A multisensory cortical network for understanding speech in noise

& In noisy environments, listeners tend to hear a speaker’s voice yet struggle to understand what is said. The most ef-fective way to improve intelligibility in such conditions is to watch the speaker’s mouth movements. Here we identify the neural networks that distinguish understanding from merely hearing speech, and determine how the brain applies visual information to improve intelligibility. Using functional mag-netic resonance imaging, we show that understanding speech-in-noise is supported by a network of brain areas including the left superior parietal lobule, the motor/premotor cortex, and the left anterior superior temporal sulcus (STS), a likely apex of the acoustic processing hierarchy. Multisensory inte-gration improves comprehension through improved commu-nication between the left temporal–occipital boundary, the left medial-temporal lobe, and the left STS. This demonstrates how the brain uses information from multiple modalities to im-prove speech comprehension in naturalistic, acoustically ad-verse conditions. &amp