Topographic Neural Networks show neural recycling of labile units during reading acquisition
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2022-05-01
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en
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Abstract
Here, we ask the question of how the formation of brain regions and changes in neuron-level specialisation
depend on environmental input changes by modelling neural recycling in a topographic
neural network. During reading acquisition, a region in the left hemisphere of the ventral visual
stream of the human brain emerges that is sensitive to written words. The emergence of this area,
the visual word form area, is strongly experience-dependent, but its predictable location points to an
underlying organisational principle that guides its emergence. It is thus hypothesised that it arises
due to ‘recycling’ of neurons that were previously not or weakly involved in object recognition. To
uncover more about the spatial changes during the formation of functionally specialised areas in the
brain, we use use a topographic neural network (TNN) to model neural recycling. To simulate reading
acquisition, we first train the network on a large-scale dataset of natural images (preliterate phase).
Next, the network is trained for 50 epochs more on word images as well (literate phase). We confirm
recycling of ‘labile’ units (non-selective to any category) and face-selective units to word-selective
units after reading acquisition. Word-selective units cluster together, especially in the later layers of
the network. We also confirm the destructive e↵ect of neural recycling on the performance on other
classes of stimuli. We conclude that the TNN serves well as a model of neural recycling, as it captures
various features of neural recycling in the human visual cortex.
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Faculteit der Sociale Wetenschappen