Visual cortex recruitment during language processing in blind individuals is explained by Hebbian learning

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Tomasello, R.; Wennekers, T.; Garagnani, M. and Pulvermüller, F.. 2019. Visual cortex recruitment during language processing in blind individuals is explained by Hebbian learning. Scientific Reports, 9, 3579. ISSN 2045-2322 [Article]

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Official URL: https://doi.org/10.1038/s41598-019-39864-1

Abstract or Description

In blind people, the visual cortex takes on higher cognitive functions, including language. Why this functional organisation mechanistically emerges at the neuronal circuit level is still unclear. Here, we use a biologically constrained network model implementing features of anatomical structure, neurophysiological function and connectivity of fronto-temporal-occipital areas to simulate word-meaning acquisition in visually deprived and undeprived brains. We observed that, only under visual deprivation, distributed word-related neural circuits ‘grew into’ the deprived visual areas, which therefore adopted a linguistic-semantic role. Three factors are crucial for explaining this deprivation-related growth: changes in the network’s activity balance brought about by the absence of uncorrelated sensory input, the connectivity structure of the network, and Hebbian correlation learning. In addition, the blind model revealed long-lasting spiking neural activity compared to the sighted model during word recognition, which is a neural correlate of enhanced verbal working memory. The present neurocomputational model offers a neurobiological account for neural changes followed by sensory deprivation, thus closing the gap between cellular-level mechanisms, system-level linguistic and semantic function.

Item Type:

Article

Identification Number (DOI):

https://doi.org/10.1038/s41598-019-39864-1

Additional Information:

Supported by the Freie Universität Berlin, Deutsche Forschungsgemeinschaft (research grant Pu 97/22-1 to FP), Engineering and Physical Sciences Research Council (EPSRC) and Biotechnology and Biological Sciences Research Council (BBSRC), UK (project grant no. EP/J004561/1: BABEL – Brain-inspired architecture for brain embodied language) and the Berlin School of Mind and Brain, Humboldt Universität (PhD fellowship to RT).

Keywords:

cortical reorganisation, semantic processing, visual impairments, Blindness, Hebbian learning, distributed neural assemblies, biological spiking neuron network

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