THE VISUAL CORTEX IN THE BLIND BUT NOT THE AUDITORY CORTEX IN THE DEAF BECOMES MULTIPLE-DEMAND REGIONS

Deprived sensory cortices in blindness and deafness show how experience can reshape the brain. Visual cortex in the blind and auditory cortex in the deaf often activate during tasks in other modalities, commonly interpreted as evidence that these regions adopt new sensory processing roles. However, such activations could instead reflect responses to task events that are independent of sensory modality. Modality independent activation is a hallmark of the multiple demand (MD) network, a set of frontal and parietal regions engaged by diverse cognitive control demands such as attention, perceptual difficulty, rule switching, working memory updating, response inhibition, decision making, and arithmetic.

Here we asked whether deprived sensory cortices, or specific foci within them, become integrated into the MD network. We tested whether the same foci within occipital cortex in the blind and auditory cortex in the deaf respond to multiple distinct task control demands.

In blind participants, control demands involving auditory working memory updating, difficult tactile decisions, time duration judgments, and sensorimotor speed robustly activated extensive bilateral occipital cortex, an effect absent in sighted controls. These occipital regions were the only areas outside the canonical frontoparietal MD network that showed consistent activation across multiple control domains. Moreover, relative to sighted participants, the blind showed higher functional connectivity between occipital cortex and frontoparietal MD regions. In contrast, early deaf participants did not show comparable activation of auditory cortex across control demands, indicating that auditory cortex does not become MD like in deafness.