there is a benefit to a different way of learning, as some synesthetes display increased efficiency of memorization.
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What gene is mutated in synesthesia?
ROBO3 is an ancient, well-conserved gene that regulates the distance that commissural axons (or those that are meant to cross the midline of the brain) are allowed to travel during development.
What is the gap in knowledge?
What is a good choice of model organism?
Zebrafish are the model organism of choice to explore this gap in knowledge due to their transparent nervous systems, their comparable color perception ability to humans, and their prior use in studies revolving around learning (and specifically learning through color associations).
How will I explore this knowledge gap?
Aim #1
In order to identify which of ROBO3's three domain types is most important for color perception, I will begin by visualizing the protein domains within homologs of ROBO3 using PFam. Then, I will align the sequences of the specific domain types separately using Clustal-W. I will identify key SNPs (or sections of the domain sequences) that generate phylogenetic trees similar to the one pictured to the right, which is grouped by color perception ability.
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With a better understanding of the significance of these SNPs, I will introduce them into zebrafish using a CRISPR/Cas9 system. Then, I will run the ROBO3 mutant fish, alongside wild-type control fish, through a color learning based maze assay, as described in Roy, et. al 2019.
Aim #2
In order to identify what genes are differentially expressed in ROBO3 mutants, I will perform RNA-seq on three critical regions within the zebrafish brain.
The dorsal pallium corresponds to the mammalian isocortex, which is involved in sensory perception and cognition. The medial pallium corresponds to the mammalian hippocampus, which is involved in spatial memory – a benchmark for learning the maze. The visual centro-posterior corresponds roughly to mammalian visual cortex, which is involved in visual perception.
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After conducting RNA-sequencing on four treatment groups - WT fish and ROBO3 mutant fish that have not run through the maze assay and WT and ROBO3 mutant that have run through the maze - and all three brain tissue samples, I will sort the resulting differentially expressed genes by GO term.
Aim #3
In order to identify new protein interactions between ROBO3 and proteins involved in color perception and learning, I identified two representative proteins to investigate further.
What are some future directions to explore?
I would like to further understand how color perception impacts learning and memory development for diverse species.
I am specifically interested in organisms with naturally enhanced color perception - like the honeybee (which has vision shifted towards the ultraviolet spectrum), mantis shrimp (which have 12 different cones), bluethroat bird (which can see all visible light and ultraviolet light), and butterflies (which have 15 types of photoreceptors). Color perception is important for learning and surviving effectively - distinguishing who might be a biologically fit mate, knowing to avoid a poisonous meal, and getting the edge on prey by seeing through visible light camouflage.
I'm also interested in better understanding how we can apply these findings to a general education application. Color psychology has begun to deepen our knowledge of colors affect the way we feel and how we approach certain environments, but implications on learning have not been extensively explored. Through future work, I would hope to better answer the question: How can we utilize color associations to become more effective educators and learners?
Presentation Drafts
steidl4.23.20.pdf |
steidl4.5.20.pdf |
steidl2.27.20.pdf |