Encoding of melody in the human auditory cortex

• Published in: bioRxiv : the preprint server for biology
• Main Authors: Sankaran, Narayan, Leonard, Matthew K, Theunissen, Frederic, Chang, Edward F
• Format: Journal Article
• Language: English
• Published: United States 19.10.2023
• DOI: 10.1101/2023.10.17.562771

Melody is a core component of music in which discrete pitches are serially arranged to convey emotion and meaning. Perception of melody varies along several pitch-based dimensions: (1) the absolute pitch of notes, (2) the difference in pitch between successive notes, and (3) the higher-order statistical expectation of each note conditioned on its prior context. While humans readily perceive melody, how these dimensions are collectively represented in the brain and whether their encoding is specialized for music remains unknown. Here, we recorded high-density neurophysiological activity directly from the surface of human auditory cortex while Western participants listened to Western musical phrases. Pitch, pitch-change, and expectation were selectively encoded at different cortical sites, indicating a spatial code for representing distinct dimensions of melody. The same participants listened to spoken English, and we compared evoked responses to music and speech. Cortical sites selective for music were systematically driven by the encoding of expectation. In contrast, sites that encoded pitch and pitch-change used the same neural code to represent equivalent properties of speech. These findings reveal the multidimensional nature of melody encoding, consisting of both music-specific and domain-general sound representations in auditory cortex. The human brain contains both general-purpose and music-specific neural populations for processing distinct attributes of melody.